I have a native (FBML) Facebook Application. I do not want to push the application visitors through the authorization process, however I do want to know their Facebook ID.
Is it possible to find the visiting users Facebook ID without requiring them to "Authorize" my Application?
Before, I said it couldn't be done - but it can.
http://developers.facebook.com/docs/authentication/canvas
Read that, it's excellent. You need to decode the Base64 string and check the signature is correct, but other than that it gets you the user id among other stuff (like a temporary access token for graph.facebook.com)
REMEMBER : You need to change the settings in the Migrations tab for the information to come through! It's a vital step, but can be overlooked...
Hope this helps :)
Stuart
Related
Apologies for the general nature of this question. Hoping this doesn't get shot down as "too broad", but oh well, here goes:
I'm writing a React Native app that is purely informational (medical information), with a Rails API for the back-end.
The first main question I have is whether its necessary (or a good idea) to use authentication at all. We don't want the user to have to enter any information to use it (username, password, etc). They should just be able to download the app and jump right in to use it and read the information it provides.
However, I'm thinking that I would at least want the API to only respond to someone hitting it from within the React Native app (or not? Is it considered a normal practice to have an API completely exposed in the case of an app like this which is purely information and doesn't have users, like a website?)
Second - at some point we may want to be able to store some simple preferences for that user (I.E., are they a patient or a doctor, so we can tailor the materials based on that / send them to a different home screen when the open the app). Wondering what strategy someone might use to store simple preferences if the user doesn't ever create an account?
I would at least want the API to only respond to someone hitting it
from within the React Native app.
This probably can't be done, as in a mobile app everyone has access to your client secret and can try to reverse engineer your code.
You could make it more difficult by sending a dynamically generated token to your API on the request, for example, a hash based on a time frame, and check if the hash was sent the correct way. Then, you'd have to obfuscate the code in order to make it difficult for someone to reverse engineer it.
Second - at some point we may want to be able to store some simple
preferences for that user (I.E., are they a patient or a doctor, so we
can tailor the materials based on that / send them to a different home
screen when the open the app). Wondering what strategy someone might
use to store simple preferences if the user doesn't ever create an
account?
If you use a Parse Server instance as your backend, you could benefit from the anonymous user functionality. As you're using a Rails API, you could generate a uuid for each installation of the app and save the preferences on your database based on that uuid. If you don't need those preferences stored on your backend, just store any information you need on the device through any abstraction of AsyncStorage.
I really do not need authentication when it comes down to it - there are no users.
I could verify that the data is coming from my app based on a user agent or a hard coded password. SSL should help keep those secret.
But yeah, there would be nothing preventing someone from disassembling the app and getting that information. Great idea by #felipe-martim about generating a dynamic token.
I really just want to prevent basic abuse, and I could deal with that if it ever happened, or protect myself with something like Rack-attack.
And storing user preferences locally should work just fine for local preferences.
Bottom line is that I'll deal with this if I ever need to / the client budget allows for it!
So I am updating an older desktop app (written in VB, .net 4.0) with facebook integration and followed the guide found here, and have been able to successfully get a token (by parsing the uri of the embedded webview if it contains "token="). Now my problem is if I try to login with a facebook account that has already approved the app in a prior session, the webview just gets redirected to https://www.facebook.com/connect/login_success.html without any token information.
Do I HAVE to log all of the tokens I generate manually (ie on successful token generation, I can call their profile info, use their FB ID as key and save the token)? Even if I do, since the email and password is input directly into the facebook login window, how do I check if the user already has a token?
Thanks in advance
The access token can change any time, you need to get it everytime. After getting the token, I immediately get the user information https://graph.facebook.com/me?access_token=??? and use that ID to find their database information.
I couldn't quickly find facebook information but on google's oauth information it says "The access token is also associated with a limited scope that define the kind of data the your client application has access to (for example "Manage your tasks"). An important goal for OAuth 2.0 is to provide secure and convenient access to the protected data, while minimizing the potential impact if an access token is stolen."
https://code.google.com/p/google-api-php-client/wiki/OAuth2
Ok so I finally figured it out myself. My mistake was apparently requesting the access_token directly (ie https://www.facebook.com/dialog/oauth?response_type=token...) to try and save time.
I fixed it by making a request for a 'code' instead (ie https://www.facebook.com/dialog/oauth?response_type=code), which I then use to make a second request to retrieve an access token as documented here: https://developers.facebook.com/docs/facebook-login/login-flow-for-web-no-jssdk/, "Exchanging code for an access token" section a bit lower on the page.
Hope this helps someone in the future, this was very frustrating on my part.
Regards,
Prince
So when you put the login button plugin on an app it seems to display the user's friends that are using said app. It displays this even to users that have NOT allowed the app access yet. For example, if you go to "Henry's Cooking App" but have never Logged into the app thru facebook, it will still show you your friends that are using the app.
