At the time of me answering this question, DotNetOpenAuth has a [public Community Tech Preview (CTP) which is available to download][1].

![Pew Pew][2]


 1. Download that source code. Should be a .7z file. You can use [7-Zip to unzip the code][3] if you don&#39;t already have it (it&#39;s free).
 2. Open up the **samples** source code solution in Visual Studio. I&#39;m using VS2010 but I think there&#39;s also a VS2008 solution file.

![More Pew Pew][4]

 3. Now, open up the web.config file for the `OAuthClient` project.
![enter image description here][5]

 4. Next, edit the following settings :-
    
    `&lt;!-- Facebook sign-up: http://developers.facebook.com/setup/ --&gt;`

    `&lt;add key=&quot;facebookAppID&quot; value=&quot;------&quot;/&gt;`

    `&lt;add key=&quot;facebookAppSecret&quot; value=&quot;------------&quot;/&gt;`
     
You can get these values from your [application on Facebook][6].

 5. Debug/Run the OAuthClient Web Application. This will start an instance of Cassini/Visual Studio Developer Server and a web browser should open:

![enter image description here][7]

Voil&#224;! you can now connect to Facebook to log in.

If you get errors, then you need to make sure that:

 1. You&#39;ve manually changed the Facebook app settings in your `web.config` file.
 2. You&#39;ve correctly setup your app settings in the Facebook developer website.

  [1]: http://sourceforge.net/projects/dnoa/files/CTP/OAuth2/
  [2]: http://i.stack.imgur.com/yiSzD.png
  [3]: http://www.7-zip.org/
  [4]: http://i.stack.imgur.com/mm2J4.png
  [5]: http://i.stack.imgur.com/BfbY6.png
  [6]: http://developers.facebook.com/docs/guides/appcenter/
  [7]: http://i.stack.imgur.com/JAjIG.png

I&#39;m currently using:

    XXX.find_or_create_by_uuid(XXXX)

Is there a way to do find or build?

Rails - find or create - is there a find or build?

I read Wikipedia&#39;s explanation of idempotence.
I know it means a function&#39;s output is determined by it&#39;s input.
But I remember that I heard a very similar concept: pure function.
I Google them but can&#39;t find their difference...

Are they equivalent?


Are idempotent functions the same as pure functions?

I&#39;ve pretty much got OpenID working using the [DotNetOpenAuth][1] library. Now I would like users to be able to use **Facebook** and **Twitter** to login. 

This requires `OAuth` so I am looking for a tutorial on how to use DotNetOpenAuth OAuth.

I&#39;m having trouble trying to find some simple tutorials on how to do this. 

Can anyone please help?


  [1]: http://www.dotnetopenauth.net/

Facebook/ Twitter with dotnetopenauth?

I've pretty much got OpenID working using the <a href="http://www.dotnetopenauth.net/" target="_blank" rel="noopener noreferrer">DotNetOpenAuth</a> library. Now I would like users to be able to use Facebook and Twitter to login.
This requires <code>OAuth</code> so I am looking for a tutorial on how to use DotNetOpenAuth OAuth.
I'm having trouble trying to find some simple tutorials on how to do this.
Can anyone please help?

I have to convert Convert Int32 into Guids and this is what I came up with.

    public static class IntExtensions
    {
        public static Guid ToGuid(this Int32 value)
        {
            if (value &gt;= 0) // if value is positive
                return new Guid(string.Format(&quot;00000000-0000-0000-0000-00{0:0000000000}&quot;, value));
            else if (value &gt; Int32.MinValue) // if value is negative
                return new Guid(string.Format(&quot;00000000-0000-0000-0000-01{0:0000000000}&quot;, Math.Abs(value)));
            else //if (value == Int32.MinValue)
                return new Guid(&quot;00000000-0000-0000-0000-012147483648&quot;);  // Because Abs(-12147483648) generates a stack overflow due to being &gt; 12147483647 (Int32.Max)
        }
    }

But it’s somehow ugly. Has anybody a better idea?

