source code bean » C#

Deploying your ASP.NET MVC3 site on Mono

Peter — Sat, 10 Mar 2012 14:26:49 +0000

In this blog post I am going to show you how easy it is to create a new ASP.NET MVC site and deploy it on Linux/Mono.

Step 1 – Create project
Create a new ASP.NET MVC 3 project. Compile and run it.

Step 2 – Add assemblies needed by Mono
Add references:
System.Web.WebPages
System.Web.WebPages.Deployment
System.Web.WebPages.Razor

Step 3 – Copy local
Make sure to set “Copy Local” to True for all of the following assemblies:
System.Web.Helpers
System.Web.Mvc
System.Web.Razor (C:\Program Files (x86)\Microsoft ASP.NET\ASP.NET Web Pages\v1.0\Assemblies\System.Web.Razor.dll)
System.Web.Routing
System.Web.WebPages
System.Web.WebPages.Deployment
System.Web.WebPages.Razor

Remove Entity Framework and other unnecessary assemblies.

Step 4 – Publish your site
Publish it to a directory and copy it to your Linux server

Step 5 – Get latest Mono and compile it from source
I run Ubuntu 11.10 on my server. Ubuntu has Mono 2.10.6 in its repository, which is quite new, but Mono is moving so fast so I recommend getting the latest version and compiling it from source. The latest version at the time of writing is 2.10.8. Nathan Bridgewater has created a script to simplify this process, if you are running Ubuntu, this is what you will need to run to install Mono:

mkdir mono-2.10
cd mono-2.10
wget --no-check-certificate https://github.com/nathanb/iws-snippets/raw/master/mono-install-scripts/ubuntu/install_mono-2.10.sh
chmod 755 install_mono-2.10.sh
./install_mono-2.10.sh

It will take a while to compile it, so now is the time to go grab a cup of coffee.

Step 6 – Run your site with xsp4
Mono have a development web server called xsp4, the first thing we are going to do is to run our site in xsp4 to make sure it works. Mono has been installed to /opt, but does not exist in our PATH, so before we can run Mono we need to setup the mono enviroment variables. To do that I found a script somewhere on the internets, monoenv.sh:

MONO_PREFIX=/opt/mono-2.10
export DYLD_LIBRARY_FALLBACK_PATH=/lib:
export LD_LIBRARY_PATH=/lib:/opt/mono-2.10/lib:
export C_INCLUDE_PATH=/include:/include
export ACLOCAL_PATH=/share/aclocal
export PKG_CONFIG_PATH=/lib/pkgconfig:/lib/pkgconfig
export PATH=/bin:/opt/mono-2.10/bin:$PATH

At your bash prompt type: source monoenv.sh

Now cd into the directory where you have your published web site and run xsp4.

Now your MVC site should be up running on Mono!

In my next blog post I will cover how to configure your site to run using Nginx and the fastcgi-mono server.

MongoDB, C# and Mono

Peter — Wed, 11 Jan 2012 18:53:48 +0000

MongoDB is one of the many free open source NoSQL databases that exist today. I wanted to try out how well the official drivers for C# worked when using Mono.

On the MongoDB web site they have pre built binaries of MongoDB for almost every platform, i grabbed the 64 bit binary for OSX. No installation is required, just unzip the file and run the “mongod” binary from the directory. There is also a binary called “mongo”, this is the mongo interactive shell which is very useful.

The C# drivers are available, both in binary form and as source, from the C# language center. To get started I fired up MonoDevelop 2.8 running on Mono 2.10.8:

MonoDevelop has matured a lot since I used it the first time. It is still not as good as Visual Studio, but it is getting there. What takes most time to get used to is the totally different set of shortcuts, and the lack of all ReSharper magic.

