#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <sys/time.h>
#include <sys/select.h>
#include <netdb.h>
#include <ctype.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>
#include <netinet/in.h>
#define RECV_BUF_LEN (1024*100)
struct hostent *host;
char domain[256] = {0};
int port = 0;
int ret_status(char *recv_buf)
{
if(NULL == recv_buf)
{
printf("recv_buf is NULL\n");
return -1;
}
int http_status = 0;
char line[256] = {0} ;
char *rest ;
rest = strstr(recv_buf,"\r\n");
if ( rest != NULL)
{
memcpy(line,recv_buf,rest-recv_buf);
if(strstr(line,"200"))
{
http_status = 200;
}
else if(strstr(line,"302") || strstr(line,"301"))
{
http_status = 302;
}
else
{
http_status = -1;
}
}
return http_status;
}
char *afresh_url(char *recv_buf)
{
char *rest = NULL;
char *new_url = NULL;
char *line = NULL;
if(NULL == recv_buf)
{
return NULL;
}
new_url = (char *)malloc(RECV_BUF_LEN);
if(NULL == new_url)
{
printf("malloc new_url error!\n");
return NULL;
}
if( strstr(recv_buf,"Location:") == NULL)
{
return NULL;
}
else
{
rest = strstr(recv_buf,"Location:")+strlen("location: ");
line = strstr(rest,"\r\n");
memcpy(new_url, rest,line-rest);
}
return new_url;
}
long ret_file_size(char *recv_buf)
{
long file_size = 0;
char *rest = NULL;
char *line = NULL;
char actual_size[RECV_BUF_LEN] = {0} ;
if( NULL == recv_buf)
{
printf("recv %s is NULL\n",recv_buf);
return -1;
}
if((strstr(recv_buf,"Content-Length")) == NULL)
{
// printf("Content-Length is NULL\n");
return -1;
}
rest = strstr(recv_buf,"Content-Length:")+strlen("Content-Length: ");
line = strstr(rest,"\r\n");
memcpy(actual_size,rest,line-rest);
file_size = atoi(actual_size);
return file_size;
}
char *down_local_file(char *src)
{
if(NULL == src)
{
return NULL;
}
char *line = NULL;
char file[100] = {0};
char *content = NULL;
char *file_name;
int len = 0;
if(strstr(src,"Content-Disposition") == 0)
{
return NULL;
}
else
{
file_name = (char *)malloc(100);
if(NULL == file_name)
{
return NULL;
}
line = strstr(src,"filename=") + 9;
if( NULL != line)
{
content = strstr(line,"\r\n");
if( content != NULL)
{
len = strlen(line) - strlen(content);
memcpy(file_name,line,len);
line[len] = 0;
}
}
}
return file_name;
}
char *down_file(char *src, char c)
{
if(NULL == src)
{
printf("The src %s is null\n",src);
exit(-1);
}
int len = 0;
len = strlen(src);
while(src[len-1])
{
if( strchr(src + (len - 1),c))
{
return (src + (len - 1));
}
else
{
len--;
}
}
return NULL;
}
char *http_request(char *url)
{
char *url_dress = NULL;
char *file_dress = NULL;
char *ret = NULL;
char *request;
struct hostent *host;
url_dress = url+strlen("http://");
file_dress = strchr(url_dress,'/');
if (file_dress)
{
memcpy(domain,url_dress,file_dress-url_dress);
}
ret = strstr(domain,":");
if(ret)
{
port = atoi(ret);
}
else
{
port = 80;
}
request = (char *)malloc(RECV_BUF_LEN);
if(NULL == request)
{
printf("malloc request error!\n");
exit(-1);
}
sprintf(request,"GET %s HTTP/1.1\r\nHost:%s\r\n\
User-Agent:Mozilla/5.0 (Windows NT 6.1; rv:12.0) Gecko/20100101 Firefox/12.0\r\n\
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8\r\n\
