Cannot download attachment in response from server - ios

Question

I have used post method in Alamofire to upload a file successfully, and I get the response from server, I can see the attachment hiding in response. When I'm trying to save the attachment in my computer, it doesn't work. Here is the code:
let urlRequest = urlRequestWithComponents(URL, parameters: parameters, imageData: fileData!)
Alamofire.upload(urlRequest.0, urlRequest.1)
.progress { (bytesWritten, totalBytesWritten, totalBytesExpectedToWrite) in
println("\(totalBytesWritten) / \(totalBytesExpectedToWrite)")
}
.response { (request, response, data, error) in
println("REQUEST \(request)")
println("RESPONSE \(response)")
println("JSON \(data)")
println("ERROR \(error)")
Here is the file in attachment I got from the server:
"Content-Disposition" = "attachment; filename=20150113171557120001.mid";
And the data shows exactly the right .mid file
JSON Optional(<4d546864 00000006 00000001 00044d54 726b0000 00540391 35350381 35350291 3a3a0281 3a3a0291 3c3c0381 3c3c0191 3e3e0381 3e3e0691 3e3e0381 3e3e0891 3e3e0381 3e3e0291 3c3c0381 3c3c0191 3d3d0381 3d3d0191 3a3a0381 3a3a0691 3a3a0381 3a3a00ff 2f00>)
ERROR nil
Here is the code I use to save the attachment in my computer:
let paths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)[0] as NSArray
let documentsDirectory = paths.objectAtIndex(0) as NSString
let path = documentsDirectory.stringByAppendingPathComponent("file.mid")
(data as NSData).writeToFile(path, atomically:true)
After I add the code of saving the attachment, there are no errors or warnings, while on output except for a thread showing like this:
thread1 exc_breakpoint(code=exc_i386_BPT, subcode=0x0)
Am I using the wrong method to save the attachment?

Answer 1

Looking at your hex representation, that looks like a MIDI file (it starts with the right bytes).
The problem is:
let paths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)[0] as NSArray
let documentsDirectory = paths.objectAtIndex(0) as NSString
You're getting the "first item" twice. That item you're trying to return as paths is not the paths array, but rather the first string in that array (because you included the [0] at the end). Thus, the attempt to cast that as an array will fail (much less the attempt to later grab the first item from it).
Simpler would be:
let documentsDirectory = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)[0] as String

Answer 2

You can use url instead of paths
let documentsUrl = NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask).first as NSURL
let fileUrl = documentsUrl.URLByAppendingPathComponent("file.mid")
data.writeToURL(fileUrl, atomically:true)