Add Post data to Image Upload - iphone

Question

I am posting an image from my IPhone app to a php page on a website using the code in this answer to this question. Essentially the code creates the correctly formatted html stream and submits it.
For Completeness, I have reposted the code.
- (BOOL)uploadImage:(NSData *)imageData filename:(NSString *)filename{
NSString *urlString = #"http://www.yourdomainName.com/yourPHPPage.php";
NSMutableURLRequest *request = [[[NSMutableURLRequest alloc] init] autorelease];
[request setURL:[NSURL URLWithString:urlString]];
[request setHTTPMethod:#"POST"];
NSString *boundary = [NSString stringWithString:#"---------------------------14737809831466499882746641449"];
NSString *contentType = [NSString stringWithFormat:#"multipart/form-data; boundary=%#",boundary];
[request addValue:contentType forHTTPHeaderField: #"Content-Type"];
NSMutableData *body = [NSMutableData data];
[body appendData:[[NSString stringWithFormat:#"\r\n--%#\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[[NSString stringWithString:[NSString stringWithFormat:#"Content-Disposition: form-data; name=\"userfile\"; filename=\"%#\"\r\n",filename]] dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[[NSString stringWithString:#"Content-Type: application/octet-stream\r\n\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[NSData dataWithData:imageData]];
[body appendData:[[NSString stringWithFormat:#"\r\n--%#--\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];
[request setHTTPBody:body];
NSData *returnData = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];
NSString *returnString = [[NSString alloc] initWithData:returnData encoding:NSUTF8StringEncoding];
return ([returnString isEqualToString:#"OK"]);
}
However I'm not clever enough :( to figure out how to add a general purpose field value eg. I would like to add a Comment field to be submitted along with the image file.
Any suggestions on how I could modify that code to add a number of fields to the POST form.
Thank you.
Update: I can get it to work by modifying the URL I post to to include GET Parameters, but I would rather use all post params.

Answer 1

It's not too difficult. The general format of a multipart/form-data post is like this:
--boundary-string
Content-Disposition: form-data; name="field1"
value1
--boundary-string
Content-Disposition: form-data; name="field2"
value2
--boundary-string--
File uploads are a special case, but you already have that handled. To add another field, you just add another block. Something like this should do it:
NSMutableData *body = [NSMutableData data];
[body appendData:[[NSString stringWithFormat:#"\r\n--%#\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[[NSString stringWithFormat:#"Content-Disposition: form-data; name=\"Comment\"\r\n\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[comment dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[[NSString stringWithFormat:#"\r\n--%#\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[[NSString stringWithFormat:#"Content-Disposition: form-data; name=\"userfile\"; filename=\"%#\"\r\n",filename] dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[#"Content-Type: application/octet-stream\r\n\r\n" dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[NSData dataWithData:imageData]];
[body appendData:[[NSString stringWithFormat:#"\r\n--%#--\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];
[request setHTTPBody:body];
BTW, you pretty much never need to call NSString's stringWithString: method. If you need a copy, call copy, and otherwise just use the string you already have. NSMutableString's stringWithString: can be useful as an alternative to [[string mutableCopy] autorelease] though.

Answer 2

First of all you should use addValue:forHTTPHeaderField: method of NSMutableURLRequest object to add headers. For example
[request addValue:#"application/octet-stream" forHTTPHeaderField:#"Content-Type"];
[request addValue:[NSString stringWithFormat:#"form-data; name=\"userfile\"; filename=\"%#\"",filename] forHTTPHeaderField:#"Content-Disposition"];
...
For second in your code after all headers are set as I described above you should set POST data with code below.
NSMutableData *body = [[NSMutableData alloc] init];
[body appendData:[[NSString stringWithString:#"name=myimagename.png"] dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[[NSString stringWithString:#"&data="] dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[NSData dataWithData:imageData]];
[body release];
[request setHTTPBody:body];
But it will work if and only if server supports such format (I mean data=image binary data&name=image name).

Answer 3

I would suggest to use ASIHttp. See ASIFormDataRequest