json http请求的承诺中的.catch子句的未接收错误

Question

我有此功能从API端点收集JSON数据：

  export const getDataAPI = (token_id) => {
  const url = `https://api.url.com/tokens/` + token_id;
  const options = {method: 'GET', headers: {Accept: 'application/json'}};
  const request = fetch(url, options)
    .then(response => { if (response.status === 200) {
        return response.json();
      } else if ([404, 429, 500].includes(response.status)) {
        return response.status;
      } else {
        return response.json()
          .then(json => {
            console.log("Error: getDataAPI response status", response.status);
            throw json;
          })
      }
    })
    .catch(error => { throw error; });
  return Promise.resolve(request);
};

我已经通过此功能收集了超过130万的记录。我想遇到任何意外的问题，以便我可以优雅地暂停几秒钟，然后重试。但是我遇到了2个错误，这些错误未发送到.CATCH子句。即使响应< / code>为空 / null / undefined，我也希望至少看到console.log的输出> 这些错误只发生一次。

undefined:1

SyntaxError: Unexpected end of JSON input
    at JSON.parse (<anonymous>)
    at Response.json (file:///home/user/node_modules/node-fetch/src/body.js:149:15)
    at runMicrotasks (<anonymous>)
    at processTicksAndRejections (node:internal/process/task_queues:96:5)
    at async file:///home/user/path/to/file.mjs:94:20

file:///home/user/node_modules/node-fetch/src/index.js:108
            reject(new FetchError(`request to ${request.url} failed, reason: ${error.message}`, 'system', error));
                   ^

FetchError: request to https://api.url.com/tokens/29727608 failed, reason: read ECONNRESET
    at ClientRequest.<anonymous> (file:///home/user/node_modules/node-fetch/src/index.js:108:11)
    at ClientRequest.emit (node:events:526:28)
    at TLSSocket.socketErrorListener (node:_http_client:442:9)
    at TLSSocket.emit (node:events:526:28)
    at emitErrorNT (node:internal/streams/destroy:157:8)
    at emitErrorCloseNT (node:internal/streams/destroy:122:3)
    at processTicksAndRejections (node:internal/process/task_queues:83:21) {
  type: 'system',
  errno: 'ECONNRESET',
  code: 'ECONNRESET',
  erroredSysCall: 'read'
}

1. 我不明白为什么这些错误不会被该功能捕获。有人可以解释一下吗？

2. 如何修复该功能，以便捕获此类错误？

3. 我应该寻找什么输出来识别这些错误，syntaxerror和fetcherror？是否有一个变量可以监视错误代码？

Answer 1

我希望至少会看到console.log的输出（“错误：getDataapi响应状态”，Response.status）;

该代码不在捕获子句中，它在然后在子句中。

return response.json()
          .then(json => {
            console.log("Error: getDataAPI response status", response.status);
            throw json;
          })

您的catch简直就是复发：

.catch(error => { throw error; });

这将给您带来未知的错误。

您需要记录/处理捕获量中的错误，而不是然后子句：

 export const getDataAPI = (token_id) => {
  const url = `https://api.url.com/tokens/` + token_id;
  const options = {method: 'GET', headers: {Accept: 'application/json'}};
  const request = fetch(url, options)
    .then(response => { if (response.status === 200) {
        return response.json();
      } else if ([404, 429, 500].includes(response.status)) {
        return response.status;
      } else {
        console.log("Error: getDataAPI response status", response.status);
        // you can swallow the error here if you want, or try to parse it anyway
        return response.json()
      }
    })
    .catch(error => { 
       console.log('Handling error', error);
       throw error;
    });

  // wrapping the request in a Promise.resolve is also unnecessary 
  // return Promise.resolve(request);
  return request;
};
 

Answer 2

在Xdumaine的帮助下，我能够弄清楚自己在做什么错。

1. 这些错误没有触发console.log报告，因为它们甚至在可以组成JSON字符串之前就提出了。

2. 该功能正在捕获错误，只有对它们没有任何做法。我发现并测试。作为演示，这是一种创建错误并确认.catch（）子句处理的方法：

   
   

export const getDataAPI = (token_id) => {
  const url = `https://api.url.com/tokens/` + token_id;
  const options = {method: 'GET', headers: {Accept: 'application/json'}};
  const request = fetch(url, options)
    .then(response => { 
        throw new SyntaxError('Hello', 'someFile.js', 10);
        if (response.status === 200) {
        return response.json();
      } else if ([404, 429, 500].includes(response.status)) {
        return response.status;
      } else {
        return response.json()
          .then(json => {
            console.log("Error: getDataAPI response status", response.status);
            throw json;
          })
      }
    })
    .catch(error => { 
      console.log('Caught error', error.name);
      throw error; 
      });
  return request;
};

3. 如上所述的页面所示，error.name.name包含错误的名称。