Get access token to facebook page - WPF - c#

I am developing a WPF application that needs post on wall of a facebook's Page, and this without login window.
Well, I want to get access token for my facebook page, and this is my code.
var fb = new FacebookClient();
string token = "";
dynamic accounts = fb.Get("/"<USER_ID>"/accounts");
foreach (dynamic account in accounts)
{
if (account.id == <PAGE_ID>)
{
token = account.access_token;
break;
}
}
But I receive a error #104. It is a simple error, that I need a access token to do this operation.
Then I use other code to get the user access token
var fb = new FacebookClient();
dynamic result = fb.Get("oauth/access_token", new
{
client_id = <PAGE_ID>,
client_secret = <APP_SECRET>,
grant_type = "fb_exchange_token",
fb_exchange_token = <USER_TOKEN>
});
But I get error #101:
"Error validating application. Cannot get application info due to a system error."
Someone knows what I have to do?
Thanks!!!

I'm not sure if you've been able to get a never expiring token for the page, so I'll explain you the steps:
Open Graph API Explorer
Select your app from the drop-down
Click "Get Access Token" button, and select the manage_pages permission.
Copy the token and run this in the browser:
https://graph.facebook.com/oauth/access_token?grant_type=fb_exchange_token&client_id={app-id}&client_secret={app-secret}&fb_exchange_token={step-3-token}
Copy the token from step-4 and paste in to the access_token field and call:
/{page-id}?fields=access_token
The token you get now is a never-expiring token, you can validate the same in Debugger .Use this in your app.
But beware, its not recommended to use this token on client side if your app is public.

If you use the fb_exchange_token call, it will give you a token that expires after 60 days. In order to make it work correctly, I had to go through the login web flow to guarantee I got an up-to-date page access token.
Go to the Facebook App dashboard
If you haven't already added the Facebook Login product, click "+ Add Product" and select Facebook Login
Enable the "embedded browser control" option and enter https://www.facebook.com/connect/login_success.html as the allowed redirect URL.
Make a Window with a WebView control on it. The WebBrowser control no longer works; the browser engine powering it is too old.
Add code to listen for the navigation to the success URL:
this.webView.NavigationCompleted += (sender, args) =>
{
if (args.Uri.AbsolutePath == "/connect/login_success.html")
{
if (args.Uri.Query.Contains("error"))
{
MessageBox.Show("Error logging in.");
}
else
{
string fragment = args.Uri.Fragment;
var collection = HttpUtility.ParseQueryString(fragment.Substring(1));
string token = collection["access_token"];
// Save the token somewhere to give back to your code
}
this.Close();
}
};
Add code to navigate to the facebook login URL:
string returnUrl = WebUtility.UrlEncode("https://www.facebook.com/connect/login_success.html");
this.webView.Source = new Uri($"https://www.facebook.com/dialog/oauth?client_id={appId}&redirect_uri={returnUrl}&response_type=token%2Cgranted_scopes&scope=manage_pages&display=popup");
Call window.ShowDialog() to pop up the login window, then grab the user access token.
Create some models to help you out:
public class AccountsResult
{
public List<Account> data { get; set; }
}
public class Account
{
public string access_token { get; set; }
public string id { get; set; }
}
Using the user access token, get the page access token:
FacebookClient userFacebookClient = new FacebookClient(userAccessToken);
var accountsResult = await userFacebookClient.GetTaskAsync<AccountsResult>("/me/accounts");
string pageAccessToken = accountsResult.data.FirstOrDefault(account => account.id == PageId)?.access_token;
if (pageAccessToken == null)
{
MessageBox.Show("Could not find page under user accounts.");
}
else
{
FacebookClient pageFacebookClient = new FacebookClient(pageAccessToken);
// Use pageFacebookClient here
}

