Bit.ly API Objective C retrieve access_token

Question

I have a quick question.

I want the user to enter his username (email) and password and I want to get an access token from the bit.ly api.

I tried so far:

NSString *authStr = [NSString stringWithFormat:@"%@:%@", @"username", @"password"];
NSData *authData = [authStr dataUsingEncoding:NSUTF8StringEncoding];
NSString *authValue = [NSString stringWithFormat:@"Basic %@", [authData base64Encoding]];
[request setValue:authValue forHTTPHeaderField:@"Authorization"];

However this does not work.

What I need is to get this command of curl to run in objective c:

curl -u "username:password" -X POST "https://api-ssl.bitly.com/oauth/access_token"

I know I can set the method to POST but I am not sure how to set username:password :|

I also tried using

curl -u "CLIENT_ID:CLIENT_SECRET" -d "grant_type=password" -d "username=USERNAME" \
-d "password=PASSWORD" https://api-ssl.bitly.com/oauth/access_token

however I still do not know how ti set the input of client id and client secret.

Any help on how I can set those information into the request would help me much!

Jack

Answer 1

Admittedly, things like AFNetworking do make working with NSURLConnection and the like a bit easier, but if you're doing this from scratch, you're close.

NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:[NSURL URLWithString:@"https://api-ssl.bitly.com/oauth/access_token"]];

The endpoint for Resource Owner Credential Grants. That will get you the access_token you need to access the rest of our API.

The trickiest part of the flow is the "Authorization" header

NSString *authString = [NSString stringWithFormat:@"%@:%@", @"<YOUR CLIENT ID>", @"<YOUR CLIENT SECRET>"];
NSData *authData = [authString dataUsingEncoding:NSUTF8StringEncoding];
NSString *base64 = [authData base64EncodedStringWithOptions:0];
NSString *authHeader = [NSString stringWithFormat:@"Basic %@", base64];
[request setValue:authHeader forHTTPHeaderField:@"Authorization"];

This will set the Authorization field to: Basic clientID:clientSecret correctly base 64'ed

From there you need to set the body to the request

NSString *postBody = [NSString stringWithFormat:@"grant_type=password&username=%@&password=%@", @"<USERNAME>", @"<PASSWORD>"];
[request setHTTPBody:[postBody dataUsingEncoding:NSUTF8StringEncoding]];

Tell the request it's POST

[request setHTTPMethod:@"POST"];

Then open a NSURLConnection and observe the 3 important delegated methods

NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
[connection start];

You will want to implement:

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData*)data
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
- (void)connectionDidFinishLoading:(NSURLConnection *)connection

Source: I write the Bitly for iPhone app. Hope this helps. Let me know if you have any questions about the API, or the example above.