PHP无依赖调用ChatGPT API报错：messages参数类型不符求助

问题脚本 #

$apiKey = "Your-API-Key";
$url = 'https://api.openai.com/v1/chat/completions';  

$headers = array(
    "Authorization: Bearer {$apiKey}",
    "OpenAI-Organization: YOUR-ORG-STRING", 
    "Content-Type: application/json"
);

// Define messages
$messages = array();
$messages["role"] = "user";
$messages["content"] = "Hello future overlord!";

// Define data
$data = array();
$data["model"] = "gpt-3.5-turbo";
$data["messages"] = $messages;
$data["max_tokens"] = 50;

// init curl
$curl = curl_init($url);
curl_setopt($curl, CURLOPT_POST, 1);
curl_setopt($curl, CURLOPT_POSTFIELDS, json_encode($data));
curl_setopt($curl, CURLOPT_HTTPHEADER, $headers);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);

$result = curl_exec($curl);
if (curl_errno($curl)) {
    echo 'Error:' . curl_error($curl);
} else {
    echo $result;
}

curl_close($curl);

API返回错误 #

{"model":"gpt-3.5-turbo","messages":{"role":"user","content":"Hello future overlord!"},"max_tokens":50}{ "error": { "message": "{'role': 'user', 'content': 'Hello future overlord!'} is not of type 'array' - 'messages'", "type": "invalid_request_error", "param": null, "code": null } }

问题原因与解决方法 #

问题出在$messages的定义上：你将$messages定义成了单个关联数组（键值对结构），但ChatGPT API要求messages参数必须是包含消息对象的数组（哪怕只有一条消息）。

错误写法分析 #

你的代码中：

$messages = array();
$messages["role"] = "user";
$messages["content"] = "Hello future overlord!";

这段代码生成的是单个关联数组，经过json_encode后会变成JSON对象：{"role":"user","content":"Hello future overlord!"}，不符合API要求的数组类型。

正确写法 #

需要把单个消息对象放进数组中：

// 方式1：分步赋值
$messages = array();
$messages[] = array(
    "role" => "user",
    "content" => "Hello future overlord!"
);

// 方式2：简洁写法
$messages = [
    ["role" => "user", "content" => "Hello future overlord!"]
];

修改后，json_encode会将messages转为JSON数组：[{"role":"user","content":"Hello future overlord!"}]，API就能正确识别参数类型了。

内容的提问来源于stack exchange，提问作者Bangkokian