Update:

Yes I know the whole thing is ugly but I am a loss of Ideas.
The problem is. I am getting data and have to store it into a Table I cannot change. The sending data primary key is a Int and the table primary key I have to store it is a Guid.
The problem is I have to understand what object the sender is talking about but can only store it as a Guid.

Update 2:

Okay I see I have to provide more info here. I am a Webservice receiving data and have to pass along data to an Interface I also can not control. So I neither can model the data received nor the (Interface)database where I have to send the data. Additionally, I have somehow have to map these two things in a way so I somehow can update an item. *sigh*


Convert Int to Guid

I have a comboBox with all of the months in it.

What I need to know is the number of days in the chosen month.

    var month = cmbMonth.SelectedIndex + 1;
    DateTime date = Convert.ToDateTime(month);

So if a user selects January, I need to save 31 to a variable.

Getting number of days in a month

I want to do this:

    public Name
    {
        get;
        set
        {
            dosomething();
            ??? = value
        }
    }

Is it possible to use the auto-generated private field? 
&lt;br&gt;Or is it required that I implement it this way:

    private string name;
    public string Name
    {
        get
        {
            return name;
        }
        set
        {
            dosomething();
            name = value
        }
    }



C# properties: how to use custom set property without private field?

How do you check that a uri string is valid (that you can feed it to the Uri constructor)?

So far I only have the following but for obvious reasons I&#39;d prefer a less brute way:

        Boolean IsValidUri(String uri)
        {
            try
            {
                new Uri(uri);
                return true;
            }
            catch
            {
                return false;
            }
        }

I tried Uri.IsWellFormedUriString but it doesn&#39;t seem to like everything that you can throw at the constructor. For example:

    String test = @&quot;C:\File.txt&quot;;
    Console.WriteLine(&quot;Uri.IsWellFormedUriString says: {0}&quot;, Uri.IsWellFormedUriString(test, UriKind.RelativeOrAbsolute));
    Console.WriteLine(&quot;IsValidUri says: {0}&quot;, IsValidUri(test));

The output will be:

    Uri.IsWellFormedUriString says: False
    IsValidUri says: True

**Update/Answer**

The Uri constructor uses kind Absolute by default. This was causing a discrepancy when I tried using Uri.TryCreate and the constructor. You do get the expected outcome if you match the UriKind for both the constructor and TryCreate.


How to check that a uri string is valid

Is it possible to change an array size after declaration?
If not, is there any alternative to arrays?  
I do not want to create an array with a size of 1000, but I do not know the size of the array when I&#39;m creating it.

change array size

Why by default were these changed when adding a new &quot;edit&quot; view? What are advantages when using `EditorFor()` vs. `TextboxFor()`?

I found this 

&gt; By default, the Create and Edit  scaffolds now use the Html.EditorFor  helper instead of the Html.TextBoxFor helper. This improves support for  metadata on the model in the form of
 data annotation attributes when the  Add View dialog box generates a view.

[Quoted from here.][1]


  [1]: https://docs.microsoft.com/en-us/aspnet/mvc/mvc3#template-scaffolding-improvements

Differences between Html.TextboxFor and Html.EditorFor in MVC and Razor

Assume this model:  

    Public Class Detail
        ...
        &lt;DisplayName(&quot;Custom DisplayName&quot;)&gt;
        &lt;Required(ErrorMessage:=&quot;Custom ErrorMessage&quot;)&gt;
        Public Property PercentChange As Integer
        ...
    end class

and the view:

    @Html.TextBoxFor(Function(m) m.PercentChange)

will proceed this html:  

       &lt;input data-val=&quot;true&quot; 
        data-val-number=&quot;The field &#39;Custom DisplayName&#39; must be a number.&quot; 
        data-val-required=&quot;Custom ErrorMessage&quot;     
        id=&quot;PercentChange&quot; 
        name=&quot;PercentChange&quot; type=&quot;text&quot; value=&quot;0&quot; /&gt;

I want to customize the `data-val-number` error message which I guess has generated because `PercentChange` is an `Integer`. I was looking for such an attribute to change it, `range` or whatever related does not work.  
I know there is a chance in editing unobtrusive&#39;s js file itself or override it in client side. I want to change `data-val-number`&#39;s error message just like others in server side.



