未处理的承诺拒绝:SyntaxError:JSON 解析错误:无法识别的令牌“<"在反应原生

问题描述

我是本机反应的新手.我创建了一个表单来将图像上传到服务器.但是当我尝试上传图片时，总是出现这样的错误 =>[未处理的承诺拒绝:SyntaxError:JSON 解析错误:无法识别的标记 '<']请帮忙谢谢.我想以多部分格式发送数据

I am new to react native. I have created a form to upload images to server. But when I try to upload images keep getting error like this =>[Unhandled promise rejection: SyntaxError: JSON Parse error: Unrecognized token '<']please help thanks. I want to send data in multipart format

这是我的代码

 const pickImage = async () => {
    let result = await ImagePicker.launchImageLibraryAsync({
      mediaTypes: ImagePicker.MediaTypeOptions.All,
     // base64: true,
    });
    if (result.cancelled) {
      return;
    }

    let localUri = result.uri;
    let filename = localUri.split('/').pop();

    let match = /\.(\w+)$/.exec(filename);
    let type = match ? `image/${match[1]}` : `image`;

    let formData = new FormData();
    formData.append('photo', { uri: localUri, name: filename, type });

    console.log(formData)
    return await fetch('https//xyxtech/Android_API_CI/upload_multipart_data', {
      method: 'POST',
      body: formData,
      // header: {
      //   'content-type': 'multipart/form-data',
      // },
      headers: {'Accept': 'application/json, text/plain, */*', 'content-type': 'multipart/form-data'},
    })
    .then((returnValue) => returnValue.json())
  // .catch(err=>err)
  .then(function(response) {
    console.log(response)
    Alert.alert("File uploaded");
    // return response.json();
  });
  };

推荐答案

这本身不是 React Native 问题.您的服务器使用无法在此处解析的非 JSON 正文进行响应:

This is not a React Native issue per se. Your server responds with non-JSON body which cannot be parsed here:

.then((returnValue) => returnValue.json())

这可能意味着您的 HTTP 请求不正确.为什么不正确 - 抱歉，无法帮助您，因为我不熟悉您尝试使用的 API.

This likely means that your HTTP request is incorrect. Why is it incorrect – sorry, can't help you, since I'm not familiar with the API you are trying to use.

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