HTTP协议GET HEAD简单介绍

 //请求url：http://down.360safe.com/inst.exe

 /*Request*/

 HEAD /inst.exe HTTP/1.1\r\n"

 "Host: down.360safe.com\r\n"

 "User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; zh-CN; rv:1.9.2.13) Gecko/20101203 Firefox/3.6.13\r\n"

 "Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8\r\n"

 "Accept-Language: zh-cn,zh;q=0.5\r\n"

 "Accept-Encoding: gzip,deflate\r\n"

 "Accept-Charset: GB2312,utf-8;q=0.7,*;q=0.7\r\n"

 "Connection: close\r\n"

 "\r\n

 /*Reponse*/

 HTTP/1.1  OK

 Server: nginx

 Date: Sat,  Jul  :: GMT

 Content-Type: application/octet-stream

 Content-Length:

 Last-Modified: Fri,  Jan  :: GMT

 Connection: close

 Expires: Sat,  Jul  :: GMT

 Cache-Control: max-age=

 Accept-Ranges: bytes

 #include <stdio.h>

 #include <stdlib.h>

 #include <string.h>

 #include <stdbool.h>

 #include <sys/socket.h>

 #include <sys/types.h>

 #include <netinet/in.h>

 #include <unistd.h>

 #include <net/if.h>

 #include <netdb.h> //gethostbyname

 #define STATUS_OK                 0

 #define STATUS_NOK                1

 #define BUFF_MAX_LEN            1024

 #define HOST_IP_LEN            32

 #define HTTP_HEAD  \

     "HEAD /%s HTTP/1.1\r\n" \

     "Host: %s\r\n" \

     "User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; zh-CN; rv:1.9.2.13) Gecko/20101203 Firefox/3.6.13\r\n" \

     "Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8\r\n" \

     "Accept-Language: zh-cn,zh;q=0.5\r\n" \

     "Accept-Encoding: gzip,deflate\r\n" \

     "Accept-Charset: GB2312,utf-8;q=0.7,*;q=0.7\r\n" \

     "Connection: close\r\n" \

     "\r\n"

 int getIPbyDomain(const char* domain, char* ip);

 int parse_http_url(const char *url, char *domain, char *header);

 /**********************************************************

  *  get host ip by domain

  **********************************************************/

 int getIPbyDomain(const char* domain, char* ip)

 {

     struct hostent *answer; 

     answer = gethostbyname(domain);

     if (NULL == answer)

     {

         return STATUS_NOK;

     }

     if (answer->h_addr_list[])

         inet_ntop(AF_INET, (answer->h_addr_list)[], ip, );

     else

         return STATUS_NOK;

     return STATUS_OK;

 }  

 /**********************************************************

  * Send a http package to detect network connecting status

  **********************************************************/

 int parse_http_url(const char *url, char *domain, char *header)

 {

     char *ptr = NULL;

     char *host = NULL;

     char *head = NULL;

     char buff[BUFF_MAX_LEN] = {}; 

     if (NULL == url || NULL == domain || NULL == header)

         return STATUS_NOK;

     memset(buff, , sizeof(buff));

     strcpy(buff, url);

     host = strtok(buff + , "/");

     head = strtok(NULL, "\0");

     if (NULL == host)

         return STATUS_NOK;

     if (NULL == head)

         head = "/";

     strcpy(domain, host);

     strcpy(header, head);

     return STATUS_OK;

 }

 int http_head_request(const char *url)

 {

     char *p = NULL;

     unsigned int dport = ;

     int fd, oneopt = ;

     char buf[BUFF_MAX_LEN] = {};

     char data[BUFF_MAX_LEN * ] = {};

     char host[BUFF_MAX_LEN] = {};

     char head[BUFF_MAX_LEN] = {};

     char hostip[HOST_IP_LEN] = {};

     struct timeval timeout = {,};

     struct sockaddr_in client;

     struct hostent *hptr;

     struct in_addr addr;

     if (url == NULL)

         return STATUS_NOK;

     if ((fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < )

         return STATUS_NOK;

     memset(&client, , sizeof(client));

     if (STATUS_NOK == parse_http_url(url, host, head))

         return STATUS_NOK;

     if (getIPbyDomain(host, hostip) != STATUS_OK)

     {

         close(fd);

         return STATUS_NOK;

     }

     client.sin_family = AF_INET;

     client.sin_port = htons(dport);

     client.sin_addr.s_addr = inet_addr(hostip); 

     if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &oneopt, sizeof(oneopt)) <  ||

         setsockopt(fd, SOL_SOCKET, SO_SNDTIMEO, (char *)&timeout, sizeof(struct timeval)) <  ||

         setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&timeout, sizeof(struct timeval)) < )

     {

         close(fd);

         return STATUS_NOK;

     }

     if (connect(fd, (struct sockaddr *)&client, sizeof(struct sockaddr)) < )

     {

         close(fd);

         return STATUS_NOK;

     }

     sprintf(data, HTTP_HEAD, head, host);

     if (send(fd, (void*)data, strlen(data), ) < )

     {

         close(fd);

         return STATUS_NOK;

     }

     printf("-------------Request-----------------\n");

     printf("%s\n", data);

     if (recv(fd, buf, sizeof(buf), ) <  )

     {

         close(fd);

         return STATUS_NOK;

     }

     printf("-------------Reponse-----------------\n");

     printf("%s\n", buf);

     close(fd);

     return STATUS_OK;

 }

 int main(int argc, char **argv)

 {

     if (argc < ) {

         printf("using %s <url>\n", argv[]);

         return -;

     }

     http_head_request(argv[]);

     return ;

 }

 [root@localhost]# ./test  http://down.360safe.com/inst.exe

 -------------Request-----------------

 HEAD /inst.exe HTTP/1.1

 Host: down.360safe.com

 User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; zh-CN; rv:1.9.2.13) Gecko/ Firefox/3.6.

 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8

 Accept-Language: zh-cn,zh;q=0.5

 Accept-Encoding: gzip,deflate

 Accept-Charset: GB2312,utf-8;q=0.7,*;q=0.7

 Connection: close

 -------------Reponse-----------------

 HTTP/1.1 200 OK

 Server: nginx

 Date: Sat, 23 Jul 2016 07:56:13 GMT

 Content-Type: application/octet-stream

 Content-Length: 1430256

 Last-Modified: Fri, 22 Jan 2016 14:49:16 GMT

 Connection: close

 Expires: Sat, 23 Jul 2016 15:56:13 GMT

 Cache-Control: max-age=28800

 Accept-Ranges: bytes