James Schubert's Development Blog

Google Chrome Extension: New Tab Redirect! STEP BY STEP

2010-02-13T19:45:00.005-05:00

Background

(see http://code.google.com/chrome/extensions/overview.html for a thorough background of Chrome Extension development)

A Google Chrome Extension is a mini web application which runs in its own process and can perform actions at a browser-level or page-level.

An extension consists (or may consist) of a number of parts:

manifest.json
Web files (html, js, css, images)
NPAPI Plugins
background.html (the long-running process)

All of these files are bundled into a package with a .crx file extension. When uploading your extension to the Google Chrome Extensions Gallery, you only zip up the files your extension needs and Google will package it properly for you.

The manifest.json file is a file which specifies properties of your extension in JavaScript Object Notation (aka JSON). For a quick intro to JSON, check out http://www.learn-ajax-tutorial.com/Json.cfm

The Manifest File

manifest.json:

   1:  {

   2:    "name": "New Tab Redirect!",

   3:    "description": "Sets a user-specified URL to load in new tabs.",

   4:    "version": "0.0.1.109",

   5:    "background_page": "background.html",

   6:    "options_page":"options.html",

   7:    "chrome_url_overrides": {

   8:      "newtab": "redirect.html"

   9:    },

  10:      "permissions": ["tabs"],

  11:      "icons": {

  12:      "128": "icon128.png",

  13:      "19":"icon19.png"

  14:    }

  15:  }

(end manifest.json)

The name, description, version, background_page, and options_page key/value pairs are pretty self-explanatory.

The "chrome_url_overrides" section is interesting. As you can see, the value for this entry is itself an object. This object allows me to override "newtab" with my own page, "redirect.html". Currently, the chromium team will only allow you to override newtab, however, I anticipate they'll allow you to override other pages in the future. For a list of url constants used within Chrome, check out the url_constants.cc file in the source code repository. Possible future overrides would be anything that is listed near the end of that file as 'const char kChromeUI*Host[]'

Back to the file. "permissions" takes an array of requested permissions. New Tab Redirect! requires permissions to update tabs. This is because we're not only redirecting to html web-hosted sites; New Tab Redirect allows you to set web pages, local files, or inherent Chrome pages.

"icons" specifies the location of the icons your extension will use. These icons will be displayed in the Gallery and in the Extensions page within Google Chrome

Remember: You must change your version number when updating your publicly hosted extension, or else Chrome won't find a new version and your users will not be updated.

The Background Page

background.html

   1:  <html>

   2:  <head>

   3:  <script type="text/javascript">

   4:  String.prototype.startsWith = function(str){

   5:      return (this.indexOf(str) === 0);

   6:  }

7:

   8:  var url = null;

   9:  var newTabId = undefined;

  10:  var protocol =  undefined;

  11:  var allowedProtocols = ["http://","https://","about:","file://",

  12:    "file:\\", "file:///", "chrome://","chrome-internal://"];

13:

  14:  function setUrl(url) {

  15:          if(protocolPasses(url)

  16:            && url.length > 8) { /* 8 is arbitrary */

  17:              this.url = url;

  18:          } else {

  19:              protocol = 'http://'; /* force http */

  20:              var right = url.split('://')

  21:              if(right != undefined && right != null && right.length > 1) {

  22:                  this.url = protocol + right[1];

  23:              } else {

  24:                  /* this will redirect to http:// if url is empty */

  25:                  this.url = protocol + url; }

  26:          }

  27:          localStorage["url"]  = this.url;

28:

  29:      function protocolPasses(url) {

  30:          if(typeof(url) == 'undefined' || url == null) { return false; }

  31:          if (url.startsWith(allowedProtocols[3])

  32:              && !url.startsWith(allowedProtocols[5])) {

  33:              url.replace(allowedProtocols[3], allowedProtocols[5]);

  34:          } else if (url.startsWith(allowedProtocols[4])) {

  35:              url.replace(allowedProtocols[4], allowedProtocols[5]);

  36:          }

37:

  38:          for(var p in allowedProtocols) {

  39:              if(url.startsWith(allowedProtocols[p])) { return true;}

  40:          }

  41:          return false;

  42:      }

  43:  }

44:

  45:  function init() {

  46:     url = localStorage["url"] || "http://www.facebook.com";

  47:  }

48:

  49:  function r(tabId) {

  50:      chrome.tabs.update(tabId, {"url":this.url});

  51:  }

52:

  53:  chrome.tabs.onUpdated.addListener(function(tabId,info,tab) {

  54:      if (info.status === 'loading')

  55:          console.log('Loading url ... ' + tab.url)

  56:      if(info.status === 'complete')

  57:          console.log('Finished loading url ... ' + tab.url)

  58:  });

59:

  60:  chrome.tabs.onCreated.addListener(function(tab) {

  61:      newTabId = tab.id

  62:  });

  63:  </script>

  64:  </head>

  65:  <body onload="init()"></body>

  66:  </html>

(end background.html)

This page is pretty self-explanatory for the most part. The background page is your long-running process, and is usually used to house any variables that are shared between pages. However, this isn't a necessity of Chrome Extension architecture. Every page in an extension can interact with any other page through chrome.extension.getViews() or chrome.extension.getBackgroundPage() . Because of the nature of New Tab Redirect, I've used a background page.

One thing of note is the initialization of the extension. Since the operation is fairly simple, allowing a user to specify a url and then redirecting to that url, the only thing I need to worry about immediately is the url. This is stored using HTML 5's local storage. If the url doesn't exit, I set it to facebook.

The setUrl function is located in the Background page and is called from options.html. It is located here so the options page isn't trying to set the url variable that is maintained by the background page. This function checks my array of allowed protocols and validates the url with some simple rules.

r(tabId) is the function which actually updates the tab when the protocol isn't an http or https protocol. The function name is short because the the code in redirect.html should be as concise as possible. This function calls the chrome.tabs.update method (one culprit behind the tabs permission requirement)

That tabId is provided via the redirect.html, which gets the currently created tab's id. However, again note that this processing only occurs when the url is local.

Options

Because the options page is simple html and styles, I'll only include the JavaScript which sets the url.

options.js

   1:  String.prototype.startsWith = function(str) {

   2:      return (this.indexOf(str)===0);

   3:  }

   4:  var chromePages = {

   5:      Extensions : "chrome://extensions/",

   6:      History : "chrome://history/",

   7:      Downloads : "chrome://downloads/",

   8:      NewTab : "chrome-internal://newtab/"

   9:  }

  10:  var aboutPages = ["about:blank","about:version", "about:plugins","about:cache",

  11:      "about:memory","about:histograms","about:dns",

  12:      "chrome://extensions/","chrome://history/",

  13:      "chrome://downloads/","chrome-internal://newtab/"];

  14:  var popularPages = {

  15:      "Facebook":"www.facebook.com",

  16:      "MySpace":"www.myspace.com",

  17:      "Twitter":"www.twitter.com",

  18:      "Digg":"www.digg.com",

  19:      "Delicious":"www.delicious.com",

  20:      "Slashdot":"www.slashdot.org"

  21:  };

22:

23:

  24:  // save options to localStorage.

  25:  function save_options() {

  26:      var url = $('#custom-url').val();

  27:      if(url == ""){

  28:          url = aboutPages[0];

  29:      }

30:

  31:      if( $.inArray(String(url), aboutPages) || isValidURL(url)) {

  32:          save(true,url);

  33:      } else {

  34:          save(false,url);

  35:      }

  36:  }

37:

  38:  function save(good,url) {

  39:      if(good) {

  40:          chrome.extension.getBackgroundPage().setUrl(url);

  41:          $('#status').text("Options Saved.");

  42:      } else {

  43:          $('#status').text( url + " is invalid. Try again (http:// is required)");

  44:      }

45:

  46:      $('#status').css("display", "block");

  47:      setTimeout(function(){

  48:          $('#status').slideUp("fast").css("display", "none");

  49:      }, 1050);

  50:  }

51:

  52:  // Restores select box state to saved value from localStorage.

