Develop Reference

Dropbox always asking permission (OAuth)

I'm implementing Dropbox access into my .NET application
I have a question about the token system by OAuth 2 from Dropbox.
The steps I followed to successfully getting data from Dropbox
ClientSecret and ClientId are given ofc
1. Authorize: by calling https://www.dropbox.com/1/oauth2/authorize
2. Verify the code by Request.QueryString("code")
3. Getting Account info with the response see below:
Getting Account info
var client = new HttpClient()
{
BaseAddress = new Uri("https://api.dropbox.com")
};
client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", token);
var response = await client.GetAsync("/1/account/info");
var AccountData = JsonConvert.DeserializeObject<DropBoxAccountData>(await response.Content.ReadAsStringAsync());
//Note: DropBoxAccountData is my custom class.
// The Token is also given don't show the code just the querystring["code"]
// that dropbox return by youre redirect_uri
Everything works fine so far.
The first step every time a user access my webpage it needs to be verified by his/her Dropbox account to allow permission from my Dropbox app.
The second time it needs to be know by the application using MSSQL Database or just session for example.
But it looks like it always expires?
Please is there someone that can point me into the right direction.

Once you have the access token ("token" in your code above), you just need to save it. It sounds like you're building a web app, so yes, you would typically store this in the user's session or perhaps associated with the user in a database, if you have such a thing.

Authenticating App with OAuth from C#

I am writing an app that will talk with Salesforce. Salesforce provides access to APIs via OAuth. I've been attempting to go through the OAuth authentication process described here. Currently, I'm attempting to authorize my app. I have the following code.
// Ask Salesforce for a request token
var request = (HttpWebRequest)(WebRequest.Create(String.Format("https://login.salesforce.com/services/oauth2/authorize?response_type=code&client_id={0}&redirect_uri=http://localhost:5004/home/AuthCallback", CONSUMER_KEY)));
request.Method = "POST";
request.ContentType = "application/json";
// Retrieve the request token from the response
var response = (HttpWebResponse)(request.GetResponse());
using (StreamReader reader = new StreamReader(response.GetResponseStream()))
{
string accessCodeData = accessCodeReader.ReadToEnd();
}
This code is triggered when a user clicks a button in my ASP.NET MVC view. When executed, this code calls to Salesforce. I see a request in fiddler. The request header looks like this:
POST /services/oauth2/authorize?response_type=code&client_id={consumerKey}&redirect_uri=http://localhost:5004/home/AuthCallback HTTP/1.1
I am in fact passing my consumer key, I'm just removing it from the example. Regardless, this request returns a 302, with a body size of 0. I might be misunderstanding something. However, I was expecting to get a request token. I was then going to use the request token to get the access token.
What am I doing wrong?

You are misusing the API.
Take a closer look at the sequence diagram at their page (under Obtaining an Access Token): in the auhorization_code flow you are supposed to redirect the browser to their page so that the user sees the login page, provides his/her credentials and you get the token back. Instead, you are trying to POST there using a web request from your server.
This particular flow belongs then to the passive flows group, this group is intended to be used in browser apps, your server redirects the browser to their server and you basically get the response to the uri passed in the redirect_uri parameter and this should point back to your application at your server.
There are other flows, of them one is suited for non-browser apps, it is called resource owner password flow. In this flow it is your application that hosts the login UI and you send the username/password to the authorization server and you get the token back. It is to be read in their docs however whether this flow is supported.
Read more here: http://aaronparecki.com/articles/2012/07/29/1/oauth2-simplified
Take a look how I handle the OAuth2 flow to Google, using the DotNetOpenAuth library. This is a direct solution, applying it to any other provider should be straightforward.
http://www.wiktorzychla.com/2014/11/simple-oauth2-federated-authentication.html