Let me break down a simple console application example on how to use MongoDB using the official driver from 10gen:

using System;
using System.Collections.Generic;
using System.Linq;
using MongoDB.Bson;
using MongoDB.Driver;
using MongoDB.Driver.Builders;
namespace MongoDbTest
{
public class Article
{
public MongoDB.Bson.ObjectId id { get; set; }
public string title { get; set; }
public string status { get; set; }
public string[] tags { get; set; }
}
class MainClass
{
public static void Main (string[] args)
{
// Connect to the database and get a colleciton
MongoServer server = MongoServer.Create ("mongodb://localhost");
MongoDatabase db = server.GetDatabase ("mongodb-tutorial");
// Get an article collection
MongoCollection articles = db.GetCollection ("articles");
// Empty the collection (so all runs of this program will result in the same output)
articles.RemoveAll ();
//
// Create two articles
//
articles.Save (new BsonDocument
{
{"title", "A MongoDB article"},
{"status", "published"},
{"tags", new BsonArray { "c#", "mongodb" }}
});
articles.Save (new BsonDocument
{
{"title", "A Mono article"},
{"status", "draft"},
{"tags", new BsonArray { "c#", "mono" }}
});

If you type this in the MongoDB shell, you will see that the following articles are stored in the database:

> db.articles.find()
        {
          "_id" : ObjectId("4f097f8e74b5b343b97f56a7"),
          "title" : "A MongoDB article",
          "status" : "published",
          "tags" : [ "c#", "mongodb" ]
        }

        {
          "_id" : ObjectId("4f097f8e74b5b343b97f56a8"),
          "title" :
          "A Mono article",
          "status" : "draft",
          "tags" : [ "c#", "mono" ]
       }

// Find and print the first article
BsonDocument firstArticle = articles.FindOne ();
PrintArticle ( // Access the properties using indexing and then casting using the .As*
firstArticle["_id"].AsObjectId,
firstArticle["title"].AsString,
firstArticle["status"].AsString,
(firstArticle["tags"].AsBsonArray).Select (x => x.AsString));
//
// Typed collections
//
// Using indexing and the .As* operations is not that convenient. A better way
// is to use a typed collection. Earlier we defined a Article class, lets use it:
MongoCollection
typedArticles = db.GetCollection
("articles");
Article typedArticle = typedArticles.FindOneAs
();
PrintArticle (typedArticle.id, typedArticle.title,
typedArticle.status, typedArticle.tags);
// Save a typed article
typedArticles.Save (new Article {
title = "An article about MonoDevelop",
status = "published",
tags = new [] {"c#", "mono", "mono-develop"},
});
//
// Querying
//
// Find article with status draft
Article draftArticle = typedArticles
.FindOneAs
(Query.EQ ("status", "draft"));
PrintArticle (draftArticle.id, draftArticle.title,
draftArticle.status, draftArticle.tags);
//
// Updating
//
// Lets update the draft article and set status published
Console.WriteLine ("Nr of published articles before update:"
+ typedArticles.Find (Query.EQ ("status", "published")).Count ());
typedArticles.Update (
new QueryDocument { { "_id", draftArticle.id } },
new UpdateDocument { { "$set", new BsonDocument ("status", "published") }
// $set is atomic
});
Console.WriteLine ("Nr of pubhlished articles after update:"
+ typedArticles.Find (Query.EQ ("status", "published")).Count ());
//
// MapReduce
//
// This will count the number of times a tag has been used by using MapReduce
var map =
"function() {" +
" this.tags.forEach(function(t) {" + // Iterate all the tags and
" emit(t, { count : 1 }); " + // emit the tag name and initial count
" })" +
"}";
var reduce =
"function(key, emits) {" + // Reduce by tag name and summarize the result
" total = 0;" +
" for (var i in emits) {" +
" total += emits[i].count;" +
" }" +
" return { count : total };" +
"}";
Console.WriteLine ("MapReduce result:");
var mr = typedArticles.MapReduce (map, reduce);
foreach (var document in mr.GetResults()) {
Console.WriteLine (document.ToJson ());
}
}
public static void PrintArticle (ObjectId id, string title,
string status, IEnumerable tags)
{
Console.WriteLine ("id: " + id + ", title: " + title);
Console.WriteLine ("- tags: " + string.Join (", ", tags));
}
}
}