  53:  function restore_options() {

  54:      var url = chrome.extension.getBackgroundPage().url || "http://www.facebook.com/";

  55:       $('#custom-url').val(url);

  56:  }

57:

  58:  function isValidURL(url) {

  59:      var urlRegxp = /^(http:\/\/www.|https:\/\/www.|ftp:\/\/www.|www.){1}([\w]+)(.[\w]+){1,2}$/;

  60:      if (urlRegxp.test(url) != true) {

  61:          return false;

  62:      } else {

  63:          return true;

  64:      }

  65:  }

66:

  67:  function saveQuickLink(url){

  68:      var uurl = unescape(url);

  69:       $('#custom-url').val(uurl);

  70:       save(true,uurl);

  71:       return false;

  72:  }

73:

  74:  $(document).ready(function(){

  75:      restore_options();

  76:      $.each(chromePages, function(k,v) {

  77:          var anchor = "<a href=\"javascript:saveQuickLink('"+v+"');\">"+k+"</a>";

  78:          $('#chromes').append("<li>" + anchor + "</li>");

  79:      });

  80:      $.each(aboutPages, function() {

  81:          if(this.startsWith("about:")) { /* quick fix to handle chrome pages elsewhere */

  82:              var anchor = "<a href=\"javascript:saveQuickLink('"+this+"');\">"+this+"</a>";

  83:              $('#abouts').append("<li>" + anchor + "</li>");

  84:          }

  85:      });

  86:      $.each(popularPages, function(k,v) {

  87:          var anchor = "<a href=\"javascript:saveQuickLink('"+v+"');\">"+k+"</a>";

  88:          $('#popular').append("<li>" + anchor + "</li>");

  89:      });

  90:  });

(end options.js)

As you can see, I've included jQuery for dom manipulation. I decided to do this because jQuery is so small and because the Options page can be whatever size you'd like (keeping in mind user experience, of course). This saved me some time from writing out a little bit of javascript.

Of note here is how I build the lists of Chrome pages, About pages, and Popular pages. This isn't included in the options.html file, which only has placeholders for the unordered lists. This allows me to go in and provide a page name and url for chromePages and popularPages, or just the url for aboutPages. If I want to add anything in the future, I'll just add a key/value pair (or url) to one of these objects. If I want to remove, likewise, I only touch the respective object.

Quick links (one from an above-mentioned object) are saved automatically, bypassing the url checking regex. However, you'll notice in the save_options function that I check first to see if the url is in the list of about pages, this is because a user will most likely enter about:memory or any valid url, and whould be less likely to enter chrome-internal://newtab/. In the future, I will probably add checks on all objects before checking a valid url, but this kind of thing happens in incremental development.

As you can see, if the user gets to save the url, the function setUrl from the background page is called via chrome.extension.getBackgroundPage().setUrl(url); Following good user interface techniques, we have to let the user know what happened, which is what the next line and the rest of the function accomplishes.

Note: The new tab url is chrome-internal:// instead of chrome://. Why is this, do you think? Don't think too hard, though. It's simple: redirect.html is now chrome://newtab/, because I've told chrome to override the newtab with my own file. You can test it out by typing chrome://newtab into Google Chrome. Try chrome-internal://newtab and see what happens? This can only be called internally, hence the name, and must be called from within an extension via chrome.tabs.update. If you don't use this internal url, when you set the url to chrome://newtab and hit CTRL+T or click the '+' tab, your tab will keep trying to call itself, and eventually stop, after doing nothing meaningful.

Redirect.html

Finally, the beast that does it all.

redirect.html

   1:  <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

   2:  <html>

   3:    <head>

   4:      <meta name="generator" content=

   5:      "HTML Tidy for Windows (vers 14 February 2006), see www.w3.org">

   6:      <title>

   7:        Redirecting...

   8:      </title>

   9:      <script type="text/javascript">

  10:      var wid, tid;

11:

  12:      function r() {

  13:          var url = localStorage["url"] || "";

  14:          if (url.toLowerCase().indexOf("http:") === 0 ||

  15:              url.toLowerCase().indexOf("https:") === 0) {

  16:              document.location.href = url;

  17:              return;

  18:          } else {

  19:              chrome.windows.getCurrent(function(w) {

  20:                  wid = w.id;

  21:                  chrome.tabs.getSelected(wid, function(t) {

  22:                      tid = t.id;

  23:                  });

  24:              });

  25:              chrome.extension.getBackgroundPage().r(tid);

  26:          }

  27:      }

  28:  </script>

  29:    </head>

  30:    <body onload="setTimeout('r()',100);r();return false;">

  31:      Redirecting...<br>

  32:      <em>If your page doesn't load within 5 seconds,

  33:        <a href="javascript:r()">click here</a></em>

  34:    </body>

  35:  </html>

(end redirect.html)

Note: I have run the redirect.html file through HTML Tidy and a JavaScript formatter at http://jsbeautifier.org/, but this file should be as compact as possible. If you were to download New Tab Redirect and look at the source code, you'd see this code is all on one line. I'm writing this for your enjoyment, though, and one-liners aren't fun to look at.

The only thing special about this file is the the onload function. You'll notice how it runs r after 100 ms, then runs it again. There is quite an odd situation here: Chrome either has to initialize localStorage, doesn't allow us to get the current window and tab id immediately, or the processing required to do so takes longer than 100ms. You could, honestly, run the redirect function through a loop until it redirects (considering the document.location.href will immediately redirect the browser tab. If the url specified by the user is local, the function gets the current window, and from that the id of the current tab, and passes that to the background page's function.

I've been asked by a user or two to remove the redirect message, but I'll keep it for now. I consider a message necessary if, for some reason, a future release of Chrome breaks the extension.

The current source code for New Tab Redirect can be accessed via your Chrome Extensions directory after installing the extension, and is availing at the New Tab Redirect Project Page on Google Code.

If you have any questions or comments about this extension, please contact me.

Quickly create a Dictionary using Linq to Objects

2010-02-10T12:43:00.004-05:00

When working with collections or lists, sometimes you just need to get a simple dictionary.

There are a number of ways to do this, but the ToDictionary method seems promising.

For isntance:

   1:  IList<Person> people = new List<Person>();

   2:  people.Add(new Person

   3:      {

   4:          FirstName = "Jim",

   5:          LastName="Schubert",

   6:          Age=29,

   7:          Phone="123-333-4444"

   8:      });

   9:  people.Add(new Person

  10:      {

  11:          FirstName = "Joe",

  12:          LastName="Schubert",

  13:          Age=25,

  14:          Phone="800-999-1111"

  15:      });

16:

  17:  Dictionary<int,string> names = people.ToDictionary(k => k.Age, v => v.FirstName);

There may not be many uses for this type of syntax, but simple transformations like this make Linq fun.

Mixing Business Logic and the Presentation Layer... Why do people do it?

2010-01-24T11:36:00.003-05:00

In .NET Application Architecture Guide, 2nd Edition, the writers explicitly say:

Do not mix different types of components in the same logical layer. Start by identifying different areas of concern, and then group components associated with each area of concern into logical layers. For example, the UI layer should not contain business processing components, but instead should contain components used to handle user input and process user requests.

This is the standard way of developing today. However, I've seen time and again where a developer will do ALL of the business logic processing in the presentation layer. More than merely being annoying, this is wrong for a number of reasons including:

redundancy in code
"scattered" logic
poor abstraction
data access in the presentation layer
strong-coupling

That's just to name a few. Every time I see this coding snafu occur, I think to myself, "Do I just not know what I'm doing?" After all, it's much more seasoned developers doing this. Then, I remind myself that object-oriented programming has changed dramatically over the past 10 years.

I can understand some points of view "Too much abstraction is a bad thing!", "Keep the logic as close to where you're using it as possible!", "I don't understand what you mean by business logic." But, ignorance of norms and coding standards doesn't inherently and automagically produce good, clean, scalable code.

N-tier architecture has now become the norm, but is it too much to ask for some logical layering within a tier?

Free Software Architecture eBooks on MSDN

2010-01-06T12:50:00.001-05:00

Microsoft Application Architecture Guide, 2nd Edition

Enterprise Solution Patterns Using Microsoft .NET

Data Access Architecture Guide

Found via http://apparchguide.codeplex.com/

UpdatePanel won't AsycPostback for anything.

