Parse URL with CGI script - facebook

I am getting response from facebook API for accesstoken but can't able to parse that because no ? symbol getting in URL
Example:
http://YOUR_URL#access_token=166942940015970%7C2.sa0&expires_in=64090
I want to get the access_token value in CGI variable.

You will not get access_token this way on server-side (which is probably case for CGI) because of # (hash sign).
Everything after # called fragment identifier and will not be passed to server. It will exist only on client-side, so you probably need to parse it's on client side or pass it to server side in other ways than regular request to this URL...

I am getting response in this URL so i need the access_token value..can't able to get from client side..

Related

Facebook Login: Is there a way to receive URL fragment in redirect as querystring parameter?

So when using Facebook login, it turns out that if you set response_type to token or code%20token then the "response data is included as a URL fragment" on the URL that redirects to your app. Seriously, why? When would that ever be useful to anyone?
Anyway, I'm hoping that this is somehow security related and that it's there for a reason other than to annoy people, but I would otherwise like to know if there's a way to disable it, since I'm using Angular and it's a real pain to handle urls with hashbangs.
If I set a response_type of code only, the code is returned as a nice and clean query parameter, but I would like to receive both in order to perform additional validations. Is there a way to change this behaviour? Thanks.
EDIT:
Well it turns out that setting a response_type of code returns #/= at the end of the url, so there's no way to get a clean querystring. It has already been established that there is no way to change this behaviour, but I'm still interested in finding out why Facebook is doing it. Is it security related? What is the purpose of these url fragments?
Answers
To your first question, I imagine you would use token when you are handling everything in-browser and not processing at the server.
To your main question, as far as I know, you can not change how Facebook redirects successful authorizations. Facebook doesn't give you the token as a clean query parameter. If you use token or code token, what you want will be in the hash fragment. Sorry.
NOTE: This may not be a problem for you. I'm not sure what you want with "additional validations", but when you use code token, exchanging the resulting code gets you a different token than the one you just got embedded in the URI. Both are now valid and will expire separately. Really, you probably need either the code or the token; both won't help you since they're not linked.
Examples of using all three methods:
If you set response_type to code you get redirected to something like:
http://example.com/redirect_uri?state=thestatepassed&code=AQDN9E9GYjA8NbyCt
87_jV5vHnCQylNxmBswo6Z1BsrR7lmTPom6wjrzfan6P4GBLDt3EQrfPg0xSLoMLxBBfscsyfSY
JNM2vu9OoqEQXXSJCTUq_fMpUwqkYbCHp-GAqL4H1ymbMz7zPKAG61V9BtKTSuez39yhawOu7l-
6ww4thP41Ka9PVcknTQ6fPjPXKYSyxEmANps9zevCPFsXpBZCO7_dms65-ZZuG2wVBd16gFnBZH
q8EY0qih6-9o61wXh7bBvVPVSZ2im7Oj1nx47YgDpbD3X0XdlVhUoGYmBdER9hNmIC2PmmY7VAo
PlYCZc#_-_
From there, you need to exchange the code through Facebook's OAuth endpoint to receive an access token. The access token can then be used against the Facebook APIs.
If you set response_type to token you get redirected to something like:
http://example.com/redirect_uri#access_token=CAACYnSxGEhsBAJBg0ohZBhAf7pKEU
sm5ytZAZBzKjISFuRun2ZByZCqEsxrVIgtiO7iIlJZBBbGm6fRPQXItZCX6YgjPknUBsr78tJtv
W6fySULrUo9vdW57ZCMUUIlNaeZAcU8DzUXKmFpgotOyhE3jXYz1c3eu00Aii0AZBsPrtrwjpwQ
mV8VYQNiqKZBIsqOrIwZD&expires_in=4168&state=thestatepassed
You have everything you need to call the Facebook APIs. The access token returned is valid, but should probably be checked against Facebook's token inspection endpoint if you're doing something server-side. (Really, at that point, just use code. I've never done it this way, so good luck.)
As you noted, the access token is now contained within the hash fragment of the url.
If you set response_type to code token you get redirected to something like:
http://example.com/redirect_uri#code=AQAtzsjPivFPsJ538KFlPuhLaK6pDMlrGDiwmi
KDcpgNfWrO1EdX5i6zK_Op2D0QDEXZLyifXxh4TSeBZCWhnkl7YV1LMyEkbPURAWSoqRoeG7tfM
4nB4nDAHOK0H9umb0KnoypRT1pP05FJKhl2QjpCJrPPFDHl6y-1X9ZMj1uVHtmPNi4tG_6QAbuL
RaGadBkekb22uJ0iwSrWc9OKi6ET70lCTYb18hbwUkzHXtTq12nNEdsDJ7Ku2wEBwMygFwErYDX
CrnPoFoah_z0UPCfv3XZLy98Dhlzw_lnx8nnCB-PCppOWRqmydvQJehPd86k&access_token=C
AACYnSxGEhsBALXHRQwfm4UoauRlZBJDVpZCiM6ZCuM3bE965F5JVBfBB8inTFdhfJ5obnonSqa
m3v8FbWhHXrhRSx4ugwAmmDaWyxmPELWqSrkrDO5ueTUXhhjiEZBTd7HjCVCSOXXhOSo3DjEVSC
lOaZBfqmXsprYyc6LJC39sroCcHYCZCv&expires_in=5183426&state=thestatepassed
Now you have both an access token and a code (that expiration applies to the token, not the code). As stated earlier, that code can be exchanged for an access token in the usual way, but the returned access token will be different from the one you just got embedded in the URI.
But, again, what you care about is in the hash fragment.
See the AngularJS doc on $location for accessing the hash. Someone more knowledgable than me can speak to how that works with routes and how best to scrape the parameters.
Well today I had the same situation and managed to resolve it in a way I could get the access token from my server.
After getting the code using response_type=code I called via GET the following url:
https://graph.facebook.com/v3.2/oauth/access_token?app_id=MY_APP_ID&code=MY_CODE&client_id=MY_APP_ID&client_secret=MY_APP_SECRET&redirect_uri=YOUR_LOGIN_REDIRECT_URI
This route returns a JSON response, which has the access_token parameter, in this way:
{
"access_token": "ABAECAEFAEFAEA...",
"type": "bearer",
"expires_in": 838383838
}
So there you go :) I hope this works for you too

