Posting Photos using Objective-C

Or more specifically, posting photos to tweetPhoto.com… but the method works for posting any image from an iPhone to any site that can accept POSTed images.

You can find the API documentation for tweetPhoto here.

Since using NSURLConnection and NSMutableRequest are covered numerous places elsewhere, I’m not going to describe much about how to make asynchronous HTTP calls.  The code below pretty much speaks for itself.

The interesting parts of this function (sendPhoto:tweet:photo:tags:longitude:latitude) are the portions involved in composing the HTTP form data to go over the wire.  Again, the code is fairly self explanatory.

The inbound (NSData*)photo should be the binary image of a picture that you will be sending to tweetPhoto (or whatever service you’re posting images to).  Please note that you will need to Change the Content-Type to match whatever images you’ll be sending (in my case, I always send .PNG images).

So, without further ado, here’s the deal-ee-oh:

-(void)sendPhoto:(NSString*)message tweet:(BOOL)tweet photo:(NSData*)photo tags:(NSString*)tags longitude:(float)longitude latitude:(float)latitude {
TweetPhotoAppDelegate* myApp = (TweetPhotoAppDelegate*)[[UIApplication sharedApplication] delegate];

NSString *url;
if (tweet) {
url = [NSString stringWithFormat:@"http://www.tweetphoto.com/uploadandpostapiwithkey.php"];
} else {
url = [NSString stringWithFormat:@"http://www.tweetphoto.com/uploadapiwithkey.php"];
}

NSString * boundary = @"tweetPhotoBoundaryParm";
NSMutableData *postData = [NSMutableData dataWithCapacity:[photo length] + 1024];

NSString * userNameString = [NSString stringWithFormat:@"Content-Disposition: form-data; name=\"username\"\r\n\r\n%@", myApp.loginString];
NSString * passwordString = [NSString stringWithFormat:@"Content-Disposition: form-data; name=\"password\"\r\n\r\n%@", myApp.passwordString];
NSString * apiString = [NSString stringWithFormat:@"Content-Disposition: form-data; name=\"api_key\"\r\n\r\n%@", apiKey];
NSString * messageString = [NSString stringWithFormat:@"Content-Disposition: form-data; name=\"message\"\r\n\r\n%@", message];
NSString * tagsString = [NSString stringWithFormat:@"Content-Disposition: form-data; name=\"tags\"\r\n\r\n%@", tags];
NSString * latString = [NSString stringWithFormat:@"Content-Disposition: form-data; name=\"latitude\"\r\n\r\n%f", latitude];
NSString * longString = [NSString stringWithFormat:@"Content-Disposition: form-data; name=\"longitude\"\r\n\r\n%f", longitude];
NSString * boundaryString = [NSString stringWithFormat:@"\r\n--%@\r\n", boundary];
NSString * boundaryStringFinal = [NSString stringWithFormat:@"\r\n--%@--\r\n", boundary];

[postData appendData:[boundaryString dataUsingEncoding:NSUTF8StringEncoding]];
[postData appendData:[userNameString dataUsingEncoding:NSUTF8StringEncoding]];
[postData appendData:[boundaryString dataUsingEncoding:NSUTF8StringEncoding]];
[postData appendData:[passwordString dataUsingEncoding:NSUTF8StringEncoding]];
[postData appendData:[boundaryString dataUsingEncoding:NSUTF8StringEncoding]];
[postData appendData:[apiString dataUsingEncoding:NSUTF8StringEncoding]];
[postData appendData:[boundaryString dataUsingEncoding:NSUTF8StringEncoding]];

if (message != nil && ![message isEqualToString:@""]) {
[postData appendData:[messageString dataUsingEncoding:NSUTF8StringEncoding]];
[postData appendData:[boundaryString dataUsingEncoding:NSUTF8StringEncoding]];
}

if (tags != nil && ![tags isEqualToString:@""]) {
[postData appendData:[tagsString dataUsingEncoding:NSUTF8StringEncoding]];
[postData appendData:[boundaryString dataUsingEncoding:NSUTF8StringEncoding]];
}

if (longitude && latitude) {
[postData appendData:[latString dataUsingEncoding:NSUTF8StringEncoding]];
[postData appendData:[boundaryString dataUsingEncoding:NSUTF8StringEncoding]];
[postData appendData:[longString dataUsingEncoding:NSUTF8StringEncoding]];
[postData appendData:[boundaryString dataUsingEncoding:NSUTF8StringEncoding]];
}

[postData appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"media\";\r\nfilename=\"media.png\"\r\nContent-Type: image/png\r\n\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
[postData appendData:photo];
[postData appendData:[boundaryStringFinal dataUsingEncoding:NSUTF8StringEncoding]];

NSMutableRequest * theRequest=(NSMutableURLRequest*)[NSMutableURLRequest requestWithURL:[NSURL URLWithString:url] cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:60.0];

[theRequest setHTTPMethod:@"POST"];

[theRequest addValue:[NSString stringWithFormat:@"multipart/form-data; boundary=%@", boundary] forHTTPHeaderField:@"Content-Type"];
[theRequest addValue:@"www.tweetphoto.com" forHTTPHeaderField:@"Host"];
NSString * dataLength = [NSString stringWithFormat:@"%d", [postData length]];
[theRequest addValue:dataLength forHTTPHeaderField:@"Content-Length"];
[theRequest setHTTPBody:(NSData*)postData];

NSURLConnection * theConnection=[[NSURLConnection alloc] initWithRequest:theRequest delegate:self];

[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
if (theConnection) {
receivedData=[[NSMutableData data] retain];
}
else {
[myApp addTextToLog:@"Could not connect to the network" withCaption:@"tweetPhoto"];
}
}