2009-12-22T16:52:00.002-05:00

I spent a lot of time today and Friday trying to get my UpdatePanel to be handled properly. No matter what I did, my asynchronous triggers were only posting back. I searched and searched, and couldn't find anything. Then, I ran across a post on asp.net's forum which had the answer.

<xhtmlConformance mode="Legacy"/> :

Change Legacy to Strict or Transitional

Don't you love Microsoft?

Other things I searched for in order to find this answer:

"IsInAsyncPostBack false masterpage", "UpdatePanel only postback", "asp:AsyncPostBackTrigger won't work"

Google Chrome Extension: New Tab Redirect!

2009-12-20T17:08:00.003-05:00

Thanks to the blizzard this weekend, I've been alone and stuck inside long enough to write an extension for Google Chrome. It's called "New Tab Redirect!" and it allows you to customize the page displayed when you add a new tab (either with CTRL+T or clicking the (+) in the title bar).

A cool thing about the extension is that it allows you to specify about: pages, URLs, or local files.

The extension is available in the extension Gallery: http://bit.ly/info/8oNcya

jQuery check/uncheck all Checkboxes in ASP.NET

2009-12-17T11:18:00.003-05:00

For some odd reason, ASP.NET GridView wraps html elements in a span element. When you apply a CssClass to the asp:CheckBox for instance, you will have a span with that class and inside you'll have an input with type=checkbox.

So how do you access all of the checkboxes?

   1:              $('.chkAllSelector > input:checkbox').click(function() {

   2:                  $('.chkRowSelector > input:checkbox').each(

   3:                      function(){

   4:                          this.checked = $('.chkAllSelector > input:checkbox').attr('checked');

   5:                      }

   6:                  );

   7:              });

   8:              $('.chkRowSelector > input:checkbox').click(function() {

   9:              if ($('.chkAllSelector > input:checkbox').is(':checked') && !($(this).is(':checked')))

  10:                  { $('.chkAllSelector > input:checkbox').removeAttr('checked'); }

  11:              });

Extending IDataReader

2009-12-16T13:01:00.003-05:00

I like to access my DataReader objects via column name. Unfortunately, IDataReader supports getting items via integer indexer.

To overcome this *obstacle*, I've written an extension method I'd like to share. It checks to see whether a column exists and has a value associated with it.

   1:      public static class IDataReaderExtension

   2:      {

   3:          /// <summary>

   4:          /// Adds the HasValue property to an IDataReader, which checks based on Column name

   5:          /// </summary>

   6:          /// <param name="reader">An IDataReader object</param>

   7:          /// <param name="column">The string column name</param>

   8:          /// <returns>boolean</returns>

   9:          public static bool HasValue(this IDataReader reader, string column)

  10:          {

  11:              if (reader.GetSchemaTable().Columns.Contains(column))

  12:                  return reader[column] != null || reader[column] != DBNull.Value;

  13:              else

  14:                  return false;

  15:          }

  16:      }

In order to use this method, you can now check:

   1:  if(reader.HasValue("MY_COLUMN"))

   2:  {

   3:      myObject.ColumnInfo = Convert.ToString(reader["MY_COLUMN"]);

   4:  }

Microsoft SQL Server's Database Publishing Wizard BatchParser error

2009-11-04T20:58:00.005-05:00

http://download.microsoft.com/download/4/4/D/44DBDE61-B385-4FC2-A67D-48053B8F9FAD/SQLServer2005_XMO_x64.msi

Could not load file or assembly 'Microsoft.SqlServer.BatchParser, Version=9.0.242.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91' or one of its dependencies. The system cannot find the file specified. Installing the above file will fix this problem on 64-bit machines!

I remember having a hard time finding the answer to this problem about a year ago, and I just ran into it again.

2009-11-03T10:56:00.004-05:00

http://datacogs.com/datablogs/archive/2005/01/28/209.aspx

Recently, I converted a project from VS2003 to VS2008. The conversion deleted a file which wasn't needed in VS2008. When I tried to "rollback" the source from source control to run in VS2003, it wouldn't rung.

Taken from the link above:

If you have a project file c:\Inetpub\wwwroot\Folder\fred.csproj then you need a corresponding webinfo file fred.csproj.webinfo. The contents of the webinfo file looks like this:

</VisualStudioUNCWeb>

Free Subversion Book by O'Reilly

2009-11-01T21:33:00.003-05:00

O'Reilly Media has released a free subversion book, located at http://svnbook.red-bean.com/

It's downloadable as a PDF, single-page HTML and multi-page HTML.

Python 3.0 handles Dictionary differently

2009-08-28T16:26:00.007-04:00

I read through Python 3.0 from Developer's Library about 2 months ago. I decided to skim through another introductory level book used at MIT so I could try keeping Python 2.5.x and Python 3.x separate.

While reading about Python 3.0, I didn't catch this difference. Dictionary processing has changed a little bit in the new version of Python.

For instance:

Python 2.5.x (pg 112 from MIT's reading material):
>>> letterCounts = {}
>>> for letter in "Mississippi":
letterCounts[letter] = letterCounts.get (letter, 0) + 1
>>> letterCounts
{’M’: 1, ’s’: 4, ’p’: 2, ’i’: 4}
>>> letterItems = letterCounts.items()
>>> letterItems.sort()
>>> print letterItems
[(’M’, 1), (’i’, 4), (’p’, 2), (’s’, 4)]
Python 3.1.x:
>>> letterCounts = {}
>>> for letter in "Mississippi":
letterCounts[letter] = letterCounts.get (letter, 0) + 1
>>> letterCounts
{'i': 4, 'p': 2, 's': 4, 'M': 1}
>>> letterItems = list(letterCounts.items())
>>> letterItems.sort()
>>> letterItems
[('M', 1), ('i', 4), ('p', 2), ('s', 4)]

This is a slight difference in code. In fact, the Python 3 code will work in previous versions. But, if you tried the Python 2.5.x code in Python 3, you will notice that letterItems can not be sorted. This is because "letterItems = letterCounts.items()" returns type: <class 'dict_items'>

An explanation of what is going on can be found here.

"Python 3.0 changes keys(), values() and items() so they return a lightweight set-like object, effectively making them behave like the olditer* methods, and removed the iter* methods themselves. In Python 3.0"

Ruby and Python in your script tags!

2009-08-14T01:37:00.002-04:00

I came across this weeks ago, and I'm surprised I never posted it. This is a javascript 'framework' to add ruby and python languages in your script tags. It's a pretty awesome idea. I haven't really tested it out, but it's worth taking a look at:

http://visitmix.com/labs/gestalt/

Keeping busy with ASP.NET MVC

2009-08-05T01:21:00.006-04:00

I'm looking for a job in "the worst recession since the great depression" blah blah blah. It really sucks.

To keep busy, I've been doing some 'freelance' work. I've been trying to expand more into MVC products by deploying a RadiantCMS site in Ruby on Rails and an e-business site I'm developing in ASP.NET MVC.

I'm liking the entire MVC mantra of keeping it DRY, or Don't Repeat Yourself. I don't know if it's because I've always hated repeating myself and this idea really hits home with me, or if it's just because it's a huge change from what I've encountered professionally and academically. Whatever it is, I love it.

One thing I love about ASP.NET MVC is it's heavy use of extension methods as "Helpers". It's easy to go overboard with helpers, but I like them anyway. One nice thing about them is that if you are like me, and sometimes forget to close some HTML tags, helpers can fix that.

