具有多接口的cURL，用于使用代理的多个连接

我需要检查从一个网站列表中的许多代理。我决定用libcurl来做这个。 我使用了这个例子，并根据我的需要进行了修改。 这是我的密码：

#include <cstdio>
#include <cstring>
#include <fstream>
#include <string>
#include <iostream>

#include <curl/curl.h>

/* somewhat unix-specific */ 
#include <sys/time.h>
#include <unistd.h>

using namespace std;

CURL * handles [100];

CURL * createProxyHandle (string proxyData){
    CURL * handle = curl_easy_init ();

    curl_slist * chunk = NULL;
    chunk = curl_slist_append(chunk, "Accept: text/html, application/xml;q=0.9, application/xhtml+xml, image/png, image/webp, image/jpeg, image/gif, image/x-xbitmap, */*;q=0.1");
    chunk = curl_slist_append(chunk, "Accept-Language: ru-RU,ru;q=0.9,en;q=0.8");
    chunk = curl_slist_append(chunk, "Accept-Encoding: gzip, deflate, sdch");

    curl_easy_setopt (handle, CURLOPT_URL, "<site>");
    curl_easy_setopt (handle, CURLOPT_CONNECTTIMEOUT, 40);
    curl_easy_setopt (handle, CURLOPT_TIMEOUT, 50);
    curl_easy_setopt (handle, CURLOPT_FRESH_CONNECT, true);
    curl_easy_setopt (handle, CURLOPT_VERBOSE, true);
    curl_easy_setopt (handle, CURLOPT_FOLLOWLOCATION, true);

    curl_easy_setopt (handle, CURLOPT_ENCODING , "gzip");
    curl_easy_setopt (handle, CURLOPT_PROXY, proxyData.c_str());
    curl_easy_setopt (handle, CURLOPT_HTTPHEADER, chunk);
    curl_easy_setopt (handle, CURLOPT_USERAGENT, "Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.65 Safari/537.36");

    return handle;
}

int main(){
    ifstream fin ("data.txt", ifstream::in);
    string proxy;

    CURLM *multi_handle;
    CURLMsg *msg;

    int msgs_left;
    int still_running;



    multi_handle = curl_multi_init();

    while (fin >> proxy){
        cout << "Proxy: " << proxy << endl;
        CURL * handle = createProxyHandle (proxy);
        curl_multi_add_handle(multi_handle, handle);
    }

    curl_multi_perform(multi_handle, &still_running);

do {
    struct timeval timeout;
    int rc; /* select() return code */ 
    CURLMcode mc; /* curl_multi_fdset() return code */ 

    fd_set fdread;
    fd_set fdwrite;
    fd_set fdexcep;
    int maxfd = -1;

    long curl_timeo = -1;

    FD_ZERO(&fdread);
    FD_ZERO(&fdwrite);
    FD_ZERO(&fdexcep);

    /* set a suitable timeout to play around with */ 
    timeout.tv_sec = 1;
    timeout.tv_usec = 0;

    curl_multi_timeout(multi_handle, &curl_timeo);
    if(curl_timeo >= 0) {
      timeout.tv_sec = curl_timeo / 1000;
      if(timeout.tv_sec > 1)
        timeout.tv_sec = 1;
      else
        timeout.tv_usec = (curl_timeo % 1000) * 1000;
    }

    /* get file descriptors from the transfers */ 
    mc = curl_multi_fdset(multi_handle, &fdread, &fdwrite, &fdexcep, &maxfd);

    if(mc != CURLM_OK)
    {
      fprintf(stderr, "curl_multi_fdset() failed, code %d.\n", mc);
      break;
    }

    /* On success the value of maxfd is guaranteed to be >= -1. We call
       select(maxfd + 1, ...); specially in case of (maxfd == -1) there are
       no fds ready yet so we call select(0, ...) --or Sleep() on Windows--
       to sleep 100ms, which is the minimum suggested value in the
       curl_multi_fdset() doc. */ 

    if(maxfd == -1) {
#ifdef _WIN32
      Sleep(100);
      rc = 0;
#else
      /* Portable sleep for platforms other than Windows. */ 
      struct timeval wait = { 0, 100 * 1000 }; /* 100ms */ 
      rc = select(0, NULL, NULL, NULL, &wait);
#endif
    }
    else {
      /* Note that on some platforms 'timeout' may be modified by select().
         If you need access to the original value save a copy beforehand. */ 
      rc = select(maxfd+1, &fdread, &fdwrite, &fdexcep, &timeout);
    }

