linux c++下载http文件并显示进度<转>

#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <stdlib.h>
#include <iostream>
#include <string.h>
#include <unistd.h>
#include <fstream>
#include <vector>
#include <pthread.h>
using namespace std;
typedef string::size_type (string::*find_t)(const string& delim,
                                                string::size_type offset) const;
vector<string> Split(const string& s,
                         const string& match,
                         bool removeEmpty=false,
                         bool fullMatch=false)
    {
        vector<string> result;                 // return container for tokens
        string::size_type start = ,           // starting position for searches
                          skip = ;            // positions to skip after a match
        find_t pfind = &string::find_first_of; // search algorithm for matches
        if (fullMatch)
        {
            skip = match.length();
            pfind = &string::find;
        }
        while (start != string::npos)
        {
            string::size_type end = (s.*pfind)(match, start);
            if (skip == ) end = string::npos;
            string token = s.substr(start, end - start);
            if (!(removeEmpty && token.empty()))
            {
                result.push_back(token);
            }
            if ((start = end) != string::npos) start += skip;
        }
        return result;
}
void SplitProperty(vector<string> property,string* name,string *value)
{
    vector<string>::iterator it=property.begin();
    if(it!= property.end())
    {
        name->clear();
        name->append(*it);
    }
    it++;
    if(it!= property.end())
    {
        value->clear();
        value->append(*it);
    }
}
int GetFileSize(char* host,char* file,string* error,int& headersize)
{
    int size=-;
    struct sockaddr_in servaddr;
    struct hostent *hp;
    string splitline="\r\n";
    string PName;
    string PValue;
    string splittagbalue=":";
    string info;
    vector<string> properties;
    vector<string> property;
    int sock_id;
    char message[*] = {};
    int msglen;
    string request;
    request.append("HEAD ");
    request.append(file);
    request.append(" HTTP/1.1\n");
    request.append("Host:");
    request.append(host);
    request.append("\r\n\r\n");
    //Get a socket
    if((sock_id = socket(AF_INET, SOCK_STREAM, )) == -) {
        error->append("Couldn't get a socket!");
        return size;
    }
    //book uses bzero which my man pages say is deprecated
    //the man page said to use memset instead. :-)
    memset(&servaddr,,sizeof(servaddr));
    //get address for google.com
    if((hp = gethostbyname(host)) == NULL) {
        error->append("Couldn't access network.");
        error->append(host);
        return size;
    }
    //bcopy is deprecated also, using memcpy instead
    memcpy((char *)&servaddr.sin_addr.s_addr, (char *)hp->h_addr, hp->h_length);
    //fill int port number and type
    servaddr.sin_port = htons();
    servaddr.sin_family = AF_INET;
    //make the connection
    if(connect(sock_id, (struct sockaddr *)&servaddr, sizeof(servaddr)) != ) {
        error->append("Couldn't connect!");
        return size;
    }
    write(sock_id,request.c_str(),request.length());
   //read the response
    msglen = read(sock_id,message,*);
    headersize= msglen;
    info.append(message,,msglen);
    close(sock_id);
    properties =Split(info,splitline,true);
    vector<string>::iterator it;
    for (it=properties.begin(); it<properties.end(); it++)
    {
        property= Split(*it,splittagbalue,true);
        SplitProperty(property,&PName,&PValue);
        if(PName=="Content-Length")
        {
            size =atoi(PValue.c_str());
            break;
        }
    }
    if(size==-)
    {
        error->append("Resource Not Found!");
    }
    return size;
}
void DownloadFile(char* host,char* file,char * savefile,float size,int& progress,int hsize)
{
    struct sockaddr_in servaddr;
    struct hostent *hp;
    string info;
    int sock_id;
    char message[] = {};
    char messagetop[]={};
    int msglen;
    float readcount=;
    string request;
    request.append("GET ");
    request.append(file);
    request.append(" HTTP/1.1\n");
    request.append("Host:");
    request.append(host);
    request.append("\r\n\r\n");
    //Get a socket
    if((sock_id = socket(AF_INET, SOCK_STREAM, )) == -) {
        return;
    }
    //book uses bzero which my man pages say is deprecated
    //the man page said to use memset instead. :-)
    memset(&servaddr,,sizeof(servaddr));
    //get address for google.com
    if((hp = gethostbyname(host)) == NULL) {
        return;
    }
    //bcopy is deprecated also, using memcpy instead
    memcpy((char *)&servaddr.sin_addr.s_addr, (char *)hp->h_addr, hp->h_length);
    //fill int port number and type
    servaddr.sin_port = htons();
    servaddr.sin_family = AF_INET;
    //make the connection
    if(connect(sock_id, (struct sockaddr *)&servaddr, sizeof(servaddr)) != ) {
        return;
    }
    //NOW THE HTTP PART!!!
    //send the request
    write(sock_id,request.c_str(),request.length());
    ofstream outfile (savefile,ofstream::binary);
    do{
         msglen = read(sock_id,message,);
         if(msglen==)
             break;
         if(readcount==)
         {
            int tempindex=;
            for(int i =hsize-;i<msglen;i++)
            {
                messagetop[tempindex]= message[i];
                tempindex=tempindex+;
            }
            outfile.write (messagetop,tempindex);
         }
         else
         {
            outfile.write (message,msglen);
         }
         readcount=readcount+msglen;
         progress=readcount/size*;
    }while(readcount<=(size+ hsize));
    outfile.close();
    close(sock_id);
    //read the response
}
float filesize;
int loadprogress=;
int hsize;
pthread_t   tUpdateWork;
void* UpdateWorCoping(void* data)
{
  DownloadFile("192.168.2.128","/games.data","/usr/games.data",filesize,loadprogress,hsize);
}
int main(int argc, char** argv)
{
    string error;
    filesize = GetFileSize("192.168.2.128","/games.data",&error,hsize);
    pthread_create(&tUpdateWork,NULL,UpdateWorCoping,);
    while(loadprogress<)
    {
        printf("Progress %d \n", loadprogress);
        usleep();
    }
    return ;
}

在使用该代码测试的时候可能会出现的问题：

1.

在DownloadFile 内的有两处：

 char message[18000] = {0};

 char messagetop[18000]={0};

可能在运行的时候造成栈溢出，所以最好是修改为动态申请空间。

另外还有一处就是GetFileSize() 内 问题同上。

2.

在DownloadFile() 内的写文件中：

里面有个for循环：for(int i = hsize -1; i<msglen ; i++)

我在亲自测试的发现 hsize - 1 会使文件保存大小跟原始文件有出入。于是暂时改成了 for(int i = hsize ; i<msglen ; i++)

不知道对于其他类型文件是否应该 做 -1 操作。待以后再测一测看看。