C++实现网络爬虫
#include <iostream> #include <vector> #include <list> #include <map> #include <queue> #include <string> #include <utility> #include <regex> #include <fstream> #include <WinSock2.h> #include <Windows.h> #pragma comment(lib, "ws2_32.lib") using namespace std; void startupWSA() { WSADATA wsadata; WSAStartup( MAKEWORD(2,0), &wsadata); } inline void cleanupWSA() { WSACleanup(); } inline pair<string, string> binaryString(const string &str, const string &dilme) { pair<string, string> result(str, ""); auto pos = str.find(dilme); if ( pos != string::npos ) { result.first = str.substr(0, pos); result.second = str.substr(pos + dilme.size()); } return result; } inline string getIpByHostName(const string &hostName) { hostent* phost = gethostbyname( hostName.c_str() ); return phost? inet_ntoa(*(in_addr *)phost->h_addr_list[0]): ""; } inline SOCKET connect(const string &hostName) { auto ip = getIpByHostName(hostName); if ( ip.empty() ) return 0; auto sock = socket(AF_INET, SOCK_STREAM, 0); if ( sock == INVALID_SOCKET ) return 0; SOCKADDR_IN addr; addr.sin_family = AF_INET; addr.sin_port = htons(80); addr.sin_addr.s_addr = inet_addr(ip.c_str()); if ( connect(sock, (const sockaddr *)&addr, sizeof(SOCKADDR_IN)) == SOCKET_ERROR ) return 0; return sock; } inline bool sendRequest(SOCKET sock, const string &host, const string &get) { string http = "GET " + get + " HTTP/1.1\r\n" + "HOST: " + host + "\r\n" + "Connection: close\r\n\r\n"; return http.size() == send(sock, &http[0], http.size(), 0); } inline string recvRequest(SOCKET sock) { static timeval wait = {2, 0}; static auto buffer = string(2048 * 100, '\0'); auto len = 0, reclen = 0; do { fd_set fd = {0}; FD_SET(sock, &fd); reclen = 0; if ( select(0, &fd, nullptr, nullptr, &wait) > 0 ) { reclen = recv(sock, &buffer[0] + len, 2048 * 100 - len, 0); if (reclen > 0) len += reclen; } FD_ZERO(&fd); } while (reclen > 0); return len > 11 ? buffer[9] == '2' && buffer[10] == '0' && buffer[11] == '0' ? buffer.substr(0, len) : "" : ""; } inline void extUrl(const string &buffer, queue<string> &urlQueue) { if (buffer.empty()) { return ; } smatch result; auto curIter = buffer.begin(); auto endIter = buffer.end(); while ( regex_search(curIter, endIter, result, regex("href=\"(https?:)?//\\S+\"") ) ) { urlQueue.push(regex_replace( result[0].str(), regex("href=\"(https?:)?//(\\S+)\""), "$2") ); curIter = result[0].second; } } void Go(const string &url, int count) { queue<string> urls; urls.push(url); for (auto i = 0; i != count; ++i) { if ( !urls.empty() ) { auto &url = urls.front(); auto pair = binaryString( url, "/" ); auto sock = connect(pair.first); if ( sock && sendRequest(sock, pair.first, "/" + pair.second) ) { auto buffer = move( recvRequest(sock) ); extUrl(buffer, urls); } closesocket(sock); cout << url << ": count=> " << urls.size() << endl; urls.pop(); } } } int main() { startupWSA(); Go("www.hao123.com", 200); cleanupWSA(); return 0; } |
