ObjC - Post a UIImage by using NSData and NSURLRequest?

Question

Hey all,

I'm trying to post an image to TwitPic.com using their API.

However, I have never posted an image using HTTPPOST or however else before.

Anybody enlighten me to how I can post NSData from a UIImage using their api?

Answer 1

TwitPic is expecting a multi-part form data. There is a great open source library called ASIHTTPRequest.

You can use their APIs and post your image as multi-part/form-data.

See below for the sample.

http://allseeing-i.com/ASIHTTPRequest/How-to-use

Answer 2

Use the UIImagePNGRepresentation function or its JPEG equivalent to turn a UIImage into an NSData:

http://developer.apple.com/iphone/library/documentation/UIKit/Reference/UIKitFunctionReference/Reference/reference.html#//apple_ref/c/func/UIImagePNGRepresentation

Answer 3

I'm trying to do this too... I think I'm close but so far no cigar - I'm getting the error 'image not found' back from the call. My code looks like this:

    NSURL *url = [NSURL URLWithString:@"http://twitpic.com/api/upload"];
NSString *username = @"myUsername";
NSString *password = @"myPassword";
NSData *twitpicImage = UIImagePNGRepresentation(imageView.image);

// Now, set up the post data:
ASIFormDataRequest *request = [[[ASIFormDataRequest alloc] initWithURL:url] autorelease];

[request setPostValue:twitpicImage forKey:@"media"];
[request setPostValue:username forKey:@"username"];
[request setPostValue:password forKey:@"password"];

// Initiate the WebService request
[request start];

The imageView.image is showing a picture on the iPhone screen so I know there's something there.

Anyone have any idea what I'm doing wrong?

Cheers,

Jamie.

Answer 4

@Jamie:

Try:

[request setData:twitpicImage forKey:@"media"];

If the image view is actually displaying an image that is stored in a file on disk, use:

[request setFile:theImagePath forKey:@"media"];

This way, ASIHTTPRequest will stream the image data from disk, so you don't have to keep an NSData instance in memory.

Ta

Ben

Answer 5

Thanks guys!

Answer 6

Instead of setPostValue for the image, use setData instead.

Answer 7

@Jamie

I keep getting an "error: 'ASIFormDataRequest' undeclared (first use in this function)" and and "error: 'request' undeclared (first use in this function)"

both on the line where you put the asiformdatarequest...

What else do you have in your code?