I’ve looked this up an embarrassing number of times – here is how you do linq projection with the extension method syntax
List<TypeClassification> typeClassifications = ctx.Classes.Select(e => new TypeClassification() {Name = e.Name, TypeClassificationID = e.ClassificationID}).ToList();
Hopefully I shall remember. I’m not sure why I can’t remember the exact syntax.
The Problem
I recently came across the conundrum of files not being availble for download after I uploaded them to Windows Azure Storage.
The Cause
Usually the problem is an incorrect mime type, but since Azure does not have mime types I had to do some more digging.
The Solution
It turns out there is a property called “ContentType” that must be set on the Azure Storage Blob programatically – here is an example
CloudBlockBlob blockBlob = container.GetBlockBlobReference(filename);
if (GetFileExtension(filename).ToUpper() == “.SWF”)
{
blockBlob.Properties.ContentType = “application/x-shockwave-flash”;
}
else if (GetFileExtension(filename).ToUpper() == “.MP4”)
{
blockBlob.Properties.ContentType = “video/mp4”;
}
blockBlob.SetProperties();
Once I did that everything worked as intended.
For some reason, most likely because you never do it more than once a year, adding ssl certificates to a server is poorly documented and unnecessarily complicated. Here are some things I learned recently about adding ssl certs on Windows Azure Websites.
I recently added a cert to this site, https://digitaltoolfactory.net which is hosted on Windows Azure Websites. It looks simple enough, just upload a file, sure it’s a .pfx file, but those are avilable aren’t they?
Off I go to NameCheap.com, plunk down my $10 and get a GeoTrust Rapid SSL Certificate. Then you have to generate a CSR – from there just go to your IIS manager and
That’s it!
There are a few caveats.
The big one is that if you have any errors in this process Azure will not tell you – instead all you will get is the big scary “This site claims to be DigitalToolFactory.net, but the actual certificate is for *.WindowsAzureWebsites.net”.
The other caveat is that Microsoft is charging $9.00 per month to host a site site with Secure Socket Layer bindings, which is ridiculous. By my estimation it costs more to host the cert than to host the actual site, which makes it unique in all web hosting. Why they do this I don’t know. I’m glad to have the option, but the amount seems ridiculous – hopefully that fee will drop soon.
I recently implemented a quick performance fix on a client’s site recently by implementing caching. I explain caching with the following metaphor.
Imagine that your site is a book. A book written in a weird mix of Latin, Sanskrit and Old Norse. It’s precise, complicated and requires translation into English by an expert translator before it can be read by the public.
Your web server translates the book. Anytime, someone tries to read the book they cannot read it directly; they need someone (the web server) to translate the book. This can take a lot of time and energy for the translator to do, but it has to be done.
To clarify, the process works like this
That all sounds good, but the problem is that the four step process has to happen each and every time anyone makes a request, especially the resource intensive step two. So, if a web page gets 1000 requests an hour, resource intensive step #2 runs 1000 times.
Now imagine if the translator makes a copy of the English translation after he sends it out the first time. The first time someone makes a request for a translation the process looks like this.
Subsequent requests for the book look like this
The first time someone makes a request the process runs a little slower, but since each subsequent request for the book omits all of the resource intensive steps, the whole process take up much less time and fewer resources, making for a much lower delivery time on average, e.g. for every 1000 requests for a page, resource intensive step #2 runs 1 time, not 999 times.
Making a photocopy is pretty close to caching. The web server makes a copy of the page it just created and sends it on it’s way to web browsers.
What are the downsides of caching, and why doesn’t everyone use it? I’ve seen two main reasons not to use caching.
That’s how I explain caching to clients. I’ve always had people find the metaphor clear and easy to understand.
This happened to me whilst working on a pre-existing site recently.
You are trying to install WordPress onto a subdirectory of an existing site that uses the .htaccess files for routing. When you try to add in the changes needed for WordPress to work you break the existing site.
WordPress .htaccess files do not play nicely with other .htaccess files
Simply add in the WordPress generated .htaccess files in the WordPress directory, and everything magically works.
For Unix people this must be obvious, but for me it was surprisingly brilliant.
A silly one this time
I was recently working on someone else’s WordPress theme that made extensive use of WordPress Widgets and the new dynamic sidebar feature. I was able to recreate the widgets (there was a working staging site) but the on the production site the widgets did not appear. What to do about disappearing WordPress widgets?