For instance, if you're always writing div tags and adding id and class attributes, you can standardize the procedure with the following two methods (I overloaded them to accept objects just as ASP.NET MVC does):

   1:    /// <summary>

   2:      /// Returns a DIV with specified attributes

   3:      /// </summary>

   4:      /// <param name="helper">HtmlHelper class to extend</param>

   5:      /// <param name="contents">Contents of the DIV element</param>

   6:      /// <param name="htmlAttributes">Attributes to apply to the DIV element</param>

   7:      /// <returns>string</returns>

   8:      public static string Div(this HtmlHelper helper, string contents, object htmlAttributes)

   9:      {

  10:          return Div(helper, contents, new RouteValueDictionary(htmlAttributes));

  11:      }

12:

  13:      /// <summary>

  14:      /// Returns a DIV with specified attributes

  15:      /// </summary>

  16:      /// <param name="helper">HtmlHelper class to extend</param>

  17:      /// <param name="contents">Contents of the DIV elemtn</param>

  18:      /// <returns>string</returns>

  19:      public static string Div(this HtmlHelper helper, string contents,

  20:          IDictionary<string, object> htmlAttributes)

  21:      {

  22:          TagBuilder tagBuilder = new TagBuilder("div")

  23:          {

  24:               InnerHtml = contents.NewlineToHtmlBreak() ?? string.Empty

  25:          };

26:

  27:          if(htmlAttributes != null)

  28:          {

  29:              tagBuilder.MergeAttributes(htmlAttributes);

  30:          }

31:

  32:          return tagBuilder.ToString();

  33:      }

this allows you to do the following in a View:

   1:  <%= Html.Div("<p>This is content in left_box and helper method</p>", new {@class="left_box"}) %>

You could, of course, call the methods Tag and pass in the string value of the tag to create, eg. a, div, p, em, etc. Then, you would have a fairly generic helper to standardize all of your tags!

Even the NewlineToHtmlBreak method on String class is an extension method which calls String.Replace(Environment.Newline, "<br />") on the string input. I've done this because it's easier/faster to rely on Intellisense to hit .n+TAB than to type out the entire method. Like I said, it is very easy to go overboard with Helpers!

Job Hunting

2009-07-08T15:04:00.003-04:00

Now that I've graduated from VCU, it's time to find a job. My wife and I started this year with plans to move out of state, but things came up and we've decided to stay in the area. That decision came a little too late, and I passed up on a couple of really good opportunities. I currently have a few prospects.

If anyone hears of any openings for an Application Developer/System Engineer, send the info my way.

Quake Tracker using Google Maps API v3 and XML/Atom feed

2009-06-17T18:38:00.024-04:00

http://www.ipreferjim.com/maps/quakes.html

For this, I used the following:

Google Maps API v3 (http://code.google.com/apis/maps/documentation/v3/)
jQuery v1.3.2 (http://jquery.com/)

First, you will need to include the google maps api in your header:

<script src="http://maps.google.com/maps/api/js?sensor=true" type="text/javascript">

This line of code is slightly different from the v2 API because an API key isn't needed. This will probably change in the near future. It is also necessary to load jQuery, which can be done by downloading it from the above link, or loading it via Google's AJAX API.

When the document is ready:

   1:  // init map

   2:  var map;

   3:  $(document).ready(function(){

   4:    var latlng = new google.maps.LatLng(35.6802, -121.1165);

   5:    var myOptions = {

   6:       zoom: 3,

   7:      center: latlng,

   8:      mapTypeControl: true,

   9:      mapTypeControlOptions: {style: google.maps.MapTypeControlStyle.DROPDOWN_MENU},

  10:      navigationControl: true,

  11:      navigationControlOptions: {style: google.maps.NavigationControlStyle.SMALL},

  12:      mapTypeId: google.maps.MapTypeId.SATELLITE

  13:      };

14:

  15:    map = new google.maps.Map(document.getElementById("map"), myOptions);

16:

  17:  });

When the map is ready:

   1:  // SEE : http://www.xml.com/pub/a/2007/10/10/jquery-and-xml.html

2:

   3:  $('#map').ready(function(){

   4:    $.ajax({

   5:      type: "GET",

   6:      url: "getxml.php?q=http://www.earthquake.usgs.gov/eqcenter/catalogs/7day-M2.5.xml",

   7:      dataType: "xml",

   8:      success: function(xml){

   9:              $(xml).find('entry').each(function(){

  10:                  // Retrieve all needed values from XML

  11:                  var title = $(this).find('title').text();

  12:                  var updated = $(this).find('updated').text();

  13:                  var link = $(this).find('link').text();

  14:                  var summary = $(this).find('summary').text();

  15:                  var coord = $(this).find('georss\\:point').eq(0).text();

  16:                  if(!coord){var coord = $(this).find('point').text();};

  17:                  var points = coord.split(' ');

  18:                  var latitude = parseFloat(points[0]);

  19:                  var longitude = parseFloat(points[1]);

  20:                  var elev = $(this).find('georss\\:elev').eq(0).text();

  21:                  if(!elev){var elev = $(this).find('elev').text();};

  22:                  var htmlString = "<b>" + title + "</b>" + "<p>" + summary + "<br>";

  23:                  // create a marker

  24:                  var myLatlng = new google.maps.LatLng(latitude,longitude);

  25:                      var marker = new google.maps.Marker(

  26:                      {

  27:                          position: myLatlng,

  28:                          map: map,

  29:                          title: title

  30:                      });

31:

  32:                      addMarkerBubble(marker, map, htmlString);

  33:                      // Show output below map

  34:                      $('<li></li>')

  35:                          .html(title + ' (updated: ' + updated + ') at ' + points[0] + ', ' + points[1])

  36:                          .appendTo('#output');

  37:              });// end each

  38:          }

  39:      }); // end $.ajax

  40:  });// end function

41:

  42:  function addMarkerBubble(marker, map, message){

  43:      // set balloon

  44:      var infowindow = new google.maps.InfoWindow(

  45:      {

  46:            content: message,

  47:        size: new google.maps.Size(400,200)

  48:      });

49:

  50:      // add listener to marker

  51:      google.maps.event.addListener(marker, 'click' ,function(){

  52:          infowindow.open(map,marker);

  53:      });

  54:  };

Explanations:

First of all, I create a global variable called map, so I can use it in each function.

Then, when the document is ready, I get a geographic coordinate which Google Maps builds from maps.LatLng. This coordinate is in California, because I know there are quakes there.

Next, I've set a number of options (lines 6-12) for the map including:

zoom level
map center
a control to allow user to change the look of the map
a control to allow user to change zoom
default map type of "SATELLITE", which shows tectonic regions

The Google Maps API v3 makes it very easy to supply these options to the Map constuctor, as you can see on line 15 of the first code snippet. The map is loaded into the DOM object supplied as the first parameter in the constructor.

The next snippet is the AJAX call to retrieve the feed and build the markers and info windows when the GET succeeds.

Inside the function call, I've used jQuery's simplified DOM access for the returned XML. On line 9 of this snippet, I find each 'entry' node and then iterate over each of these nodes to find the text of each node value.

On lines 15-16 and 20-21, I check the variables because some browsers properly process namespaced nodes and some don't. This simple check allows the application to display properly in Chrome, Safari, Firefox, and Internet Explorer.

Next, I create a marker on the map at the given coordinate and give it a title (tooltip).

On line 32, I call the function 'addMarkerBubble' to create an info window and add the event to the map. After this, I add the title and updated date to a div element below the map.

JavaScript & CSS Modal Loading DIV

2009-06-16T21:21:00.006-04:00

Things I've used in this:

Prototype Javascript (http://prototypejs.org/)
Loading image (http://www.ajaxload.info/)
Script & CSS

What I do here is build a DIV element and show it on the page while Prototype's Ajax Request object is loading. Then, when the Request is finished, the DIV is removed from the document.

Here is the script necessary to make a request and build/show/remove the DIV.

