How do I format an OpenAI API request in Swift?

I need to use the OpenAI API and am struggling to format the request. I started by referencing the curl code that is listed in the OpenAI API playground, and this code worked in my terminal. That request is here:

curl https://api.openai.com/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $OPENAI_API_KEY" \
  -d '{
  "model": "gpt-4o",
  "messages": [
    {
      "role": "user",
      "content": [
        {
          "type": "text",
          "text": "Write a haiku about weightlifting"
        }
      ]
    }
  ],
  "temperature": 1,
  "max_tokens": 2048,
  "top_p": 1,
  "frequency_penalty": 0,
  "presence_penalty": 0,
  "response_format": {
    "type": "text"
  }
}'

Then, I started working on translating that request into swift instead of curl. I've been referencing some YouTube tutorials, and here is my code so far.

let openAiUrl = URL(string: "https://api.openai.com/v1/chat/completions")!
var request = URLRequest(url: openAiUrl)
request.setValue("application/json", forHTTPHeaderField: "Content-Type")
request.addValue("Bearer \(openAiApiKey)", forHTTPHeaderField: "Authorization")
request.httpMethod = "POST"
let httpBody: [String: Any] = [
    "messages" : [
        {
            "role": "user", //Error: consecutive statements on a line must be separated by ';'
            "content": "Write a haiku about weightlifting"
        }
    ],
    "model": "gpt-4o",
    "max_tokens" : 100,
    "temperature": String(temperature),
    "frequency_penalty": 0,
    "presence_penalty": 0,
    "response_format": { //Error: consecutive statements on a line must be separated by ';'
        "type": "text"
    }
]

I am getting the error that says "Consecutive statements on a line must be separated by ';'" on the two lines that are using curly braces.

What do I need to do to format the API request? The temperature variable is a Double that is currently set to 1.0.

Try this approach using a JSONEncoder to encode the json parameters, such as:

            let body = """
{
                    "messages" : [
                        {
                            "role": "user",
                            "content": "Write a haiku about weightlifting"
                        }
                    ],
                    "model": "gpt-4o",
                    "max_tokens" : 100,
                    "temperature": 1.0,
                    "frequency_penalty": 0,
                    "presence_penalty": 0,
                    "response_format": { 
                        "type": "text"
                    }
}
"""
            
            do {
                request.httpBody = try JSONEncoder().encode(body)

                let (responseData, response) = try await URLSession.shared.data(for: request)

                print("-----> \n \(String(data: responseData, encoding: .utf8) as AnyObject) \n")

            } catch {
                print("---> error: \(error)")
            }

EDIT-1

Here is my test code using SwiftUI. Since I don't have a key I cannot fully test this code, but it compiles and gives some info about the response.

import SwiftUI

struct ContentView: View {
    let openAiApiKey = "for testing"
    
    var body: some View {
        Text("testing")
            .task {
                await doPost()
            }
    }
    
    func doPost() async {
        let openAiUrl = URL(string: "https://api.openai.com/v1/chat/completions")!
        
        var request = URLRequest(url: openAiUrl)
        request.setValue("application/json", forHTTPHeaderField: "Content-Type")
        request.addValue("Bearer \(openAiApiKey)", forHTTPHeaderField: "Authorization")
        request.httpMethod = "POST"
        
        let body = """
{
"messages": [
{
"role": "user",
"content": "Write a haiku about weightlifting"
}
],
"model": "gpt-4o",
"max_tokens" : 100,
"temperature": 1.0,
"frequency_penalty": 0,
"presence_penalty": 0,
"response_format": { 
    "type": "text"
}
}
"""
        do {
            request.httpBody = try JSONEncoder().encode(body)
            
            let (responseData, response) = try await URLSession.shared.data(for: request)
            print("-----> responseData \n \(String(data: responseData, encoding: .utf8) as AnyObject) \n")
        }
        catch { print(error) }
    }
}

EDIT-2

another alternative,

struct ContentView: View {
    let openAiApiKey = "for testing"
    
    var body: some View {
        Text("testing")
            .task {
                let url = URL(string: "https://api.openai.com/v1/chat/completions")!
                var request = URLRequest(url: url)
                request.httpMethod = "POST"
                request.setValue("application/json", forHTTPHeaderField: "Content-Type")
                request.setValue("Bearer \(openAiApiKey)", forHTTPHeaderField: "Authorization")
                
                let requestBody: [String: Any] = [
                    "model": "gpt-4o",
                    "messages": [
                        [
                            "role": "user",
                            "content": [
                                [
                                    "type": "text",
                                    "text": "Write a haiku about weightlifting"
                                ]
                            ]
                        ]
                    ],
                    "temperature": 1,
                    "max_tokens": 2048,
                    "top_p": 1,
                    "frequency_penalty": 0,
                    "presence_penalty": 0,
                    "response_format": [
                        "type": "text"
                    ]
                ]
                
                do {
                    request.httpBody = try JSONSerialization.data(withJSONObject: requestBody)
                    
                    let (responseData, response) = try await URLSession.shared.data(for: request)
                    print("-----> responseData \n \(String(data: responseData, encoding: .utf8) as AnyObject) \n")
                }
                catch { print(error) }
                
            }
    }
}