I am new to Facebook app development and have stumbled across a road block. After reading the documentation, I sort of understand that the process of using Facebook login is done in there steps: user authentication -> app authorization -> app authentication. I see where the app authroization/authentication is done, but I can't seem to figure out how to bring up a "user login" screen of Facebook on my WPF. Can anyone advise? Thanks!
First of all you need to register a application in Facebook. Don't forget to give a canvas url when registering an application. After registration you should get app id and app secret values.
https://www.facebook.com/dialog/oauth?client_id=YOUR_APP_ID&redirect_uri=YOUR_URL
YOUR_APP_ID means your application id
YOUR_URL means that application canvas url.
Wpf has a web browser control, you just call the Navigate function and give this url. You should get a Facebook login dialog.
After giving the correct user id and password, Facebook should popup a permission dialog then click the Allow button , you should get a code with redirect url. Then you should parse the code from this url and create a web request to get an access token:
https://graph.facebook.com/oauth/access_token?client_id=YOUR_APP_ID&redirect_uri=YOUR_URL& client_secret=YOUR_APP_SECRET&code=THE_CODE_FROM_ABOVE
YOUR_APP_ID is application id
YOUR_URL is application redirect url
YOUR_APP_SECRET means application secret
THE_CODE_FROM_ABOVE code get from above.
After executing this request, you should get an access token. Using this token you can access Facebook functionality from your application.
Related
I am attempting to implement a simple Facebook login flow for a web application using HTTP redirects, as detailed at https://developers.facebook.com/docs/facebook-login/manually-build-a-login-flow/v2.2.
For the purposes of making this question generic, let's say the application URL is www.example.com/app.php. On the application page, there is a link which directs users to Facebook's OAuth endpoint, where ideally:
they log in to Facebook (if not already logged in) and approve my application permission to access their public profile
they are then redirected back to my application's URL along with some extra parameters appended (e.g. www.example.com/app.php?code=...&access_token=... if the login was successful, or www.example.com/app.php?error_reason=...&error=...&error_description=... if login/app approval was unsuccessful)
The Facebook OAuth endpoint is:
www.facebook.com/dialog/oauth?client_id=12345&redirect_uri=www.xyz.com/app.php
where I have filled in the client_id and redirect_uri parameters with my application's ID and my application's URL respectively.
What actually happens whenever I access the link is that it immediately redirects back to my application's homepage - without ever showing a login dialog of any kind. This happens with Firefox and with Chrome - both when I am logged in to Facebook and when I am not, in normal sessions and in incognito sessions with no plugins enabled. From the browser inspector, I can see that the Facebook OAuth page is definitely requested but is straight away 302 redirecting to my application page with just a code parameter appended.
www.example.com/app.php?code=...
This also happens when the Facebook OAuth link is accessed from pages other than my application's URL (e.g. if I click the link from www.example.com/other_page.htm).
I am unsure what I am doing wrong here; the application URL (www.example.com/app.php) is approved on my app dashboard in as many places as I could find, and changing the request_uri parameter to any other URL results in an error page. I have also tried urlencode()ing my application URL before passing it in the request_uri parameter, but the result remains the same. I don't know what to try next as as far as I can tell I have followed Facebook's manual login guide as closely as possible.
what I need: upload photos to user's fan page as a page, using an app for that
what I have: my website which does uploading, and a user, who created fan page and application, and that app's id and secret
what I do:
call FB.init() with that appId
call FB.login() with manage_pages,publish_stream permissions - this prompts FB login popup where user is asked to login and then to authenticate the app. As the result I get app access token.
Send request to https://graph.facebook.com/oauth/access_token?client_id=APP_ID&client_secret=APP_SECRET&grant_type=fb_exchange_token&fb_exchange_token=TOKEN_FROM_ABOVE to get extended app token valid for 2 months (and therefore page tokens will be extended as well as described here)
Send request to https://graph.facebook.com/me/accounts?access_token=TOKEN_FROM_ABOVE to get a list of pages user manages, and let user to choose the page he wants to publish to.
That gives me PAGE access token I can use to publish photos to user's FAN page using /albumId/photos/ API call.
what is the problem:
the "via" link in the photo redirects user to MY website (where user has authenticated his app to upload to his page):
that is because I had to ask user to enter my website's URL in app settings, otherwise Facebook login dialog will complain:
SO MY QUESTIONS ARE:
Am I doing this right? am I missing something probably?
If I am - then how can I get that "via" link to link to user's website?
Thank you.
how can I get that "via" link to link to user's website?
Not at all, because this always links to the app that was used making a post/upload.
What you could try though is having your website redirect when a user is coming to your site from Facebook. Which post/feed story the user is coming from should be passed to your site as parameters; then you’d only have to figure out which user made that post (look it up in your database), and redirect to their homepage.
I ended up adding client's website URL as a query string parameter into "Site URL" field in the application settings - and then I need to modify my site's backend to do redirects:
http://mysite.com/?redirect=http://client-site.com
In my facebook app I need to authenticate users on a different domain (not facebook.com), for example xxx.facebook.com, is it possible?
Yes, it is possible, only IF facebook endorse it.
For example when we log in the Developers.facebook.com.
Each domain is a child of facebook which mean that you need to have approval by Facebook to create a sub-domain.(well you won't create it but they will)
a little bit of search in the dev section resulted in this,
User authentication and app authorization are handled at the same time by redirecting the user to our OAuth Dialog. When invoking this dialog, you must pass in your app id that is generated when you create your application in our Developer App (the client_id parameter) and the URL that the user's browser will be redirected back to once app authorization is completed (the redirect_uri parameter). The redirect_uri must be within the same domain as the Site URL you specify in Web site tab of the Developer App:
https://www.facebook.com/dialog/oauth?
client_id=YOUR_APP_ID&redirect_uri=YOUR_URL
If the user is already logged in, we validate the login cookie that we have stored on the user's browser, authenticating the user. If the user is not logged in, they are prompted to enter their credentials:
Hope this help
I am a little confused with the Facebook call back URL. I am building a iPhone application with Facebook login. So I will receive the access token from Facebook after the user logged in. Then I save this access token to my local (server side) DB. After that I want to use this access token to sent for example a post via C#.
What should I define for the callback URL? What is the importance of this?
The callback url is used to provide fast app switching, that is, the user of your app is first redirect to facebook app or site to do the login, then it invokes the url you did define and, if properly configured, it will be redirected to your app again.
You can specify the callback url from developers section on facebook, then you have to support it in the your app plist.
I'm writing a Windows Phone App and am using the OAuth interface.
When I navigate to the auth url the first time it shows the login UI. Subsequent times I'm redirected directly to my facebook app page with showing the login UI. Presumably because the login is cached in a cookie or something. All good so far.
The problem comes in when I need to switch users. Is there a way to force the facebook oauth url to clear previous creds and show the login screen?
Thanks!
Log the user out of Facebook using the url below:
https://www.facebook.com/logout.php?access_token=ACCESS_TOKEN&confirm=1&next=REDIRECT
Now, in order to log a user out of Facebook you need to use this url:
"https://www.facebook.com/logout.php?next="+your_site_url_registered _on_fb+"&access_token="+accessToken