Related

Authorization from C# with auth2 and linkedin

I have a WebApi that I want to authorize my user with his linkedin information (as in create an access token and inject it in to my owin).
So far I have tried to work with Sparkle.Linkedin and this is what I have
public LinkedInLogic() {
// create a configuration object
_config = new LinkedInApiConfiguration(ApiKey, ApiSecret);
// get the APIs client
_api = new LinkedInApi(_config);
}
public Uri GetAuthUrl() {
var scope = AuthorizationScope.ReadBasicProfile;
var state = Guid.NewGuid().ToString();
var redirectUrl = "http://localhost:1510/api/login/RedirectAuth";
return _api.OAuth2.GetAuthorizationUrl(scope, state, redirectUrl);
}
public void GetAccessToken(string code) {
//If I do api.GetAccessToken(code); here I get an access token
var request = System.Net.WebRequest.Create("http://localhost:1510/api/token?grant_type=authorization_code&code=" + code);
request.GetResponse(); // my owin authorization
}
So I first get the Authorization Url -> it opens a popup -> I enter my data and it goes back to a controller which fires up GetAccessToken.
Problem is even if I completely authorize with linkedin I am not sure how to authorize with my own webapi. So I tried to send an http request to my owin token giver but it doesn't like it. There is also doesn't seem to be anyway I can return the access token back to the user so he can use it in his session.
Any ideas?
Not too sure if the sparkle is working anymore since the changes that where made by Linkedin on May 2015

