IBM函数不产生任何输出

Question

在运行这个IBM函数时，我遇到了一些问题：

    /**
  *
  * main() will be run when you invoke this action
  *
  * @param Cloud Functions actions accept a single parameter, which must be a JSON object.
  *
  * @return The output of this action, which must be a JSON object.
  *
  */

function main(params) {

    const https = require('https');

https.get('https://api.nasa.gov/planetary/apod?api_key=DEMO_KEY', (resp) => {
  let data = '';

  // A chunk of data has been recieved.
  resp.on('data', (chunk) => {
    data += chunk;
  });

  // The whole response has been received. Print out the result.
  resp.on('end', () => {
    console.log(JSON.parse(data).explanation);
  });

}).on("error", (err) => {
  console.log("Error: " + err.message);
});

}

我的问题是，这个函数的第一个调用(至少前3-4)不会产生输出。随后的调用运行正常，日志显示正确。我怎样才能解决这种不可预测的行为呢？当然，我想在这个函数的第一次调用时检索我的数据。谢谢。

Answer 1

Node.js使用非阻塞异步编程模型.这个main函数在HTTP可用之前返回。

返回承诺将允许您等待HTTP响应。

function main(params) {
  return new Promise((resolve, reject) => {
    const https = require('https');

    https.get('https://api.nasa.gov/planetary/apod?api_key=DEMO_KEY', (resp) => {
      let data = '';

      // A chunk of data has been recieved.
      resp.on('data', (chunk) => {
        data += chunk;
      });

      // The whole response has been received. Print out the result.
      resp.on('end', () => {
        const explanation = JSON.parse(data).explanation
        console.log(explanation);

        resolve({ explanation })
      });

    }).on("error", (err) => {
      console.log("Error: " + err.message);
      reject({ error: err.message })
    });

  })
}

Answer 2

另外还有两件事要检查：

1. 确保将.json附加到您的端点

• 示例：https://<ibm-domain>/api/v1/web/<username>/default/<function>.json

1. 确保在Enable as Web Action侧边栏菜单中选择Endpoints。

另外，您应该能够返回一个async主函数来代替Promise对象。

async function main(params) {
  try {
    // some `await` function
  } catch (e) {
    // catch `await` errors
  }
}

module.exports = main;