Facebook server-side OAuth 2.0 on localhost:8080 can't get access token missing redirect_uri

There are many other question related to this, but they didn't help me fix my problem.
I'm using the Facebook server-side login for a website, which I want to test locally. The path that initiates the login action is [http://localhost:8080/fblogin] (this redirects to the Facebook login dialogue, and goes from there).
I can successfully get the code, but when I try to exchange that for an access token, I get the following error:
{"error":{"message":"Missing redirect_uri parameter.","type":"OAuthException","code":191}}
I am providing the redirect_uri, url encoded and it is the same as the one I use to get the first code. Here is the url I'm using to request the access token (with the all-caps query string parameters replaced with their actual values, of course):
https://graph.facebook.com/oauth/access_token?client_id=CLIENT_ID&redirect_uri=http%3A%2F%2Flocalhost%3A8080%2Ffblogin&client_secret=CLIENT_SECRET&code=CODE_FROM_FB
I suspect this might have to do with how my app is set up on Facebook. Here are the values I have set:
Display Name: (an actual display name here)
App Domains: localhost
Contact email: (an actual email here)
Site URL: [http://localhost:8080/fblogin]
What do I need to tweak in the settings to get this to work? Or does this look correct?
By the way, if it makes any difference, I am using the Play! framework, version 2.0.1
After digging around a little more, I found that it was necessary for me to use POST when sending the request from my server to get the access token.
Interesting that using POST worked for you as this didn't for me.
In any case, did you add the query parameters using setQueryParameter()? (see How to make multiple http requests in play 2?)

