快速发送多部分表单数据

Question

我使用下面的代码发送多部分参数

 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

图像 url 和其余数据但是我会收到 Satus 代码 500 我知道这个错误是服务器端的但是 android 版本使用相同的 api url 并且运行良好我知道这个代码可以修复并且也许小的改变可以修复这个代码的工作

Answer 1

• 使用URL而不是NSURL
• var request = URLRequest 是可变的，使用它代替 NSMutableURLRequest
• var data = Data() 是可变的，使用它代替 NSMutableData
• 使用Data(contentsOf:options:)方法安全地追加文件blob数据
• 参数中缺少content-type，因此if let contentType = param["content-type"] { ... } 将无法继续，使用application/octet-stream 默认mime 类型
• 根据服务器的不同，可能需要为上传文件提供文件名

我解决了上述所有问题并将URLRequest.httpBody 生成代码移至以下扩展。

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"
    }
}

用法

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)

注意上面的参数

• file 键代表URL 对象或文件路径字符串。
• fileName: image.png 用于后端，代表文件名。

最后添加标题并创建URLSession.shared.dataTask 作为您的原始代码。

Update-2 函数而不是扩展

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
}

用法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()