【转】网络爬虫获取网站图片

  转自：http://blog.csdn.net/huangxy10/article/details/8120106

  备注：把项目属性中的字符集改成多字节集合?  

  1 // 网络爬虫.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
/*

int _tmain(int argc, _TCHAR* argv[])
{
    return 0;
}

*/

//#include <Windows.h>  
#include <string>  
#include <iostream>  
#include <fstream>  
#include <vector>  
#include "winsock2.h"  
#include <time.h>  
#include <queue>  
#include <hash_set>  
  
#pragma comment(lib, "ws2_32.lib")   
using namespace std;  
  
#define DEFAULT_PAGE_BUF_SIZE 1048576  
  
queue<string> hrefUrl;  
hash_set<string> visitedUrl;  
hash_set<string> visitedImg;  
int depth=0;  
int g_ImgCnt=1;  
  
//解析URL，解析出主机名，资源名  
bool ParseURL( const string & url, string & host, string & resource){  
    if ( strlen(url.c_str()) > 2000 ) {  
        return false;  
    }  
  
    const char * pos = strstr( url.c_str(), "http://" );  
    if( pos==NULL ) pos = url.c_str();  
    else pos += strlen("http://");  
    if( strstr( pos, "/")==0 )  
        return false;  
    char pHost[100];  
    char pResource[2000];  
    sscanf( pos, "%[^/]%s", pHost, pResource );  
    host = pHost;  
    resource = pResource;  
    return true;  
}  
  
//使用Get请求，得到响应  
bool GetHttpResponse( const string & url, char * &response, int &bytesRead ){  
    string host, resource;  
    if(!ParseURL( url, host, resource )){  
        cout << "Can not parse the url"<<endl;  
        return false;  
    }  
      
    //建立socket  
    struct hostent * hp= gethostbyname( host.c_str() );  
    if( hp==NULL ){  
        cout<< "Can not find host address"<<endl;  
        return false;  
    }  
  
    SOCKET sock = socket( AF_INET, SOCK_STREAM, IPPROTO_TCP);  
    if( sock == -1 || sock == -2 ){  
        cout << "Can not create sock."<<endl;  
        return false;  
    }  
  
    //建立服务器地址  
    SOCKADDR_IN sa;  
    sa.sin_family = AF_INET;  
    sa.sin_port = htons( 80 );  
    //char addr[5];  
    //memcpy( addr, hp->h_addr, 4 );  
    //sa.sin_addr.s_addr = inet_addr(hp->h_addr);  
    memcpy( &sa.sin_addr, hp->h_addr, 4 );  
  
    //建立连接  
    if( 0!= connect( sock, (SOCKADDR*)&sa, sizeof(sa) ) ){  
        cout << "Can not connect: "<< url <<endl;  
        closesocket(sock);  
        return false;  
    };  
  
    //准备发送数据  
    string request = "GET " + resource + " HTTP/1.1
Host:" + host + "
Connection:Close

";  
  
    //发送数据  
    if( SOCKET_ERROR ==send( sock, request.c_str(), request.size(), 0 ) ){  
        cout << "send error" <<endl;  
        closesocket( sock );  
        return false;  
    }  
  
    //接收数据  
    int m_nContentLength = DEFAULT_PAGE_BUF_SIZE;  
    char *pageBuf = (char *)malloc(m_nContentLength);  
    memset(pageBuf, 0, m_nContentLength);  
  
    bytesRead = 0;  
    int ret = 1;  
    cout <<"Read: ";  
    while(ret > 0){  
        ret = recv(sock, pageBuf + bytesRead, m_nContentLength - bytesRead, 0);  
          
        if(ret > 0)  
        {  
            bytesRead += ret;  
        }  
  
        if( m_nContentLength - bytesRead<100){  
            cout << "
Realloc memorry"<<endl;  
            m_nContentLength *=2;  
            pageBuf = (char*)realloc( pageBuf, m_nContentLength);       //重新分配内存  
        }  
        cout << ret <<" ";  
    }  
    cout <<endl;  
  
    pageBuf[bytesRead] = '';  
    response = pageBuf;  
    closesocket( sock );  
    return true;  
    //cout<< response <<endl;  
}  
  
//提取所有的URL以及图片URL  
void HTMLParse ( string & htmlResponse, vector<string> & imgurls, const string & host ){  
    //找所有连接，加入queue中  
    const char *p= htmlResponse.c_str();  
    char *tag="href="";  
    const char *pos = strstr( p, tag );  
    ofstream ofile("url.txt", ios::app);  
    while( pos ){  
        pos +=strlen(tag);  
        const char * nextQ = strstr( pos, """ );  
        if( nextQ ){  
            char * url = new char[ nextQ-pos+1 ];  
            //char url[100]; //固定大小的会发生缓冲区溢出的危险  
            sscanf( pos, "%[^"]", url);  
            string surl = url;  // 转换成string类型，可以自动释放内存  
            if( visitedUrl.find( surl ) == visitedUrl.end() ){  
                visitedUrl.insert( surl );  
                ofile << surl<<endl;  
                hrefUrl.push( surl );  
            }  
            pos = strstr(pos, tag );  
            delete [] url;  // 释放掉申请的内存  
        }  
    }  
    ofile << endl << endl;  
    ofile.close();  
  
