1.如何维护代理ip库？
想要使用代理ip，那就必须有一个一定数量、足够有效的代理ip库，在学习阶段，随便玩玩那就只能从免费的代理ip网站上抓取,没有一定数量的代理刷文章流浪量非常慢，首先就是要维护好自己的代理ip库
之前用过的西刺代理、66ip比较靠谱，西祠好像有反扒，遇到过一次，不知道是西祠网站的问题还是反扒的策略，这两个网站每分钟抓取的能用的代理大概有2,3个,这已经算的上比较客观的了， data5u、快代理、ip3366网页端更新的非常少，而且有效性比较低，快代理抓取网页还必须设置useragent,发现设置后获取的ip的端口和网页端不一致，很玩味是吧，没办法免费的就是这样，不然人家就收费了，当然付费的代理也不稳定，但肯定是比免费的好很多。
维护代理质量
从网页端抓取下来的代理，肯定是要经过验证再入库的，最简单的方式就是发起一个请求状态码是否为200。我推荐的免费代理还是上面两个西刺代理和66ip，相对其他的免费代理有效性、数量都比较高。
代理如何储存
我使用的是redis来存储这些有效代理，数据结构最好是采用set，不允许存储相同的ip。代理的有效性无法得知，有的可能是几十秒钟，有的几十分钟，在使用的时候应该记录那些多次不能使用的ip，达到一定次数，应该从set中删除掉。无法确定代理的时效，代理ip要及时使用，可以使用定时器定时从redis中取出代理。
2.反爬虫的一些常见的机制？
反爬虫的原则就是判断是否是一个真实的用户，一些比较重要的数据会利用多种机制混合，让爬虫的代价变大甚至无法爬取,header里面的字段设置、ip限制、cookie等
ip限制
一些网站为了防止爬虫，可能会对每个ip进行访问频率的限制，访问频率一个是速度，可以同thread.sleep来进行休眠，暂停一会儿再进行爬取；一个ip次数这个我们可以通过抓取的免费代理来设置。
header里的限制
user-agent ：用户代理，这个非常简单，可以收集一些常见的浏览器代理头，在请求的时候随机设置user-agent
referer ：访问目标链接是从哪个链接条过来的，做防图片的盗链可以用它来处理，当然这个refresh也是可以伪造。
cookie：登录后或其他的一些用户操作，服务端会返回一些cookie信息，没有cookie很容易被识别为伪造请求，可以在本地通过js，根据服务端返回的一些信息，本地区设置cooke，当然这个实际中并没有这么简单，一般会涉及到加密解密的过程。这个是爬虫的一个难点。
3.使用代理ip刷新csdn文章的浏览量
csdn文章的浏览量还是比较好刷的，前提的是你有足够多的代理，没有更多的代理效率会非常慢。前面一篇文章我们已经从几个免费的代理网站抓取了代理，这里就不多做介绍了，这里我们接着上一篇的拿来就用。c#批量抓取免费代理并验证有效性。1.我使用的多线程批量发送请求，效率更好，每个线程平均分配一定数量的代理执行请求。2.定时获取redis中代理3.使用system.collections.concurrent 命名空间下concurrentdictionary字典集合来统计失败的次数，如果达到一定次数就直接从库中删除该代理。关于代码中主要功能是实现，不足的地方就是代理太少，效率不高。
效果如图：
昨天晚上看了篇文章，（这里是随便csdn或者其他地方的有浏览量的文章），刷的时间不短，主要是因为代理太少了。
主要代码如下：
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class program { static bool finishiscompleted=true; static concurrentdictionary<string, int> failstatis;//保存请求失败的ip地址:key 失败次数：value static string refreshlink = "https://blog.csdn.net/baijifeilong/article/details/80734388"; static string requestsuccesskey,requestfailkey; static async task main(string[] args) { threadpool.setminthreads(500, 100); failstatis = new concurrentdictionary<string, int>(); requestsuccesskey = "list_request_success"+datetime.now.tostring("hhmm"); requestfailkey = "list_request_fail" + datetime.now.tostring("hhmm"); timer timer = new timer(async (state) => { if (finishiscompleted) { finishiscompleted = false; //获取代理 var proxyips = redishelper.getproxy(); int threadcount = 1; if (proxyips.count > 10) { threadcount = proxyips.count / 10; } //平均分配给每个thread执行15个请求 int requestcount = proxyips.count / threadcount; for (var i = 0; i < threadcount; i++) { var templist = proxyips.getrange(i * requestcount, requestcount); if (i == threadcount - 1) { templist.addrange(proxyips.getrange(threadcount * requestcount, proxyips.count - threadcount * requestcount)); } thread thread = new thread(async () => { //执行发起请求 await finish(templist); }); thread.start(); } } }, "processing timer event", 0, 1000*30); console.readline(); } public static async task finish(list<string> proxyips) { for (int i = 0; i < proxyips.count; i++) { string ip = proxyips[i]; int index = ip.indexof(":"); string ipaddress = ip.substring(0, index); int ipport = int.parse(ip.substring(index + 1)); //随机休眠 thread.sleep(new random().next(1,4)*1000); await get(ipaddress, ipport, 10000, randomuseragent(), refreshlink, () => { redishelper.addrequestok(requestsuccesskey,ip+" "+datetime.now.toshorttimestring(),true); console.foregroundcolor = consolecolor.white; console.writeline(ip+" success"); }, (error) => { redishelper.addrequestok(requestfailkey, ip + " " + datetime.now.toshorttimestring(),false); console.foregroundcolor = consolecolor.red; console.writeline(ipaddress+error+"失败"+(failstatis.containskey(ip)?failstatis[ip] :1)+"次"); if (failstatis.containskey(ip)) { if (failstatis[ip] == 6) { redishelper.removesetvalue(ip); } else failstatis[ip]++; } else { failstatis.addorupdate(ip, 1,(key,oldvalue)=>oldvalue+1); } } ); } finishiscompleted = true; } private static string randomuseragent() { string[] usersagents = new string[] { "mozilla/5.0 (linux; u; android 2.3.7; en-us; nexus one build/frf91) applewebkit/533.1 (khtml, like gecko) version/4.0 mobile safari/533.1", "mqqbrowser/26 mozilla/5.0 (linux; u; android 2.3.7; zh-cn; mb200 build/grj22; cyanogenmod-7) applewebkit/533.1 (khtml, like gecko) version/4.0 mobile safari/533.1", "juc (linux; u; 2.3.7; zh-cn; mb200; 320*480) ucweb7.9.3.103/139/999", "mozilla/5.0 (windows nt 6.1; wow64; rv:7.0a1) gecko/20110623 firefox/7.0a1 fennec/7.0a1", "opera/9.80 (android 2.3.4; linux; opera mobi/build-1107180945; u; en-gb) presto/2.8.149 version/11.10", "mozilla/5.0 (linux; u; android 3.0; en-us; xoom build/hri39) applewebkit/534.13 (khtml, like gecko) version/4.0 safari/534.13", "mozilla/5.0 (iphone; u; cpu iphone os 3_0 like mac os x; en-us) applewebkit/420.1 (khtml, like gecko) version/3.0 mobile/1a542a safari/419.3", "mozilla/5.0 (iphone; u; cpu iphone os 4_0 like mac os x; en-us) applewebkit/532.9 (khtml, like gecko) version/4.0.5 mobile/8a293 safari/6531.22.7", "mozilla/5.0 (ipad; u; cpu os 3_2 like mac os x; en-us) applewebkit/531.21.10 (khtml, like gecko) version/4.0.4 mobile/7b334b safari/531.21.10", "mozilla/5.0 (blackberry; u; blackberry 9800; en) applewebkit/534.1+ (khtml, like gecko) version/6.0.0.337 mobile safari/534.1+", "mozilla/5.0 (hp-tablet; linux; hpwos/3.0.0; u; en-us) applewebkit/534.6 (khtml, like gecko) wosbrowser/233.70 safari/534.6 touchpad/1.0", "mozilla/5.0 (symbianos/9.4; series60/5.0 nokian97-1/20.0.019; profile/midp-2.1 configuration/cldc-1.1) applewebkit/525 (khtml, like gecko) browserng/7.1.18124", "mozilla/5.0 (compatible; msie 9.0; windows phone os 7.5; trident/5.0; iemobile/9.0; htc; titan)", "mozilla/5.0 (windows nt 6.1) applewebkit/537.36 (khtml, like gecko) chrome/41.0.2228.0 safari/537.36", "mozilla/5.0 (macintosh; intel mac os x 10_10_1) applewebkit/537.36 (khtml, like gecko) chrome/41.0.2227.1 safari/537.36", "mozilla/5.0 (x11; u; linux x86_64; zh-cn; rv:1.9.2.10) gecko/20100922 ubuntu/10.10 (maverick) firefox/3.6.10", "mozilla/5.0 (windows nt 5.1; u; en; rv:1.8.1) gecko/20061208 firefox/2.0.0 opera 9.50", "mozilla/5.0 (windows nt 6.1; wow64) applewebkit/534.57.2 (khtml, like gecko) version/5.1.7 safari/534.57.2", "mozilla/5.0 (windows nt 6.1; wow64) applewebkit/537.36 (khtml, like gecko) chrome/30.0.1599.101 safari/537.36", "mozilla/5.0 (compatible; msie 9.0; windows nt 6.1; wow64; trident/5.0; slcc2; .net clr 2.0.50727; .net clr 3.5.30729; .net clr 3.0.30729; media center pc 6.0; .net4.0c; .net4.0e; lbbrowser) ", "mozilla/5.0 (compatible; msie 9.0; windows nt 6.1; wow64; trident/5.0; slcc2; .net clr 2.0.50727; .net clr 3.5.30729; .net clr 3.0.30729; media center pc 6.0; .net4.0c; .net4.0e; qqbrowser/7.0.3698.400)", "mozilla/5.0 (windows nt 6.1; wow64) applewebkit/537.36 (khtml, like gecko) chrome/38.0.2125.122 ubrowser/4.0.3214.0 safari/537.36", "mozilla/5.0 (linux; u; android 2.2.1; zh-cn; htc_wildfire_a3333 