MFC download and save file code reprint via URL

Http://blog.csdn.net/charlessimonyi/article/details/8666108?utm_source=tuicool&utm_medium=referral

We know that the Windows API for network connectivity is in Wininet.h, and in MFC, these APIs are encapsulated as classes.

CInternetSession class: Directly inherits from the CObject class, which is used to establish a session with an Internet server

CInternetConnection class: Helps users manage connections to Internet servers while also providing some functions to complete and respond to server communications

The CInternetConnection class also derives three classes:

CHttpConnection class: Managing Connections to HTTP Servers

CFtpConnection class: For managing connections to FTP servers

CGopherConnection class: Managing Connections to Gopher servers

We need CInternetSession, CHttpConnection, chttpfile to implement download and save files based on URLs.

What does chttpfile use to do? It can be associated with a Web object that the URL points to, because CHttpFile inherits and CFile, we can download it from the HTTP server just like a CFile file.

MFC is the CHttpFile object through the read and write to complete the dialogue with the HTTP server, including Get/post submit data, receive data.

Here is my own write a function based on the URL to download and save the file, note that you need to use the MFC project in the precompiled header file to include # include <AFXINET.H>, because the above-mentioned classes are all in this header file.

The first parameter is a URL, and the second parameter is the save path.

return value:

0: Successful Download save

-1:url not correct

-2: Failed to establish network connection

-3: Failed to initiate a GET request to the server

-4: The server does not accept requests

-5: Parameter one cannot be empty

-6: Parameter two cannot be empty

-7: Failed to create or write to file when saving file

1INT GetFile (ConstCString strURL,ConstCString Strsavepath)2 {3     //Check the two parameters passed in4     if(Strurl.isempty ())5         return-5;6     if(Strsavepath.isempty ())7         return-6;8 9Unsigned ShortNport;//used to save the destination HTTP service PortTenCString strserver, Strobject;//strserver is used to save the server address, Strobject is used to save the file object name OneDWORD Dwservicetype,dwret;//Dwservicetype is used to save the service type, Dwret is used to save the status number returned by the Submit GET request A  -     //parse URL, get information -     if(!AfxParseURL (strURL, Dwservicetype, strserver, Strobject, nport)) the     { -         //parse failed, the URL is incorrect -         return-1; -     } +     //Create a network Connection object, an HTTP connection object pointer, and a pointer to the Httpfile file object for the connection, note that the delete - CInternetSession intsess; +CHttpFile *phtfile =NULL; A     //Establish a network connection atCHttpConnection *phtcon =intsess. GetHttpConnection (strserver,nport); -     if(Phtcon = =NULL) -     { -         //failed to establish network connection - intsess. Close (); -         return-2; in     } -     //initiating a GET request toPhtfile = phtcon->openrequest (chttpconnection::http_verb_get,strobject); +     if(Phtfile = =NULL) -     { the         //failed to initiate GET request * intsess. Close (); $         DeletePhtcon;phtcon =NULL;Panax Notoginseng         return-3; -     } the     //Submit Request +Phtfile->SendRequest (); A     //Gets the status number returned by the server thePhtfile->QueryInfoStatusCode (dwret); +     if(Dwret! =HTTP_STATUS_OK) -     { $         //server does not accept requests $ intsess. Close (); -         DeletePhtcon;phtcon =NULL; -         DeletePhtfile;phtfile =NULL; the         return-4; -     }Wuyi     //Get File Size theUINT Nfilelen = (UINT) phtfile->getlength (); -DWORD Dwread =1;//used to identify how much read, 1 is to enter the loop Wu     //Creating Buffers -CHAR *szbuffer =Newchar[nfilelen+1]; About TRY $     { -         //Create a file -CFile Picfile (strsavepath,cfile::modecreate| cfile::modewrite|cfile::shareexclusive); -          while(dwread>0) A         {   +             //emptying buffers thememset (Szbuffer,0, (size_t) (nfilelen+1)); -             //read to buffer $Dwread = phtfile->Read (Szbuffer,nfilelen); the             //Write to File the Picfile.write (szbuffer,dwread); the         } the         //Close File - picfile.close (); in         //Freeing Memory the         Delete[]szbuffer; the         DeletePhtfile; About         DeletePhtcon; the         //Turn off network connections the intsess. Close (); the     } + CATCH (cfileexception,e) -     { the         //Freeing MemoryBayi         Delete[]szbuffer; the         DeletePhtfile; the         DeletePhtcon; -         //Turn off network connections - intsess. Close (); the         return-7;//Read and write file exceptions the     } the End_catch the         return 0; -}

MFC download and save file code reprint via URL