send multi part form data in swift

Question

I used this code below to send multipart params

 let headers = [
        "Content-Type": "application/x-www-form-urlencoded",
        "Authorization": "Bearer \(myToken)",
        "cache-control": "no-cache"
    ]

    let parameters = [
        [
            "name": "firstname",
            "value": "alex"
        ],
        [
            "name": "lastname",
            "value": "black"
        ],
        [
            "name": "birthdate_day",
            "value": "1"
        ],
        [
            "name": "birthdate_month",
            "value": "5"
        ],
        [
            "name": "birthdate_year",
            "value": "1989"
        ],
        [
            "name": "gender",
            "value": "m"
        ],
        [
            "name": "avatar",
            "fileName": "\(imageURL)"
        ]
    ]

    let boundary = "Boundary-\(NSUUID().uuidString)"

    var body = ""
    let error: NSError? = nil
    for param in parameters {
        let paramName = param["name"]!
        body += "--\(boundary)\r\n"
        body += "Content-Disposition:form-data; name=\"\(paramName)\""
        if let filename = param["fileName"] {
            if let contentType = param["content-type"] {
            do {
                let fileContent = try String(contentsOfFile: filename, encoding: String.Encoding.utf8)
                if (error != nil) {
                    print(error as Any)
                }

                body += "; filename=\"\(filename)\"\r\n"
                body += "Content-Type: \(contentType)\r\n\r\n"
                body += fileContent
            } catch {
                print(error)
            }
            }
        } else if let paramValue = param["value"] {
            body += "\r\n\r\n\(paramValue)"
        }
    }

    let postData = NSMutableData(data: body.data(using: String.Encoding.utf8)!)

    let request = NSMutableURLRequest(url: NSURL(string: "myUrl")! as URL,
                                      cachePolicy: .useProtocolCachePolicy,
                                      timeoutInterval: 10.0)
    request.httpMethod = "POST"
    request.allHTTPHeaderFields = headers
    request.httpBody = postData as Data

    let session = URLSession.shared
    let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
        if (error != nil) {
            print(error as Any)
        } else {
            let httpResponse = response as? HTTPURLResponse
            print(httpResponse?.statusCode as Any)
        }
    })

    dataTask.resume()
    return dataTask

the image url and the rest of the data But I will receive Satus code 500 I know that this error is server side But the android version is using the same api url and that's working well I know that this code can be fix and maybe small changes can fix this code for working

Are you trying to upload the image at `imageURL`? Or are you really just sending the server a URL for some image? Also you say “multipart” (in which case you’d do something like https://stackoverflow.com/a/26163136/1271826), but your header says `x-www-form-urlencoded` (which suggests that you’re not sending the file and instead doing something like https://stackoverflow.com/a/26365148/1271826). — Rob, May 05 '19 at 16:53
@imike +1, multipart requests from iOS are a huge pain in the ass - just use Alamofire or CodyFire. — Oscar Apeland, May 06 '19 at 08:32

AamirR · Answer 1 · 2019-06-06T14:56:24.177

use URL instead of NSURL
var request = URLRequest is mutable, use this instead of NSMutableURLRequest
var data = Data() is mutable, use this instead of NSMutableData
append the file blob data safely using Data(contentsOf:options:) method
content-type is missing in parameters, so if let contentType = param["content-type"] { ... } will fail to proceed, using application/octet-stream default mime type
depending on the server, it might be necessary to provide a filename for the uploads

I fixed all above concerns and moved the URLRequest.httpBody generating code to following extension.

extension URLRequest {
    private func formHeader(_ name: String, crlf: String, fileName: String? = nil, mimeType: String? = nil) -> String {
        var str = "\(crlf)Content-Disposition: form-data; name=\"\(name)\""
        guard fileName != nil || mimeType != nil else { return str + crlf + crlf }

        if let name = fileName {
            str += "; filename=\"\(name)\""
        }
        str += crlf
        if let type = mimeType {
            str += "Content-Type: \(type)\(crlf)"
        }
        return str + crlf
    }

    private func getFileUrl(_ file: Any) -> URL? {
        if let url = file as? String {
            return URL(string: url)
        }
        return file as? URL
    }

    private func getFileData(_ url: URL) -> Data? {
        do {
            return try Data(contentsOf: url, options: .mappedIfSafe)
        } catch {
            print(error)
            return nil
        }
    }

    mutating func setPost(body parameters: [[String: Any]]) {
        let boundary = "Boundary+\(arc4random())\(arc4random())"
        self.setValue("multipart/form-data; boundary=\(boundary)", forHTTPHeaderField: "Content-Type")

        var data = Data()
        data.append("--\(boundary)".data(using: .utf8)!)