   1:  /** Main.js

   2:   * @author Jim Schubert

   3:   * (c) 2009

   4:   */

5:

   6:  function showContent(file){

   7:      var content = new Ajax.Request(file,

   8:          {

   9:              method:'get',

  10:              onLoading: showLoading(),

  11:              onSuccess: function(request)

  12:              {

  13:                  var contentDIV = document.getElementById('content');

  14:                  contentDIV.innerHTML = "";

  15:                  contentDIV.innerHTML = request.responseText;

16:

  17:                  closeLoading();

  18:              },

  19:              onFailure: function(){ alert('Cannot process your request.');}

  20:              // onComplete: closeLoading()

  21:          });

  22:  };

23:

  24:  function onImgError(source) {

  25:    source.src = "img/img_error.png";

  26:    // disable onerror to prevent endless loop

  27:    source.onerror = "";

  28:    return true;

  29:  };

30:

  31:  function showLoading() {

  32:      // create div element

  33:      var overlayDIV = document.createElement('div');

  34:      var loadingDIV = document.createElement('div');

  35:      overlayDIV.setAttribute('id', 'overlay');

  36:      overlayDIV.setAttribute('class', 'overlay');

  37:      overlayDIV.style.visibility = 'visible';

38:

  39:      loadingDIV.setAttribute('id', 'loading');

  40:      loadingDIV.setAttribute('class', 'modalPopup');

  41:      loadingDIV.innerHTML = '<center><img src="img/ajax-loader.gif"><br>Loading...</center>';

42:

  43:      overlayDIV.appendChild(loadingDIV);

  44:      var content = document.getElementById('bodyDocument');

  45:      if (content) {

  46:          content.appendChild(overlayDIV);

  47:          var overlay = document.getElementById('overlay');

  48:          if (overlay) {

  49:              overlay.style.visibility = 'visible';

  50:              overlay.style.height = '100%';

  51:          }

  52:      }

53:

  54:      return true;

  55:  };

56:

  57:  function closeLoading(){

  58:      var overlayDIV = document.getElementById('overlay');

  59:      var loadingDIV = document.getElementById('loading');

60:

  61:      if (overlayDIV) {

  62:          if (loadingDIV) {

  63:              overlayDIV.removeChild(loadingDIV);

  64:              document.getElementById('bodyDocument').removeChild(overlayDIV);

  65:          }

  66:          // else {alert("can't find loadingDIV")}

  67:      }

  68:      // else{ alert("Can't find overlay.");}

69:

  70:      return true;

  71:  };

Here is the stylesheet needed to make the dialog "modal".

   1:  .overlay {

   2:      visibility: hidden;

   3:      position: absolute;

   4:      left: 0px;

   5:      top: 0px;

   6:      width:100%;

   7:      height:100%;

   8:      text-align:center;

   9:      z-index: 1000;

  10:      filter:alpha(opacity=70) !important;

  11:      opacity:0.8 !important;

  12:      elevation:above !important;

  13:      /* background-color:Gray !important; */

  14:      background-image: url(../img/overlay.png);

  15:  }

16:

  17:  .modalPopup

  18:  {

  19:      display: block;

  20:      margin-left: auto;

  21:      margin-right: auto;

  22:      width:180px;

  23:      margin: 100px auto;

  24:      background-color:#F1F1F1 !important;

  25:      border:1px solid #000;

  26:      padding:15px;

  27:      text-align:center;

  28:      elevation:above !important;

  29:  }

In order to use this code, you'll have to give your body tag an id of 'bodyDocument', and the div tag to receive your ajax request should be called 'content'.
I've also included an image error detecting script, which replaces broken images with a default image. Unfortunately, if you're trying to produce 100% compliant HTML documents, this won't be compliant unless you're using HTML5. In order to use this, you'll have to do something like <img src='asdf.gif' onerror='javascript:onImgError(this)' alt='image'>
I've left some code commented out, which will help in debugging your efforts. And, in the stylesheet, you have the option of using a flat background instead of a PNG with transparency.

Example Ruby code

2009-05-18T00:43:00.004-04:00

I decided to do some of those Facebook puzzles in Ruby. I won't post everything I do, because I would consider that cheating (after all, you can win prizes!).

However, considering this is a very simple script, and I'm doing it more for learning Ruby than to enter into Facebook's puzzles, I will post this one.

This is the first puzzle, called Hoppity Hop:

private
@file_exists = false
def get_integer(filename)
    if File::exists?(filename)
        file = File.open(filename) 
        line = file.gets.strip!
        file.close
        @file_exists = true
        return line.to_i
    else
        @file_exists = false
        return 0 #zero files present
    end
end

def get_string(num)
    if(num%3 == 0 && num%5 == 0)
        print "Hop\n"
    elsif num%3 == 0
        print "Hoppity\n"
    elsif num%5 == 0
        print "Hophop\n"
    else
        return #nothing
    end    
end

def hip_hop(arg)
    num = get_integer(arg)
    if(num > 0 && @file_exists)        
        for i in 1..num.to_i
            get_string(i)
        end
    else
        puts "File not found"
    end
end

public

arg = ARGV[0].to_s # this is the name of the file
if(/\D/ =~ arg)
    puts "Please enter a positive integer as the filename."
else
    unless arg == nil
        hip_hop(arg)
    end
end

Ruby on Rails, Aptana Studio

2009-05-09T18:06:00.004-04:00

This weekend, I decided to give Ruby on Rails a go, considering I just finished school and I'll have plenty of free time to explore.

I downloaded Aptana Studio and installed Ruby, Rails, PHP, and a few extra ruby gems for fun. Then, I went over to the Rails Guide to follow along and do some learnin'. At the end of the guide, I ran the completed blog application and received errors. A little googling helped me find the solution.

Apparently, Aptana doesn't install the latest build of gems from its repositories, and the guide was written for the newest version.

As noodlygod writes on the forum linked above:

Hello, I just thought I'd post something as I had the same problem on Windows.

I tried running the command "gem install rails --source http://gem.rubyonrails.org" but I received the error: "actionpack requires rack (>= 0.9.0, runtime)"

So I ran "gem install rack" which installed something And then "gem install rails --source http://gem.rubyonrails.org" and it installed 2.3.0 just fine.

Based on this post: http://railsforum.com/viewtopic.php?pid=89050 I also changed my rails version in environment.rb to "2.3.0" and renamed "application.rb" to "application_controller.rb" and everything is working. Thanks a bunch for the info!

Useful Serialization Methods of LINQ to SQL objects

2009-04-30T22:40:00.003-04:00

I am just going through a project for my senior "Projects in Information Systems" class, commenting most of the complex logic. I came across these two methods I wrote to serialze LINQ to SQL objects. They came in pretty handy, so I thought I'd share even though they don't have error-handling. I'm not too embarrassed.

The way I used them was pretty ghetto, I was having troubles getting the objects I needed to serialize to be used in a Session object (I thnk it had something to do with an Order_Details table having two foreign keys to the same table, Ledger, for an IN and OUT field). Anyway, I serialed the object to XML and just stored the whole string into a listBox's value. I know that's begging for poor performance, and overriding the data validation checks is opening the ASP.NET page up for security issues, but the only people who are going to use this are me and my instructor. So, it was a quick work around. I could have stored it in a Session Object as a string, but then I would have had to call some funky work around for the listBox. Anyway, enough about that.

1:

   2:          /// <summary>

   3:          /// Serializes a LINQ object to an XML string

   4:          /// </summary>

   5:          /// <typeparam name="T">Type of the Object</typeparam>

   6:          /// <param name="linqObject">The LINQ object to convert</param>

   7:          /// <returns>string</returns>

   8:          public static string SerializeLINQtoXML<T>(T linqObject)

   9:          {

  10:              // see http://msdn.microsoft.com/en-us/library/bb546184.aspx

  11:              DataContractSerializer dcs = new DataContractSerializer(linqObject.GetType());

12:

  13:              StringBuilder sb = new StringBuilder();

  14:              XmlWriter writer = XmlWriter.Create(sb);

  15:              dcs.WriteObject(writer, linqObject);

  16:              writer.Close();

17:

  18:              return sb.ToString();

  19:          }

20:

  21:          /// <summary>

  22:          /// Deserializes an XML string to a LINQ object

  23:          /// </summary>

  24:          /// <typeparam name="T">The type of the LINQ Object</typeparam>

  25:          /// <param name="input">XML input</param>

  26:          /// <returns>Type of the LINQ Object</returns>

  27:          public static T DeserializeLINQfromXML<T>(string input)

  28:          {

  29:              DataContractSerializer dcs = new DataContractSerializer(typeof(T));

30:

  31:              TextReader treader = new StringReader(input);

  32:              XmlReader reader = XmlReader.Create(treader);

  33:              T linqObject = (T)dcs.ReadObject(reader, true);

  34:              reader.Close();

35:

  36:              return linqObject;

  37:          }

38:

Storing Generics in ASP.NET Profile object

2009-04-25T15:34:00.004-04:00

Sometimes, I'll come across a problem that I research for an hour or two. When I find the solution, I think "Wow, that should have been the first thing I tried!"

This is one of those occasions.

I decided to use the ASP.NET profile instead of Session objects to store a list of products. So, in web.config, I tried a number of "work-arounds" that I found online, including:

   1:  <profile>

   2:  ...