Implementing External Authentication for Mobile App in ASP.NET WebApi 2

I'm trying to build an API (using ASP.NET WebApi) that will be consumed by a native mobile app for a school project. (I'm not concerned about/developing the mobile app, this responsibility falls on a different member)
I'm at a point where I need to implement a token based Facebook login. There are a lot of tutorials available for how to implement this feature for browser based apps (this is pretty straight forward and most of it comes inbuilt), but I don't think I follow how this would work with native apps. What I don't understand is how the redirects would work?
According to this link, nothing needs to be handled specifically by my server. And I don't think I understand how this would work? How would the tokens from Facebook be handled?
Also, what part of token handling should I implement, I couldn't really find good documentation for WebApi external login authentication.
Anyway, if someone could point me to the exact flow of token exchanges that happen and what is implemented by default by ASP.NET, that would be super helpful.
Also, the biggest point of confusion for me is I don't understand how the token returned by Facebook will be handled.
I assume the token will be returned to the client (mobile app), how do I get access to it on my server?
How do I create a local token from facebook's token?
Is this all done internally/auto-magically by ASP.NET?
I'm sorry if this is something I should've been able to figure out. I did do quite a bit of research and I found myself drowning in (related & unrelated) information. I don't think I even know how to search for the information I need.
Some links I've read:
Claims And Token Based Authentication (ASP.NET Web API)
Token Based Authentication using ASP.NET Web API 2, Owin, and Identity
ASP.NET Web API 2 external logins with Facebook and Google in AngularJS app
I had to do pretty much the same thing for an application I was working on. I also had a lot of trouble finding information about it. It seemed like everything I found was close to what I needed, but not exactly the solution. I ended up taking bits and pieces from a bunch of different blog posts, articles, etc. and putting them all together to get it to work.
I remember two of the links you posted "Claims and Token Based Authentication" and "ASP.NET Web API 2 external logins with Facebook and Google in AngularJS app" as being ones that had useful information.
I can't give you a comprehensive answer since I don't remember everything I had to do, nor did I even understand everything I was doing at the time, but I can give you the general idea. You are on the right track.
Essentially I ended up using the token granted by Facebook to confirm that they were logged into their Facebook account, created a user based on their Facebook user ID, and granted them my own bearer token that they could use to access my API.
The flow looks something like this:
Client authenticates with Facebook via whatever method (we used oauth.io)
Facebook returns them a token
Client sends token information to the registration endpoint of my WebApi controller
The token is validated using Facebook's Graph API, which returns user info
A user is created in the database via ASP.NET Identity with their Facebook user ID as the key
Client sends token information to the authentication endpoint of my WebApi controller
The token is validated using Facebook's Graph API, which returns user info
The user info is used to look up the user in the database, confirm they have previously registered
ASP.NET Identity is used to generate a new token for that user
That token is returned to the client
Client includes an Authorization header in all future HTTP requests with the new token granted by my service (ex. "Authorization: Bearer TOKEN")
If the WebApi endpoint has the [Authorize] attribute, ASP.NET Identity will automatically validate the bearer token and refuse access if it is not valid
There ended up being a lot of custom code for implementing the OAuth stuff with ASP.NET Identity, and those links you included show you some of that. Hopefully this information will help you a little bit, sorry I couldn't help more.
I followed this article. The flow is basically this
The server has the facebook keys just like with web login
The app asks for available social logins and displays buttons (you can hardcode this I guess)
When a button is pressed the app opens a browser and sets the URL to the one related to the specified social login. The ASP.NET then redirects the browser to facebook/google/whatever with the appropriate Challenge
The user might be logged in or not and might have given permission to your app or not. After he gives the permissions facebook redirects back to the provided callback URL
At that point you can get the external login info from the SignInManager and check if the user already exists and if you should create a new account
Finally a token is generated and the browser is redirected to a URL in which the token is placed. The app gets the token from the URL and closes the browser. Uses the token to proceed with API requests.
Honestly I have no idea if this approach is legit...
The code of the action buttons should redirect to:
public async Task<IEnumerable<ExternalLoginDto>> GetExternalLogins(string returnUrl, bool generateState = false)
{
IEnumerable<AuthenticationScheme> loginProviders = await SignInManager.GetExternalAuthenticationSchemesAsync();
var logins = new List<ExternalLoginDto>();
string state;
if (generateState)
{
const int strengthInBits = 256;
state = RandomOAuthStateGenerator.Generate(strengthInBits);
}
else
{
state = null;
}
foreach (AuthenticationScheme authenticationScheme in loginProviders)
{
var routeValues = new
{
provider = authenticationScheme.Name,
response_type = "token",
client_id = Configuration["Jwt:Issuer"],
redirect_uri = $"{Request.Scheme}//{Request.Host}{returnUrl}",
state = state
};
var login = new ExternalLoginDto
{
Name = authenticationScheme.DisplayName,
Url = Url.RouteUrl("ExternalLogin", routeValues),
State = state
};
logins.Add(login);
}
return logins;
}
The code for the callback action:
[Authorize(AuthenticationSchemes = "Identity.External")]
[Route("ExternalLogin", Name = "ExternalLogin")]
public async Task<IActionResult> GetExternalLogin(string provider, string state = null, string client_id = null, string error = null)
{
if (error != null)
{
ThrowBadRequest(error);
}
if (!User.Identity.IsAuthenticated)
{
return new ChallengeResult(provider);
}
string providerKey = User.FindFirstValue(ClaimTypes.NameIdentifier);
var externalLoginInfo = new ExternalLoginInfo(User, User.Identity.AuthenticationType, providerKey, User.Identity.AuthenticationType);
if (externalLoginInfo.LoginProvider != provider)
{
await HttpContext.SignOutAsync(IdentityConstants.ExternalScheme);
return new ChallengeResult(provider);
}
var userLoginInfo = new UserLoginInfo(externalLoginInfo.LoginProvider, externalLoginInfo.ProviderKey, externalLoginInfo.ProviderDisplayName);
User user = await UserManager.FindByLoginAsync(externalLoginInfo.LoginProvider, externalLoginInfo.ProviderKey);
if (client_id != Configuration["Jwt:Issuer"])
{
return Redirect($"/#error=invalid_client_id_{client_id}");
}
if (user != null)
{
return await LoginWithLocalUser(user, state);
}
else
{
string email = null;
string firstName = null;
string lastName = null;
IEnumerable<Claim> claims = externalLoginInfo.Principal.Claims;
if (externalLoginInfo.LoginProvider == "Google")
{
email = claims.FirstOrDefault(c => c.Type == ClaimTypes.Email)?.Value;
firstName = claims.FirstOrDefault(c => c.Type == ClaimTypes.GivenName)?.Value;
lastName = claims.FirstOrDefault(c => c.Type == ClaimTypes.Surname)?.Value;
}
else if (externalLoginInfo.LoginProvider == "Facebook")
{
email = claims.FirstOrDefault(c => c.Type == ClaimTypes.Email)?.Value;
string[] nameParts = claims.First(c => c.Type == ClaimTypes.Name)?.Value.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
firstName = nameParts?.First();
lastName = nameParts?.Last();
}
//some fallback just in case
firstName ??= externalLoginInfo.Principal.Identity.Name;
lastName ??= externalLoginInfo.Principal.Identity.Name;
user = new User
{
UserName = email,
Email = email,
FirstName = firstName,
LastName = lastName,
EmailConfirmed = true //if the user logs in with Facebook consider the e-mail confirmed
};
IdentityResult userCreationResult = await UserManager.CreateAsync(user);
if (userCreationResult.Succeeded)
{
userCreationResult = await UserManager.AddLoginAsync(user, userLoginInfo);
if (userCreationResult.Succeeded)
{
return await LoginWithLocalUser(user, state);
}
}
string identityErrrors = String.Join(" ", userCreationResult.Errors.Select(ie => ie.Description));
Logger.LogWarning($"Error registering user with external login. Email:{email}, Errors:" + Environment.NewLine + identityErrrors);
return Redirect($"/#error={identityErrrors}");
}
}
private async Task<RedirectResult> LoginWithLocalUser(User user, string state)
{
await HttpContext.SignOutAsync(IdentityConstants.ExternalScheme);
DateTime expirationDate = DateTime.UtcNow.AddDays(365);
string token = user.GenerateJwtToken(Configuration["Jwt:Key"], Configuration["Jwt:Issuer"], expirationDate);
return Redirect($"/#access_token={token}&token_type=bearer&expires_in={(int)(expirationDate - DateTime.UtcNow).TotalSeconds}&state={state}");
}

How to check logged in facebook user in ASP.NET MVC 4?