    tag ="<img ";  
    const char* att1= "src="";  
    const char* att2="lazy-src="";  
    const char *pos0 = strstr( p, tag );  
    while( pos0 ){  
        pos0 += strlen( tag );  
        const char* pos2 = strstr( pos0, att2 );  
        if( !pos2 || pos2 > strstr( pos0, ">") ) {  
            pos = strstr( pos0, att1);  
            if(!pos) {  
                pos0 = strstr(att1, tag );  
            continue;  
            } else {  
                pos = pos + strlen(att1);  
            }  
        }  
        else {  
            pos = pos2 + strlen(att2);  
        }  
  
        const char * nextQ = strstr( pos, """);  
        if( nextQ ){  
            char * url = new char[nextQ-pos+1];  
            sscanf( pos, "%[^"]", url);  
            cout << url<<endl;  
            string imgUrl = url;  
            if( visitedImg.find( imgUrl ) == visitedImg.end() ){  
                visitedImg.insert( imgUrl );  
                imgurls.push_back( imgUrl );  
            }  
            pos0 = strstr(pos0, tag );  
            delete [] url;  
        }  
    }  
    cout << "end of Parse this html"<<endl;  
}  
  
//把URL转化为文件名  
string ToFileName( const string &url ){  
    string fileName;  
    fileName.resize( url.size());  
    int k=0;  
    for( int i=0; i<(int)url.size(); i++){  
        char ch = url[i];  
        if( ch!='\'&&ch!='/'&&ch!=':'&&ch!='*'&&ch!='?'&&ch!='"'&&ch!='<'&&ch!='>'&&ch!='|')  
            fileName[k++]=ch;  
    }  
    return fileName.substr(0,k) + ".txt";  
}  
  
//下载图片到img文件夹  
void DownLoadImg( vector<string> & imgurls, const string &url ){  
  
    //生成保存该url下图片的文件夹  
    string foldname = ToFileName( url );  
    foldname = "./img/"+foldname;  
    if(!CreateDirectory( (LPCSTR)foldname.c_str(),NULL ))  
        cout << "Can not create directory:"<< foldname<<endl;  
    char *image;  
    int byteRead;  
    for( int i=0; i<imgurls.size(); i++){  
        //判断是否为图片，bmp，jgp，jpeg，gif   
        string str = imgurls[i];  
        int pos = str.find_last_of(".");  
        if( pos == string::npos )  
            continue;  
        else{  
            string ext = str.substr( pos+1, str.size()-pos-1 );  
            if( ext!="bmp"&& ext!="jpg" && ext!="jpeg"&& ext!="gif"&&ext!="png")  
                continue;  
        }  
        //下载其中的内容  
        if( GetHttpResponse(imgurls[i], image, byteRead)){  
            if ( strlen(image) ==0 ) {  
                continue;  
            }  
            const char *p=image;  
            const char * pos = strstr(p,"

")+strlen("

");  
            int index = imgurls[i].find_last_of("/");  
            if( index!=string::npos ){  
                string imgname = imgurls[i].substr( index , imgurls[i].size() );  
                ofstream ofile( foldname+imgname, ios::binary );  
                if( !ofile.is_open() )  
                    continue;  
                cout <<g_ImgCnt++<< foldname+imgname<<endl;  
                ofile.write( pos, byteRead- (pos-p) );  
                ofile.close();  
            }  
            free(image);  
        }  
    }  
}  
  
  
  
//广度遍历  
void BFS( const string & url ){  
    char * response;  
    int bytes;  
    // 获取网页的相应，放入response中。  
    if( !GetHttpResponse( url, response, bytes ) ){  
        cout << "The url is wrong! ignore." << endl;  
        return;  
    }  
    string httpResponse=response;  
    free( response );  
    string filename = ToFileName( url );  
    ofstream ofile( "./html/"+filename );  
    if( ofile.is_open() ){  
        // 保存该网页的文本内容  
        ofile << httpResponse << endl;  
        ofile.close();  
    }  
    vector<string> imgurls;  
    //解析该网页的所有图片链接，放入imgurls里面  
    HTMLParse( httpResponse,  imgurls, url );  
      
    //下载所有的图片资源  
    DownLoadImg( imgurls, url );  
}  
  
void main()  
{  
    //初始化socket，用于tcp网络连接  
    WSADATA wsaData;  
    if( WSAStartup(MAKEWORD(2,2), &wsaData) != 0 ){  
        return;  
    }  
  
    // 创建文件夹，保存图片和网页文本文件  
    CreateDirectory((LPCSTR) "./img",0);  
    CreateDirectory((LPCSTR)"./html",0);  
    //string urlStart = "http://hao.360.cn/meinvdaohang.html";  
  
    // 遍历的起始地址  
    // string urlStart = "http://www.wmpic.me/tupian";  
    string urlStart = "http://item.taobao.com/item.htm?spm=a230r.1.14.19.sBBNbz&id=36366887850&ns=1#detail";  
      
    // 使用广度遍历  
    // 提取网页中的超链接放入hrefUrl中，提取图片链接，下载图片。  
    BFS( urlStart );  
  
    // 访问过的网址保存起来  
    visitedUrl.insert( urlStart );  
  
    while( hrefUrl.size()!=0 ){  
        string url = hrefUrl.front();  // 从队列的最开始取出一个网址  
        cout << url << endl;  
        BFS( url );                   // 遍历提取出来的那个网页，找它里面的超链接网页放入hrefUrl，下载它里面的文本，图片  
        hrefUrl.pop();                 // 遍历完之后，删除这个网址  
    }  
    WSACleanup();  
    return;  
}