   3:        <properties>

   4:          <add name="RecentlyViewed" allowAnonymous="false" type="System.Collections.Generic.List`1[Model.Product]" serializeAs="Xml"/>

   5:        </properties>

   6:  </profile>

The problem I was having, and it seems a lot of people are having, is that System.Collections.Generic.List`1[Model.Product] throws an error. For some people, it seems to work. Well, I tried changing the lt and gt in the generic list so the XML would parse it as it is written in the code-behind. That didnt work.

The solution: Create a class which inherits from List<Model.Product>

For instance:

   1:  using System;

   2:  using System.Collections.Generic;

3:

   4:  namespace Model

   5:  {

   6:      /// <summary>

   7:      /// This class wraps the Generic List into a class to serialize in Profile provider

   8:      /// </summary>

   9:      [Serializable]

  10:      public class RecentlyViewed : List<Model.Product>

  11:      {

  12:          public RecentlyViewed()

  13:          {

  14:          }

  15:      }

  16:  }

This works beautifully! Now, in web.config, you can do the following:

   1:  <profile>

   2:  ...

   3:        <properties>

   4:          <add name="RecentlyViewed" allowAnonymous="false" type="Model.RecentlyViewed" serializeAs="Xml"/>

   5:        </properties>

   6:  </profile>

Displaying multiple fields in a Dropdownlist's DataTextField

2009-04-14T16:19:00.004-04:00

I've encountered this problem on occasion, where I want to display more than one field in a dropdownlist's DataTextField property. In the past, I've overcome this problem by rewriting a SQL statement, or adding another column in the database itself to accomodate my needs.

In one of my classes (INFO 465: Projects in Information Systems @ VCU), we're working from a database which we're not allowed to change. The reason we can't change it is because the instructor uses the same database for his examples. I could just write another method into my business logic layer, but it would get cluttered pretty quickly.

So, I decided to make use of LINQ and found the following solution:

   1:  ddlUsers.DataSource = BLL.Employee.GetEmployees()

   2:                  .Select(be =>

   3:                      new {

   4:                          ID = be.Id,

   5:                          FullName = String.Format("{0}{1}{2}",

   6:                                      be.LastName,

   7:                                      (!string.IsNullOrEmpty(be.FirstName) ? ", " : string.Empty),

   8:                                      be.FirstName)

   9:                          }).AsEnumerable();

This takes the List of Business Entity objects and uses the LINQ select statement to generate an implicit/anonymous object from that. The only downfall to this method is that the new object only has local scope. But, since I'm only using this in a dropdown, it's a pretty nifty trick.

T-SQL Multi-Table Delete

2009-04-01T13:56:00.004-04:00

I was trying to run a DELETE query on multiple tables and I kept getting this error: The DELETE statement conflicted with the REFERENCE constraint

I'm not that great with SQL, but I can get by. DELETEs have always been somethng that have given me trouble. So, I thought I'd share this simple fix.

DELETE FROM PRODUCT
FROM BOOK
WHERE BOOK.ID = PRODUCT.BOOK_ID
AND BOOK.ID = @BOOK_ID

You just have to make sure you put the table with the FK as the first table in the query.

I guess I should have paid a little more attention in Database class. We learned Oracle, which is different from Microsoft's SQL in many ways.

LINQ: more like "Luckily I Never Quit"

2009-03-28T13:07:00.004-04:00

I've been using LINQ quite a bit lately. As the blog title says: luckily, I never quit.

There are a lot of things to get used to with LINQ. For one, it uses deferred queries. When you make a change, you must submit changes before the change is reflected in the database. Yes, this mirrors the actions when working directly with a database (COMMIT), but when you're thinking of it as application logic, it seems counter-intuitive.

<aside>

At school, I'm in a class called INFO 465: Projects in Information Systems. The class is slow-going. At VCU, there are three tracks of studies in Information Systems: Application Development, Business Analysis, and Network Administration. Unfortunately, most of the people in BA and Networking are there because they don't want to do any programming at all. You would think a class geared to using your course skills would accommodate each track equally?

That's not the case in this class. There are two projects. One is individual work and the other is group work. The individual project is really just a large programming assignment to create an "Enterprise System" for a landscaping company. Luckily, the company consists of the landscaper, a truck, and his helper.

Anyway, to get back on track, we're allowed to do our project any way we want. Most of the people in the class chose to do Windows Forms using VB.NET examples provided by the teacher. Good luck with that! I chose to use ASP.NET, AJAX, Web Services, and LINQ. I chose this route because I wanted this class to be a learning experience, not just a copy-paste session for 3 hours a week.

</aside>

Back to LINQ. To be quick about development, I've decided to use GridViews, DetailsViews, and LinqDataSources. Every time I try to link a LinqDataSource to a GridView's selected key, I get this message:

Operator '==' incompatible with operand types 'Int32' and 'Object'

Here is an example of the LinqDataSource that throws this error:

<asp:LinqDataSource ID="srcSelectedOrder" runat="server" 
        ContextTypeName="INFO465_First_Web.DatabaseMaps.OrdersDataContext" 
        EnableDelete="True" EnableInsert="True" EnableUpdate="True" TableName="Orders" 
        Where="Id == @Id">
        <WhereParameters>
            <asp:ControlParameter ControlID="GridView1" Name="Id" 
                PropertyName="SelectedValue" Type="Int32" />
        </WhereParameters>
    </asp:LinqDataSource>

The problem is where you have the Where clause "Id == @Id". For some reason, the data source thinks @Id is an object instead of an Int32, even though Type="Int32" in the WhereParameters.

The fix is the change this to Where="Id == Int32?(@Id)". I don't know why this is. I mean, if you're taking a primary key as the DataKeyName, it is being passed as Int32 in the WhereParameters, why do you have to cast it? Maybe the LinqDataSource automatically converts Id == @Id to an SQL query that would look like "Id == '2'", and you have to cast to Int32 explicitly so it will look like "Id == 2" in the query? Again, this is another place that LINQ just seems backwards.

Here is the fixed data source:

<asp:LinqDataSource ID="srcSelectedOrder" runat="server" 
        ContextTypeName="INFO465_First_Web.DatabaseMaps.OrdersDataContext" 
        EnableDelete="True" EnableInsert="True" EnableUpdate="True" TableName="Orders" 
        Where="Id == Int32?(@Id)">
        <WhereParameters>
            <asp:ControlParameter ControlID="GridView1" Name="Id" 
                PropertyName="SelectedValue" Type="Int32" />
        </WhereParameters>
    </asp:LinqDataSource>

(I always format my code with http://www.manoli.net/csharpformat/)

C++ Templated QuickSort Algorithm

2009-03-19T09:17:00.002-04:00

It has been over a month since I posted. I've been really busy with all of my classes. So, instead of going too in depth with anything, I'm just going to share some code we've written. This is a QuickSort Algorithm that we adapted from the MIT Intro to Algorithms book. We just finished it last night (less than 12 hours ago), so it's not fully tested.

   1:  #ifndef _QUICKSORT_H

   2:  #define _QUICKSORT_H

3:

   4:  #include <vector>

5:

   6:  using namespace std;

7:

   8:  namespace QuickSort

   9:  {

10:

  11:  /*

  12:      QuickSort Algorithm using Templates

13:

  14:      Algorithm was adapted from:

  15:          Introduction to Algorithms

  16:          By Thomas H. Cormen, Charles E. Leiserson, Ronald L. Rivest, Clifford Stein

  17:          Contributor Thomas H. Cormen

  18:          Edition: 2, illustrated

  19:          Published by MIT Press, 2001

  20:          ISBN 0262032937, 9780262032933

  21:          1180 pages

  22:      Accessed March 2009

  23:      via http://books.google.com/books?id=NLngYyWFl_YC

  24:      See pages 145-147

25:

  26:  */

  27:      template<class T>

  28:      class QuickSort

  29:      {

  30:      public:

  31:          vector<T> *sortingArray;

  32:          int left;

  33:          int right;

34:

  35:          // Constructors

  36:          QuickSort();

  37:          QuickSort(vector<T> *sortArray);

  38:          QuickSort(vector<T> *sortArray, int startIndex, int endIndex);

39:

  40:          /**********************************************************************

  41:          * Partition and Swap Functions

  42:          **********************************************************************/

  43:          int Partition(vector<T> *sortArray, int startIndex, int endIndex);

