iOS Swift中URL Session以form-data提交手机号参数问题求助

Let's break down what's going wrong in your current code and fix it step by step:

Key Issues in Your Code #

1. Incorrect Content-Type Header:
   • You have a typo (Contet-Type instead of Content-Type).
   • The header value format is wrong—it should use a semicolon to separate the boundary, not a colon: multipart/form-data; boundary=\(boundary).
2. Wrong HTTP Body Format:
   • You're using NSKeyedArchiver and JSONSerialization, which produce plist and JSON data respectively. Neither is the correct format for multipart form-data.
3. Unnecessary Accept Header:
   • Setting Accept to multipart/form-data is probably unnecessary unless the API explicitly returns form-data. Most APIs return JSON, so use application/json instead.

Corrected Code #

Here's how to properly construct and send multipart form-data:

func registerService() {
    print("register tapped")
    
    // Guard against nil mobile number to avoid crashes
    guard let mobileNumber = mobileNumber else {
        print("Mobile number is nil")
        return
    }
    
    let parameters: [String: String] = ["mobile": mobileNumber]
    guard let url = URL(string: "http://54.251.198.30/api/user/login") else {
        print("Invalid URL")
        return
    }
    
    var req = URLRequest(url: url)
    req.httpMethod = "POST"
    
    let boundary = "Boundary-\(UUID().uuidString)"
    // Fix Content-Type header with correct syntax
    req.setValue("multipart/form-data; boundary=\(boundary)", forHTTPHeaderField: "Content-Type")
    // Set Accept header to expect JSON response (adjust if your API uses a different format)
    req.setValue("application/json", forHTTPHeaderField: "Accept")
    
    // Build the proper multipart form-data body
    let httpBody = createMultipartFormData(with: parameters, boundary: boundary)
    req.httpBody = httpBody
    
    let session = URLSession.shared
    session.dataTask(with: req) { data, response, error in
        // Handle request errors first
        if let error = error {
            print("Request error: \(error.localizedDescription)")
            return
        }
        
        // Log the status code for debugging
        if let httpResponse = response as? HTTPURLResponse {
            print("Status code: \(httpResponse.statusCode)")
        }
        
        // Ensure we have data to parse
        guard let data = data else {
            print("No data received from server")
            return
        }
        
        // Try decoding the response
        do {
            let jsonResponse = try JSONDecoder().decode(LoginBase.self, from: data)
            print(jsonResponse)
        } catch {
            print("Decoding error: \(error.localizedDescription)")
            // Print raw response string to debug mismatched structs
            if let rawResponse = String(data: data, encoding: .utf8) {
                print("Raw server response: \(rawResponse)")
            }
        }
    }.resume()
}

// Helper function to construct multipart form-data body
private func createMultipartFormData(with parameters: [String: String], boundary: String) -> Data {
    let body = NSMutableData()
    
    for (key, value) in parameters {
        // Add boundary separator
        body.append("--\(boundary)\r\n".data(using: .utf8)!)
        // Specify field name in Content-Disposition header
        body.append("Content-Disposition: form-data; name=\"\(key)\"\r\n\r\n".data(using: .utf8)!)
        // Append the field value
        body.append("\(value)\r\n".data(using: .utf8)!)
    }
    
    // Add closing boundary to end the form-data
    body.append("--\(boundary)--\r\n".data(using: .utf8)!)
    
    return body as Data
}

Explanation of Changes #

• Guard Clauses: Added checks for nil mobile number and invalid URL to prevent unexpected crashes.
• Corrected Headers: Fixed the Content-Type header typo and format, and set the Accept header to expect JSON (adjust this if your API returns a different response type).
• Multipart Body Builder: The createMultipartFormData helper constructs the proper form-data format by:
  • Adding boundary strings to separate each field.
  • Including Content-Disposition headers to define each field's name.
  • Appending the field values and closing the form with a final boundary.
• Improved Error Handling: Added detailed error logging for request issues, missing data, and decoding failures, plus raw response output to help debug mismatched response structures.

Notes #

• If you need to add file uploads later, you can extend the helper function to include file data with appropriate Content-Type headers for the file type (e.g., image/jpeg for photos).
• Ensure your LoginBase struct exactly matches the structure of the API's JSON response to avoid decoding errors.

内容的提问来源于stack exchange，提问作者Al Mustakim