    switch(rc) {
    case -1:
      /* select error */ 
      break;
    case 0:
    default:
      /* timeout or readable/writable sockets */ 
      curl_multi_perform(multi_handle, &still_running);
      break;
    }
  } while(still_running);

   while ((msg = curl_multi_info_read(multi_handle, &msgs_left))) {
        if (msg->msg == CURLMSG_DONE) {
          printf("Finished with %d\n", msg->data.result);
        }
      }
    cout << "Completed" << endl;
    curl_multi_cleanup(multi_handle);

    return 0;
}

代理不可靠，但我在输出中看到：

Proxy: 69.12.64.105:8089
Proxy: 69.12.64.105:7808
Proxy: 210.245.20.170:80
Proxy: 190.74.165.109:8080
Proxy: 39.184.2.111:8123
Proxy: 190.201.166.37:8080
Proxy: 190.36.85.199:8080
Proxy: 92.255.231.54:8080
Proxy: 124.126.126.101:80
Proxy: 43.250.255.65:8080
Proxy: 69.12.64.106:7808
Proxy: 201.217.213.166:8080
Proxy: 178.169.90.188:8888
Proxy: 124.248.205.25:8080
Proxy: 39.190.82.133:8123
Proxy: 190.77.230.36:8080
* Rebuilt URL to: <site>
* Hostname was NOT found in DNS cache
*   Trying 69.12.64.105...
* Rebuilt URL to: <site>
* Hostname was NOT found in DNS cache
*   Trying 69.12.64.105...
* Rebuilt URL to: <site>
* Hostname was NOT found in DNS cache
*   Trying 210.245.20.170...
* Rebuilt URL to: <site>
* Hostname was NOT found in DNS cache
*   Trying 190.74.165.109...
* Rebuilt URL to: <site>
* Hostname was NOT found in DNS cache
*   Trying 39.184.2.111...
* Rebuilt URL to: <site>
* Hostname was NOT found in DNS cache
*   Trying 190.201.166.37...
* Rebuilt URL to: <site>
* Hostname was NOT found in DNS cache
*   Trying 190.36.85.199...
* Rebuilt URL to: <site>
* Hostname was NOT found in DNS cache
*   Trying 92.255.231.54...
* Rebuilt URL to: <site>
* Hostname was NOT found in DNS cache
*   Trying 124.126.126.101...
* Rebuilt URL to: <site>
* Hostname was NOT found in DNS cache
*   Trying 43.250.255.65...
* Rebuilt URL to: <site>
* Hostname was NOT found in DNS cache
*   Trying 69.12.64.106...
* Rebuilt URL to: <site>
* Hostname was NOT found in DNS cache
*   Trying 201.217.213.166...
* Rebuilt URL to: <site>
* Hostname was NOT found in DNS cache
*   Trying 178.169.90.188...
* Rebuilt URL to: <site>
* Hostname was NOT found in DNS cache
*   Trying 124.248.205.25...
* Rebuilt URL to: <site>
* Hostname was NOT found in DNS cache
*   Trying 39.190.82.133...
* Rebuilt URL to: <site>
* Hostname was NOT found in DNS cache
*   Trying 190.77.230.36...
* Connected to 69.12.64.105 (69.12.64.105) port 8089 (#0)
* Establish HTTP proxy tunnel to <site>:443
> CONNECT <site>:443 HTTP/1.1
Host: <site>:443
User-Agent: Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.65 Safari/537.36
Proxy-Connection: Keep-Alive
Accept: text/html, application/xml;q=0.9, application/xhtml+xml, image/png, image/webp, image/jpeg, image/gif, image/x-xbitmap, */*;q=0.1
Accept-Language: ru-RU,ru;q=0.9,en;q=0.8
Accept-Encoding: gzip, deflate, sdch

< HTTP/1.1 503 Service Unavailable
< Server: squid/3.2.13
< Mime-Version: 1.0
< Date: Mon, 20 Apr 2015 23:00:24 GMT
< Content-Type: text/html
< Content-Length: 3694
< X-Squid-Error: ERR_DNS_FAIL 0
< 
* Received HTTP code 503 from proxy after CONNECT
* Connected to 69.12.64.105 (69.12.64.105) port 7808 (#1)
* Establish HTTP proxy tunnel to <site>:443
> CONNECT <site>:443 HTTP/1.1
Host: <site>:443
User-Agent: Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.65 Safari/537.36
Proxy-Connection: Keep-Alive
Accept: text/html, application/xml;q=0.9, application/xhtml+xml, image/png, image/webp, image/jpeg, image/gif, image/x-xbitmap, */*;q=0.1
Accept-Language: ru-RU,ru;q=0.9,en;q=0.8
Accept-Encoding: gzip, deflate, sdch

