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：
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
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
dy("nrwz");