如何在nodejs同步中进行此请求调用？ [英] How can I make this call to request in nodejs synchronous?

问题描述

我的nodejs应用程序中有一个名为get_source_at的函数。它需要一个uri作为参数，其目的是从该uri返回源代码。我的问题是我不知道如何使函数同步调用请求，而不是给它回调函数。我希望控制流停止加载uri所需的几秒钟。我怎样才能实现这个目标？

I have a function in my nodejs application called get_source_at. It takes a uri as an argument and its purpose is to return the source code from that uri. My problem is that I don't know how to make the function synchronously call request, rather than giving it that callback function. I want control flow to halt for the few seconds it takes to load the uri. How can I achieve this?

function get_source_at(uri){
    var source;
    request({ uri:uri}, function (error, response, body) {
        console.log(body);
    });
    return source;
}

另外，我读过有关'事件'以及节点是如何' '我应该在编写代码时尊重它。我很高兴这样做，但我必须有一种方法来确保我在继续我的应用程序的控制流之前从uri获得源代码 - 所以如果不是通过使函数同步，那怎么办呢？ ？

Also, I've read about 'events' and how node is 'evented' and I should respect that in writing my code. I'm happy to do that, but I have to have a way to make sure I have the source code from a uri before continuing the control flow of my application - so if that's not by making the function synchronous, how can it be done?

推荐答案

您应该避免同步请求。如果您想要同步控制流程，可以使用 async 。

You should avoid synchronous requests. If you want something like synchronous control flow, you can use async.

async.waterfall([
    function(callback){
        data = get_source_at(uri);
        callback(null, data);
    },
    function(data,callback){
        process(data, callback);
    },
], function (err,result) {
    console.log(result)
});

承诺运行流程 strong> after get_source_at 返回。

The process is promised to be run after get_source_at returns.

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