Output from the program:

id: 4f0989fc74b5b3458ae38105, title: A MongoDB article
- tags: c#, mongodb
id: 4f0989fc74b5b3458ae38105, title: A MongoDB article
- tags: c#, mongodb
id: 4f0989fc74b5b3458ae38106, title: A Mono article
- tags: c#, mono
Nr of pubhlished articles before update:2
Nr of pubhlished articles after update:3
MapReduce result:
{ “_id” : “c#”, “value” : { “count” : 3.0 } }
{ “_id” : “mongodb”, “value” : { “count” : 1.0 } }
{ “_id” : “mono”, “value” : { “count” : 2.0 } }
{ “_id” : “mono-develop”, “value” : { “count” : 1.0 } }

Using the C# driver for MongoDB, is as you can see, very straight forward. Usually when I run applications on Mono I make sure to build all libraries using the Mono compiler, to make sure the Microsoft compiler have not used any optimizations that is not supported under Mono (I have run into this issue in the past). However, in this case the .NET binaries on the MongoDB site seems to work just fine under Mono. I also downloaded the MongoDB C# driver source and build them using MonoDevelop without any problems.

One improvement I would like to see is LINQ support in the driver. It would be so much more convenient to be able to use LINQ and strongly typed objects to query the database or create MapReduce-functions.

String interning in C#

Peter — Wed, 07 Dec 2011 11:15:33 +0000

Last week a coworker sent me an interesting piece of code:

const string a = "";
const string b = "";
const string c = "hello";
const string d = "hello";
Console.WriteLine(ReferenceEquals(string.Empty, string.Empty)
? "Not so surprising…"
: "Oh, the humanity!");
Console.WriteLine(ReferenceEquals(a, string.Empty)
? "But I thought string was a reference type!"
: "Seems fair…");
Console.WriteLine(ReferenceEquals(a, b)
? " But I thought string was a reference type!"
: " Seems fair…");
Console.WriteLine(ReferenceEquals(c, d)
? " But I thought string was a reference type!"
: " Seems fair…");

Running the program will, maybe a bit surprising, produce:

Not so surprising…
But I thought string was a reference type!
But I thought string was a reference type!
But I thought string was a reference type!

The reason to this is what is called String interning. The CLR basically holds a hashmap of all the strings in the program (edit: string literals), one entry per unique string. So two identical strings will always have the same reference even though they are defined in different places. String interning is mainly used to speed up string comparisons (no need to check char by char if they are identical, if they have the same reference they are equal), but also to reduce the memory footprint of the application.

Updated version of SignalRChat

Peter — Fri, 07 Oct 2011 08:10:55 +0000

Yesterday I uploaded a slightly updated version of the test application I have built using SignalR. Besides from looking much better, it now uses the high level Hubs API (instead of the connection API) that SignalR provides.

You find it here: http://signalrchat.apphb.com/

And you can find the source on GitHub: http://github.com/moberg/SignalRChat

Reference types are always passed by value in C#

Peter — Mon, 02 May 2011 06:05:00 +0000

Last week i had a discussion with a friend about C# and passing parameters to methods. My friend asked why it is possible to use the ‘ref’ keyword for a reference type in C# when passing it to a method, he was under the impression that reference types are passed by reference to methods. This seems to be a quite common misunderstanding about C#, to make it clear:

Reference types are always passed to methods by value (unless you use the ‘ref’ keyword)

What happens when you call a method with a reference type as parameter is that the value of the reference (the pointer, an address to pointing to the referenced object) is passed to the method (by value). What this means is that you can not modify the original reference, but you can modify the object it is referencing (pointing to).

By using the ‘ref’ keyword you will pass the address of the reference to the method, which means that you can modify its value.