< HTTP/1.1 503 Service Unavailable
< Server: squid/3.2.13
< Mime-Version: 1.0
< Date: Mon, 20 Apr 2015 23:00:25 GMT
< Content-Type: text/html
< Content-Length: 3694
< X-Squid-Error: ERR_DNS_FAIL 0
< 
* Received HTTP code 503 from proxy after CONNECT
* Connected to 43.250.255.65 (43.250.255.65) port 8080 (#9)
* Establish HTTP proxy tunnel to <site>:443
> CONNECT <site>:443 HTTP/1.1
Host: <site>:443
User-Agent: Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.65 Safari/537.36
Proxy-Connection: Keep-Alive
Accept: text/html, application/xml;q=0.9, application/xhtml+xml, image/png, image/webp, image/jpeg, image/gif, image/x-xbitmap, */*;q=0.1
Accept-Language: ru-RU,ru;q=0.9,en;q=0.8
Accept-Encoding: gzip, deflate, sdch

< HTTP/1.1 200 OK
< 
* Proxy replied OK to CONNECT request
* found 173 certificates in /etc/ssl/certs/ca-certificates.crt
* Connected to 69.12.64.106 (69.12.64.106) port 7808 (#10)
* Establish HTTP proxy tunnel to <site>:443
> CONNECT <site>:443 HTTP/1.1
Host: <site>:443
User-Agent: Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.65 Safari/537.36
Proxy-Connection: Keep-Alive
Accept: text/html, application/xml;q=0.9, application/xhtml+xml, image/png, image/webp, image/jpeg, image/gif, image/x-xbitmap, */*;q=0.1
Accept-Language: ru-RU,ru;q=0.9,en;q=0.8
Accept-Encoding: gzip, deflate, sdch

< HTTP/1.1 200 Connection established
< 
* Proxy replied OK to CONNECT request
* found 173 certificates in /etc/ssl/certs/ca-certificates.crt
* Connected to 190.77.230.36 (190.77.230.36) port 8080 (#15)
* Establish HTTP proxy tunnel to <site>:443
> CONNECT <site>:443 HTTP/1.1
Host: <site>:443
User-Agent: Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.65 Safari/537.36
Proxy-Connection: Keep-Alive
Accept: text/html, application/xml;q=0.9, application/xhtml+xml, image/png, image/webp, image/jpeg, image/gif, image/x-xbitmap, */*;q=0.1
Accept-Language: ru-RU,ru;q=0.9,en;q=0.8
Accept-Encoding: gzip, deflate, sdch

< HTTP/1.0 200 Connection established
< Proxy-agent: tinyproxy/1.8.2
< 
* Proxy replied OK to CONNECT request
* found 173 certificates in /etc/ssl/certs/ca-certificates.crt
* Connected to 39.184.2.111 (39.184.2.111) port 8123 (#4)
* Establish HTTP proxy tunnel to <site>:443
> CONNECT <site>:443 HTTP/1.1
Host: <site>:443
User-Agent: Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.65 Safari/537.36
Proxy-Connection: Keep-Alive
Accept: text/html, application/xml;q=0.9, application/xhtml+xml, image/png, image/webp, image/jpeg, image/gif, image/x-xbitmap, */*;q=0.1
Accept-Language: ru-RU,ru;q=0.9,en;q=0.8
Accept-Encoding: gzip, deflate, sdch

* Proxy CONNECT aborted due to timeout
* Connection time-out
* Closing connection 5
* Connection time-out
* Closing connection 6
* Connection time-out
* Closing connection 7
* Connection time-out
* Closing connection 8
* SSL connection timeout
* Closing connection 9
* SSL connection timeout
* Closing connection 10
* Connection time-out
* Closing connection 11
* Connection time-out
* Closing connection 12
* Connection time-out
* Closing connection 13
* Connection time-out
* Closing connection 14
* SSL connection timeout
* Closing connection 15
* Connection timed out after 50056 milliseconds
* Connection timed out after 50055 milliseconds
Finished with 56
Finished with 56
Finished with 56
Finished with 28
Finished with 28
Finished with 28
Finished with 28
Finished with 28
Finished with 28
Finished with 28
Finished with 28
Finished with 28
Finished with 28
Finished with 28
Finished with 28
Finished with 28
Completed

在某些情况下，确实有很多代理是不好的，但列表中并非所有的curl都从代理接收答案，发送标题，仅此而已。我分别测试了这些代理，它们都正常。 我无法理解curl multi发生了什么。

