TheUnical Technologies Blog » VB.Net

Simple 5 Steps to publish on a facebook wall using DotNet C#/ cSharp

Steven Wall — Sun, 07 Mar 2010 07:47:02 +0000

There are many Libraries available for C# and Dotnet to publish on facebook.

According to facebook Wiki posting on a wall is very confusing and very difficult to write a program to publish on a wall.

I spent around 2 weeks reading many articles and many documents, Wiki on facebook but in vein and tried many ways and finally I got one workable model. Below are 5 simple steps to publish on a Facebook wall.

Step1: Login to Facebook

First login to Facebook and goto the url http://www.facebook.com/developers/ then

Click on “+ Set Up New Application” button to start creating the application as shown below.

Provide the application name, click agree for facebook terms and click on “Create Application” button.

Fill in application Name

Now Application is created for you. Just copy the Application API Key, Application Secret and Application ID details which will be used to write the application code.

Now goto Canvas link and enter any url.

Next goto Connect URL link and enter the same url.

Then click on Save. That’s it we have created a facebook application with an Iframe.

Now Copy Application API Key, Application Secret and Application ID details which will be used to write the application code.

Now download any of the available libraries on facebook http://wiki.developers.facebook.com/index.php/User:ASP.NET

(OR)

Microsoft SDK for Facebook Platform, which supports Facebook Connect, FBML and IFrame canvas page applications, and ASP.NET MVC. For issues and discussions about the SDK see the project on Codeplex.

Step2: Generate One Time Session key

How to generate One Time Session key:

Run below URL to get temporary token for the selected user by logging into Facebook.

https://login.facebook.com/code_gen.php?api_key=API_KEY&v=1.0

Note: Please replace “API_KEY” with your application API key from above page.

Then we will get a temporary token key.

This is one time token key that we can use to generate a permanent session key. Careful! Don’t try to execute this programs many times

Step3: Generate one time session key

Below is the sample code to generate one time session key.

For example, the full URL for logging in a user could be:

http://www.facebook.com/login.php?api_key=YOURAPIKEY&connect_display=popup&v=1.0&next=http://www.facebook.com/connect/login_success.html&cancel_url=http://www.facebook.com/connect/login_failure.html&fbconnect=true&return_session=true&session_key_only=true&req_perms=read_stream,publish_stream,offline_access

If the user is redirected to the URL specified by the next parameter, then Facebook grants your application a session. This session is appended to the URL as a JSON-decodable object of the form:

&session={“session_key”:”SESSIONKEY”, “uid”:USERID, “expires”:0 || UNIXTIME, “secret”:”SESSIONSECRET”}

In continuing with the above example, the redirect for a successful login would be:

http://www.facebook.com/connect/login_success.html?session=%7B%22session_key%22%3A%223.kxhAu6W0qo_bLGjmdWrgfw__.86400.1243443600-688626964%22%2C%22uid%22%3A%22688626964%22%2C%22expires%22%3A1243443600%2C%22secret%22%3A%220NVNMxpO6jVyDcVCvVv_PA__%22%2C%22sig%22%3A%22ac1c0c77c137567389defea70481b7aa%22%7D

If the user grants your application the offline_access extended permission, 0 gets returned for expires and the session never expires unless the user removes the application. In this case, you should store the session key so the user doesn’t have to log in the next time he or she launches your application.

Once the browser has been redirected successfully and you have your session information, you should automatically close the browser window.
Note: The above code will execute only once. We should note down the above session key, This will be used to auto login into the application.

If you don’t save these session key values you should generate other token key to create one time session key.

Step4:

Giving Permission to your application to publish on facebook wall. To give permission just replace the your API key in below URL and execute in browser.

http://www.facebook.com/login.php?api_key=APIKEYXxxxxxxxxxxxxxxxxx&connect_display=popup&v=1.0&next=http://www.facebook.com/connect/login_success.html&cancel_url=http://www.facebook.com/connect/login_failure.html&fbconnect=true&return_session=true&req_perms=read_stream,publish_stream,offline_access

Then you must see the below 3 Screens

If you don’t see the below then your call back URL or Canvas URL must be incorrect, please check again your application settings and execute the URL again.

Then on final page, you will see a success message. That’s it you have given permission for read_stream,publish_stream and offline_access.

Step5: Publishing the message with Image and link on Facebook Wall using cSharp/ C#

Publishing a Post With Image and Action Link in C# using facebook developer toolkit v2

C# Code to create facebook object with onetime session key and publishing the message on Facebook Wall.

public void Post(facebook.API fbAPI, string appLink)
{
 string response = fbAPI.stream.publish( "publish steven on facebook.",
new attachment() {
name = "I am a good guy !", href = appLink, caption = "{*actor*} Steven Publish on facebook wall",
description = "Helping other people, I became a new good guy.", properties = null,
 media = new List() { new attachment_media_image()
{ src = "http://blog.theunical.com/wp-content/uploads/2009/11/start-application.jpg", href = appLink } } },
new List() { new action_link() { text = "Become a good guy",
 href = appLink } }, null, 0);
}

Now you will see the post on wall Great.

So thrilling isn’t we can also publish photos videos on wall.

http://wiki.developers.facebook.com/index.php/Stream.publish

have a great day

– Steven

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