This is a short example illustrating this (remember, in C#, a string is a reference type):

class Program
{
static void Main(string[] args)
{
string s = "orig value";
Console.WriteLine("Orig value: " + s);
MyFunc1(s);
Console.WriteLine("After MyFunc1: " + s);
MyFunc2(ref s);
Console.WriteLine("After MyFunc2: " + s);
}
public static void MyFunc1(string s)
{
s = "new value 1";
}
public static void MyFunc2(ref string s)
{
s = "new value 2";
}
}

Output:
Orig value: orig value
After MyFunc1: orig value
After MyFunc2: new value 2

A simple image sprite generator in C#

Peter — Mon, 18 Apr 2011 20:17:01 +0000

Last week I posted the source code to a small program I wrote in Java to merge images into a sprite. This week I present the same application but in C#, pretty much translated line by line

using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Linq;
namespace NSpriteGenerator
{
class Program
{
static void Main(string[] args)
{
if (args.Length != 2)
{
Console.WriteLine("Usage: NSpriteGenerator {path to images} {output file}");
return;
}
var imagePath = args[0];
var outputFile = args[1];
var imageFolder = new DirectoryInfo(imagePath);
// Read images
var imageList = imageFolder.GetFiles("*.png")
.Select(file => Image.FromFile(file.FullName));
// Find max width and total height
var maxWidth = 0;
var totalHeight = 0;
foreach(var image in imageList)
{
totalHeight += image.Height;
if (image.Width > maxWidth)
maxWidth = image.Width;
}
Console.WriteLine(string.Format("Number of images: {0}, total height: {1}px, width: {2}", imageList.Count(), totalHeight, maxWidth));
// Create the actual sprite
var currentY = 0;
using (var bitmap = new Bitmap(maxWidth, totalHeight))
{
using (var canvas = Graphics.FromImage(bitmap))
{
foreach (var image in imageList)
{
canvas.DrawImage(image, 0, currentY);
currentY += image.Height;
}
canvas.Save();
}
Console.WriteLine("Writing sprite: "+ outputFile);
bitmap.Save(outputFile, ImageFormat.Png);
}
}
}
}

Output from a run:

PS C:\dev\NSpriteGenerator> .\NSpriteGenerator.exe C:\temp\gfx c:\temp\sprite.png Number of images: 10, total height: 640px, width: 34 Writing sprite: c:\temp\sprite.png

AppHarbor – Heroku for .NET?

Peter — Wed, 06 Apr 2011 20:24:31 +0000

I have been reading about this new startup that offers a service called AppHarbor. It seems very much as the same idea as Heroku for Ruby, but for .NET. The basic idea is that you deploy your code by pushing your code onto the server using Git, the server then builds, runs unit tests and deploys your application. Super simple!

When I first read about AppHarbor I got the impression that is was running ontop of Microsoft Azure, which turned out to be all wrong. AppHarbor is running in the Amazon Cloud on EC2 instances. When it comes to databases AppHarbor provides access to MySQL and MSSQL. Interestingly they recommend users to use MySQL:

“we expect to be able to offer MySQL on faster hardware and with more redundancy than SQL Server at the same price point. If you are planning to build an app on top of AppHarbor and have the option, we recommend you go with MySQL.”

Another interesting choice is that they have chosen Nginx as their proxy/load balancer.

Ok, let me show you how easy it is to create a simple ASP.NET MVC 3 application and deploy it on AppHarbour The first step is to go to appharbor.com and register an account. Once created you will be able to create your first app:

Give your application and press create. You have done all the configuring you need to do at AppHarbor.

Lets create a MVC 3 project with unit tests:

Make sure your project builds and that the tests passes. Also make sure you have Git installed, if not you can fetch it from here. Now open a shell and cd into the folder where you created your application.