How to change &#39;data-val-number&#39; message validation in MVC while it is generated by @Html helper

I use the HTML Helpers to render my fields:

    &lt;%=Html.EditorFor(m =&gt; m.User.Surname)%&gt;

and the output would be something like this:

    &lt;input class=&quot;text-box single-line&quot; id=&quot;User_Surname&quot; 
              name=&quot;User.Surname&quot; type=&quot;text&quot; value=&quot;&quot; /&gt;

The helper uses the className + &#39;.&#39; &#232; fieldName to build the id.  
I need to pass the id to a jQuery function. Is there a way to have it without hardcoding it?
Maybe an helper which can use the ASP.NET MVC2 conventions?


How to get the HTML id generated by asp.net MVC EditorFor

How do I add `data-*` html attributes using TextboxFor?

This is what I currently have:

    @Html.TextBoxFor(model =&gt; model.Country.CountryName, new { data-url= Url.Action(&quot;CountryContains&quot;, &quot;Geo&quot;) })

As you see, the `-` is causing a problem here `data-url`. Whats the way around this?

Html5 data-* with asp.net mvc TextboxFor html attributes

Using a FileStreamResult in ASP.NET MVC 3, I get a response header like

    X-SourceFiles =?UTF-8?B?RDpcUHJvamVjdFxqYWNvYlx0ZXN0?=

Anyone knows what this header means, and what&#39;s its purpose?

What does the X-SourceFiles header do?

I am building an [`OAuth 1.0(a)`][1] authorization server using [`DotNetOpenAuth`][2] (NuGet package `DotNetOpenAuth.OAuth.ServiceProvider, version = 4.1.4.12333`). The server is hosted in an ASP.NET application but that&#39;s irrelevant to the question.

My [`ServiceProvider`][3] is configured like this:

    private ServiceProvider GetServiceProvider()
    {
        var baseUri = &quot;http://myauth.com&quot;;
        return new ServiceProvider(
            new ServiceProviderDescription
            {
                UserAuthorizationEndpoint = new MessageReceivingEndpoint(
                    new Uri(baseUri + &quot;/get_request_token&quot;), 
                    HttpDeliveryMethods.GetRequest
                ),
                RequestTokenEndpoint = new MessageReceivingEndpoint(
                    new Uri(baseUri + &quot;/authorize&quot;), 
                    HttpDeliveryMethods.PostRequest
                ),
                AccessTokenEndpoint = new MessageReceivingEndpoint(
                    new Uri(baseUri + &quot;/get_token&quot;), 
                    HttpDeliveryMethods.PostRequest
                ),
                ProtocolVersion = ProtocolVersion.V10a,
                TamperProtectionElements = new ITamperProtectionChannelBindingElement[] 
                {
                    new PlaintextSigningBindingElement(),
                    new HmacSha1SigningBindingElement(),
                },
            },
            tokenManager,
            new OAuthServiceProviderMessageFactory(tokenManager)
        );
    }

The relevant part of my `get_request_token` endpoint looks like this:

    var serviceProvider = GetServiceProvider();
    var tokenRequest = serviceProvider.ReadTokenRequest();

Now when a consumer sends the following request to this endpoint:

    GET /get_request_token?oauth_nonce=C5657420BCE5F3224914304376B5334696B09B7FFC17C105A7F9629A008869DC&amp;oauth_timestamp=1356006599&amp;oauth_consumer_key=sampleconsumer&amp;oauth_signature_method=plaintext&amp;oauth_signature=samplesecret%26&amp;oauth_version=1.0&amp;oauth_callback=http%3a%2f%2flocalhost%3a30103%2fCustomOAuth1 HTTP/1.1
    
