通过WINET实现的http断点下载

head文件

httpdown.h

#pragma once#include <afxinet.h>#define HTTP_MAX_TASK_NUM 1024#define SZ_HEAD "Accept: */*/r/nUser-Agent: Mozilla/4.0 (compatible; MSIE 5.00; Windows 98)/r/n"struct TASK{CString url;CString savepath;CString filename;DWORD filetotalsize;DWORD filecurrentdownsize;int speed;int taskid;int state;//0空闲 1下载中 2下载完成 3下载失败int isruning;//0 停止 1运行中CRITICAL_SECTION c_s;};class HttpDownload{public:HttpDownload(void);~HttpDownload(void);int InitMission();int ClearMission();int AddHttpMission(CString url,CString savepath,CString filename);int StopMission(int taskid);int GetMissionStatus(int taskid,int &state,int &speed,DWORD &filetotalsize,DWORD &filecurrentdownsize);public:TASK tasklist[HTTP_MAX_TASK_NUM];CRITICAL_SECTION c_s;};

 

具体实现

httpdown.cpp

#include "StdAfx.h"#include "./httpdownload.h"#include <Mmsystem.h>void Download(CString url,CString savepath,CString filename,TASK *task);UINT DownloadThread(LPVOID lpPram){TASK *task=(TASK*)(lpPram);Download(task->url,task->savepath,task->filename,task);return 1;}void Download(CString url,CString savepath,CString filename,TASK *task){CFile file;CString filepath;if(savepath.Right(1)!="//"){ filepath.Format("%s//%s",savepath,filename);}else{ filepath.Format("%s%s",savepath,filename);}CFileException fileException;if(!file.Open(filepath,CFile::modeCreate|CFile::modeNoTruncate|CFile::modeReadWrite|CFile::shareDenyWrite|CFile::typeBinary,&fileException)){ printf("open file fail [%d]/n",fileException.m_cause); task->state=3; return;}CString strRangeQuest;if (file.GetLength()>0){ file.SeekToEnd(); strRangeQuest.Format( _T("%sRange: bytes=%d-/r/n"), SZ_HEAD,file.GetLength()); task->filecurrentdownsize=file.GetLength();}else{ strRangeQuest = SZ_HEAD;}CInternetSession session;CHttpConnection* pHttpConnection = NULL;CHttpFile* pHttpFile = NULL;CString strServer, strObject;INTERNET_PORT wPort;DWORD dwType;const int nTimeOut = 2000;session.SetOption(INTERNET_OPTION_CONNECT_TIMEOUT, nTimeOut); //重试之间的等待延时session.SetOption(INTERNET_OPTION_CONNECT_RETRIES, 1); //重试次数char* pszBuffer = NULL;try{ AfxParseURL(url, dwType, strServer, strObject, wPort); pHttpConnection = session.GetHttpConnection(strServer, wPort); //pHttpFile = pHttpConnection->OpenRequest(CHttpConnection::HTTP_VERB_GET, strObject); pHttpFile=pHttpConnection->OpenRequest(CHttpConnection::HTTP_VERB_GET,strObject,NULL,1,NULL,NULL,INTERNET_FLAG_DONT_CACHE); pHttpFile->AddRequestHeaders(strRangeQuest); if(pHttpFile->SendRequest() == FALSE) return; DWORD dwStateCode; pHttpFile->QueryInfoStatusCode(dwStateCode); if(dwStateCode == HTTP_STATUS_OK || dwStateCode == HTTP_STATUS_PARTIAL_CONTENT) { char szInfoBuffer[1000]; //返回消息 DWORD dwInfoBufferSize = sizeof(szInfoBuffer); BOOL bResult = FALSE; bResult = pHttpFile->QueryInfo(HTTP_QUERY_CONTENT_LENGTH, (void*)szInfoBuffer,&dwInfoBufferSize,NULL); task->filetotalsize=atoi(szInfoBuffer)+task->filecurrentdownsize; DWORD starttime=timeGetTime(); const int BUFFER_LENGTH = 1024 * 10; pszBuffer = new char[BUFFER_LENGTH]; //读取文件的缓冲 UINT nRead = pHttpFile->Read(pszBuffer, BUFFER_LENGTH); //读取服务器上数据 UINT nReadCount=0; while(nRead>0) { file.Write(pszBuffer,nRead);//写到本地文件 EnterCriticalSection(&task->c_s); task->filecurrentdownsize+=nRead; DWORD