First we need to configure git with your name, the email you used to register at AppHarbor and last the git postBuffer size:

PS C:\dev\appharbor\MyCoolApp> git config --global user.name SourceCodeBean PS C:\dev\appharbor\MyCoolApp> git config --global user.email mail@sourcecodebean.com PS C:\dev\appharbor\MyCoolApp> git config --global http.postBuffer 52428800

After this we initiate the git repository:

PS C:\dev\appharbor\MyCoolApp> git init PS C:\dev\appharbor\MyCoolApp> git add . PS C:\dev\appharbor\MyCoolApp> git commit -m "initial commit"

And when this is done we add AppHarbor as a remote repository:

PS C:\dev\appharbor\MyCoolApp> git remote add appharbor https://moberg@appharbor.com/mycoolapp-1.git

We are now set to push our code onto AppHarbor. To push it just type:

PS C:\dev\appharbor\MyCoolApp> git push appharbor master

We should now be able to see the project building:

Hopefully it built successfully. A problem I ran into was that I had ASP.NET MVC 3 RC installed and AppHarbor had the RTM version installed, this caused my first attempt to build my project to fail. After upgrading my local version and fixing the project I pushed a new version that built without problems.

We can now browse to the site (yay! that was way easier than setting up IIS manually):

Failing tests

Ok, lets change something in our application that will make a test fail:

Now we are going to be bad and not run our unit tests before commiting and pushing the code

PS C:\dev\appharbor\MyCoolApp> git commit -a -m "a failing test" PS C:\dev\appharbor\MyCoolApp> git push appharbor master

.. and we are building again

Woot! The build has failed!

We can easily see that it is the test that verifies the text on the start page that has failed

Ok, lets fix it!

Commit and push it again. And wait for the build to complete.

Yay! Our new version built successfully!

Lets check it out:

Rolling back to a previous version

Being able to rollback an update is sometimes necessary and AppHarbor makes it ridiculously simple, all you need to do is to press the “Deploy” link next to an old version. Clicking it will build and deploy the selected version.

We can now see that it is the first version that is active

I love the idea behind AppHarbor, this is really how sites should be deployed! However, using AppHarbor also means giving up some control over your environment. It will be interesting to see how they handle, for example, upgrades between different versions of IIS, installation of service packs, etc. Two features i miss is the ability to run background jobs and a distributed cache to use, but hopefully it will be coming to AppHarbor. AppHarbor still a very young startup, and so far what I have seen is really impressive!

MVC 3 RTM Install Error (after upgrading to VS2010 SP1)

Peter — Thu, 24 Mar 2011 18:28:54 +0000

Yesterday I installed Visual Studio 2010 SP1 on my home computer. After the installation I wanted to upgrade MVC3 to the RTM version (I had the RC version installed), so i uninstalled the RC and downloaded the new version. The installation came half way, then stopped, in the log file i found this:

Installation failed with error code: (0×80070643)

Not very helpful, but at least something to google. Then I found this blog post. The author describes pretty much the same issue that I had, so I did what he suggested, unpacked the installer using 7-Zip and installed the MSI packages in the following order:

1. aspnetwebpages.msi
2. aspnetwebpagesvs2010tools.msi
3. aspnetmvc3.msi
4. aspnetmvc3vs2010tools.msi
5. nuget.msi

This happily installed MVC3 without complaining. Thanks Michael!

The must have tools for C# development

Peter — Tue, 08 Mar 2011 07:00:01 +0000

Visual Studio 2010

I don’t think Visual Studio needs an introduction. VS 2010 brought us .NET 4.0 that contains a lot of new goodies!

ReSharper

ReSharper is the absolut must have for Visual Studio. It provides very improved navigation and search, refactoring, code generation, code cleanup and unit testing. I have gotten so used to having ReSharper installed so today I have a really hard time using Visual Studio without it.

