Stanza Catalog Update

I’ve continued enhancing the Stanza catalog I created earlier. New features include purchase links and Google Analytics tracking. I reverse-engineered the FeedBooks API and the feeds to figure out how to do some of these things. Also I’ve been reading the OPDS spec (an industry-standard successor to the Stanza format) to add support for e-readers on other platforms. For example Aldiko officially supports OPDS, but it recognizes Stanza tags as well.  It crashes if you try to open a PDF file however – so it just needs to be sent the right mime type.

Here’s the snippet where I reference the custom Analytics class I added:

 p.StoreDescription += Mises.Domain.Mobile.Analytics.GetAnalyticsImageTag(this.request.RequestContext.HttpContext);
                            var content = new TextSyndicationContent(p.StoreDescription,
                            item.Content = content;

And here’s how to add external links to a book info view:

                                new SyndicationLink(
                                    new Uri(string.Format("{0}&utm_source=MisesCatalog", p.ProductId)), "alternate", "Purchase at the Mises Store",
                                    "text/html", 0));
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10 simple questions to evaluate a software development organization

All credit and inspiration for the questions below goes to Joel Spolsky’s The Joel Test and Bill Tudor’s 2010 update.

My version differs in two aspects:  First, has just ten questions ordered from highest to lowest priority (in my personal opinion).  Second, in addition to yes/no questions, it asks open-ended questions intended to give more informative answers in an interview or an analysis of a software team.

  1. Do you use source control? What kind?  What are the requirements/checks to check in code (assignment to work items, unit tests, peer review, etc)?
  2. Do you use a bug database to track all issues? How do you track progress and manage change?
  3. Do you use the best tools money can buy? For example: MSDN/Apple Dev accounts, dual monitors, and powerful workstations.
  4. Do you have a dedicated QA team? Are they involved in the requirement/release management process?
  5. Do you fix bugs and write new code at the same time? How do you balance the two?
  6. Do programmers have quiet working conditions and team meeting rooms?  Describe them.
  7. Do you solicit feedback from end users or customers during the development process?  How is it used?
  8. Do you do a daily build? Do your builds include automated unit tests?
  9. Do you have a requirements management system? Is it integrated with your source control?
  10. Do you create specification/requirements documents? Do you do it before, during, or after writing code?

Bad developer ≠ novice developer

My post on the nature of programming seems to have struck a nerve. Many commenters pondered what makes a developer great. “Ka” thought that:

“You [are] not born [a] good or great programmer, you become one with time and study and hard work. At the beginning, everybody is a bad programmer.”

I disagree. Developers are not born “great,” but greatness does not automatically come with experience. Conversely, lack of experience does not make a developer “bad.” The difference between a great developer and a bad developer is not in their domain knowledge, but their methodology. The distinguishing mark of a great developer is that he codes consciously. Put another way, a good developer always knows why he is doing something. From the perspective of personal ethics, this requires intellectual courage and integrity.

Let me give an illustration of what I mean from personal experience:

When I got into Objective-C development, I was a “bad” developer. Most of my experience is with .Net code. Jumping into the iPhone dev world was intimidating. As as a result, I lacked the courage to learn the architecture. I tried to manipulate blocks of code found on the web without understanding what they were doing. I would copy and paste blocks of code and just change variable names. When things didn’t work, I would look for another block of code to substitute for the failing one, or enter “debugging hell” – running code over and over, making random changes and seeing if they worked. This is the hallmark of a bad developer – imitating without understanding. I kept this up for over a year. It’s not that I didn’t try to learn the language. I got several books and watched iTunes U classes. But the way I used the learning materials was to memorize blocks of code and look for places to stuff them into my code. I wasn’t actually learning the platform, just collecting samples. Some developers spend their entire careers this way. They carry collections of old code everywhere they go, and just grab chunks to insert into new programs. They may never select File => New File or File => New Project in their whole career.

