Question

I’ve been working on getting an image to upload from my iOS app to my Grails backend without any success. After talking (indirectly) to another developer it was suggested that I change my content type from multipart/form-data to multipart/binary. The Objective-C code was written after looking at numerous examples.

The request is being handled by the controller but when I attempt to access the file in the request (request.fileName(‘imageToAttach’)) I get a null value.

Here are the three parts of my app (backend and client side) in question. Anyone see what I might be doing wrong?

+ (BOOL)uploadImage:(UIImage *)image withName:(NSString *)fileName toURL:(NSURL *)url {
// url points to /my/uploadImage which is the uploadImage action in MyController
NSData *imageData = UIImageJPEGRepresentation(image, 100);
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:url];
[request setHTTPMethod:@"POST"];

NSString *boundary = @"0xOhHaiICanHazB0undary";
NSString *contentType = [NSString stringWithFormat:@"multipart/binary; boundary=%@", boundary];
[request addValue:contentType forHTTPHeaderField:@"Content-Type"];

NSMutableData *body = [NSMutableData data];
[body appendData:[[NSString stringWithFormat:@"\n--%@--\n",boundary] dataUsingEncoding: NSUTF8StringEncoding]];
[body appendData:[[NSString stringWithFormat:@"Content-Disposition: binary; name=\"imageToAttach\"; filename=\"%@\"\n",fileName]dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[[NSString stringWithFormat:@"Content-Type: application/octet-stream\n\n"] dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[NSData dataWithData:imageData]];
[body appendData:[[NSString stringWithFormat:@"\n--%@--\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];
[request setHTTPBody:body];

NSData *returnData = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];
NSString *returnString = [[NSString alloc] initWithData:returnData encoding:NSUTF8StringEncoding];

NSLog(@"%@",returnString);

return YES;

}

MyController.groovy:

def attachImageToOi = {
println "Uploading image..."
def result
def fileNames = []

if(request.method == 'POST') {
    def imageFile = request.getFile('imageToAttach')
    println imageFile?.inputStream?.text
    if (imageFile && !imageFile.isEmpty()){
        def imagePath = fileUploadService.uploadFile(imageFile, params.imageFileName, "/userFiles")
        if (imagePath != null) {
            fileNames << imagePath
        }
    } else {
        println "Looks like the image file is empty or null..."
    }
} else {
    render "This action only accepts POST"
    return
}

result = [status:200, data:[fileNames:fileNames]]
render result as JSON
return

}

FileUploadService.groovy:

def uploadFile(MultipartFile file, String name, String destinationDirectory) {

def servletContext = ServletContextHolder.servletContext
def storagePath = servletContext.getRealPath(destinationDirectory)

// create storage path directory if it does not exist
def storagePathDirectory = new File(storagePath)
if (!storagePathDirectory.exist()) {
    println "Creating directory: ${storagePath}"
    if (storagePathDirectory.mkdirs()){
        println "success"
    } else {
        println "failed"
    }
}

// store the file
if (!file.isEmpty()) {
    def fullPathToFile = "${storagePath}/${name}"
    file.transferTo(new File(fullPathToFile))
    println "Saved file: ${fullPathToFile}"
    return fullPathToFile
} else {
    println "File ${file.inspect()} was empty!"
    return null
}

}

Answer 1

Looks like there are a few structural issues with the request generated by your Obj-C code. Here are a few pointers and a code sample: http://lists.apple.com/archives/web-dev/2007/Dec/msg00017.html