Some useful shortcuts

Ctrl+T : Go to type
Ctrl+Shift-T : Go to file
Alt-Ins: Generate code (constructors, properties, implementing/overriding members)
Alt+Enter : Show available quick-fixes and context actions
Ctrl+Space : Symbol Code Completion
Ctrl+Alt+Space : Smart Code Completion
Shift+F12 : Find usages
Ctrl+Shift+R : Refactor this
Ctrl+R+R : Rename this
Ctrl+R+M: Extract method
Ctrl+R+V : Introduce variable
Ctrl+R+F : Introduce field
Ctrl+R+P : Introduce parameter
Alt+Shift+L : Locate in Solution Explore

PowerCommands for Visual Studio 2010

PowerCommands 10.0 is a set of useful extensions for the Visual Studio 2010 adding additional functionality to various areas Visual Studio. This is some of the commands I find must useful:

Copy References
Paste References
Copy As Project Reference
Edit Project File
Open Containing Folder
Open Command Prompt Here
Unload Projects
Reload Projects

Visual Studio 2010 – Productivity Power Tools

Productivity Power Tools from the Microsoft Visual Studio team contains a lot of great extensions

Very much improved dialog for add reference
Solution Naigator – a enhanced Solution Explorer
Improved tab system for editor
Highlight current line (isn’t it weird that VS is missing this feature?)

One annoying ‘feature’ is the triple click to navigate to source, never got it to work properly so I disabled it. Some shortcuts also colide with ReSharper so some tweaking is needed to make it work perfectly.

Thoughts on the Nokia / Windows Phone 7 deal

Peter — Tue, 01 Mar 2011 07:28:21 +0000

For the last week the news that Nokia has chosen Windows Phone 7 as their main operating system for all their new smart phones has been all over the news. A lot of people are very upset and say that Nokia should have gone with Android instead, or that they should have invested more in their own linux os Meego. Personally, looking at the options Nokia had, I think this is might be the best move Nokia could have done. Let me explain why.

For years Nokia has been struggling keeping Symbian alive. Symbian is an old operating system and has well served it purpose in millions of Nokia phones. However, during the last few years Nokia has totally failed on innovating, pretty much every other vendor now have smart phones running Andriod that offers more features and a better user experience then what Nokia can offer. Nokia needed to make a drastic change and the choices at this time were not that many.

Meego
Android
Windows Phone 7

Meego is Nokias in house developed linux based operating system. The vision behind Meego is great, but development has been too slow. From what I have seen of Meego it is a great operating system if you want to customize and geek around with your phone, but it is not yet ready for prime time. Another problem with Meego is that it is lacking an ecosystem of applications and developers (such as App store for IPhone or Android Market). Placing the bet on Meego would have been extremely risky and Nokia knows this.

Android seemed like the most obvious choice for Nokia. This is what most other vendors are offering and there is a big ecosystem around Android. The problem with it is Nokias limited way of differentiating themselves, they do not just want to become another “Android vendor”. Sure there are several ways they could have differentiated themselves on Android, just like HTC and Samsung are trying to do, but it seems like this was not enough for Nokia.

Windows Phone 7 was released at MWC in 2010 and is a totally new operating system from Microsoft. It is based on Windows Embedded Compact 7 with a new UI layer called Metro. It does not inherit anything from the horrible mess that was Windows Mobile 6. The deal Nokia made with Microsoft gives Nokia ‘special privileges’ to WP7, that other manufactures do not get. It is not clear yet exactly what this means, but what is clear is that this will make Nokia the main WP7 vendor on the market, clearly better than being just another Android vendor.

So will it be successful? Time will tell, but Microsoft has put a lot of money into WP7 and will not let it fail. At the same time Nokia has a reach that no other cell phone vendor has (they are still the by far biggest manufacturer of phones in the world), so if they are able to successfully build an application ecosystem around WP7 I think it will be a success and we will get a mobile space with three main players, Apple iOS, Android and WP7. Competition is good and vendors need other choices than Android for their phones (iOS is apple only, so in a way it does not play the same game).

For C# developers, such as my self, i think getting full backing from Nokia is good news. I would love to develop applications on the Windows Phone 7 platform. From what I have seen from the tools it integrates very well with Visual Studio and seems to be a lot of fun to work with. Maybe now is the time to start learning it?