nodejs多进程爬虫,榨干CPU

原文来自:snippets.barretlee.com,只是为了自己学习收集特意fork了一遍。如有侵权,联系删除:i@webcliwn.net

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var cheerio = require('cheerio');
var request = require('request');
var cluster = require('cluster');
var mkdirp = require('mkdirp');
var path = require('path');
var fs = require('fs');

var numCPUs = require('os').cpus().length;
var baseURL = {YOUR_SPIDER_URL};
var catesQueue = [];
var subCateQueue = [];

function run (cates){

if(cluster.isMaster) {
Object.keys(cates).forEach(function(cate){
Object.keys(cates[cate]).forEach(function(subCate){
catesQueue.push({
dir: path.join('./pool', cate, subCate),
url: cates[cate][subCate],
type: "list"
});
});
});

while(numCPUs--) {
var c = cluster.fork();
if(catesQueue.length) {
c.send(catesQueue.shift());
c.on("message", function(msg){
if(typeof msg === "object") {
if(msg.type == "list") {
subCateQueue.push(msg);
}
if(catesQueue.length) {
c.send(catesQueue.shift());
} else if(subCateQueue.length) {
var list = subCateQueue.shift();
list.type = list.dir.indexOf('article') > -1 ? "article" : "imgs";
c.send(list);
} else {
console.log(msg.dir + ' done.');
}
} else {
console.log(msg);
}
});
}
}
} else if(cluster.isWorker) {
process.on('message', function(msg) {
var type = msg.type;
var url = msg.url;
var dir = msg.dir;
switch(type) {
case "list":
getList(url).then(function(data){
msg.subCatePages = data;
process.send(msg);
});
break;
case "article":
if(!fs.existsSync(msg.dir)) mkdirp.sync(msg.dir);
if(msg.subCatePages && msg.subCatePages.length) {
getSubCateList(msg).then(function(){
process.send("\n\n" + msg.dir + " OVER\n\n");
});
} else {
process.send("\n\n" + msg.dir + " OVER\n\n");
}
break;
case "imgs":
default:
process.send(msg);
}
});
}
}


// GET sub cate
function getList(url) {

return new Promise(function(resolve, reject){
process.send("Process: " + url);
request({
url: url,
timeout: 8E3
}, function(err, res, body) {
if(err || !body) {
resolve(); return
}
resolve(cheerio.load(body, {
normalizeWhitespace: false,
decodeEntities: false
}));
});
}).then(function($){
if(!$ || !$.html()) {
return [];
}
var num = +$(".num").eq(0).attr("href").split("_")[2].split(".")[0];
var ret = [];
while(num--) {
ret.push(url.replace(/_\d+/, function($0, $1) {
return $0 + (num == 0 ? "" : "_" + num);
}));
}
return ret;
});
}

// GET sub cate list
function getSubCateList(msg) {
return !msg.subCatePages.length ? Promise.resolve()
: new Promise(function(resolve, reject){
var url = msg.subCatePages.shift();
process.send("getSubCateList Process: " + url + ", type: " + msg.type);
request({
url: url,
timeout: 5E3
}, function(err, res, body) {
if(err || !body) {
resolve(); return
}
resolve(cheerio.load(body, {
normalizeWhitespace: false,
decodeEntities: false
}));
});
}).then(function($){
if(!$ || !$.html()) {
return getSubCateList(msg);
}
var details = [];
$("td a[href^='/article']").each(function(){
details.push(baseURL + $(this).attr("href"));
});
return getContent(details, msg).then(function(msg){
getSubCateList(msg);
});
}).catch(function(){
return getSubCateList(msg);
});
}

// GET content
function getContent(queue, msg) {
console.log("\n" + queue.length + "\n");
return !queue.length ? Promise.resolve(msg)
: new Promise(function(resolve, reject){
var url = queue.shift();
process.send("getContent Process: " + url + ", type: " + msg.type);
request({
url: url,
timeout: 5E3
}, function(err, res, body) {
if(err || !body) {
resolve(); return
}
resolve(cheerio.load(body, {
normalizeWhitespace: false,
decodeEntities: false
}));
});
}).then(function($){
if(!$ || !$.html()) {
return getContent(queue, msg);
}
if(msg.type == "article") {
var ctt = $("#MyContent").html();
var title = $(".title").text();
if(ctt) {
ctt = "<style>.body{-webkit-tap-highlight-color:transparent;font-size:16px;color:#2f2f2f;background:#fff;font-family:Georgia,serif;}.content{padding:20px 5%;max-width:700px;margin:0 auto;line-height:1.5}h2{line-height:50px;font-size:24px;}</style><div class='content'><h2>" + title + "</h2>" + ctt + "</div>"
}
var file = path.join(msg.dir, title.replace(/[\*\&\\\/\?\|\:\<\>\n\.\ "'\,\(\)]/gim, "").toString() + ".html");
console.log('File Path: ' + file);
fs.writeFileSync(file, ctt, 'utf8');
return getContent(queue, msg);
} else if(msg.type == "imgs") {
var pics = [];
var title = $(".title").text();
var dir = path.join(msg.dir, title.replace(/[\*\&\\\/\?\|\:\<\>\n\.\ "'\,\(\)]/gim, "").toString());
if(!fs.existsSync(dir)) {
fs.mkdirSync(dir);
}
$("#MyContent img").each(function(){
var src = $(this).attr("src");
if(src && (pics.indexOf(src) == -1)) {
var file = path.join(dir, src.slice(src.lastIndexOf("/") + 1));
console.log('File Path: ' + file);
request(url).pipe(fs.createWriteStream(file));
}
});
return getContent(queue, msg);
}
}).catch(function(){
return Promise.resolve(msg);
});
}

// function getImg(queue, dir){

// }

if(cluster.isMaster) {
// Get the main categories.
var categories = {};
var promise = new Promise(function(resolve, reject){
request(baseURL, function(err, res, body){
resolve(body);
});
}).then(function(data){
var $ = cheerio.load(data, {
normalizeWhitespace: false,
decodeEntities: false
});
var cates = {};
$("#menu_box ul").each(function(){
var cate;
var subCate = {};
var links = $(this).find("li a");
if(links.length) {
links.each(function(){
var text = $(this).text();
var href = $(this).attr('href');
if(href && href.indexOf('/') > -1) {
subCate[text] = baseURL + href;
} else {
cate = text;
}
});
cates[cate] = subCate;
}
});
// Enter spider
console.log("Start Spider Man");
run(cates);
});
} else {
run();
}