Url's containing authentication secrets and app ID's

We received a request to create a REST api. I was a little confused in the example of provided by our client. As you can see below, they've identified the app_id and secret in the URL before the #. The remainder of the URI looks like what I would expect.
Is this valid? I thought maybe this is some weird cURL format I haven't seen before.
https://{application_id}:{api_secret}#api.example.com/entity/{entity_id}/
https://{application_id}:{api_secret}#api.example.com/entity/{entity_id}/entity_locations/{locations_id}/
Just seeing if anyone has seen this format before?
A URI is made up of various parts, one of them being the authority part, which can feature optional username:password element.
The full scheme is:
scheme://username:password#domain:port/path?query_string#fragment_id
This way your REST api remains stateless [not relying on previous app states like storing stuff in session]. But I advice you not to explicitly go with the username:password#stuff route, but to rely on Basic HTTP Auth, so the credentials are sent encoded in Base64 at least.
EDIT: a brief note about BasicAuth now you're asking - things go like this:
you make a request to http://johndoe:12345#service/api/foo/bar;
are credentials good? Ok, you get a 200 OK response with proper body;
are they not? You get a 401 Unauthorized response.
In the latter case, it's the browser [or any other program / script performing the request] that should prompt the user with the login popup.
Usually browsers ask you to cache credentials not to ask them every time, but this does not mean that they are not sent - it's just that every request to protected resources are featured with such header:
Authorization Basic base64encode(username:password)
Where base64encode is your custom way to encode the username:password string.

Facebook server-side authentication flow: is this the right "code?"

I'm using FB.login on the JS client and want to verify the user's identity on the server. So, the client gets a signedRequest from facebook and sends it to the server. The server splits on the period, and decodes the second part of the signedRequest into a json object.
What should I be using for "code" when I send my server-side request to
https://graph.facebook.com/oauth/access_token?
client_id=YOUR_APP_ID
&redirect_uri=YOUR_REDIRECT_URI
&client_secret=YOUR_APP_SECRET
&code=CODE_GENERATED_BY_FACEBOOK
My decoded json looks something like:
{"algorithm":"HMAC-SHA256","code":"2.AQCPA_yfx4JHpufjP.3600.1335646800.1-5702286|l11asGeDQTMo3MrMx3SC0PksALj6g","issued_at":1335642445,"user_id":"5232286"}
Is that the code I need? Does it need to be B64 encoded? If this isn't the code, what code should I use?
_
What I've tried:
The request I'm trying to use is:
https://graph.facebook.com/oauth/access_token?client_id=295410083869479&redirect_uri=https://squaredme.appspot.com/facebookredirect&client_secret=44f1TOPSECRETbb8e&code=2.AQCPA_yfx4JHpufjP.3600.1335646800.1-5702286|l11asGeDQTMo3MrMx3SC0PksALj6g
but this returns the error:
{"error":{"message":"Error validating verification code.","type":"OAuthException","code":100}}
I can't tell if this is because I'm using a bad code, or what. Noteably, this is running on my local dev server, and squaredme.appspot.com definitely does NOT resolve to my IP. I don't know if facebook checks that or what - I'm assuming I'd get a better error message. Thanks for any direction!
You are trying to somehow combine the two flows together and that's why things don't work well.
When facebook POSTs into the iframe with your app url and a signed request there are two options, the easy one being that the user is already authenticated and then the signed request will have all the necessary data (including a signed request), then you just load the canvas page and use the JS SDK to get an access token there as well, but in this case there's no need to use the FB.login (since it opens a popup and will automatically close it), you can use the FB.getLoginStatus method which won't annoy the user.
If the user is not authenticated then the sign request will be missing the things you need to use the graph api.
You then redirect the user to the auth dialog, and since you are loaded in an iframe you'll need to return a html response which redirects the parent window using javascript, like:
top.location.href = "AUTH_DIALOG_URL";
When the use is done (accepted or rejected the app) he will be redirected to the "redirect_uri" you added as a parameter to the auth dialog.
If the user accepted your app then you'll be getting the "code" parameter in the query string.
You then take the code, exchange it with an access token as you posted in your question, and then redirect the user back to "apps.facebook.com/YOUR_APP".
When the page then loads the user is already authenticated and you'll be getting a full signed request.
I hope this clarifies things for you, recheck the Server-Side flow it pretty much covers it all.
I also had some trouble with that, then I found the solution here in StackOverflow.
There are two kinds of "code" provided by facebook. One comes inside the signedRequest in the cookie generated by the client-side flow. The Facebook's JS SDK handles this codes and get a access token without telling us anything.
The other type of code comes attached as a query to your redirect URI (http://www.yoururl.com/index.php?code=AAAgyiaus...), when you navigate to OAuth URL (server-side flow). With this code, you go to a Token URL and get your access token.
When you are using the server-side flow, you need to indicate a redirect URI both in the OAuth URL AND in the Token URL, and they have to be exactly the same, so a missing slash or a query string can be a lot of problem.
The codes are different from each other. When you use the both things together, appears to be impossible to get a access token using the code that was inside the cookie's signedRequest.
BUT, it is not. The magic is: the code from signedRequest is associated with NO URI, so as long as the redirect_uri is a mandatory field, all you have to do is to pass it blank when you navigate to the Token URL.
So the final solution is: grab the signedRequest from the cookie, parse it in your server to obtain the code, then read the Token URL:
https://graph.facebook.com/oauth/access_token?
client_id=YOUR_APP_ID
&redirect_uri=&client_secret=YOUR_APP_SECRET
&code=CODE_INSIDE_THE_SIGNED_REQUEST
It looks like a hack, so I don't know how long it's gonna work, but it's working right now.

