当出现狂野的第9步时,我正在学习本教程。
此问题与上一个问题(HTTP COLLECT)相同,因为您需要使用http.get()。但是,这次您将获得三个URL作为前三个命令行参数。
您必须收集每个网址提供给您的完整内容,然后将其打印到控制台(标准输出)。您不需要打印长度,只需将数据打印为字符串;每个网址一行。问题在于您必须按照与作为命令行参数提供的URL相同的顺序打印它们。
我的代码是(只是在他喜欢的时候它没有工作):
http = require("http");
var url = [process.argv[2], process.argv[3], process.argv[4]];
var responses = [];
var completed_responses = 0;
for(var i in url){
http.get(url[i], function(response){
var content = "";
//if(completed_responses == url.length){
response.setEncoding("utf-8");
response.on("data", function(data){
content += data;
})
response.on("error", console.error);
response.on("end", function(end){
console.log(content);
});
})
}
答案是:
var http = require("http");
var bl = require("bl");
var results = [];
var count = 0;
function printResults(){
for(var i = 0; i < 3; i++)
console.log(results[i]);
}
function httpGet(index){
http.get(process.argv[2 + index], function(response){
response.pipe(bl(function(err, data){
if (err)
return console.error(err);
results[index] = data.toString();
count++;
if(count == 3)
printResults()
}))
})
}
for(var i = 0; i < 3; i++)
httpGet(i);
什么是正确答案没有BL / AFTER / ETC ?
感谢所有人!
答案 0 :(得分:0)
当我第一次学习节点时,我自己完成了这个教程,我记得教程的这一步。解决方案相当平庸。无论如何,为了你的答案:
NodeJs Asynchronous programming - Coordinating parallel calls
您可以查看问题中的代码并进行我在答案中建议的修复。这应该解决它没有BL / Async /无论教程提到的其他什么。
答案 1 :(得分:0)
这是我的Juggling Async挑战代码,不使用任何第三方库。
var http = require("http");
var urls = [process.argv[2], process.argv[3], process.argv[4]];
var urlResults = new Array("", "", "");
var allDoneCount = 0;
urls.forEach(function (_url) {
http.get(_url, function (resp) {
resp.on("data", function (data) {
if (_url === urls[0]) {
urlResults[0] += data.toString();
} else if (_url === urls[1]) {
urlResults[1] += data.toString();
} else {
urlResults[2] += data.toString();
}
})
resp.on("end", function () {
allDoneCount++;
if (allDoneCount === 3) {
console.log(urlResults[0]);
console.log(urlResults[1]);
console.log(urlResults[2]);
}
})
resp.on("error", function (err) {
console.log(err);
})
}).on("error", function (err) {
console.log(err);
})
})
答案 2 :(得分:0)
这是无需任何外部模块(http; P除外)的方法。
const http = require('http'); //http module
let results = ["", "", ""]; //this will store the data from http.get()
let counter = 0; //to keep a counter for no of httpget's done
//it will iterate when counter is 3 i.e. the 'end' for all
function print() {
for (let i = 0; i < 3; i++) {
console.log(results[i]);
}
}
//accept index(for process.argv) as parameter
function httpGetter(i) {
//http.get method on the url first encountered, 2+i because 2 values are reserved
http.get(process.argv[2 + i], (res) => {
//for converting (res)ponse to string/alternatively toString() method can be used
res.setEncoding('utf8');
//event data on the url, callback with recived chunk as parameter
res.on('data', function(chunk) {
//appending the recived chunk to that element of results corresponding to 'i' of httpGetter function
results[i] += chunk;
});
//event end, when no more data is read
//runs every time for each value of 'i' that is for each url
res.on('end', function() {
//to keep count
counter++;
//when 3 that is when data from all inputs receved
if (counter === 3) {
//print function simply iterating over results array
print();
}
});
})
}
//inputs are recieved from here
for (let i = 0; i < 3; i++) {
//i can be index for results
httpGetter(i);
}