Add Post data to Image Upload

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.

score 3 · Accepted Answer · answered Jun 08 '11 at 10:37

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.

score 1 · Answer 2 · answered May 25 '11 at 11:23

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).

You do not seem to understand how HTTP file uploads work. Most servers (e.g. everything done in PHP) require multipart/form-data rather than application/x-www-form-urlencoded. And your sample code will fail if the image data happens to contain a 0x26 byte. — Anomie, Jun 08 '11 at 10:42
@Anomie: you are correct! According to rfc1867 my answer is wrong. I apologize for the incorrect answer. Please minus it. — Konstantin Chugalinskiy, Jun 08 '11 at 13:13

score 1 · Answer 3 · answered Jun 08 '11 at 06:08

1

I would suggest to use ASIHttp. See ASIFormDataRequest

answered Jun 08 '11 at 06:08

Sagar

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Add Post data to Image Upload

3 Answers3