build/frg83d) applewebkit/533.1 (khtml, like gecko) version/4.0 mobile safari/533.1", "mozilla/5.0 (blackberry; u; blackberry 9800; en) applewebkit/534.1+ (khtml, like gecko) version/6.0.0.337 mobile safari/534.1+", "mozilla/5.0 (compatible; msie 9.0; windows phone os 7.5; trident/5.0; iemobile/9.0; htc; titan)", "mozilla/4.0 (compatible; msie 6.0; ) opera/ucweb7.0.2.37/28/999", "openwave/ ucweb7.0.2.37/28/999", "nokia5700/ ucweb7.0.2.37/28/999", "ucweb7.0.2.37/28/999", "mozilla/5.0 (hp-tablet; linux; hpwos/3.0.0; u; en-us) applewebkit/534.6 (khtml, like gecko) wosbrowser/233.70 safari/534.6 touchpad/1.0", "mozilla/5.0 (linux; u; android 3.0; en-us; xoom build/hri39) applewebkit/534.13 (khtml, like gecko) version/4.0 safari/534.13", "opera/9.80 (android 2.3.4; linux; opera mobi/build-1107180945; u; en-gb) presto/2.8.149 version/11.10", "mozilla/5.0 (ipad; u; cpu os 4_3_3 like mac os x; en-us) applewebkit/533.17.9 (khtml, like gecko) version/5.0.2 mobile/8j2 safari/6533.18.5", }; random random = new random(); var randomnumber = random.next(0, usersagents.length); return usersagents[randomnumber]; } public static async task get(string proxyip, int proxyport,int timeout, string randomuseragent, string url, action success, action<string> fail) { httpwebrequest request = null; httpwebresponse response = null; try { request = (httpwebrequest)webrequest.create(url); request.timeout = timeout; request.useragent = randomuseragent; request.proxy = new webproxy(proxyip,proxyport); response = await request.getresponseasync() as httpwebresponse; if (response.statuscode == httpstatuscode.ok) { success(); } else { fail(response+":"+response.statusdescription); } } catch (exception ex) { fail(ex.message.tostring()); } finally { if (request != null) { request.abort(); request = null; } if (response != null) { response.close(); response = null; } } } } |
redishelper.cs
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public class redishelper { private static readonly object locker = new object(); private static connectionmultiplexer _redis; private const string connecttionstring = "127.0.0.1:6379,defaultdatabase=3"; public const string redis_set_ket_success = "set_success_ip"; private static connectionmultiplexer manager { get { if (_redis == null) { lock (locker) { if (_redis != null) return _redis; _redis = getmanager(); return _redis; } } return _redis; } } private static connectionmultiplexer getmanager(string connectionstring = null) { if (string.isnullorempty(connectionstring)) { connectionstring = connecttionstring; } return connectionmultiplexer.connect(connectionstring); } public static void addrequestok(string key,string value,bool issuccess) { var db = manager.getdatabase(); if(issuccess) db.listleftpush(key,value); else db.listleftpush(key, value); } public static list<string> getproxy() { list<string> result = new list<string>(); var db = manager.getdatabase(); var values = db.setmembers(redis_set_ket_success); foreach (var value in values) { result.add(value.tostring()); } return result; } public static bool insertset(string value) { var db = manager.getdatabase(); return db.setadd(redis_set_ket_success, value); } public static bool removesetvalue(string value) { var db = manager.getdatabase(); return db.setremove(redis_set_ket_success,value); } } |
原文链接：https://www.cnblogs.com/zhangmumu/p/9275383.html