Still no solution how to simple post a Facebook wall

I need to post a message from my personal website to the website´s facebook wall page. I dont want the user to authenticate against facebook, instead a default website account should be used(probably the facebook app).
This is what I have :
Created facebook App at https://developers.facebook.com
Add Facebook.dll to my ASP.NET webform site(the personal site)
Included the following code :
FacebookClient client = new FacebookClient();
result = client.Get("oauth/access_token", new
{
client_id = ConfigurationManager.AppSettings["FacebookAppId"],
client_secret = ConfigurationManager.AppSettings["FacebookAppSecret"],
grant_type = "client_credentials"
});
client.AccessToken = result.access_token;
result = client.Post("1418771281723422/feed", new { message = "Test Message from app" });
result = client.Get("1418771281723422");
This returns the following exception on client.Post
A first chance exception of type 'Facebook.FacebookOAuthException'
occurred in Facebook.dll
Additional information: (OAuthException - #200) (#200) The user hasn't
authorized the application to perform this action
What am I doing wrong and why is it so hard to do this simple task?

Of course you need to authorize a User to post on Facebook - else it would be incredibly easy to create a spam App.
What you need is a Page Access Token, take a look at the Facebook docs about the different Tokens and how to get them: https://developers.facebook.com/docs/facebook-login/access-tokens
More information about Access Tokens: http://www.devils-heaven.com/facebook-access-tokens/
The code is in PHP, but the text is valid for every language anyway.
This is how to generate an Extended Page Token with PHP: http://www.devils-heaven.com/extended-page-access-tokens-curl/
An Extended Page Token may be exactly what you need, it is valid forever and you can post "as Page" with it.
Doing this with ASP.NET should be pretty similar, but you don´t really need that Facebook SDK if you take a look at the tutorial for extending a Page Token with CURL. This question may help you: curl Request with ASP.NET
To create an Extended Page Token only for yourself, i suggest creating it without any coding:
Use the Graph API Explorer to create a User Access Token with your App.
Extend the User Access Token: https://graph.facebook.com/oauth/access_token?grant_type=fb_exchange_token&client_id=[app-id]&client_secret=[app-secret]&fb_exchange_token=[short-lived-token]
Put that resulting User Token in the "Access Token" field of the Graph API Explorer
Make a call to /me/accounts to get a list of all your Facebook Pages
Take the Access Token of your Page and use it in a server side call for posting
It´s explained in this article: http://www.devils-heaven.com/facebook-access-tokens/

How can I download HTML content of Facebook about pages

I have developed an application to download user names and Ids from face book graph API. But I cannot get their public information like birthdays.
So my approach is to download HTML of about pages and read Birthday from that.
my code follows; I developed my application in MVC4:
public ActionResult ExternalLoginCallback(string returnUrl)
{
AuthenticationResult result = OAuthWebSecurity.VerifyAuthentication(Url.Action("ExternalLoginCallback", new { ReturnUrl = returnUrl }));
if (!result.IsSuccessful)
{
return RedirectToAction("ExternalLoginFailure");
}
if (result.ExtraData.Keys.Contains("accesstoken"))
{
Session["facebooktoken1"] = result.ExtraData["accesstoken"];
string fbToken = result.ExtraData["accesstoken"];
ViewBag.TokenToview = fbToken;
ViewBag.Id = 5;
WebRequest myWebRequest = WebRequest.Create("https://www.facebook.com/amila.u.abeyrathne/about");
WebResponse myWebResponse = myWebRequest.GetResponse();
Stream ReceiveStream = myWebResponse.GetResponseStream();
Encoding encode = System.Text.Encoding.GetEncoding("utf-8");
StreamReader readStream = new StreamReader(ReceiveStream, encode);
string strResponse = readStream.ReadToEnd();
}
When I use this I only get html of LOG IN page of facebook. How can I use my facebook login session in this application?

To get information like this, you'd need to hit Facebook Graph API endpoints like mentioned here
. You'd need an access token gneerated with the necessary permissions as specified here in order to submit a working request. I'm assuming the access token you're using in this code is generated by querying OAuth in the specified manner.