在这个curl中，multi接口有一些限制。我意识到我使用了以下限制功能：

NSS SSL连接 HTTP代理连接操作 作为这个问题的解决方案，我使用了带有POSIX线程的curl easy接口，它工作得很好。这是我的解决方案，简单地说，这是一些安全使用多线程TLS的代码：

#define USE_GNUTLS

#include <cstdio>
#include <pthread.h>

#include <curl/curl.h>

/* we have this global to let the callback get easy access to it */
static pthread_mutex_t *lockarray;

#ifdef USE_GNUTLS
#include <gcrypt.h>
#include <errno.h>

GCRY_THREAD_OPTION_PTHREAD_IMPL;

void init_locks(void)
{
  gcry_control(GCRYCTL_SET_THREAD_CBS);
}

#define kill_locks()
#endif

static void *pull_one_url(void *url)
{
    FILE * file = fopen ("/dev/null", "w");

    CURL * handle = curl_easy_init ();

    curl_slist * chunk = NULL;
    chunk = curl_slist_append(chunk, "Accept: text/html, application/xml;q=0.9, application/xhtml+xml, image/png, image/webp, image/jpeg, image/gif, image/x-xbitmap, */*;q=0.1");
    chunk = curl_slist_append(chunk, "Accept-Language: ru-RU,ru;q=0.9,en;q=0.8");
    chunk = curl_slist_append(chunk, "Accept-Encoding: gzip, deflate, sdch");

    curl_easy_setopt (handle, CURLOPT_URL, "https://www.avito.ru");
    curl_easy_setopt (handle, CURLOPT_CONNECTTIMEOUT, 30);
    curl_easy_setopt (handle, CURLOPT_TIMEOUT, 30);
    curl_easy_setopt (handle, CURLOPT_FRESH_CONNECT, true);
    //curl_easy_setopt (handle, CURLOPT_VERBOSE, true);
    curl_easy_setopt (handle, CURLOPT_FOLLOWLOCATION, true);
    curl_easy_setopt (handle, CURLOPT_WRITEDATA, file);
    curl_easy_setopt (handle, CURLOPT_TCP_KEEPALIVE, 0L);

    curl_easy_setopt (handle, CURLOPT_ENCODING , "gzip");
    curl_easy_setopt (handle, CURLOPT_PROXY, (const char*) url);
    curl_easy_setopt (handle, CURLOPT_HTTPHEADER, chunk);
    curl_easy_setopt (handle, CURLOPT_USERAGENT, "Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.65 Safari/537.36");

    CURLcode res = curl_easy_perform (handle);
    if (res != CURLE_OK){
        printf ("Proxy %s failed with: %d (%s)\n", (const char*) url, res, curl_easy_strerror (res));
    } else {
        long http_code = 0;
        curl_easy_getinfo (handle, CURLINFO_RESPONSE_CODE, &http_code);

        printf("Proxy %s finished with code: %d\n", (const char*) url, http_code);
    }


    curl_easy_cleanup (handle);

    return NULL;
}

const int NUMT = 21;

const char * urls[] = {
        "69.12.64.105:8089",
        "69.12.64.105:7808",
        "210.245.20.170:80",
        "190.74.165.109:8080",
        "39.184.2.111:8123",
        "190.201.166.37:8080",
        "190.36.85.199:8080",
        "92.255.231.54:8080",
        "124.126.126.101:80",
        "43.250.255.65:8080",
        "69.12.64.106:7808",
        "201.217.213.166:8080",
        "178.169.90.188:8888",
        "124.248.205.25:8080",
        "39.190.82.133:8123",
        "190.77.230.36:8080",
        "201.243.204.230:8080",
        "190.201.58.26:8080",
        "178.166.155.36:8080",
        "183.221.188.66:8123",
        "207.66.105.37:24040",
};


int main(int argc, char **argv)
{
    pthread_t tid[NUMT];
    int i;
    int error;
    (void)argc; /* we don't use any arguments in this example */
    (void)argv;

    /* Must initialize libcurl before any threads are started */
    curl_global_init(CURL_GLOBAL_ALL);

    init_locks();

    for(i=0; i< NUMT; i++) {
        error = pthread_create(&tid[i],
                               NULL, /* default attributes please */
                               pull_one_url,
                               (void *)urls[i]);
        if(0 != error)
            fprintf(stderr, "Couldn't run thread number %d, errno %d\n", i, error);
        else
            fprintf(stderr, "Thread %d, gets %s\n", i, urls[i]);
    }

    /* now wait for all threads to terminate */
    for(i=0; i< NUMT; i++) {
        error = pthread_join(tid[i], NULL);
        fprintf(stderr, "Thread %d terminated\n", i);
    }

    kill_locks();

    return 0;
}