After writing a lot of bad, buggy code, I drifted back to the comfort of .Net. Recently however, I decided to change my attitude. I started by downloading some iPhone code samples and open-source applications. I started in main.m and went through each line of code. If I didn’t understand exactly why a certain symbol was used or what it did, I looked it up. I spent a lot of time on Cocoa Dev, and Stack Overflow looking up things like the reasons why you would assign, retain, or copy a property, or when exactly you need to release an object (for alloc, new, copy or retain) or what you can do with respondsToSelector. There’s really not that much complexity to programming languages – but if you don’t take the time to learn how things work, they will always seem difficult and mysterious. If I had just looked this stuff up to begin with, I would have been far more productive. But, I was intimidated by the environment and tried to shortcut the learning process by imitating without understanding.

Understanding anything complex requires the courage and integrity to engage in difficult, exhausting mental effort. It’s tempting to cheat yourself. It’s easier spend more time in endless copying and debugging that take the effort to understand and create. In the short run, it saves time. But in the long run, developers who understand their craft are magnitudes more productive than the monkey see-monkey do coders. This is the difference between the unprincipled kind of laziness that trades understanding for time and the principled kind of laziness which saves time by understanding.

There’s no happy ending to my story — yet. The proof of a developer is in his work, not his book smarts, and I have yet to produce something to brag about.

For more on the traits of great developers, read these posts by Dave Child and micahel.

Get the MD5 hash of a file in .Net

MSDN has a page on how to get the MD5 hash of a string.

Easy enough, but if you follow their example exactly for a file and use File.ReadAllText() to get the string, you will get the wrong MD5 string for binary files. Instead, use File.ReadAllBytes() to bypass encoding issues. (This also applies to SHA1 hashing.)

private static string GetMD5Hash(string filePath)
            byte[] computedHash = new MD5CryptoServiceProvider().ComputeHash(File.ReadAllBytes(filePath));
            var sBuilder = new StringBuilder();
            foreach (byte b in computedHash)
            return sBuilder.ToString();

Creating a Stanza Catalog with ASP.Net MVC 2.0

Stanza is a book reader for the iPhone/iPad.  One of Stanza’s features is the ability to browse specially formatted book catalogs.  While it has a number of built-in catalogs, you can also add your own.  I have created such a catalog with ASP.Net MVC 2.0 (screenshots).  The Stanza catalog format is pretty simple – just AtomPub with some proprietary attributes for images and things like search.  This was a quick and easy project because the .Net Framework 4.0 has the System.ServiceModel.Syndication namespace which does all the RSS/Atom feed generation.  We just have to add some custom attributes and serialize the feed to the browser.

Here is a quick overview of the code (Links are to the latest version of the source code in my SVN browser.  You can get the project from SVN here (guest/guest).)  The LiteratureCatalog and LiteratureCatalog.Tests projects have the relevant code.

Update: The Stanza catalog format works equally well with Aldiko, an e-reader for Android.


This is the default controller specified in global.asax.  It defers to MisesFeeds to generate the feed items and to FeedResult to serialize and write out the feed.

Sample Method:

public FeedResult Journal(int journalId)
var feeds = new MisesFeeds(Request);
SyndicationFeed feed = feeds.GetJournalFeed(journalId);
return new FeedResult(new Atom10FeedFormatter(feed));


MisesFeed contains all the code to generate a SyndicationFeed object containing a List of SyndicationItem.  Note the Stanza-specific links added in search list-builder and the final helper method:

item.Links.Add(new SyndicationLink(new Uri(DataFormat.GetAbsoluteURL(p.Logo)),
public SyndicationFeed CreateFeedFromSyndicationItemList(IEnumerable postItems, string title,
string description)
var feed = new SyndicationFeed(title, description, new Uri(feedUri), postItems)
Copyright = new TextSyndicationContent(Configuration.Copyright),
Language = "en-US"
var self = new SyndicationLink(new Uri(Host + HttpUtility.UrlEncode("/Catalog/"))"self""", Type, 0);
feed.Links.Add(new SyndicationLink(new Uri(Host + "/Catalog/Search/?q={searchTerms}",true),"search","Search Catalog",Type,0));
return feed;


FeedWriter inherits from ActionResult.  It just writes the SyndicationFeed out with an XmlTextWriter:

public override void ExecuteResult(ControllerContext context)
if (context == null)
throw new ArgumentNullException("context");
HttpResponseBase response = context.HttpContext.Response;
response.ContentType = !string.IsNullOrEmpty(ContentType) ? ContentType : "application/atom+xml";
if (ContentEncoding != null)
response.ContentEncoding = ContentEncoding;
if (feed != null)
using (var xmlwriter = new XmlTextWriter(response.Output))
xmlwriter.Formatting = Formatting.Indented;

Thanks to DamienG for the FeedResult class.