It is not possible to get those information from facebook graph Search.The solution is to develop application that can log in to facebook and scrap the HTML of the facebook wall of each user whom userids have being downloaded. After scraping the HTML read the text from htlm is the solution. But it is not that much accurate. Birthdays and other information in the about page is not possible to read on that way either because there is no way to navigate to the about page in that way.

Ur application session data cannot be read by facebook API, so need to send the token in subsequent requests.
Getting FB Page data from facebook using C#

I think your approach is wrong. when you log in to a website it is created session cookie in client browser. Then it append to each request header when send request to that web site again. session cookie created on client browser not the server.
What you are doing is you send request to facebook from your server not from the client. Then there is no valid session cookie append to your request.
If you what to go this way you have to read the facebook page using javascript. But it is not the recommended way.
You need to crate facebook app for your website.
Then need to Select permissions to request from users. (for your case use user_birthday )
Then authenticate your website using that app. Then you can get what ever the details that you want using graph api if users gave permission.

facebook c# sdk getting started

I would like to write a console application that automatically posts information to my wall once every morning.
I have signed up for facebook developer and have a AppID and App Secret
I have been trying to play with the C# facebook SDK and looked through several examples.
Seems like the examples get a user token - but have to use a browser that is in windows forms. This is an automated process - so I dont want to have a user present.
Ive also created some examples using the application token - but it does not seem to be able to write to the wall.
I wrote the Twitter equivalent very quickly. I must be missing something here ???
What is the proper way to proceed?
It seems that all I should need to is:
FaceBookClient(appID, appSecret)
and then just
FaceBookClient.Put(message)
???
clarification added:
Playing with the C# facebook sdk winform application
I had to change their FacebookLoginDialog.cs to use the folling URL:
https://graph.facebook.com/oauth/access_token?grant_type=client_credentials&client_id=APPID&client_secret=APPSECRET&scope=user_about_me,publish_stream,offline_access
which returns an accesskey in WebBrowser.DocumentText
If I then call:
var fb = new FacebookClient(_accessToken);
dynamic parameters = new ExpandoObject();
parameters.message = "Hello World!";
dynamic result = fb.Post("me/feed", parameters);
I get the exception:
(OAuthException) An active access token must be used to query information about the current user.
If I change the code above to NOT use that access token - but use the appID and Appsecret:
FacebookClient myFacebookClient = new FacebookClient("APPID", "APPSECRET");
dynamic parameters = new ExpandoObject();
parameters.message = "Hello World!";
dynamic result = myFacebookClient.Post("me/feed", parameters);
Then I get the exception:
(OAuthException) An active access token must be used to query information about the current user.
I guess it is the same exception

Here is what I found.
Download the facebook C# sdk source code and samples from http://facebooksdk.codeplex.com/
Unzip the code and load into Visual Studio the Facebook C# SDK sample called CS-WinForms.
At the top of Form1.cs - enter your application ID
Run the application.
Form1.cs pops up with a button "Login to Facebook". Click the button.
FacebookLoginDialog.cs pops up with a browser window in it displaying facebook asking for permissions.
FacebookLoginDialog.cs creates a browser window that will go to your user on facebook and request permissions. By default those permissions are: user_about_me,publish_stream,offline_access.
Offline_access means the AccessToken you get - never expires
Click "OK" in Facebook to allow the application to access your facebook data.
FacebookLoginDialog.cs should find that you logged in and get the access token that never expires.
The access token is a string.
Insert a break point so that you can copy this access token. Save this access token as you can use it from now on to access to Facebook.
Facebook developers website has some tools that you can use to check the access token
https://developers.facebook.com/tools/debug/access_token
You can enter your access token and click "Debug" and it should list your applicationID, UserID, and for "expires" it should say "never".
Once you have this access token - then you can simply write code like:
var fb = new FacebookClient(AccessToken);
dynamic parameters = new ExpandoObject();
parameters.message = FacebookString;
dynamic result = fb.Post("me/feed", parameters);
var id = result.id;
to post message to Facebook!

You should request offline_access in addition to publish_stream. Once you have the never-expiring token, store that in your app.