  44:          void Swap(int l, int k);

45:

  46:      };

47:

  48:      template<class T>

  49:      QuickSort<T>::QuickSort()

  50:      {

  51:          sortingArray = new vector<T>();

  52:          left = 0;

  53:          right = 0;

  54:      }

55:

  56:      template<class T>

  57:      QuickSort<T>::QuickSort(vector<T> *sortArray)

  58:      {

  59:          int startIndex = 0;

  60:          int endIndex = 0;

61:

  62:          endIndex = (int)(*sortArray).size() - 1;

63:

  64:          QuickSort(sortArray, startIndex, endIndex);

  65:      }

66:

  67:      template<class T>

  68:      QuickSort<T>::QuickSort(vector<T> *sortArray, int startIndex, int endIndex)

  69:      {

  70:          if(startIndex >= endIndex)

  71:          {

  72:              return;

  73:          }

74:

  75:          // *initialize* the array

  76:          sortingArray = sortArray;

77:

  78:          // For instance: 1..n

  79:          left = startIndex;

  80:          right = endIndex;

81:

  82:          if(left < right)

  83:          {

  84:              // get pivot

  85:              int pivot = Partition(sortingArray, left, right);

86:

  87:              // sort left side

  88:              QuickSort(sortingArray, left, (pivot-1));

89:

  90:              // sort right side

  91:              QuickSort(sortingArray, (pivot+1), right);

  92:          }

  93:      }

94:

  95:      template<class T>

  96:      int QuickSort<T>::Partition(vector<T> *sortArray, int startIndex, int endIndex)

  97:      {

  98:          // initially this start - 1 when startIndex is 0.

  99:          int l = startIndex - 1;

 100:          int k = endIndex;

 101:

 102:          for(int i = startIndex; i <= k - 1; i++)

 103:          {

 104:              // Go until you find a value smaller than the last value.

 105:              if((*sortArray)[i] <= (*sortArray)[k])

 106:              {

 107:                  // increment l

 108:                  l++;

 109:

 110:                  // swap i and j

 111:                  // NOTE: this is supposed to swap j with itself the first time.

 112:                  Swap(l, i);

 113:              }

 114:          }

 115:

 116:          // when loop is finished, swap

 117:          Swap(l + 1, k);

 118:

 119:          return l + 1;

 120:      }

 121:

 122:      template<class T>

 123:      void QuickSort<T>::Swap(int l, int k)

 124:      {

 125:          // create temp variable

 126:          T tmp;

 127:

 128:          // store first element in temp

 129:          tmp =(*sortingArray)[l];

 130:

 131:          // swap second element to first element

 132:          (*sortingArray)[l] = (*sortingArray)[k];

 133:

 134:          // put temp variable in second element

 135:          (*sortingArray)[k] = tmp;

 136:      }

 137:

 138:  }

 139:

 140:  #endif

My beginnings in C++

2009-02-02T23:26:00.003-05:00

This semester (my final semester at VCU), I am taking INFO 450: Advanced Programming, which concentrates in C++. We're learning both native and managed C++. Our first assignment was simple: a console application to calculate the monthly payments on a car loan, based on interest rate, total loan, and loan duration. That was pretty easy.

This assignment was pretty rough. We had to code a fully functional ATM application, which uses a hardcoded bank database, accounts, authentication, withdrawal & deposit simulation, etc. We were told that we could mirror the ATM case study at the end of our Learn to Program C# 2005 by Deitel (the book from intermediate programming).

After mirroring the C# code, I kept getting error after error. It was ridiculous how every error stemmed from how header files were used in my code. Eventually, I worked out the problems with the header files. Then, I kept getting this compiler error: LNK2019. I searched and searched online, and couldn't find a suitable answer. Finally, I retraced all my code, and realized that I had three classes (Withdrawal, Deposit, BalanceInquiry) all overriding the virtual function 'Execute' from class Transaction, but that class wasn't marked virtual. This probably should have been the first place I looked, but keep in mind we were given this assignment the day after we learned about references.

To make a long story short, I was receiving LNK2019 errors because of my virtual functions. The error was caused by declaring the function as "virtual void Execute();" instead of "virtual void Execute() = 0;" Embarrassingly, that little mistake took me forever to figure out. I somewhat hope that whatever path I take in the future uses tools with less cryptic error messages.

C# Insertion Sorting algorithm

2009-02-02T17:12:00.004-05:00

Here is a console application to test an Insertion Sorting algorithm adapted from chapter 2 of MIT's Introduction to Algorithms. I thought this might come in handy for any beginners, as well as a fun way to test your computer's performance.
My desktop averages about 24.9 seconds, which, of course, depends on how scattered the integers are in the array.

   1:  using System;

   2:  using System.Collections.Generic;

   3:  using System.Linq;

   4:  using System.Text;

5:

   6:  namespace InsertionSorting

   7:  {

   8:      class Program

   9:      {

  10:          static void Main(string[] args)

  11:          {

  12:              // int[] A = {5, 2, 4, 6, 1, 3};

  13:              int initializer = 100000;

  14:              int[] A = new int[initializer];

15:

  16:              for (int c = 0; c < A.Length; c++)

  17:              {

  18:                  A[c] = c;

  19:              }

20:

  21:              // Random shuffle

  22:              Random rand = new Random();

  23:              for (int d = 0; d < A.Length; d++)

  24:              {

  25:                  int firstInt = A[d];

  26:                  int swapIndex = rand.Next(initializer);

  27:                  int secondInt = A[swapIndex];

28:

  29:                  A[d] = secondInt;

  30:                  A[swapIndex] = firstInt;

  31:              }

32:

  33:              //Console.Write("Array before sorting: ");

  34:              //foreach (int number in A)

  35:              //{

  36:              //    Console.Write("{0} ", number);

  37:              //}

  38:              //Console.WriteLine("");

39:

  40:              int key;

  41:              int i;

  42:              int j;

43:

  44:              Console.Write("Insertion Sorting array of {0} numbers, please wait...", initializer);

45:

  46:              DateTime start = DateTime.Now;

  47:              for (j = 1; j < A.Length; j++)

  48:              {

  49:                  key = A[j];

  50:                  i = j;

51:

  52:                  while (i > 0 && A[i - 1] > key)

  53:                  {

  54:                      A[i] = A[i-1];

  55:                      i--;

  56:                  };

57:

  58:                  A[i] = key;

  59:              }

  60:              DateTime finish = DateTime.Now;

61:

  62:              //Console.Write("Array after sorting: ");

  63:              //foreach (int number in A)

  64:              //{

  65:              //    Console.Write("{0} ", number);

  66:              //}

67:

  68:              Console.WriteLine("");

  69:              Console.WriteLine("Duration: {0} seconds", (finish - start).ToString());

  70:          }

  71:      }

  72:  }

73:

Silverlight 2.0, broken XAML Intellisense fix

2009-01-01T14:13:00.002-05:00

I installed all the necessary files for Silverlight today. When I created a project, the xaml document didn't have intellisense and opened as a text instead of XML-based document. I tried a few fixes, one guy recommended right-clicking on the file and choosing "Open with.." and selected XML Editor as the default. This didn't work for me. I tried following Karen Meier's fix here. That didn't work either. Then, I figured I would try resetting Visual Studio. So, checking the documentation on devenv switches, specifically this one, I ran devenv /resetskippkgs and checked the intellisense. This fixed my XAML intellisense!

Visual Studio 2010: Logging in

2008-12-28T14:24:00.004-05:00

I downloaded Visual Studio 2010 CTP a week ago. I fiddled around with it for about 30 minutes, trying to login to the accounts provided by the preview. From the download site:

The following logon accounts and passwords have been preconfigured on the VPC: Administrator: TFSSETUP, password: 1Setuptfs (use this account to explore the CTP) Administrator: Administrator,password: P2ssw0rd User: TFSREPORTS, password: 1Reports User: TFSSERVICE, password: 1Service

The passwords weren't working for me, so I mixed them up. Finally, I gave up. Today, I took a break from reading for my Winter Intercession course, and decided to run the Visual Studio 2010 image again. I realized Virtual PC had start it up with numlock on. Because I'm using a notebook PC, it's easy to forget that the right half of the keyboard doubles as a numeric keypad with numlock. So, I turned numlock off, and I was able to log in. I can't wait for Visual Studio 2010 to be released. I especially like the WiX integration. Sure, WiX offers the same integration for Visual Studio 2008, but it's nice to see Microsoft attempting to make installers less of a hassle for developers. It took me about a week of researching different installers to finally settle on WiX. When I get a chance, I'm going to look into custom actions using Powershell to retrieve version numbers and edit localization files with updated versions. Now, I guess it's back to coursework.

