Download the C ++ code of an object through HTTP and compile and run it.

First create a website on the local machine, enable it, and then you can test it. Problem: You need to select a non-sustainable connection in the HTTP request header. If you do not write this row while Recv () will keep waiting for the input. (Personal understanding, no information found, do not know if it is correct) // httpclient. hfile # ifndef httpclient_h _ # define httpclient_h _ # include <string> # include <Winsock. h> # include <iostream> # include <fstream> # pragma comment (Lib, "ws2_32.lib") // # define tempdirectory "C: \" using namespace STD; class httpclient {public: httpclient (void );~ Httpclient (void); bool httpclient: downloadfile (socket parmsock, string servername, string sourcepath, string filename, string localdirectory, string port);}; # endif // httpclient. CPP file # include "httpclient. H "httpclient: httpclient (void) {} httpclient ::~ Httpclient (void) {}// for example servername = "127.0.0.1" or "localhost" // sourcepath = "/ABC/" // filename = "config. XML "// localdirectory =" C: \ "bool httpclient: downloadfile (socket parmsock, string servername, string sourcepath, string filename, string localdirectory, string port) {ofstream fout; string newfile = localdirectory + filename; // identifies the Chinese path and file name STD: locale: Global (STD: locale (""); fout. open (Newfile. c_str (), ios_base: Binary); If (! Fout. is_open () {cout <"Open newfile error! "<Endl;} Char szbuffer [1024]; // convert'' in the directory and file name to "% 20" // sourcepathint NPOs = sourcepath. find (""); While (NPOs + 1) {NPOs = sourcepath. find (""); If (NPOs =-1) break; sourcepath. replace (NPOs, strlen (""), "% 20");} // filenamenpos = filename. find (""); While (NPOs + 1) {NPOs = filename. find (""); If (NPOs =-1) break; filename. replace (NPOs, strlen (""), "% 20");} string requestfile = sourcepath + filename; //////////////////////////////////////// /////////////// // format the HTTP header // sprintf (szbuffer, "Get % s HTTP/1.1 \ r \ n", requestfile. c_str (); // strcat (szbuffer, "Host:"); strcat (szbuffer, servername. c_str (); strcat (szbuffer, ":"); strcat (szbuffer, port. c_str (); strcat (szbuffer, "\ r \ n"); // The third line // strcat (szbuffer, "accept :*/*"); /* strcat (szbuffer, "\ r \ n "); //// // The fourth line (optional) strcat (szbuffer, "User-Agent: generaldownloadapplication"); strcat (szbuffer, "\ r \ n"); * // the fifth line of the non-persistent connection strcat (szbuffer, "connection: close "); strcat (szbuffer," \ r \ n "); // The last line of strcat (szbuffer," \ r \ n "); int nret = Send (parmsock, szbuffer, strlen (szbuffer), 0); If (nret = socket_error) {cout <"Send () error" <Endl; closesocket (parmsock); Return false ;} /// receive the file contents and print to stdout //////////////////////////// /// // HTTP header, the size should not exceed 1024 bytes, only processing is performed at the first reception ///////////////////////////////// /// // nret = Recv (parmsock, szbuffer, sizeof (szbuffer), 0); If (nret = socket_error) {cout <"Recv () error" <Endl; closesocket (parmsock); fout. close (); wsacleanup (); Return false ;} //////////////////////////////////////// //////////////

// Determine whether the file exists

        std::string strBuffer = szBuffer; 

        std::string firstString = strBuffer.substr(0,strBuffer.find("\r\n")); 

        int File_Exist = firstString.find("200"); 

        if(File_Exist == -1) 

        {  

              cout<<"File not found in the web."<<endl;  

              return false; 

         }

// Get the start position of the file content int I = 0; while (1) {If (szbuffer [I] = '\ R ') & (szbuffer [I + 1] = '\ n') & (szbuffer [I + 2] =' \ R ') & (szbuffer [I + 3] = '\ n') {break;} I ++;} // start int filebegin = I + 4; //////////////////////////////////////// /// // for (I = filebegin; I <nret; I ++) {fout. write (& szbuffer [I], sizeof (szbuffer [I]);}/* Static int COUNT = 0; count + = nret-filebegin ;*/

While (1) {// wait to receive, nret = numberofbytesreceived nret = Recv (parmsock, szbuffer, sizeof (szbuffer), 0); If (nret = socket_error) {cout <"Recv () error" <Endl; closesocket (parmsock); fout. close (); wsacleanup (); Return false ;} //////////////////////////////////////// /// // cout <"\ nrecv () returned "<nret <" bytes "<Endl; If (nret = 0) break; // write to stdoutcount + = NRE T; fout. write (szbuffer, nret);} closesocket (parmsock); fout. close (); wsacleanup (); Return true;} // main. CPP file # include "httpclient. H "// # include <iostream> int main () {httpclient m; // M. downloadfile ("localhost", "/ABC/", "config. XML "," d :\\ "); STD: String url =" http: // localhost/water lilies.jpg "; STD: String localdirectory =" D: \ China \ "; STD: string port =" 5550 "; // cout <m. contentlengthint <Endl; // cout <m. R Angeint <Endl; //////////////////////////////////////// /// // STD:: String removeprotocol; STD: String servername; STD: String sourcepath; STD: String filename; int ret; ret = URL. find ("http: //"); If (Ret! =-1) {removeprotocol = URL. substr (strlen ("http: //");} else {removeprotocol = URL;}/* ret = URL. find ("https: //"); If (Ret! =-1) {removeprotocol = URL. substr (strlen ("https: //");} else {removeprotocol = URL;} */ret = removeprotocol. find_first_of ('/'); servername = removeprotocol. substr (0, RET); int net = removeprotocol. find_last_of ('/'); sourcepath = removeprotocol. substr (Ret, net-ret + 1); filename = removeprotocol. substr (net + 1 ); //////////////////////////////////////// /// // wsadata; int nret; // ini Tialize Winsock. dll // nret = wsastartup (0x101, & wsadata); If (nret) {wsacleanup (); Return false;} If (wsadata. wversion! = 0x101) {wsacleanup (); Return false;} in_addr iahost; lphostent lphostentry; iahost. s_addr = inet_addr (servername. c_str (); If (iahost. s_addr = inaddr_none) {// wasn' t an IP address string, assume it is a name lphostentry = gethostbyname (servername. c_str ();} else {// It was a valid IP address string lphostentry = gethostbyaddr (const char *) & iahost, sizeof (struct in_addr), af_inet );} if (lphostentry = NULL) {cout <"gethostbyname () error" <Endl; return false ;} /// create a TCP/IP stream socket // socket parmsock; parmsock = socket (af_inet, sock_stream, ipproto_tcp); If (parmsock = invalid_socket) {cout <"socket () error" <Endl; return false;} // find the port number for the HTTP service on TCP // lpservent; sockaddr_in saserver; lpservent = getservbyname ("HTTP", "TCP"); If (lpservent = NULL) saserver. sin_port = htons (80); elsesaserver. sin_port = lpservent-> s_port; // fill in the rest of the server address structure // saserver. sin_family = af_inet; saserver. sin_addr = * (lpin_addr) * lphostentry-> h_addr_list); // connect the socket // nret = connect (parmsock, (lpsockaddr) & saserver, sizeof (sockaddr_in); If (nret = socket_error) {cout <"Connect () error" <Endl; closesocket (parmsock); Return false ;} //////////////////////////////////////// /// // M. downloadfile (parmsock, servername, sourcepath, filename, localdirectory, Port); System ("pause"); Return 0 ;}