I want to check if a user is already logged in with facebook in ASP.NET MVC4. I'm using Facebook C# SDK.
I have this code for getting the access_token from facebook:
public ActionResult FacebookCallback(string code)
{
var fb = new FacebookClient();
dynamic result = fb.Post("oauth/access_token", new
{
client_id = "XXXXXXXXXXXXXX",
client_secret = "XXXXXXXXXXXXXXXXXXX",
redirect_uri = RedirectUri.AbsoluteUri,
code = code
});
var accessToken = result.access_token;
Session["AccessToken"] = accessToken;
fb.AccessToken = accessToken;
dynamic me = fb.Get("me?fields=first_name,last_name,id,email");
string email = me.email;
FormsAuthentication.SetAuthCookie(email, false);
return RedirectToAction("Index", "Home");
}
I don't know how to check if user is already logged in. Please help.
The most easiest way in my opinion if your willing to checkout Facebooks javascript SDK, then there is a FB.getLoginStatus method which will give you the info you need.
Taken from facebook's dev site:
FB.getLoginStatus(function(response) {
if (response.status === 'connected') {
// the user is logged in and has authenticated your
// app, and response.authResponse supplies
// the user's ID, a valid access token, a signed
// request, and the time the access token
// and signed request each expire
var uid = response.authResponse.userID;
var accessToken = response.authResponse.accessToken;
} else if (response.status === 'not_authorized') {
// the user is logged in to Facebook,
// but has not authenticated your app
} else {
// the user isn't logged in to Facebook.
}
});
There is also the user_online_presence extended permission here. Probably not what you want, but using FQL, you can request the online_presence field here, but note this only returns if the user is logged into facebook user chat.

How to login to Instagram from codebehind?

I need to show images of a specific instagram user on my webpage.
As stated in the Instagram API documentation I need to get authenticated to be able to "browse" a user's feed.
"We only require authentication in cases where your application is making requests on behalf of a user (commenting, liking, browsing a user’s feed, etc.)."
(http://instagram.com/developer/authentication/)
So as stated in the API documentation, I send a request to this URL:
https://instagram.com/oauth/authorize/?display=touch&client_id=[ClientID]
&redirect_uri=[callbackuri]/&response_type=token
to be redirected to another URL: http://your_redirect_uri?code=CODE to be able to get the access_token (CODE) to be able to call the instagram RESTful services with it.
The problem is that if my website visitor is not logged in to Instagram, he/she will be forwarded to a login page to authenticate first and only then I can get an access token.
My question is: how can I bypass this login page by automatically login with my application's instagram account from the codebehind (or probably by javascript!)?
I am using C# and Instasharp(http://instasharp.org/) by the way.
Any ideas?
Thank you in advance!
first of create Developer app in Instagram and get consumerkey & consumersecret and set path call back url somthing link http://localhost:3104/Instagram.aspx
private void Authentication()
{
string rest = string.Empty;
GlobusInstagramLib.Authentication.ConfigurationIns config = new GlobusInstagramLib.Authentication.ConfigurationIns("https://instagram.com/oauth/authorize/", ConfigurationManager.AppSettings["consumerKey"], ConfigurationManager.AppSettings["consumerSecret"], ConfigurationManager.AppSettings["callbackurl"], "https://api.instagram.com/oauth/access_token", "https://api.instagram.com/v1/", "");
oAuthInstagram _api = oAuthInstagram.GetInstance(config);
rest = _api.AuthGetUrl("likes+comments+basic+relationships");
Response.Redirect(rest);
}
Automatic redirect on this page and call this code
public void Instagram()
{
string code = (String)Request.QueryString["code"];
oAuthInstagram objInsta = new oAuthInstagram();
GlobusInstagramLib.Authentication.ConfigurationIns configi = new GlobusInstagramLib.Authentication.ConfigurationIns("https://api.instagram.com/oauth/authorize/", ConfigurationManager.AppSettings["consumerKey"], ConfigurationManager.AppSettings["consumerSecret"], ConfigurationManager.AppSettings["callbackurl"], "http://api.instagram.com/oauth/access_token", "https://api.instagram.com/v1/", "");
oAuthInstagram _api = new oAuthInstagram();
_api = oAuthInstagram.GetInstance(configi);
AccessToken access = new AccessToken();
access = _api.AuthGetAccessToken(code);
string accessToken = access.access_token;
string id =access.user.id;
}
you will get token and user id

