我如何在node.js中将npm请求模块与bluebird一起使用

Question

webCheck.js

var request = require("request");
var Promise = require("bluebird");



module.exports = {
    check : function(address){
        var length;
        request(address).on('response',function(response){
        response.on('data',function(data){
            length = data.length;
            console.log("in : ",length); //  
        })
    });
    console.log("out : ",length);
    return length;
}
}

main.js

var webCheck = require('./webCheck.js');

    module.exports = {
    run : function(){
        console.log("result : ",webCheck.check("http://localhost:3000/status"));
        ...

Terminal

out :  undefined
result :  undefined
in : 821

I want to check the length of the website. However, the function that checks the website is not synchronous.

I want to return length after the request has been completed.

How can I do? I want to use bluebird module.

Answer 1

To be able to use the request module with bluebird promises, the documentation suggests to install request-promise . So after installing request , also npm install request-promise .

Then you have to make sure the check function returns this promise, so the caller can wait for it's result:

var request = require("request-promise");

module.exports = {
    check : function(address) {
        return request(address)
            .on('response', function(response) {
                return response;
            });
    }
}

Finally, the call in the main.js needs to wait for the promise to resolve, before the result can be used:

var webCheck = require('./webCheck.js');

module.exports = {
    run : function() {
        webCheck.check("http://localhost:3000/status").then(function(response) {
            console.log(response);
        });
    }
    ...
}