Let’s see how to upload any file to a web server, using only Apple’s built-in URLSession. Most of the examples in the Internet utilize dataTask and not the uploadTask. Also the examples I found demonstrate only the uploading of the image files. That’s why I decided to share a working code for building up a multipart/form-data request, that can be used in combination with uploadTask.
// generate boundary string using a unique string
let boundary = UUID().uuidString
// Set the URLRequest to POST and to the specified URL
var request = URLRequest(url: url)
request.httpMethod = "POST"
request.addValue("Bearer \(yourAuthorizationToken)", forHTTPHeaderField: "Authorization")
// Content-Type is multipart/form-data, this is the same as submitting form data with file upload
// in a web browser
request.setValue("multipart/form-data; boundary=\(boundary)", forHTTPHeaderField: "Content-Type")
let fileName = fileURL.lastPathComponent
let mimetype = mimeType(for: fileName)
let paramName = "file"
let fileData = try? Data(contentsOf: fileURL)
var data = Data()
// Add the file data to the raw http request data
data.append("\r\n--\(boundary)\r\n".data(using: .utf8)!)
data.append("Content-Disposition: form-data; name=\"\(paramName)\"; filename=\"\(fileName)\"\r\n".data(using: .utf8)!)
data.append("Content-Type: \(mimetype)\r\n\r\n".data(using: .utf8)!)
data.append(fileData!)
data.append("\r\n--\(boundary)--\r\n".data(using: .utf8)!)
// do not forget to set the content-length!
request.setValue(String(data.count), forHTTPHeaderField: "Content-Length")
As you can see, it’s pretty straightforward. First we create a request, setting Content-Type to “multipart/form-data” and Authorization token if required. You can set any other values if you web service requires. The second is to create the data that confirms to the multipart/form-data protocol. For we want to upload any kind of files, the mime type is recognized automatically:
private func mimeType(for path: String) -> String {
let pathExtension = URL(fileURLWithPath: path).pathExtension as NSString
guard
let uti = UTTypeCreatePreferredIdentifierForTag(kUTTagClassFilenameExtension, pathExtension, nil)?.takeRetainedValue(),
let mimetype = UTTypeCopyPreferredTagWithClass(uti, kUTTagClassMIMEType)?.takeRetainedValue()
else {
return "application/octet-stream"
}
return mimetype as String
}
So now we have two peaces of puzzle. To bring them together just use the uploadTask(with:data:) function:
session.uploadTask(with: request, from: data)
The webservice should be happy now with your upload file call.
Fröhliche Nachrichten – die LieferscheinApp steht ab sofort für alle iPhone- und iPad-Nutzer zur Verfügung. Es handelt sich dabei um einen Lieferscheinblock für Rundholztransport. Kommt es etwa bekannt vor? Ja natürlich, HISLIS! Die LieferscheinApp ist zwar nicht ganz das gleiche wie die Android Umsetzung, geht aber in die gleiche Richtung. Es umfasst die Möglichkeit, die üblichen Lieferscheinfelder auszufüllen, Holzdaten zu erfassen und Fotos anzuhängen. In der Test-Phase sind auch Pro Features freigeschaltet: PDF-, CSV- und Email-Export. Wir freuen uns auf euer Feedback!
