Linux企业级项目实践之网络爬虫（4）——主程序流程

当我们设计好程序框架之后就要开始实现它了。第一步当然是要实现主程序的流程框架。之后我们逐渐填充每个流程的细节和其需要调用的模块。

主程序的流程如下：

1、  解析命令行参数，并根据参数跳转到相应的处理分支

2、  解析配置文件

3、  载入处理模块

4、  加载种子URL

5、  启动抓取任务

主程序的代码如下：

int main(int argc, void *argv[])
{
   struct epoll_event events[10];
   int daemonized = 0;
   char ch;

   while ((ch = getopt(argc, (char* const*)argv, "vhd")) != -1) {
        switch(ch) {
            case 'v':
                version();
                break;
            case 'd':
                daemonized = 1;
                break;
            case 'h':
            case '?':
            default:
                usage();
        }
   }

   g_conf = initconfig();
   loadconfig(g_conf);

   set_nofile(1024);

   vector<char *>::iterator it = g_conf->modules.begin();
   for(; it != g_conf->modules.end(); it++) {
        dso_load(g_conf->module_path, *it);
   }

   if (g_conf->seeds == NULL) {
        SPIDER_LOG(SPIDER_LEVEL_ERROR, "Wehave no seeds, Buddy!");
   } else {
        int c = 0;
        char ** splits =strsplit(g_conf->seeds, ',', &c, 0);
        while (c--) {
            Surl * surl = (Surl*)malloc(sizeof(Surl));
            surl->url =url_normalized(strdup(splits[c]));
            surl->level = 0;
            surl->type = TYPE_HTML;
            if (surl->url != NULL)
                push_surlqueue(surl);
       }
   }       

   if (daemonized)
        daemonize();

   chdir("download");

   int err = -1;
   if ((err = create_thread(urlparser, NULL, NULL, NULL)) < 0) {
        SPIDER_LOG(SPIDER_LEVEL_ERROR,"Create urlparser thread fail: %s", strerror(err));
   }

   int try_num = 1;
   while(try_num < 8 && is_ourlqueue_empty())
        usleep((10000 << try_num++));

   if (try_num >= 8) {
        SPIDER_LOG(SPIDER_LEVEL_ERROR, "NOourl! DNS parse error?");
   }

   if (g_conf->stat_interval > 0) {
        signal(SIGALRM, stat);
        set_ticker(g_conf->stat_interval);
   }

   int ourl_num = 0;
   g_epfd = epoll_create(g_conf->max_job_num);

   while(ourl_num++ < g_conf->max_job_num) {
        if (attach_epoll_task() < 0)
            break;
   }

   int n, i;
   while(1) {
        n = epoll_wait(g_epfd, events, 10,2000);
        printf("epoll:%d\n",n);
        if (n == -1)
            printf("epollerrno:%s\n",strerror(errno));
        fflush(stdout);

        if (n <= 0) {
            if (g_cur_thread_num <= 0&& is_ourlqueue_empty() && is_surlqueue_empty()) {
                sleep(1);
                if (g_cur_thread_num <= 0&& is_ourlqueue_empty() && is_surlqueue_empty())
                    break;
            }
        }

        for (i = 0; i < n; i++) {
            evso_arg * arg = (evso_arg*)(events[i].data.ptr);
            if ((events[i].events &EPOLLERR) ||
                (events[i].events &EPOLLHUP) ||
                (!(events[i].events &EPOLLIN))) {
                SPIDER_LOG(SPIDER_LEVEL_WARN,"epoll fail, close socket %d",arg->fd);
                close(arg->fd);
                continue;
            }
            epoll_ctl(g_epfd, EPOLL_CTL_DEL,arg->fd, &events[i]); /* del event */

            printf("helloepoll:event=%d\n",events[i].events);
            fflush(stdout);
            create_thread(recv_response, arg,NULL, NULL);
        }
   }

   SPIDER_LOG(SPIDER_LEVEL_DEBUG, "Task done!");
   close(g_epfd);
   return 0;
}