To see the catalog, get the Stanza app, tap “Get Books”, “Shared”, “Add Book Source”, then add the URL

Some lesser-known truths about programming

My experience as a programmer  has taught me a few things about writing software. Here are some things that people might find surprising about writing code:

  • Averaging over the lifetime of the project, a programmer spends about 10-20% of his time writing code, and most programmers write about 10-12 lines of code per day that goes into the final product, regardless of their skill level. Good programmers spend much of the other 90% thinking, researching, and experimenting to find the best design. Bad programmers spend much of that 90% debugging code by randomly making changes and seeing if they work.
  • A good programmer is ten times more productive than an average programmer. A great programmer is 20-100 times more productive than the average. This is not an exaggeration – studies since the 1960’s have consistently shown this. A bad programmer is not just unproductive – he will not only not get any work done, but create a lot of work and headaches for others to fix.

    “A great lathe operator commands several times the wage of an average lathe operator, but a great writer of software code is worth 10,000 times the price of an average software writer.” –Bill Gates

  • Great programmers spend little of their time writing code – at least code that ends up in the final product. Programmers who spend much of their time writing code are too lazy, too ignorant, or too arrogant to find existing solutions to old problems. Great programmers are masters at recognizing and reusing common patterns. Good programmers are not afraid to refactor (rewrite) their code  to reach the ideal design. Bad programmers write code which lacks conceptual integrity, non-redundancy, hierarchy, and patterns, and so is very difficult to refactor. It’s easier to throw away bad code and start over than to change it.
  • Software development obeys the laws of entropy, like any other process. Continuous change leads to software rot, which erodes the conceptual integrity of the original design. Software rot is unavoidable, but programmers who fail to take conceptual integrity into consideration create software that rots so so fast that it becomes worthless before it is even completed. Entropic failure of conceptual integrity is probably the most common reason for software project failure. (The second most common reason is delivering something other than what the customer wanted.) Software rot slows down progress exponentially, so many projects face exploding timelines and budgets before they are mercifully killed.
  • A 2004 study found that most software projects (51%) will fail in a critical aspect, and 15% will fail totally. This is an improvement since 1994, when 31% failed.
  • Although most software is made by teams, it is not a democratic activity. Usually, just one person is responsible for the design, and the rest of the team fills in the details.
  • Programming is hard work. It’s an intense mental activity. Good programmers think about their work 24/7. They write their most important code in the shower and in their dreams. Because the most important work is done away from a keyboard, software projects cannot be accelerated by spending more time in the office or adding more people to a project.

Add a Facebook Like button to your page

Adding a “Like” button using the Facebook JavaScript API is easy:

        &lt;fb:like href=&quot;"&gt;
        window.fbAsyncInit = function () {
            FB.init({ appId: 'your app id', status: true, cookie: true,
                xfbml: true
        (function () {
            var e = document.createElement('script'); e.async = true;
            e.src = document.location.protocol +
        } ());

Continuous paging in Windows Phone 7

Here’s a quick and dirty implementation of continuous paging with Windows Phone 7. These code snippets are from a project using the GalaSoft MVVM Light Toolkit and Ninject, however you can adapt to fit your model. The paging and data binding functionality is abstracted in the base class PagedListViewModelBase so that the paging functionality can be easily applied to different kinds of lists – the lists inherit from PagedObject, which has a NumberOfResults property.




private void profiles_MouseLeftButtonDown(object sender, System.Windows.Input.MouseButtonEventArgs e)
            ((SomeViewModel)(this.DataContext)).RowTouchedCommandHandled(e); // this just calls the method in the viewmodel - you can call it directly if your aren't using MVVM