        let crlf = "\r\n"
        for parameter in parameters {
            guard let paramName = parameter["name"] as? String else { continue }

            if let value = parameter["value"] {
                let header = formHeader(paramName, crlf: crlf)
                data.append("\(header)\(value)".data(using: .utf8)!)
            } else if let file = parameter["file"], let fileUrl = getFileUrl(file), let fileData = getFileData(fileUrl) {
                let fileName = parameter["fileName"] as? String
                let contentType = parameter["content-type"] as? String
                let header = formHeader(paramName, crlf: crlf, fileName: fileName ?? fileUrl.lastPathComponent, mimeType: contentType ?? "application/octet-stream")
                data.append(header.data(using: .utf8)!)
                data.append(fileData)
            } else {
                print("\(paramName): empty or invalid value")
                continue
            }
            data.append("\(crlf)--\(boundary)".data(using: .utf8)!)
        }
        data.append("--\(crlf)".data(using: .utf8)!)
        self.httpBody = data
        self.httpMethod = "POST"
    }
}

Usage

let parameters = [
    ["name": "firstname", "value": "alex"],
    ["name": "avatar", "file": URL],
    ["name": "avatar", "file": "file:///", "fileName": "image.png", "content-type": "image/png"]
]
request.setPost(body: parameters)

Note above in parameters

file key represents either a URL object or file path String.
fileName: image.png is for backend, represents name of the file.

Finally add headers and create URLSession.shared.dataTask as your original code.

Update-2 function instead of an extension

func getParameterData(_ name: String, parameter: [String : Any]) -> Data? {
    var str = "\r\nContent-Disposition: form-data; name=\"\(name)\""

    if let value = parameter["value"] {
        return "\(str)\r\n\r\n\(value)".data(using: .utf8)!
    }

    guard
        let file = parameter["file"],
        let url = (file is String ? URL(string: file as! String) : file as? URL)
    else {
        return nil
    }

    let data: Data
    do {
        data = try Data(contentsOf: url, options: .mappedIfSafe)
    } catch {
        print(error)
        return nil
    }

    let fileName = (parameter["fileName"] as? String) ?? url.lastPathComponent
    str += "; filename=\"\(fileName)\"\r\n"

    let contentType = (parameter["content-type"] as? String) ?? "application/octet-stream"
    str += "Content-Type: \(contentType)\r\n"

    return (str + "\r\n").data(using: .utf8)! + data
}

func setPostRequestBody(_ request: inout URLRequest, parameters: [[String: Any]]) {
    let boundary = "Boundary+\(arc4random())\(arc4random())"
    request.setValue("multipart/form-data; boundary=\(boundary)", forHTTPHeaderField: "Content-Type")

    var data = Data()
    data.append("--\(boundary)".data(using: .utf8)!)

    for parameter in parameters {
        guard
            let name = parameter["name"] as? String,
            let value = getParameterData(name, parameter: parameter)
        else {
            continue
        }

        data.append(value)
        data.append("\r\n--\(boundary)".data(using: .utf8)!)
    }
    data.append("--\r\n".data(using: .utf8)!)
    request.httpBody = data
}

Usage-2

var request = URLRequest(url: URL(string: "myUrl")!, cachePolicy: .useProtocolCachePolicy, timeoutInterval: 10.0)
setPostRequestBody(&request, parameters: [
    ["name": "firstname", "value": "alex"],
    ["name": "avatar", "file": URL object or path String]
])

let dataTask = URLSession.shared.dataTask(with: request) { data, response, error in
    guard error != nil else {
        print(error!.localizedDescription)
        return
    }

    let statusCocde = (response as? HTTPURLResponse)?.statusCode
    print(statusCode ?? 0)
    if let data = data {
        print(String(data: data, encoding: .utf8) ?? "")
    }
}
dataTask.resume()

can you help me to make it a function like above code that I sent here please ? because I again received status code 500 — Saeed Rahmatolahi, May 06 '19 at 06:54
thanks so formHeader is Header right? and where is the web service Url ? I can't find that in this function so It's just make body right? to complete web service I need to add that to my method or not ? can you edit my code please to use that ? — Saeed Rahmatolahi, May 06 '19 at 07:28
I change the name to `getParameterData`, it parses the parameter for value, also few improvements to the `setPostRequestBody` function — AamirR, May 06 '19 at 07:40
thanks I will test that so after getting success I can get error response and status code right? — Saeed Rahmatolahi, May 06 '19 at 08:30
sorry man But That doen't worked for me this function is different that I used before Because I doesn't have task.resume() at the end of the function — Saeed Rahmatolahi, May 06 '19 at 09:25

send multi part form data in swift

1 Answers1