Visual Studio error, debugger can't start

2008-12-22T00:33:00.003-05:00

"The components for the 64-bit debugger are not registered. Please repair your Visual Studio 2008 Remote Debugger installation via ‘Add or Remove Programs’ in Control Panel" So, I uninstalled EVERYTHING related to Visual Studio. I assume it was a problem with SP1 and my XP 64-bit operating system. The reason I think this is the case: when I tried running the installer for the remote debugger from the VS2008 dvd, it had the options for repair and remove. Running either option gave me this message: "Error 1324: The folder path folder name contains an invalid character." Could that be 'Program Files (x86)' by any chance? Why Microsoft would choose to name a system folder with a character the windows installer considers invalid is beyond me. Anyway, the way I thought I'd share how I fixed the issue. -Download Microsoft's Windows Install Clean Up utility from: http://support.microsoft.com/kb/290301/ -Run the utility and remove ONLY Microsoft Visual Studio Remote Debugger -Run the debugger setup from the dvd Hopefully that will save someone a headache.

WiX Installer Update

2008-12-19T21:42:00.010-05:00

One thing that has caused me quite a few problems with my WiX installer was optionally displaying a dialog to enter SQL information when the database is installed.

I may change the database to be a critical element of the intall, but I thought this would be a good share.

Based on:

http://msdn.microsoft.com/en-us/library/aa368012(VS.85).aspx

and

http://geekswithblogs.net/jwatson/archive/2006/11/03/96052.aspx

To set the next button to display based on features chosen in the feature tree, you can do someting like this:

< publish dialog="CustomizeDlg" control="Next" event="NewDialog" value="SqlSetupDlg"> 1 </publish> Where "Database" is the name of the feature you want to install.

other access prefixes are:

(none) Installer property: Value of property (Property) table.
% Environment variable: Value of environment variable.
$ Component table key: Action state of the component.
? Component table key: Installed state of the component.
& Feature table key: Action state of the feature.
! Feature table key: Installed state of the feature.

WiX: First impressions.

2008-12-15T19:04:00.006-05:00

After working with WiX today, I realized that it's not perfect. But, it isn't horrible. Maybe my issues are from following "tutorials" that are written for WiX 2.0, while I'm using WiX 3.0.

Whatever the reason, I have encountered only a few problems so far:

1. < removefolder id="FolderName" on="uninstall" > this caused a lot of errors. I don't know if WiX 3.0 has changed how it handles removal of folders? I noticed when I uninstall without specifying , it actually removes the folder properly. (I'm using this on a folder under ProgramMenuFolder)

2. Creating a new UI and adding dialogs was a pain. Referencing my dialog with DialogRef="NewDialogName" kept throwing errors. Quite a few google searches later, I still couldn't find a fix or a reason for the errors. The resolution: instead of creating the dialog in a different file as a Fragment, I just added it to the file modeled after WixUI_Mondo. After doing this, the dialog worked. Maybe fragments are broken? Or, maybe I wasn't compiling and linking the library properly.

3. Many tutorials refer to a tool called tallow to create a Fragment of Components/Files. But, the tool is now called Heat. It's a useful tool, but I'm still having problems getting Fragments that I create to work right. That's about it, I will write up some solutions to these problems if I find them.

Windows Installer Dilemma

2008-12-14T10:15:00.002-05:00

My current task is to create an installer. The dilemma: Visual Studio doesn't provide a very robust Setup and Deployment project. The options? 1. Create a WiX Project 2. Write a bootstrapper/custom GUI/etc. and P/Invoke msi.dll 3. InstallShield ($$$) 4. Wise ($$$) 5. Nullsoft Scriptable Install System Here's what I've run into. WiX is pretty straight-forward and configurable. It is also open source, so you are able to rewrite the user-interfaces to fit your needs. The only thing is that the whole project is in XML, which means creating a dialog means setting values for buttons, labels, and textboxes manually. I've thought about writing a short program to create the dialogs for me, which I may still do. The problem I've found with WiX: I can't figure out how to refer to code (Assembly Info). I have found two possibilities: replace WiX version via PowerShell script and using MSBuild tasks. However, my development team wants to make the project as simple as possible. Using WiX already means that everyone will have to install WiX in order to build the file properly. This will only be a problem until the next version of Visual Studio, which is supposed to ship with WiX installed. Option 2 is one that I got from Rick Brewster, of Paint.NET fame. Well, not directly from him. Scott Hanselman has an excellent podcast which details the Paint.NET installer. It is beautiful in it's simplicity. I'll leave a few things out, to tailor it to my discussion. I'll start from the outside-in.

The installer comes as an executable created by NSIS (#5 above). This installer basically acts as a zip file, which extracts the contents to the user's application folder and runs the bootstrapper.
The bootstrapper checks for the proper version of Windows, and .NET
If the requirements .NET aren't met, the .NET redistributable installer can be run from the directory.
When everything is good, a custom GUI setup program runs.
The program gathers necessary information, injecting it into the MSI installer which is actually the same one created by Visual Studio.
Then, any number of MSI installers can be run.

This method of staging, bootstrapping, gathering, and then running seems the most efficient. The problem is that the whole MSI interoperability means having a full understanding of Windows Installer technology. It is possible, however, to simplify this even further. On the progress form, use msiexec and switches. Because I'm not that interested in fully understanding the Windows Installer technology at the moment, this option is a little more than I want to get into. But, I have actually started a project that uses a very similar method. InstallShield and Wise cost money, so they are not options for me. NSIS is another excellent option. The only problem I see with it is that it's like learning another scripting language. Although it is very simple, it doesn't particularly appeal to me. XML, however, does. So, it looks like I'm going to go with WiX as my choice to create an installer.

.NET development

2008-12-13T10:55:00.002-05:00

I consider myself a .NET developer. I don't consider myself good at it. There are always things to learn, and new facets of development that I didn't realize existed. I plan on keeping this blog as a way to keep tabs on what I've been doing. I am currently working at Agility Healthcare Solutions, on a Rich Internet Application used to track patients, staff, equipment, and beds in a hospital environment using RFID. The language of choice is C#. Be sure to check back regularly, maybe you'll find something of use.

James Schubert's Resume.doc

1989-01-18T00:44:00.000-05:00

James Schubert

Phone: (507) 724-8237 Email: james.schubert@gmail.com

Education

Virginia Commonwealth University Richmond, VA

Bachelor of Science in Business, May 2009

Major: Information Systems (Application Development)

GPA: 3.98

Honors

Academic Achievement Award, Spring/Fall 2006, Spring 2007

William O. Edwards Scholarship for Merit, 2007-2008, 2008-2009

Member, Beta Gamma Sigma International Business Honor Society, 2008

Member, Phi Kappa Phi Honor Society, 2008

Student of the Year Award, Information Systems, VCU School of Business, April 2009

Skills

Design (Visio, Rational Rose)

Development (C#.NET, Visual C++, XML/XSL, Python)

Web Technologies (ASP.NET, PHP, AJAX, JavaScript, jQuery, HTML, XHTML, CSS)

Database Systems (MS-SQL, MySQL, Oracle)

Deployment (Windows Installer XML v3)

.NET Frameworks (1.1/2.0/3.0/3.5/3.5 SP1)

Experience

September 2009-Present, Primescape Solutions, Inc. Reston, VA

Consultant

Perform major enhancements and add functionality to a web application using ASP.NET 1.1, C# and Oracle 9i
Comply with coding and security standards for federal government client

September 2008-February 2009, Agility Healthcare Solutions Richmond, VA

Intern

Performed bug fixes and application enhancements in an HL7-compliant Rich Internet Application using ASP.NET 3.5 and C#
Worked with development team as part of a mixed Agile/Scrum methodology
Provided feedback on application complexity and usability to team leader