SomeViewModel.cs: inherits from PagedListViewModelBase

/// This is the only view-specific code you need for rendering and paging.  All the paging and databinding is handled by PagedListViewModelBase
/// SelectionChanged handlers can go here or in the base class
 public override void GetDataFromWebService(object obj)
            // Get Data:
            if (!IsLoading)
                IsLoading = true;
                var svc = new ProfileWebService(_userService.Current(), webService);
                svc.GetSearchResults(CurrentPage, OnItemsRetrieved);

PagedListViewModelBase.cs: contains the databinding and paging functionality

protected ObservableCollection _pagedObjectList;
// An ObservableCollection object generates NotifyPropertyChanged events to let the UI know when to update
 public ObservableCollection PagedObjectList
                if (_pagedObjectList == null &amp;&amp; !IsLoading)
                    if (!IsInDesignMode)
                        // design mode
                return _pagedObjectList;
                _pagedObjectList = value;
protected int CurrentPage { get; set; }
protected bool IsLoading;
	///  Handles touches from user and decided when to add the next page to the list
       public void RowTouchedCommandHandled(MouseButtonEventArgs obj)
            var personalProfile = ((PagedObject)(((FrameworkElement)obj.OriginalSource).DataContext));
            if (personalProfile.GetType() != typeof(PersonalProfile))
            int index = PagedObjectList.IndexOf(personalProfile);
            Debug.WriteLine("Current index: " + index);
            Debug.WriteLine("NumberOfResults: " + personalProfile.NumberOfResults);
            if (!IsLoading &amp;&amp; personalProfile.NumberOfResults &gt; PagedObjectList.Count &amp;&amp; index &gt; PagedObjectList.Count - 6) // if less than six items from the end, get the next page
                CurrentPage += 1;
                Debug.WriteLine("Next page: " + CurrentPage);
public abstract void GetDataFromWebService(object obj);        
  protected void OnItemsRetrieved(List pagedObjects, Error error)
            if (error == null)
                if (_pagedObjectList == null)
                    _pagedObjectList = new ObservableCollection();
                pagedObjects.ForEach(p =&gt; _pagedObjectList.Add(p));
                IsLoading = false;
                Error = error;
/// You don't need all these conversions if you use a single type for your lists.            
/// .Net 4.0 adds support for co-variance, which allows casting a generic collection to base type
 protected void OnItemsRetrieved(List profileList, Error error)
            var objList = new List();
            OnItemsRetrieved(objList, error);


    public class PagedObject : ModelBase
        /// <summary>
        /// Total number of results for this search
        /// </summary>
        public int NumberOfResults { get; set; }

Using Reflection to serialize DTO’s

Suppose that you have a DTO (data transfer object) that you want to convert into a parameter array to be saved to file or sent over the web. You could serialize it and convert it to XML or JSON. But maybe you want to send it in an HTTP POST or GET and you don’t want to know anything about the class itself. You could use Reflection to iterate through the properties and extract the property names and values and output them to a string.

For example, this code will convert a class into a string suitable for a REST API call:

var properties = prefs.GetType().GetProperties(BindingFlags.Public | BindingFlags.Instance);
           properties.ToList().ForEach(property =&gt;
                                               var hasDataMemberAttribute = property.GetCustomAttributes(typeof(DataMemberAttribute), false);
                                               if (hasDataMemberAttribute.Length == 1)
                                                   string name = property.Name.ToLower();
                                                   string value = String.Empty;
                                                   object objValue = property.GetValue(prefs, null);
                                                   if (null != objValue)
                                                       value = objValue.ToString();
                                                   // Only serialize properties marked with the [DataMember] attribute:
                                                   var hasBrokerMapAttribute = property.GetCustomAttributes(typeof(DataMemberBrokerMapAttribute),
                                                   if (hasBrokerMapAttribute.Length == 1)
                                                       name = ((DataMemberBrokerMapAttribute)hasBrokerMapAttribute[0]).Key;
                                                   if (value.Length &gt; 0)
                                                       filter.Append(String.Concat("/", name, "=", value));
           Debug.WriteLine("Search Filter:" + filter);
           return filter.ToString();