What I'm trying to do is use this feature to grab an array of fb-userids from the plugin so I can do a query on my DB to show the POTENTIAL user a little more info. For example let's say you have 2 friends that already use "Henry's Cooking App": Joe and Karen. If I could get their userid I could then show you something like "Joe just cooked Veal Scallopini, and Karen is perfecting her Tonkatsu Curry".
I know you could do this easily IF you had the authentication token, but that is only obtained after the user logs in. I'm trying to leverage the fact that fb seems to think it's OK to show your friends that are using the app BEFORE you sign up for the app.
The only super hacky way I could think of to do it is the fact that I could pull the href attribute of elements matching $(".uiFacePileItem a") which gives a link to the user profile which I could then grab the username or UID from. This seems like it could break easily though, anyone have a better idea? Thanks!
The only super hacky way I could think of to do it is the fact that I could pull the href attribute of elements matching $(".uiFacePileItem a") which gives a link to the user profile which I could then grab the username or UID from.
You can’t do that, because the Facebook login dialogs are not running under your domain – so the Same Origin Policy prevents you from interacting with the DOM of these dialogs.
I'm trying to leverage the fact that fb seems to think it's OK to show your friends that are using the app BEFORE you sign up for the app.
Well, it’s certainly (more) OK if Facebook does that – because that doesn’t give any information away to third parties (meaning you as the app developer/provider) – only the user sees that.
It would not be OK if Facebook would let you access this info, at a point where I haven’t even decided to use your app yet – totally a case of „none of your business”.
After I decide to use your app, you may have access to certain information. Before that – No Way, José.
I'm trying to add a "share via twitter" link to our website. I'm aware of the standard http://twitter.com/home?status=TWEET method, and it works good enough for my purposes when the user is logged in to twitter already.
If, however, the user is not logged in, twitter displays the login form first (which is only reasonable). After the login, the home screen is displayed without the tweet content.
Am I missing something obvious, or is this a know flaw in this method? If so, what is the easiest way (apart from using services like TweetMeme, which I noticed asks for login in advance) to make the share button work as expected?
If the user is not signed in when accessing http://twitter.com/home?status=TWEET it seems that the status is indeed forgotten. This would be a Twitter website issue and not something you're doing wrong.
Update: Use this URL instead: http://twitter.com/intent/tweet?text=TWEET
TweetMeme, on the other hand, uses its own Twitter "application" via the OAuth authentication, requiring users to log in before retweeting using TweetMeme, and is smart enough to include the tweet message in the OAuth callback URL so that it's not forgotten.
So really, you can:
Use TweetMeme, where the user would have to log in, but at least have the tweet be remembered once that's done;
Create your own Twitter application that uses the same tweeting functionality as TweetMeme; or
Use Twitter.com's less-than-desirable status updater and hope the user is logged in, or hope that they're smart enough to click the back button a couple times and click on your link again if needed.
Just use the following url and parameters
http://twitter.com/share?text=YOUR-TEXT&url=YOUR-URL
Then it works.
I am designing a twitter iPhone app for my school. I wanted to moderate the users who can access the school account. In simple terms i do not want to use the original twitter server but make it local to only few users. Simply lets say a twitter for class. This will be running on our server and only few people can access it. I am very cofused about this any open sugeestions would help me.
Please help
Simplest way - twitter allows "protected profiles", where only users you are following can see your updates.. This is basically a whitelist of people who can see your statuses..
If you wish to allow multiple users to post from the same account, without hardcoding the twitter account into the application.. you could create your own API, essentially just a proxy for the twitter API..
You could then add your own level of authentication over this, so each user would have their own account (and you don't give out the shared account's login details)
In pseudo code, the application would be something like..
if request['username'] not in ['bob', 'alice']:
raise AuthError
if request['password'] != ['theuserspassword']:
raise AuthError
twitter_api = TwitterLibrary.login("sharedaccount", "secretpassword")
switch request['api_method']:
case "getPublicTimeline":
return twitter_api.getPublicTimeline()
case "postStatus":
return twitter_api.postStatus(request['something'])
Final option I can think of - you could run your own Twitter-like site.. There are plenty of "twitter clones", such as status.net (which is the code that runs identi.ca)
status.net and several other similar projects have Twitter-compatible API's, so you could quite easily take an open-source client (NatsuLiphone for example), and, with permission, rebrand and modify it to use the URL of your own site.
I'm not exactly sure what you mean by "not want to use the original twitter server". If you only want a few people to see the updates from that classes twitter account you could protect the updates and only allow students to follow the account.
However, this should help you create/customize your own twitter iPhone application. This is a link to Stanford's CS-193P course on Cocoa Development. The assignments in the class are creating and customizing a twitter client. All of the project files are available online.
http://www.stanford.edu/class/cs193p/cgi-bin/index.php
I hope this helps.
Create a regular twitter app that requires credentials, don't hard code the credentials in the app. Problem solved. Anybody could get the app on their phone, but only people previously authenticated on twitter would be able to actually use it. If you want to use Oauth you have do this anyway.