c++ http客户端下载文件断点续传原理-优快云博客

本文链接：https://blog.youkuaiyun.com/liuynbin/article/details/17757217

本文展示了一个使用C语言进行TCP客户端编程的例子。该程序通过socket API创建连接，并向指定服务器发送HTTP请求来获取资源。文章详细介绍了如何定义服务器地址结构、建立连接以及发送带有范围请求头的HTTP GET请求。

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#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <netdb.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <stdlib.h>

#define DEST_IP "192.168.1.115"
#define DEST_PORT 80
#define BUFF_SIZE 1024*2
int main(){
    int sockfd;
    struct sockaddr_in dest_addr;
    if((sockfd= socket(AF_INET,SOCK_STREAM,0))==-1){
        perror("socket");
        exit(1);
    }
    dest_addr.sin_family = AF_INET;
    dest_addr.sin_port = htons(DEST_PORT);
    dest_addr.sin_addr.s_addr = inet_addr(DEST_IP);
    bzero(&(dest_addr.sin_zero),8);
    if(connect(sockfd,(struct sockaddr *)&dest_addr,sizeof(struct sockaddr))==-1)
    {
        perror("connect");
        close(sockfd);
        exit(1);
    }
    
    
    char requestHeader[256];
    char* m_path = "a.flv";
    int start_size=0;
    int end_size=start_size+500;
    int len = sprintf(requestHeader,"GET /%s HTTP/1.1\r\n"
        "Host: %s\r\n"
        "Range: bytes=%d-%d\r\n"    //从m_receivedDataSize位置开始
        "Connection: keep-alive\r\n"
        "\r\n",m_path,DEST_IP,start_size,end_size);
    printf("len=%d\n",len);
    
    int size;
    char buff[BUFF_SIZE];
    write(sockfd,requestHeader,len);
    while((size=read(sockfd,buff,BUFF_SIZE))>0){
        printf("[size=%d] [content=%s]\n",size,buff);
    }    
    return 0;
}