elapsed=timeGetTime()-starttime; nReadCount+=nRead; if(elapsed>3000) { task->speed=(nReadCount/1024)/(elapsed/1000); starttime=timeGetTime(); nReadCount=0; } //printf("task speed=%d/n",task->speed); LeaveCriticalSection(&task->c_s); nRead = pHttpFile->Read(pszBuffer, BUFFER_LENGTH); if(task->isruning==0) { break; } } delete[]pszBuffer; pszBuffer = NULL; file.Close(); EnterCriticalSection(&task->c_s); task->state=2; LeaveCriticalSection(&task->c_s); } else { delete[]pszBuffer; pszBuffer = NULL; if(pHttpFile != NULL) { pHttpFile->Close(); delete pHttpFile; pHttpFile = NULL; } if(pHttpConnection != NULL) { pHttpConnection->Close(); delete pHttpConnection; pHttpConnection = NULL; } session.Close(); file.Close(); EnterCriticalSection(&task->c_s); task->state=3; LeaveCriticalSection(&task->c_s); return; }}catch(...){ delete[]pszBuffer; pszBuffer = NULL; if(pHttpFile != NULL) { pHttpFile->Close(); delete pHttpFile; pHttpFile = NULL; } if(pHttpConnection != NULL) { pHttpConnection->Close(); delete pHttpConnection; pHttpConnection = NULL; } session.Close(); file.Close(); EnterCriticalSection(&task->c_s); task->state=3; LeaveCriticalSection(&task->c_s); return;}if(pHttpFile != NULL) pHttpFile->Close();if(pHttpConnection != NULL) pHttpConnection->Close();session.Close();}HttpDownload::HttpDownload(void){InitializeCriticalSection(&c_s);InitMission();}HttpDownload::~HttpDownload(void){DeleteCriticalSection(&c_s);for(int i=0;i<HTTP_MAX_TASK_NUM;i++){ tasklist[i].state=0; tasklist[i].taskid=0; tasklist[i].filetotalsize=0; tasklist[i].filecurrentdownsize=0; tasklist[i].isruning=0; tasklist[i].speed=0; DeleteCriticalSection(&tasklist[i].c_s);}}int HttpDownload::InitMission(){for(int i=0;i<HTTP_MAX_TASK_NUM;i++){ tasklist[i].state=0; tasklist[i].taskid=i+1; tasklist[i].filetotalsize=0; tasklist[i].filecurrentdownsize=0; tasklist[i].isruning=0; tasklist[i].speed=0; InitializeCriticalSection(&tasklist[i].c_s);}return 1;}int HttpDownload::ClearMission(){for(int i=0;i<HTTP_MAX_TASK_NUM;i++){ tasklist[i].isruning=0;}return 1;}int HttpDownload::AddHttpMission(CString url,CString savepath,CString filename){int taskid=-1;EnterCriticalSection(&c_s); for(int i=0;i<HTTP_MAX_TASK_NUM;i++){ if(tasklist[i].state==0) { tasklist[i].url=url; tasklist[i].savepath=savepath; tasklist[i].filename=filename; tasklist[i].state=1; tasklist[i].isruning=1; taskid=tasklist[i].taskid; AfxBeginThread(DownloadThread,&tasklist[i]); break; }}LeaveCriticalSection(&c_s);return taskid;}int HttpDownload::StopMission(int taskid){int index=taskid-1;int ret=-1;if(index>=0){ EnterCriticalSection(&tasklist[index].c_s); if(tasklist[index].state!=0) { tasklist[index].isruning=0; ret=1; } LeaveCriticalSection(&tasklist[index].c_s);}return ret;}int HttpDownload::GetMissionStatus(int taskid,int &state,int &speed,DWORD &filetotalsize,DWORD &filecurrentdownsize){int index=taskid-1;int ret=-1;if(index>=0){ EnterCriticalSection(&tasklist[index].c_s); if(tasklist[index].state!=0) { state=tasklist[index].state; speed=tasklist[index].speed; filetotalsize=tasklist[index].filetotalsize; filecurrentdownsize=tasklist[index].filecurrentdownsize; ret=1; } LeaveCriticalSection(&tasklist[index].c_s);}return ret;}