Accept-Language: zh-cn,zh;q=0.8,en-us;q=0.5,en;q=0.3\r\n\
Accept-Encoding: gzip,deflate\r\n\
Connection: keep-alive\r\n\r\n",file_dress,domain);
return request;
}
int main(int argc, char *argv[])
{
char *url;
int sockefd;
char *ret = NULL;
char *buffer ;
char *head_buffer = NULL;
char header[RECV_BUF_LEN] = {0};
struct sockaddr_in server_addr;
FILE *fp = NULL;
char *request;
int i = 0;
char *file_dress = NULL;
char *file_name;
char *local_file = NULL;
int send = 0;
int totalsend = 0;
int nbytes = 0;
char *url_address = NULL;
int http_status = 0;
struct timeval start_time,end_time;
float timeuse;
FILE *file ;
char url_link[200] = {0};
char *url_ret;
if (argc != 2)
{
fprintf(stderr,"Usage: %s web address \n",argv[0]);
exit(-1);
}
url = argv[1];
do {
request = http_request(url);
if((host = gethostbyname(domain)) == NULL)
{
printf("Get host name error!\n");
exit(-1);
}
gettimeofday(&start_time,NULL);
if((sockefd = socket(AF_INET,SOCK_STREAM,0)) == -1)
{
printf("Socket error!\n");
exit(-1);
}
bzero(&server_addr,sizeof(server_addr));
server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(port);
server_addr.sin_addr = *((struct in_addr *)host->h_addr);
if (connect(sockefd, (struct sockaddr *)(&server_addr),sizeof(struct sockaddr)) == -1)
{
printf("connect error!\n");
exit(-1);
}
send = 0;
totalsend = 0;
nbytes = strlen(request);
while(totalsend < nbytes)
{
send = write(sockefd ,request + totalsend,nbytes - totalsend);
if (send == -1)
{
printf("send error!\n");
exit(-1);
}
totalsend += nbytes;
printf("%d bytes send OK!\n",totalsend);
}
long file_size = 0;
int mark = 1;
int count=0;
buffer = (char *)malloc(RECV_BUF_LEN);
do
{
memset(buffer,0,RECV_BUF_LEN);
nbytes = recv(sockefd,buffer,RECV_BUF_LEN,0);
if (mark > 0) {
mark = 0;
head_buffer = strstr(buffer,"\r\n\r\n")+4;
memcpy(header,buffer,head_buffer-buffer);
printf("%s\n",header);
file_size = ret_file_size(header);
http_status = ret_status(header);
if(http_status == 200)
{
file_name = down_local_file(header);
if(NULL == file_name)
{
file_name = down_file(url,'/')+1;
fp = fopen(file_name,"w");
if(NULL == fp)
{
printf("open file %s failed!",local_file);
exit(-1);
}
}
else
{
fp = fopen(file_name,"w");
if(NULL == fp)
{
printf("open file %s failed!",local_file);
exit(-1);
}
}
count = fwrite(head_buffer,1,nbytes-(head_buffer - buffer),fp);
// printf("%s\t%d",head_buffer,strlen(head_buffer));
//printf("head_buffer %s\n",head_buffer);
//printf("--------------\n");
url = NULL;
}
else if(http_status == 302)
{
url = afresh_url(header);
}
}
else
{
fwrite(buffer,1,nbytes,fp);
fflush(fp);
count+=nbytes;
}
if(count == file_size)
{
break;
}
}while(nbytes > 0);
printf("total:%d\n",count);
free(request);
free(buffer);
close(sockefd);
}while(url != NULL );
gettimeofday(&end_time,NULL);
timeuse = 1000000*(end_time.tv_sec - start_time.tv_sec) + end_time.tv_usec - start_time.tv_usec;
timeuse /= 1000000;
printf("Used time: %f\n",timeuse);
fclose(fp);
free(url);
return 0;
}
来源：https://www.cnblogs.com/emodj/archive/2013/03/27/2985239.html