Upload image to server - Swift 3

Question

I want to send an image as a parameter along with my request. I have used the code below to call my POST request but I don't know how to append image to the body.

I am getting the image through image picker as follows:

if let image = info[UIImagePickerControllerOriginalImage] as? UIImage {

My request is formed as below

var request = URLRequest(url: URL(string: "")!) // link removed
        request.httpMethod = "POST"
        let postString = "user_id=\(userId)&image=\(image)"
        request.httpBody = postString.data(using:.utf8)

        let task = URLSession.shared.dataTask(with: request) { data, response, error in
            guard let data = data, error == nil else {               // check for fundamental networking error
                return
            }
            do {
                let json = try JSONSerialization.jsonObject(with: data, options: .mutableContainers) as? AnyObject

                if let parseJSON = json {
                    print("resp :\(parseJSON)")
                }
            } catch let error as NSError {
                print("error : \(error)")
            }
        }
        task.resume()

I am new to Swift. I have seen this through multipart/form-data but unable to implement it myself. I do not want to encode it in base 64 format. Please help me in this.

Answer 1

I use the following structure for sending images:

func createRequestBodyWith(parameters:[String:NSObject], filePathKey:String, boundary:String) -> NSData {
    
    let body = NSMutableData()

    for (key, value) in parameters {
        body.appendString(string: "--\(boundary)\r\n")
        body.appendString(string: "Content-Disposition: form-data; name=\"\(key)\"\r\n\r\n")
        body.appendString(string: "\(value)\r\n")
    }

    body.appendString(string: "--\(boundary)\r\n")

    let mimetype = "image/jpg"

    let defFileName = "yourImageName.jpg"
        
    let imageData = UIImageJPEGRepresentation(yourImage, 1)

    body.appendString(string: "Content-Disposition: form-data; name=\"\(filePathKey!)\"; filename=\"\(defFileName)\"\r\n")
    body.appendString(string: "Content-Type: \(mimetype)\r\n\r\n")
    body.append(imageData!)
    body.appendString(string: "\r\n")

    body.appendString(string: "--\(boundary)--\r\n")

    return body
}



func generateBoundaryString() -> String {
    return "Boundary-\(NSUUID().uuidString)"
}



extension NSMutableData {
    func appendString(string: String) {
        let data = string.data(using: String.Encoding.utf8, allowLossyConversion: true)
        append(data!)
    }
}

then you have to create body in your function like following:

request.httpBody = self.createRequestBodyWith(parameters:yourParamsDictionary, filePathKey:yourKey, boundary:self.generateBoundaryString)

Answer 2

Swift 4.2

func uploadImage(paramName: String, fileName: String, image: UIImage) {
    let url = URL(string: "http://api-host-name/v1/api/uploadfile/single")

    // generate boundary string using a unique per-app string
    let boundary = UUID().uuidString

    let session = URLSession.shared

    // Set the URLRequest to POST and to the specified URL
    var urlRequest = URLRequest(url: url!)
    urlRequest.httpMethod = "POST"

    // Set Content-Type Header to multipart/form-data, this is equivalent to submitting form data with file upload in a web browser
    // And the boundary is also set here
    urlRequest.setValue("multipart/form-data; boundary=\(boundary)", forHTTPHeaderField: "Content-Type")

    var data = Data()

    // Add the image 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: image/png\r\n\r\n".data(using: .utf8)!)
    data.append(image.pngData()!)

    data.append("\r\n--\(boundary)--\r\n".data(using: .utf8)!)

    // Send a POST request to the URL, with the data we created earlier
    session.uploadTask(with: urlRequest, from: data, completionHandler: { responseData, response, error in
        if error == nil {
            let jsonData = try? JSONSerialization.jsonObject(with: responseData!, options: .allowFragments)
            if let json = jsonData as? [String: Any] {
                print(json)
            }
        }
    }).resume()
}

If you have any header to add, you can add it via urlRequest.setValue method.

Source: https://fluffy.es/upload-image-to-server/