linux httpget 网络编程 C语言

在实现httpget的方法在线获取服务器上的文件内容，需要注意的是在获取过程中的主要核心流程，具体代码如下

#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <netinet/in.h>
#include <stdlib.h>
#include <errno.h>
#include <stdlib.h>
#define BUFSIZE (8<<10)
#define h_addr h_addr_list[0]

void DownLoad(char *url){
    int socketfd;
    struct sockaddr_in addr;
    struct hostent *pURL;
    int i=0;
    char myurl[BUFSIZ];
    char *pHost =0,*pGet =0;
    char host[BUFSIZ],GET[BUFSIZ];
    char Header[BUFSIZ];
    FILE * pf;

    char text[BUFSIZE];
    memset(myurl,0,BUFSIZE);
    memset(host,0,BUFSIZE);
    strcpy(myurl,url);

    for (i=0,pHost= myurl;*pHost!='/'&&*pHost!='\0';pHost++,i++)
    {
        host[i] = *pHost;
    }
    host[i]='\0';
    strcpy(GET,pHost);
    memset(Header,'\0',BUFSIZ);

    socketfd = socket(AF_INET,SOCK_STREAM,0);
    pURL = gethostbyname(host);

    bzero(&addr,sizeof(struct sockaddr_in));
    addr.sin_family = AF_INET;
    addr.sin_addr.s_addr = *((unsigned long*)pURL->h_addr);
    addr.sin_port = htons(80);


    strcat(Header,"GET ");
    strcat(Header,GET);
    strcat(Header," HTTP/1.0\r\n");
    strcat(Header, "Accept: */*\r\n"); //image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/vnd.ms-excel, application/msword, application/vnd.ms-powerpoint,
    strcat(Header, "Accept-Language: cn\r\n");
    strcat(Header, "User-Agent: Mozilla/4.0\r\n");
    strcat(Header,"Host: ");
    strcat(Header,host);
    strcat(Header,"\r\nConnection: Keep-Alive\r\n");
    strcat(Header, "\r\n\r\n");

    int status;
    if((status = connect(socketfd,(struct sockaddr *)&addr,sizeof(addr)))<0)
    {
        perror("connect failed!\n");
        exit(-1);
    }

    int sentbytes;
    if((sentbytes = send(socketfd,Header,strlen(Header),0)) <0 )
    {
        perror("send failed!\n");
        exit(-1);
    }

    printf("%s\n",Header);
    pf = fopen("/home/ganchuhui/myget/1.txt","w");

    if(recv(socketfd,text,BUFSIZE,0)<0){
        perror("recv failed!\n");
        exit(-1);
    }
    printf("the text is: %s\n", text);

    fclose(pf);
    close(socketfd);


}
int main(){
    char a[256];
    printf(" style="color:#0000CC;">);
    scanf("%s",a);
    DownLoad(a);
}