stdout 总是在字符 8192 处切断流

Question

我正在使用 spawn 模块并执行 curl 命令并从服务器获得 JSON 响应。这是我的代码 -

var spawn = require('child_process').spawn;
log.debug("Executing curl command for getting all artifacts");

var artifacts_data = spawn('bash module_features/init_get_all_artifacts.sh', [
    host_url, access_token, project_id
], {
        shell: true
   });
artifacts_data.stdout.setEncoding('utf8');
var stdout = "";
artifacts_data.stdout.on('data', (data) => {
    stdout += data.toString();
    try {
        var artifact_array = JSON.parse(stdout);
        log.debug(artifact_array);
        if (artifact_array != null || artifact_array != undefined){
            res.send(200, { status: 'success', message: artifact_array });
        }else{
            log.debug('Artifact list not found.');
            res.send(400, { status: 'error', message: 'In else :: somthing went wrong' });
        }
    } catch (error) {
        log.debug("There was some error in parsing artifacts JSON");
        res.send(400, { status: 'error', message: 'somthing went wrong' });
    }

});

但是，我得到了半个字符串（8192 个字符），这是不正确的 JSON。请帮助我增加 stdout 或任何替代解决方案的字符限制。

感谢任何帮助。

Answer 1

我解决了这个问题。

var data = '';
artifacts_data.stdout.on('data',(data) => {
    stdout += data.toString();
});

artifacts_data.stdout.on('end',(data) => {
    try {
         var artifact_array = JSON.parse(stdout);
         log.debug(artifact_array);
         if (artifact_array != null || artifact_array != undefined){
            res.send(200, { status: 'success', message: artifact_array });
         }else{
              log.debug('Artifact list not found.');
              res.send(400, { status: 'error', message: 'In else :: somthing went wrong' });
         }
    } catch (error) {
          log.debug("There was some error in parsing artifacts JSON");
          res.send(400, { status: 'error', message: 'somthing went wrong' });
    }

});

如果我们在 Web 应用程序中处理 IO，我们必须坚持使用异步方法。

Answer 2

iSmita 建议的 end 事件的问题是它仅在进程退出时触发。所以你会失去反应能力，尤其是当你期待不止一个答案时。

如果消息以 \n 结尾，您可以像这样做一些更通用的事情：

let stdoutBuffer = ""
// Stdout messages catching
process.stdout.on('data', (data) => {
  data = data.toString() // Convert chunk to string

  // Add too buffer but no process util the end
  stdoutBuffer += data

  // Split if several lines at once
  const answers = stdoutBuffer.split('\n')

  // Send the last part to the buffer.
  // If the end was '\n' so the buffer will be set back with an empty string.
  // If their is no '\n' so the buffer won't be consumed and answers will be empty.
  stdoutBuffer = answers.pop()

  answers.forEach((a) => {
    // do some stuff with the answer
  })
})

stdout 总是在字符 8192 处切断流

stdout always cuts off the stream at character 8192

curl

stdout

spawn

child-process

node.js