Submit POST request from Cocoa to Tumblr

Question

This piece of code does not work, I get an "Authentication Error" message. response from the server. Any ideas?

NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL: [NSURL URLWithString:@"http://www.tumblr.com/api/write"]]; [request setHTTPMethod:@"POST"]; [request addValue:_tumblrLogin forHTTPHeaderField:@"email"]; [request addValue:_tumblrPassword forHTTPHeaderField:@"password"]; [request addValue:@"regular" forHTTPHeaderField:@"type"]; [request addValue:@"theTitle" forHTTPHeaderField:@"title"]; [request addValue:@"theBody" forHTTPHeaderField:@"body"]; NSLog(@"Tumblr Login:%@\nTumblr Password:%@", _tumblrLogin, _tumblrPassword); [NSURLConnection connectionWithRequest:request delegate:self]; [request release]; 

Both _tumblrLogin and _tumblrPassword are executed via stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding elsewhere in my code. My email address is in the form "[e-mail]". It works great for logging directly into tumblr, but I wonder if the "+" character causes encoding problems? This did not slip away. Should it be?

---

Thanks to Martin's suggestion, I am now using CFURLCreateStringByAddingPercentEscapes to avoid entering a username and password. I still have the same problem, although my authentication does not work.

Answer 1

The problem is that you are not creating the proper HTTP POST request. A POST request requires a properly formatted multi-page MIME-encoded body containing all the parameters that you want to send to the server. You are trying to set parameters as HTTP headers that will not work at all.

This code will do what you want, especially pay attention to the NSString categories that create a valid MIME Multipart string:

 @interface NSString (MIMEAdditions) + (NSString*)MIMEBoundary; + (NSString*)multipartMIMEStringWithDictionary:(NSDictionary*)dict; @end @implementation NSString (MIMEAdditions) //this returns a unique boundary which is used in constructing the multipart MIME body of the POST request + (NSString*)MIMEBoundary { static NSString* MIMEBoundary = nil; if(!MIMEBoundary) MIMEBoundary = [[NSString alloc] initWithFormat:@"----_=_YourAppNameNoSpaces_%@_=_----",[[NSProcessInfo processInfo] globallyUniqueString]]; return MIMEBoundary; } //this create a correctly structured multipart MIME body for the POST request from a dictionary + (NSString*)multipartMIMEStringWithDictionary:(NSDictionary*)dict { NSMutableString* result = [NSMutableString string]; for (NSString* key in dict) { [result appendFormat:@"--%@\r\nContent-Disposition: form-data; name=\"%@\"\r\n\r\n%@\r\n",[NSString MIMEBoundary],key,[dict objectForKey:key]]; } [result appendFormat:@"\r\n--%@--\r\n",[NSString MIMEBoundary]]; return result; } @end @implementation YourObject - (void)postToTumblr { NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL: [NSURL URLWithString:@"http://www.tumblr.com/api/write"]]; [request setHTTPMethod:@"POST"]; //tell the server to expect 8-bit encoded content as we're sending UTF-8 data, //and UTF-8 is an 8-bit encoding [request addValue:@"8bit" forHTTPHeaderField:@"Content-Transfer-Encoding"]; //set the content-type header to multipart MIME [request addValue: [NSString stringWithFormat:@"multipart/form-data; boundary=%@",[NSString MIMEBoundary]] forHTTPHeaderField: @"Content-Type"]; //create a dictionary for all the fields you want to send in the POST request NSDictionary* postData = [NSDictionary dictionaryWithObjectsAndKeys: _tumblrLogin, @"email", _tumblrPassword, @"password", @"regular", @"type", @"theTitle", @"title", @"theBody", @"body", nil]; //set the body of the POST request to the multipart MIME encoded dictionary [request setHTTPBody: [[NSString multipartMIMEStringWithDictionary: postData] dataUsingEncoding: NSUTF8StringEncoding]]; NSLog(@"Tumblr Login:%@\nTumblr Password:%@", _tumblrLogin, _tumblrPassword); [NSURLConnection connectionWithRequest:request delegate:self]; [request release]; } @end 

Answer 2

According to the answers to this question stringByAddingPercentEscapesUsingEncoding: does not perform full escape encoding. For some reason, the CoreFoundation version of this method does, however:

 [(NSString *) CFURLCreateStringByAddingPercentEscapes(NULL, (CFStringRef)[[self mutableCopy] autorelease], NULL, CFSTR("=,!$&'()*+;@?\n\"<>#\t :/"), kCFStringEncodingUTF8) autorelease]; 

You can also use the NSMutableString replaceOccurencesOfString:withString:options: method to perform a manual replacement, but this method is more repetitive and verbose. ( See here .)