Parse facebook code param

I'm tring to authenticate with facebook using the following request:
https://www.facebook.com/dialog/oauth?client_id=MYAPPID&redirect_uri=http://localhost:3000/oauth/callback.html&scope=email
The response is the following:
http://localhost:3000/oauth/callback.html?code=AQA6VzXu_In9_GIiqu-GFEo6d8sA4jM5L6rLQWtL9g2aMo2Ju5h9j_uCcqR-w7cYifyi0IYsOHtOk5S_jKBBlgQatybYDHOfSs2EpA3H3NHQIDIaKmC-9kje9_QQbhPd0Ge1pP-52OR7iOQWc_R8D-YapXcArTAmpIHLBHatOSHB0x3lFv4DVUECfb1IdYIZlVM#_=_
The problem is that I'm unable to retrieve an access token from this code. It should normally have a dot delimiter (".") whereas this has none, that's why I'm unable to decode it.
Any ideas on what I'm doing wrong?
You shouldn'T be able to decode it, it's not a signed_request.
You need to send a request to
https://graph.facebook.com/oauth/access_token?
client_id=YOUR_APP_ID&redirect_uri=YOUR_URL&
client_secret=YOUR_APP_SECRET&code=THE_CODE_YOU_RECEIVED
in order to get an access token
There is a difference between CODE and TOKEN, both are very widely confused.
Client-side login (Javascript + HTML)
If you want to use javascript only (work with HTML only) as it is probably your case you should add &response_type=token to your first request.
Also, I don't think you actually need to split and work with the token but give the JS api to do it for you.
Server-side login (PHP)
You know have a user that a accessed your page with the CODE.
Now you must access, with your server-side script, this url and it will return the access_token.
https://graph.facebook.com/oauth/access_token?
client_id=YOUR_APP_ID&redirect_uri=YOUR_URL&
client_secret=YOUR_APP_SECRET&code=CODE
If your callback was a PHP you could just filegetcontents along with json_decode but I recommend using the official Facebook SDK.
Highly recommended doc page -
http://developers.facebook.com/docs/authentication/