为什么request.on()在Node.js中不起作用 [英] Why doesn't request.on() work in Node.js

问题描述

我正在尝试使用节点请求模块从第三方服务中获取一些数据，并从函数中以字符串形式返回此数据.我的理解是request()返回可读流，因为您可以执行request(...).pipe(writeableStream)-我认为-暗示我可以执行

I'm trying to get some data from a third party service using the node request module and return this data as string from a function. My perception was that request() returns a readable stream since you can do request(...).pipe(writeableStream) which - I thought - implies that I can do

function getData(){
    var string;

    request('someurl')
        .on('data', function(data){
             string += data;
        })
        .on('end', function(){
            return string;
        });
}

但这确实不起作用.我认为我对request()或节点流的实际工作方式有一些误解.有人可以在这里消除我的困惑吗?

but this does not really work. I think I have some wrong perception of how request() or node streams really work. Can somebody clear up my confusion here?

推荐答案

它确实按照您解释的方式工作.也许您面临的问题是由于node.js的异步特性造成的.我很确定您正在以同步方式调用getData().尝试此操作，看看您是否在request呼叫中未返回任何内容:

It does work exactly the way you explained. Maybe the problem that you're facing is due to the asynchronous nature of node.js. I'm quite sure you're calling your getData() in a synchronous way. Try this and see if you're request call is not returning something:

request('someurl')
  .on('data', function(data){
    console.log(data.toString());
  .on('end', function(){
    console.log("This is the end...");
  });

在此处中查看这篇文章.它并不短，但是它说明了如何编写代码以应对这种情况.

Take a look at this piece of article here. It's not short, but it explains how to write your code in order to deal with this kind of situation.

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