    Host: localhost:8180
    Connection: close

(broken for clarity):

    oauth_nonce=C5657420BCE5F3224914304376B5334696B09B7FFC17C105A7F9629A008869DC
    oauth_timestamp=1356006599
    oauth_consumer_key=sampleconsumer
    oauth_signature_method=plaintext
    oauth_signature=samplesecret%26
    oauth_version=1.0
    oauth_callback=http%3a%2f%2flocalhost%3a30103%2fCustomOAuth1

The `serviceProvider.ReadTokenRequest()` method throws an exception:

    The UnauthorizedTokenRequest message required protections {All} but the channel could only apply {Expiration, ReplayProtection}.
       at DotNetOpenAuth.Messaging.Channel.ProcessIncomingMessage(IProtocolMessage message)
       at DotNetOpenAuth.Messaging.Channel.ReadFromRequest(HttpRequestBase httpRequest)
       at DotNetOpenAuth.Messaging.Channel.TryReadFromRequest[TRequest](HttpRequestBase httpRequest, TRequest&amp; request)
       at DotNetOpenAuth.OAuth.ServiceProvider.ReadTokenRequest(HttpRequestBase request)
       at DotNetOpenAuth.OAuth.ServiceProvider.ReadTokenRequest()
       at OAuthServers.OAuth1.Services.OAuth1Service.Any(GetRequestTokenRequest request)
       at lambda_method(Closure , Object , Object )
       at ServiceStack.ServiceHost.ServiceRunner`1.Execute(IRequestContext requestContext, Object instance, TRequest request)

On the other hand if the client sends the following request:

    GET /get_request_token?oauth_callback=http%3a%2f%2flocalhost%3a65271%2foauth1%2fHandleAccessToken&amp;oauth_consumer_key=sampleconsumer&amp;oauth_nonce=rGFvxlWm&amp;oauth_signature_method=HMAC-SHA1&amp;oauth_signature=HV%2f5Vq%2b0cF3NrtiISE9k4jmgCrY%3d&amp;oauth_version=1.0&amp;oauth_timestamp=1356007830 HTTP/1.1

    Host: localhost:8180
    Connection: close

(broken for clarity):

    oauth_callback=http%3a%2f%2flocalhost%3a65271%2foauth1%2fHandleAccessToken
    oauth_consumer_key=sampleconsumer
    oauth_nonce=rGFvxlWm
    oauth_signature_method=HMAC-SHA1
    oauth_signature=HV%2f5Vq%2b0cF3NrtiISE9k4jmgCrY%3d
    oauth_version=1.0
    oauth_timestamp=1356007830

it succeeds. 

As you can see the only difference between those 2 requests is the `oauth_signature_method` being used. In the first case `PLAINTEXT` is used whereas in the second `HMAC-SHA1`.

Is it possible to make DotNetOpenAuth accept a `PLAINTEXT` signature method for the request token endpoint along with the GET verb (even if the [`OAuth 1.0(a) specification`][4] recommends POST to be used for this endpoint)? Is there some config option that could *relax* this requirement on the server? 

At the moment modifying the client is not an option for me.


  [1]: http://oauth.net/core/1.0a
  [2]: http://www.dotnetopenauth.net/
  [3]: https://github.com/AArnott/dotnetopenid/blob/master/src/DotNetOpenAuth.OAuth.ServiceProvider/OAuth/ServiceProvider.cs
  [4]: http://oauth.net/core/1.0a/#rfc.section.6.1.1

Content Type	Original Author	Original Content on Stackoverflow
Question	chobo2	View Question on Stackoverflow
Solution 1 - C#	Pure.Krome	View Answer on Stackoverflow

Facebook/ Twitter with dotnetopenauth?

C# Problem Overview

C# Solutions

Solution 1 - C#

Are idempotent functions the same as pure functions?

Rails - find or create - is there a find or build?

Attributions