我目前已经在swiftUI中使用Alamofire创建了一个REST API。该请求是指向以下URL的post方法：https://api.openai.com/v1/engines/text-davinci-002/completions，它基本上是向OpenAI API发送一个问题，并 * 假定 * 以JSON格式获得答案。我在OpenAI中创建了一个API密钥，并将其包含在我的代码中。
我面临的问题是，当获得输入时，我收到以下错误：
Error: Response status code was unacceptable: 400.
我首先试图确定我的API密钥是否正确，它确实是正确的。我还试图看看一个cURL语句是否能工作来检查它是否是URL的错误。
我使用了以下cURL语句：

curl -X POST \
  https://api.openai.com/v1/engines/text-davinci-002/completions \
  -H 'Authorization: Bearer my-api-key' \
  -H 'Content-Type: application/json' \
  -d '{
        "prompt": "What is quantum mechanics?",
        "temperature": 0.7,
        "max_tokens": 20,
        "top_p": 1,
        "frequency_penalty": 0,
        "presence_penalty": 0
}'

它运行良好，并给了我一个正确的输出：

{"id":"cmpl-6hhWBlzZHrLtV4RKCtjL63CLoTvPi","object":"text_completion","created":1675873407,"model":"text-davinci-002","choices":[{"text":"\n\nQuantum mechanics is a branch of physics that studies the behavior of matter and energy in the","index":0,"logprobs":null,"finish_reason":"length"}],"usage":{"prompt_tokens":5,"completion_tokens":20,"total_tokens":25}}

如果有用的话，下面是我的代码：

//
//  chat.swift
//  titan
//
//  Created by Refluent on 08/02/2023.
//

import SwiftUI
import Alamofire

struct Message: Hashable {
    let sender: String
    let content: String
}

struct OpenAIResponse: Decodable {
    let completions: [Completion]
    
    struct Completion: Decodable {
        let text: String
    }
}

struct chatView: View {
    @State private var response: String = ""
    @State private var messages: [Message] = []
    @State private var userInput: String = ""
    
    let apiKey = "my-api-key"
    let model = "text-davinci-002"
    
    var body: some View {
        VStack {
            Text("Response from OpenAI API:")
            List(messages, id: \.self) { message in
                Text("\(message.sender): \(message.content)")
            }
            
            TextField("Enter your question", text: $userInput)
                .padding()
            
            Button(action: {
                self.sendRequest()
            }) {
                Text("Send")
            }
        }
    }
    
    func sendRequest() {
        let headers: HTTPHeaders = ["Authorization": "Bearer \(apiKey)", "Content-Type": "application/json"]
        
        let parameters: Parameters = ["prompt": userInput, "model": model]
        
        messages.append(Message(sender: "Me", content: userInput))
        userInput = ""
        
        AF.request("https://api.openai.com/v1/engines/text-davinci-002/completions", method: .post, parameters: parameters, headers: headers)
            .validate()
            .responseDecodable(of: OpenAIResponse.self) { response in
                switch response.result {
                case .success(let value):
                    let text = value.completions[0].text
                    self.messages.append(Message(sender: "ChatGPT", content: text))
                case .failure(let error):
                    self.messages.append(Message(sender: "ChatGPT", content: "Error: \(error.localizedDescription)"))
                }
            }
    }
}

有关我的代码的更多上下文，请参阅：
我向this URL发送一个post请求，然后获取输出并将其保存在原始输入旁边的数组中，输入和输出随后显示为聊天。
有人知道为什么我会收到这个错误吗？我错过了代码中的关键部分吗？
提前谢谢你。