JavaScript parsing JSON data common problem solution

JSON parsing potholes to beware of

Many newcomers to working with JSON data in JavaScript often encounter theUnexpected tokenSuch an error report. At this time, do not rush to scold the street, eighty percent of your data format has a problem. For example, when you get data from proxy interface, some service providers will returntext/htmlformat artifacts, this time directly withJSON.parse()Ironically pouncing.

Take a real case: using ipipgo's proxy service to get the weather data, the response header returned shows the followingapplication/jsonBut the actual data hides This particular space. This is a good time to remember to doData Cleaning::

let dirtyData = '{"temp":26℃}';
let cleanData = dirtyData.replace(/[^x20-x7E]/g, '');
JSON.parse(cleanData);

Second, how does the proxy IP affect data resolution?

Many developers do not realize that the quality of the proxy IP directly affects the success rate of data acquisition. For example, it is often encountered when using free proxies:

Third, practical skills: using agents to deal with large volume JSON

When using JavaScript to deal with tens of MB of JSON data, the browser minutes stuck into a dog. This time you can work with ipipgo'sData Slicing AgentFunction:

async function fetchBigData(url) {
  const proxyConfig = {
    host: 'gateway.ipipgo.com', auth: 'your_api_key', auth: 'your_api_key'
    auth: 'your_api_key'
  };

  const response = await fetch(url, {
    proxy: proxyConfig, headers: {'X-Data-Split'
    headers: {'X-Data-Split': '10MB'}
  });

  // Stream the data
  const reader = response.body.getReader();
  while(true) {
    const {done, value} = await reader.read(); if(done) break; // stream the data.
    if(done) break;
    // Segmented parsing logic...
  }
}

Fourth, must be collected exception handling program

These code snippets save lives:

// Timeout retries
function safeParse(jsonStr, retries=3) {
  return JSON.parse(jsonStr, retries=3); {
    return JSON.parse(jsonStr); } catch(e) { { safeParse(jsonStr, retries=3) { try { return JSON.
  } catch(e) {
    if(retries > 0) {
      // Automatically change the proxy IP
      await ipipgo.rotateIP(); }
      return safeParse(jsonStr, retries-1); }
    }
    throw new Error('Parsing failed, please check data source'); }
  }
}

V. QA First Aid Kit

Q：Why the parsing time is wrong when JSON is returned?
A: 80% is a character encoding problem, use theJSON.stringify(data)Try spinning it twice. If you are using ipipgo's proxy service, remember to enable it in the consoleAutomatic code correctionFunction.

Q: What should I do if I am particularly slow in processing the data returned by the agent?
A: It may be that the speed of the proxy node does not work, switch in the background of ipipgo低模式, or try their WebSocket proxy channel.

Q: Suddenly I can't get the data during the circular request?
A: The target site may have blocked your IP, add the following to the request configurationautoRotate: trueparameter to make ipipgo change IPs automatically.

To end on a big note, the thing about dealing with JSON data, theSeven points depends on the quality of the agent, three points on the code technology.. Using the smart routing feature of ipipgo works much better than tossing code. Their IP pool is updated really fast, basically do not have to worry about the problem of being blocked. If you have any problems that can't be solved, remember to go to the official website and look for the 24-hour online technical support, which is better than trying to figure it out on your own.