C#: Get a user access token

I'm developing a desktop application in C#.
After visiting https://www.facebook.com/dialog/oauth?client_id=123 the user logs in and the user access token is attached to the redirect uri. Its no problem, when the loginpage is displayed in a webbrowser control in my form, so i can extract the token from the url.
But this is not the way i want to get the token. My question is, is there a way to obtain the freshly created token via an Graph API call?
Because i want to display the login page in the user's standard browser and not in this embedded webbrowser. All my efforts to get the user access token have been resulted in getting the app access token, which is useless in this case.
Any hints are appreciated.
// This is very raw, And Note it is a MVC3 solution, but it is in C# and I hope it helps.
// It is basically a C# version of the PHP example on FB for 'Server Side Flow'
// I have been at it for a while and had to go through some pain
// Please note the bug I read about that states the redirect_uri must be the same for both //requests
// Also read that someone had an issue if the redirect_uri did not end in '/'
// Post back if you hae any ?s as I am just starting this project and am going to try and //incorporate the C# FaceBook SDK
public class AccountController : Controller
{
// LoginWithFaceBook
// First Contact with FB - oauth?client_id ... redirect_uri = /Account/FacebookLinker
// according to a bug files on FB redirect_uri MUST BE SAME FOR both trips ( to get the 'code' then exchange the code for 'access_token'
public ActionResult ConnectFaceBookAccount()
{
string APP_ID = HttpContext.Application["FacebookAppId"].ToString();
string redirect_uri = HttpContext.Application["FacebookOAuthRedirect"].ToString();
string state = HttpContext.Application["state_guid"].ToString();
// in this View I simply link to this URL
ViewBag.FaceBookOAuthUrl = "https://www.facebook.com/dialog/oauth?client_id=" + APP_ID + "&redirect_uri="+redirect_uri+"&state=" + state+"&display=popup";
return View();
}
// Account/FacebookLinker
// redirect_uri for both getting 'code' and exchanging for 'access_token'
public ActionResult FacebookLinker()
{
if (!Request.IsAuthenticated)
{
Response.Redirect("/Account/LogOn");
}
// Per FB DOC, Make sure 'state' var returned is same one you sent to reduce chance of Cross Site Forgery
if (Request.QueryString["state"].ToString() == HttpContext.Application["state_guid"].ToString())
{
try
{
string FBcode = Request.QueryString["code"].ToString();
string APP_ID = HttpContext.Application["FacebookAppId"].ToString();
string APP_SECRET = HttpContext.Application["FacebookAppSecret"].ToString();
string redirect_uri = HttpContext.Application["FacebookOAuthRedirect"].ToString();
string FBAccessUrl = "https://graph.facebook.com/oauth/access_token?client_id=" + APP_ID + "&redirect_uri=" + redirect_uri + "&client_secret=" + APP_SECRET + "&code=" + FBcode;
string accessToken = null;
// Send the request to exchange the code for access_token
var accessTokenRequest = System.Net.HttpWebRequest.Create(FBAccessUrl);
HttpWebResponse response = (HttpWebResponse) accessTokenRequest.GetResponse();
// handle response from FB
// this will not be a url with params like the first request to get the 'code'
Encoding rEncoding = Encoding.GetEncoding(response.CharacterSet);
using(StreamReader sr = new StreamReader(response.GetResponseStream(),rEncoding))
{
// parse the response to get the value of the 'access_token'
accessToken = HttpUtility.ParseQueryString(sr.ReadToEnd()).Get("access_token");
}
//TODO
// Add to the accessToken for the Logged in User.Identity to a FBUSERS Model
// WHen someone Logs in Check to see if they are also in FB
// ON Login Page add option to login with FaceBook
return View();
}
catch (Exception exp)
{
// try to get token failed
}
}
else
{
// state var form FB did not match state var sent
}
return View();
}
I think this is achievable via URL protocol handlers;
Create a custom URL protocol handler (MSDN: Registering an Application to a URL Protocol)
Create a facebook page that passes user access token to your url handler (ex. myfbapp://accesstoken/{token})
Set oauth redirect_uri to your facebook page
Parse access token in your application

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