我尝试从3个来源收集数据,但是这些都是异步的。因此,我试图计算回调。这是我为此目的编写的代码。
var http = require('http');
var data_str1 = '';
var data_str2 = '';
var data_str3 = '';
var ended = 0;
function callback1(response){
response.on('end', function(){ended++;});
response.on('data', function(data){
data_str1 += data;
});
}
function callback2(response){
response.on('end', function(){ended++;});
response.on('data', function(data){
data_str2 += data;
});
}
function callback3(response){
response.on('end', function(){ended++;});
response.on('data', function(data){
data_str3 += data;
});
}
http.get(process.argv[2], function(response){
callback1(response);
if (ended == 3) console.log(data_str1);
});
http.get(process.argv[3], function(response){
callback2(response);
if (ended == 3) console.log(data_str2);
});
http.get(process.argv[4], function(response){
callback3(response);
if (ended == 3) console.log(data_str3);
});
您能告诉我这段代码有什么问题吗?
最佳答案
这是我的解决方案。我已经测试过并且可以正常工作。
var http = require('http');
var concat = require('concat-stream');
var urls = [];
var responses = [];
var count = 0;
for (var i = 2; i < process.argv.length; i++) {
urls.push(process.argv[i]);
}
function readResponse(index) {
http.get(urls[index], function(response) {
response.pipe(concat(function(data) {
responses[index] = data.toString();
count++;
if (count == 3) {
responses.forEach(function(response) {console.log(response);});
}
}));
});
}
for (var i = 0; i < urls.length; i++) {
readResponse(i);
}
关于node.js - 如何计算回调?,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/34352459/