NSURLSession POST Request API - ios

Question

I am trying to upload the image as multipart form-data, but i am getting the error that status code 404 from server. Can anyone point out the mistake i am doing in this?
Server accepts "file" as key of the image that we are uploading.
This is what i am tried so far...
public func UPLOADING(url: String,parameters: Dictionary<String,AnyObject>?,filename:String,image:UIImage, success:((NSDictionary) -> Void)!, failed:((NSDictionary) -> Void)!, errord:((NSError) -> Void)!) {
let TWITTERFON_FORM_BOUNDARY:String = "AaB03x"
let url = NSURL(string: url)!
let request:NSMutableURLRequest = NSMutableURLRequest(url: url as URL, cachePolicy: NSURLRequest.CachePolicy.reloadIgnoringCacheData, timeoutInterval: 10)
let MPboundary:String = "--\(TWITTERFON_FORM_BOUNDARY)"
let endMPboundary:String = "\(MPboundary)--"
//convert UIImage to NSData
let data:NSData = UIImagePNGRepresentation(image)! as NSData
let body:NSMutableString = NSMutableString();
// with other params
if parameters != nil {
for (key, value) in parameters! {
body.appendFormat("\(MPboundary)\r\n" as NSString)
body.appendFormat("Content-Disposition: form-data; name=\"\(key)\"\r\n\r\n" as NSString)
body.appendFormat("\(value)\r\n" as NSString)
}
}
// set upload image, name is the key of image
body.appendFormat("%#\r\n",MPboundary)
body.appendFormat("Content-Disposition: form-data; file=\"\(filename)\"\"\r\n" as NSString)
body.appendFormat("Content-Type: image/png\r\n\r\n")
let end:String = "\r\n\(endMPboundary)"
let myRequestData:NSMutableData = NSMutableData();
myRequestData.append(body.data(using: String.Encoding.utf8.rawValue)!)
myRequestData.append(data as Data)
myRequestData.append(end.data(using: String.Encoding.utf8)!)
let content:String = "multipart/form-data; boundary=\(TWITTERFON_FORM_BOUNDARY)"
request.setValue(content, forHTTPHeaderField: "Content-Type")
request.setValue("\(myRequestData.length)", forHTTPHeaderField: "Content-Length")
request.httpBody = myRequestData as Data
request.httpMethod = "POST"
let task = URLSession.shared.dataTask(with: request as URLRequest, completionHandler: {
data, response, error in
if error != nil {
print(error!)
errord(error! as NSError)
return
}
print(response ?? "")
do {
let responseObject:[String:Any]? = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as? [String:Any]
if let responseDictionary = responseObject as NSDictionary? {
success(responseDictionary)
} else {
}
} catch let error as NSError {
print(error.localizedDescription)
}
})
task.resume()
}
In viewDidload,
let image = UIImage(named: "ed1.png",
in: Bundle(for: type(of: self)),
compatibleWith: nil)
UPLOADING(url: "url-of-site", parameters: nil, filename: "ed1.png", image: image!, success: { (sucDict) in
print(sucDict)
}, failed: { (failedDict) in
print(failedDict)
}) { (error) in
print(error.description)
}

Answer 1

I see several issues, mostly minor:
Your Content-Disposition: line is missing the 'name=file;' bit. This is one major reason why it isn't working.
Your boundary is way too short (by at least twenty characters or so; the upper bound is 70 characters, and you should use a good percentage of them). A short boundary runs a real risk of appearing in the actual data you're trying to send.
You should really be using NSData for constructing the entire body, rather than using a mutable string up until the last part.
Ideally, as you do so, you should check whether the boundary appears in any of the values, and if so, generate a new boundary and start over, until you succeed.
The Content-Type field should really be present on for every part unless the value is guaranteed to be 7-bit ASCII, because the Content-Type provides the character encoding (UTF-8, in this case). Otherwise, weird things may happen.
You should probably have a trailing CRLF after the end boundary, just for readability when debugging, though that shouldn't cause a failure.
Finally, if you're uploading to a public service like Twitter, you may need to add some sort of API key, either in the URL or in a request header, and the API might issue an error if that key is missing.
But none of those reasonably explain a 404 error. That should only be issued if the path to the script itself is wrong. This might be caused by something subtle, such as iOS preferring to hit servers via their IPv6 address over IPv4, and the IPv6 side of your web server might be misconfigured. Or it might be the wrong URL. Either way, the only way to debug that is to dig into your server logs and see what file it was trying to read, then figure out why that file doesn't exist.