I had changed the name of the theme. For some reason the register_sidebar has to have the name hard coded, for example
register_sidebar( array( 'name' => __( 'Banner Area', 'themename' ), 'id' => 'Banner-area', 'description' => __( 'Banner area', 'themename' ),
'before_widget' => ' <div>',
'after_widget' => '</div>', 'before_title' => '<div><h1>', 'after_title' => '</h1></div>', ) );
Just change the name of the theme to the new name and you’re all set!
You have created a lovely model in asp.net mvc 4, using Entity Framework and a whole host of attributes. One of the properties of your model looks like this
[Required]
[Display(Name = “Expiration Month (MM)”)]
[StringLength(2,ErrorMessage = “You must enter two digits”, MinimumLength = 1)]
[Range(1,12, ErrorMessage = “You must enter a valid month”)]
public int ExpirationMonth { get; set; }
That yields an error of
Unable to cast object of type ‘System.Int32’ to type ‘System.String
When the form is submitted, but not when the object is created (which is a bit odd)
It turns out that you cannot use the StringLength data attribute on an int data type. You would think you could since all you are actually interested in with that data attribute is the number of digits, but the data gods have decreed that you can’t.
Just comment out StringLength and use the Range Attribute.
I was using the wonderful SignalR libraries to create a status window (I have a VERY long running process in my new Data Hammer project, it takes about 15 minutes to run) and I need to inform the user on where the process is at any given time. My original code looked like this
public class Chat : Hub
{
public void Send(int id)
{DataHammerContext ctx = new DataHammerContext();
while (true)
{string strName=ctx.ProcessSteps.Find(id).Name;
Clients.All.addMessage(“Status: ” + strName);
Thread.Sleep(1000);
}
}
}
And this would always display the same status, quite maddening.
After much investigation I realized that my model of how Signal R works was flawed. For whatever reason (by which I mean too long to go into here) the data context does not update with the while loop.
The fix is simple, just recreate the data context every time and everything works like it should – here is a sample of the updated code.
public class Chat : Hub
{
public void Send(int id)
{
while (true)
{DataHammerContext ctx = new DataHammerContext();
string strName=ctx.ProcessSteps.Find(id).Name;
Clients.All.addMessage(“Status: ” + strName);
Thread.Sleep(1000);}
}
}
You are trying to configure Widlcard routing (i.e. something like http://domain.com/SomeUserName/) and find it problematic.
That is largely by design – wildcard routing is resource intensive and rarely needed.
If you want to do it anyway, use the following routes
routes.MapRoute(“Default”, “”, new { controller = “Home”, action = “Index”, id = UrlParameter.Optional });
routes.MapRoute(“CatchAll”, “{*id}”, new { controller = “Home”, action = “Handle”, id = “” });
Things to note
Okay, after some more digging (and some failed integration tests) here is what you have to do
Add in the following routes
routes.MapRoute(“Handle”, “Home/Handle/{id}”, new { controller = “Home”, action = “Handle”, id = “” });
routes.MapRoute(“User”, “{*id}”, new { controller = “Home”, action = “Index”, id = “” });
routes.MapRoute(“Default”, “{controller}/{action}/{id}”, new { controller = “Home”, action = “Index”, id = UrlParameter.Optional });
And then create an action called “Handler”, and change your Index action on your home controller to look like this
public ActionResult Index(string id=””)
{
if (!string.IsNullOrWhiteSpace(id))
{
return RedirectToAction(“Handle”, new {@id = id});
}
else {
return View();
}
What does this do? It routes all wildcard traffic to your Index controller, which then hands it off to the “Handle” Action. You would think that you could just hand everything off to the Handle action, but if you do that, then your Index action becomes inaccessible, and in some circumstances you get a recursive loop where the handle action is called endlessly. That does show an interesting error screen though.
One annoying side effect of this course of action is the need to map out each and every route explicitly, otherwise the wildcard route will pick it up and hand it off to the “Handle” action, which will take it somewhere where you do not want it to go.
You are attempting to change a database column of type decimal from a precision of two decimal place to one decimal place via data annotations, and there does not seem to be a good way to do it.
There isn’t a good way to do it.
However, there is at least one non-elegant way to do it – in your OnModelCreating code in your data context, enter in the following piece of code
protected override void OnModelCreating(System.Data.Entity.DbModelBuilder modelBuilder)
{
modelBuilder.Entity().Property(xx=>xx.Handicap).HasPrecision(12, 1);
base.OnModelCreating(modelBuilder);}
The “HasPrecision” part is the key – the second parameter is the number of decimal places to use
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