Flutter 使用 http.MultipartRequest 返回 415 Unsupported Media Type

Question

我想使用 http.MultipartRequest 添加带有文件附件的帖子。这是颤振中的代码：

Future<String> savePost({String content = '', XFile? file}) async{
    String messageRes = '';
    try {
      final uri = Uri.parse('$urlBase/api/posts');
      Map<String, String> headers= <String,String>{
        'Authorization':'Bearer ${Global.user!.token}',
        'content-type': 'application/json; charset=UTF-8;',
        'Accept' : 'application/json',
      };

      Map<String, String> data = {
        "content": content
      };

      var request = http.MultipartRequest('POST', uri)
        ..headers.addAll(headers)
      ..fields.addAll(data);

      if(file != null){
        request.files.add(
            http.MultipartFile(
                'picture',
                File(file.path).readAsBytes().asStream(),
                File(file.path).lengthSync(),
                filename: file.name
            )
        );
      }

      var res = await request.send();
      if(res.statusCode == 200){
        messageRes = '200';
      }else{
        messageRes = '${res.statusCode} ${res.reasonPhrase}';
      }
    } catch (e) {
      messageRes = e.toString();
    }
    return messageRes;
  }

我使用的 Beckend 是 .Net 6：

[HttpPost]
        // api/posts
        public async Task<IActionResult> AddPost(CreatePostDto createDto)
        {}

public class CreatePostDto
    {
        public string Content { get; set; }
    }

我用邮递员测试了api，一切都很好。但是当使用上面的代码使用颤振时，我得到错误 415。请帮助我我哪里出错了。

Answer 1

    Future<String> savePost({String content = '', XFile? file}) async {
    String messageRes = '';
    try {
      final uri = Uri.parse('$urlBase/api/posts');
      Map<String, String> headers = <String, String>{
        'Authorization': 'Bearer ${Global.user!.token}',
        'content-type': 'application/json; charset=UTF-8;',
        'Accept': 'application/json',
      };

     

      var request = http.MultipartRequest('POST', uri)..headers.addAll(headers);

      request.fields['createDto'] = (content);

      if (file != null) {
        request.files.add(http.MultipartFile.fromBytes('picture', await File(file.path).readAsBytes(), filename: file.name));
      }

      var res = await request.send();
      if (res.statusCode == 200) {
        messageRes = '200';
      } else {
        messageRes = '${res.statusCode} ${res.reasonPhrase}';
      }
    } catch (e) {
      messageRes = e.toString();
    }
    return messageRes;
  }

尝试这个

[HttpPost("AddPost")]
public async Task<IActionResult> AddPost([FromForm] IFormFile picture,string content)
 {
    var contentValue =  Request.Form.FirstOrDefault(x=>x.Key == "createDto").Value;
         
    CreatePostDto createPostDto = new CreatePostDto{
       content:contentValue
  };

}