C++实现网络爬虫
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 " + "HOST: " + host + " " + "Connection: close "; 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， ''); 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; }
