在NodeJS上實現高性能代理

Question

我使用NodeJS和Luminati代理，但是當發生502錯誤時，我需要request another ip。他們的文檔本身就有一個非常完整的例子，但它太完整了，讓我感到困惑。

我無法將該示例適用於我的方案。

這裏是他們的榜樣，也負責處理502錯誤：

var request = require('request-promise'); 
var promise = require('bluebird'); // promises lib used by request-promise 
var lookup = promise.promisify(require('dns').lookup); 
var http = require('http'); 
var username = 'myusername'; 
var password = 'mypassword'; 
var port = 22225; 
var at_req = 0; 
var n_total_req = 1000; 
var n_parallel_exit_nodes = 100; 
var switch_ip_every_n_req = 50; 
var max_failures = 3; 
var req_timeout = 60*1000; 

function main(){ 
    http.Agent.defaultMaxSockets = Infinity; 
    for (var i=0; i < n_parallel_exit_nodes; i++) 
     new Session(i).start(); 
} 

function Session(id){ 
    this.id = id; 
    this.n_req_for_exit_node = 0; 
    this.fail_count = 0; 
    this.switch_session_id(); 
} 

var proto = Session.prototype; 

proto.start = proto.next = function(){ 
    if (at_req >= n_total_req) 
     return this.cleanup(); // all done 
    at_req++; 
    var _this = this; 
    promise.try(function(){ 
     if (!_this.have_good_super_proxy()) 
      return _this.switch_super_proxy(); 
    }).then(function(){ 
     if (_this.n_req_for_exit_node==switch_ip_every_n_req) 
      _this.switch_session_id(); 
     var options = { 
      url: 'http://lumtest.com/myip.json', 
      timeout: req_timeout, 
      pool: _this.pool, 
      forever: true, 
      proxy: _this.super_proxy_url, 
     }; 
     return request(options); 
    }).then(function success(res){ 
     console.log(res); 
     _this.fail_count = 0; 
     _this.n_req_for_exit_node++; 
    }, function error(err){ 
     if (err.statusCode 
      && !status_code_requires_exit_node_switch(err.statusCode)) 
     { 
      // this could be 404 or other website error 
      _this.n_req_for_exit_node++; 
      return; 
     } 
     _this.switch_session_id(); 
     _this.fail_count++; 
    }).finally(function(){ 
     _this.next(); 
    }); 
}; 

proto.have_good_super_proxy = function(){ 
    return this.super_proxy_host && this.fail_count < max_failures; 
}; 

proto.update_super_proxy_url = function(){ 
    this.super_proxy_url = 'http://'+username+ 
     '-session-'+ 
     this.session_id+':'+password+'@'+this.super_proxy_host+':'+port; 
}; 

proto.switch_session_id = function(){ 
    connection_pool_cleanup(this.pool); 
    this.pool = {}; 
    this.session_id = (1000000 * Math.random())|0; 
    this.n_req_for_exit_node = 0; 
    this.update_super_proxy_url(); 
}; 

proto.switch_super_proxy = function(){ 
    var _this = this; 
    this.switch_session_id(); 
    return promise.try(function(){ 
     return lookup('session-'+_this.session_id+ 
      '.'+ 
      'zproxy.luminati.io'); 
    }).then(function success(res){ 
     _this.super_proxy_host = res; 
     _this.update_super_proxy_url(); 
    }); 
}; 

proto.cleanup = function(){ 
    connection_pool_cleanup(this.pool); 
}; 

function connection_pool_cleanup(pool){ 
    if (!pool) 
     return; 
    for (let key in pool) 
    { 
     var sockets = pool[key].sockets; 
     for (let name in sockets) 
      sockets[name].forEach(s=>s.destroy()); 
    } 
} 

function status_code_requires_exit_node_switch(status_code){ 
    return [403, 429, 502, 503].indexOf(status_code)>=0; 
} 

main(); 

我的代碼：

function add(req, res, next) { 
    request({ url: 'myurl', proxy: 'myproxy' }, (err, response, body) => { 
    if (err) { 
     return next(err); 
    } 

    res.json(body); 
    }); 
}; 

function list(req, res, next) { 
    request({ url: 'myurl', proxy: 'myproxy' }, (err, response, body) => { 
    if (err) { 
     return next(err); 
    } 

    res.json(body); 
    }); 
}; 

我如何調整我的代碼，請求另一個IP以同樣的方式作爲例子嗎？

Answer 1

的代碼可以這樣寫重試失敗：

const request = require('request-promise'); 
    const co = require('co'); 

    function add(req, res, next) { 
     co(function*(){ 
      let last_err; 
      const max_try = 10, max_fail = 3; 
      for (let count=0, fail = 0; count<max_try; count++) 
      { 
       try { 
        let body = yield request({url: 'myurl', proxy: 'myproxy'}); 
        res.json(body); 
        return; 
       } catch(err){ 
        last_err = err; 
        fail++; 
        if (fail==max_fail) 
        { 
         fail = 0; 
         proxy = 'myproxy2'; // switch proxy 
        } 
       } 
       } 
       next(last_err); 
      }); 
    };