TWSignedRequest.m

//
//    TWSignedRequest.m
//    TWiOSReverseAuthExample
//
//    Copyright (c) 2012 Sean Cook
//
//    Permission is hereby granted, free of charge, to any person obtaining a
//    copy of this software and associated documentation files (the
//    "Software"), to deal in the Software without restriction, including
//    without limitation the rights to use, copy, modify, merge, publish,
//    distribute, sublicense, and/or sell copies of the Software, and to permit
//    persons to whom the Software is furnished to do so, subject to the
//    following conditions:
//
//    The above copyright notice and this permission notice shall be included
//    in all copies or substantial portions of the Software.
//
//    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
//    OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
//    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
//    NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
//    DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
//    OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
//    USE OR OTHER DEALINGS IN THE SOFTWARE.
//

#import "OAuthCore.h"
#import "TWSignedRequest.h"

#define TW_HTTP_METHOD_GET @"GET"
#define TW_HTTP_METHOD_POST @"POST"
#define TW_HTTP_METHOD_DELETE @"DELETE"
#define TW_HTTP_HEADER_AUTHORIZATION @"Authorization"

#define kTWConsumerKey TWITTER_CONSUMER_KEY
#define kTWConsumerSecret TWITTER_CONSUMER_SECRET

@interface TWSignedRequest()
{
    NSURL *_url;
    NSDictionary *_parameters;
    TWSignedRequestMethod _signedRequestMethod;
}

- (NSURLRequest *)_buildRequest;

@end

@implementation TWSignedRequest
@synthesize authToken = _authToken;
@synthesize authTokenSecret = _authTokenSecret;

- (id)initWithURL:(NSURL *)url
       parameters:(NSDictionary *)parameters
    requestMethod:(TWSignedRequestMethod)requestMethod;
{
    self = [super init];
    if (self) {
        _url = url;
        _parameters = parameters;
        _signedRequestMethod = requestMethod;
    }
    return self;
}

- (NSURLRequest *)_buildRequest
{
	NSString *method;

	switch (_signedRequestMethod) {
		case TWSignedRequestMethodPOST:
			method = TW_HTTP_METHOD_POST;
			break;
		case TWSignedRequestMethodDELETE:
			method = TW_HTTP_METHOD_DELETE;
			break;
		case TWSignedRequestMethodGET:
		default:
			method = TW_HTTP_METHOD_GET;
	}

	//  Build our parameter string
	NSMutableString *paramsAsString = [[NSMutableString alloc] init];
	[_parameters enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop)
										{
											[paramsAsString appendFormat:@"%@=%@&", key, obj];
										}];

	//  Create the authorization header and attach to our request
	NSData *bodyData = [paramsAsString dataUsingEncoding:NSUTF8StringEncoding];
	NSString *authorizationHeader = OAuthorizationHeader(_url, method, bodyData,
														 [TWSignedRequest consumerKey],
														 [TWSignedRequest consumerSecret],
														 _authToken, _authTokenSecret);

	NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:_url];
	[request setTimeoutInterval:8];	// isn't 8 seconds more than long enough?
	[request setHTTPMethod:method];
	[request setValue:authorizationHeader forHTTPHeaderField:TW_HTTP_HEADER_AUTHORIZATION];
	[request setHTTPBody:bodyData];

	return request;
}

- (void)performRequestWithHandler:(SLRequestHandler)handler
{
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0),
				   ^{
					   NSHTTPURLResponse *response;
                       NSError *error;
                       NSData *data
					     = [NSURLConnection sendSynchronousRequest:[self _buildRequest]
												 returningResponse:&response
															 error:&error];
						handler(data, response, error);
                   });
}

// OBFUSCATE YOUR KEYS!
+ (NSString *)consumerKey
{
    NSAssert([kTWConsumerKey length] > 0, @"You must enter your consumer key in Build Settings.");
    return kTWConsumerKey;
}

// OBFUSCATE YOUR KEYS!
+ (NSString *)consumerSecret
{
    NSAssert([kTWConsumerSecret length] > 0, @"You must enter your consumer secret in Build Settings.");
    return kTWConsumerSecret;
}

@end