llm openai 标准对话/v1/chat/completions 如何传递文件

文件分为图片和其他。文件可以通过公网可访问的url或者base64传递。文件不允许通过公网url访问，只允许先上传到文件系统，先获取fileid，然后把fileid传给/v1/chat/completions 接口即可。

图片公网URL案例：

{
  "model": "gpt-4o",
  "messages": [
    {
      "role": "user",
      "content": [
        { "type": "text", "text": "描述这张图片" },
        { "type": "image_url", "image_url": { "url": "https://your-minio.com/image.jpg" } }
      ]
    }
  ]
}

图片Base64案例：

{
  "model": "gpt-4o",
  "messages": [
    {
      "role": "user",
      "content": [
        { "type": "text", "text": "描述这张图片" },
        {
          "type": "image_url",
          "image_url": {
            "url": "data:image/jpeg;base64,/9j/4AAQSkZJRgABAQAAAQ..."
          }
        }
      ]
    }
  ]
}

普通文件案例：

{
  "model": "gpt-4o",
  "messages": [
    {
      "role": "user",
      "content": [
        { "type": "text", "text": "总结这个PDF" },
        { "type": "file", "file": { "file_id": "file-abc123" } }
      ]
    }
  ]
}

多图多文件混合的请求结构：

{
  "model": "gpt-4o",
  "messages": [
    {
      "role": "user",
      "content": [
        { "type": "text", "text": "请对比这两份文档和这两张图片的内容" },

        { "type": "image_url", "image_url": { "url": "data:image/jpeg;base64,/9j/..." } },
        { "type": "image_url", "image_url": { "url": "https://your-minio.com/photo.png" } },

        { "type": "file", "file": { "file_id": "file-abc123" } },
        { "type": "file", "file": { "file_id": "file-def456" } }
      ]
    }
  ]
}