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HTTP请求和IP/TCP实现GET请求实现POST请求：参考：回到顶部
HTTP请求和IP/TCP
所谓的HTTP协议是基于IP/TCP协议的， 所以要获取远端的html数据只要创建socket对象就足够了；
HTTP是基于IP/TCP加上了网络请求的固定格式， 比如：
运行下面代码
methodURLContent-hostContent-TypeContent-Length
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实现GET请求
把组合成的数据按照固定的格式发送给服务器， 服务器解析相应的格式， 然后返回服务器数据：
运行下面代码
#include <stdio.h>#include <sys/socket.h>#include <sys/types.h>#include <time.h>#include <errno.h>#include <signal.h>#include <stdlib.h>#include <string.h>#include <unistd.h>#include <sys/wait.h>#include <sys/time.h>#include <netinet/in.h>#include <arpa/inet.h>#define IPSTR "42.121.252.58" //服务器IP地址;#define PORT 80#define BUFSIZE 1024int main(int argc, char **argv){int sockfd, ret, i, h;struct sockaddr_in servaddr;char str1[4096], str2[4096], buf[BUFSIZE], *str;socklen_t len;fd_set t_set1;struct timeval tv;//创建套接字if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0 ) {printf("创建网络连接失败,本线程即将终止---socket error!\n");exit(0);};bzero(&servaddr, sizeof(servaddr));servaddr.sin_family = AF_INET;servaddr.sin_port = htons(PORT);if (inet_pton(AF_INET, IPSTR, &servaddr.sin_addr) <= 0 ){printf("创建网络连接失败,本线程即将终止--inet_pton error!\n");exit(0);};if (connect(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) < 0){printf("连接到服务器失败,connect error!\n");exit(0);}printf("与远端建立了连接\n");memset(str2, 0, 4096);strcat(str2, "theDataToPost");str=(char *)malloc(128);len = strlen(str2);sprintf(str, "%d", len);memset(str1, 0, 4096);strcat(str1, "GET /ymnets/p/6255674.html HTTP/1.1\n");strcat(str1, "Host: \n");strcat(str1, "Content-Type: text/html\n");strcat(str1, "Content-Length: ");strcat(str1, str);strcat(str1, "\n\n");strcat(str1, str2);strcat(str1, "\r\n\r\n");printf("%s\n",str1);ret = write(sockfd,str1,strlen(str1));if (ret < 0) {printf("发送失败！错误代码是%d，错误信息是'%s'\n",errno, strerror(errno));exit(0);}else{printf("消息发送成功，共发送了%d个字节！\n\n", ret);}FD_ZERO(&t_set1);FD_SET(sockfd, &t_set1);while(1){sleep(2);tv.tv_sec= 0;tv.tv_usec= 0;h= 0;printf("--------------->1");h= select(sockfd +1, &t_set1, NULL, NULL, &tv);printf("--------------->2");//if (h == 0) continue;if (h < 0) {close(sockfd);printf("在读取数据报文时SELECT检测到异常，该异常导致线程终止！\n");return -1;};if (h > 0){memset(buf, 0, 4096);i= read(sockfd, buf, 4095);if (i==0){close(sockfd);printf("读取数据报文时发现远端关闭，该线程终止！\n");return -1;}printf("%s\n", buf);}}close(sockfd);return 0;}
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实现POST请求：
C实现POST请求参考代码， 只要把请求类型从GET改为POST， 然后把请求的数据代入到请求头中即可：
运行下面代码
#include <stdio.h>#include <sys/socket.h>#include <sys/types.h>#include <time.h>#include <errno.h>#include <signal.h>#include <stdlib.h>#include <string.h>#include <unistd.h>#include <sys/wait.h>#include <sys/time.h>#include <netinet/in.h>#include <arpa/inet.h>#define IPSTR "61.147.124.120"#define PORT 80#define BUFSIZE 1024int main(int argc, char **argv){int sockfd, ret, i, h;struct sockaddr_in servaddr;char str1[4096], str2[4096], buf[BUFSIZE], *str;socklen_t len;fd_set t_set1;struct timeval tv;if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0 ) {printf("创建网络连接失败,本线程即将终止---socket error!\n");exit(0);};bzero(&servaddr, sizeof(servaddr));servaddr.sin_family = AF_INET;servaddr.sin_port = htons(PORT);if (inet_pton(AF_INET, IPSTR, &servaddr.sin_addr) <= 0 ){printf("创建网络连接失败,本线程即将终止--inet_pton error!\n");exit(0);};if (connect(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) < 0){printf("连接到服务器失败,connect error!\n");exit(0);}printf("与远端建立了连接\n");memset(str2, 0, 4096);strcat(str2, "qqCode=287101329");str=(char *)malloc(128);len = strlen(str2);sprintf(str, "%d", len);memset(str1, 0, 4096);strcat(str1, "POST /webservices/qqOnlineWebService.asmx/qqCheckOnline HTTP/1.1\n");strcat(str1, "Host: \n");strcat(str1, "Content-Type: application/x-www-form-urlencoded\n");strcat(str1, "Content-Length: ");strcat(str1, str);strcat(str1, "\n\n");//str2的值为post的数据strcat(str1, str2);strcat(str1, "\r\n\r\n");printf("%s\n",str1);ret = write(sockfd,str1,strlen(str1));if (ret < 0) {printf("发送失败！错误代码是%d，错误信息是'%s'\n",errno, strerror(errno));exit(0);}else{printf("消息发送成功，共发送了%d个字节！\n\n", ret);}FD_ZERO(&t_set1);FD_SET(sockfd, &t_set1);while(1){sleep(2);tv.tv_sec= 0;tv.tv_usec= 0;h= 0;printf("--------------->1");h= select(sockfd +1, &t_set1, NULL, NULL, &tv);printf("--------------->2");//if (h == 0) continue;if (h < 0) {close(sockfd);printf("在读取数据报文时SELECT检测到异常，该异常导致线程终止！\n");return -1;};if (h > 0){memset(buf, 0, 4096);i= read(sockfd, buf, 4095);if (i==0){close(sockfd);printf("读取数据报文时发现远端关闭，该线程终止！\n");return -1;}printf("%s\n", buf);}}close(sockfd);return 0;}
POST请求的方式可以再改改：
运行下面代码
#include <stdio.h>#include <sys/socket.h>#include <sys/types.h>#include <time.h>#include <errno.h>#include <signal.h>#include <stdlib.h>#include <string.h>#include <unistd.h>#include <sys/wait.h>#include <sys/time.h>#include <netinet/in.h>#include <arpa/inet.h>#define IPSTR "61.147.124.120"#define PORT 80#define BUFSIZE 1024int main(int argc, char **argv){int sockfd, ret, i, h;struct sockaddr_in servaddr;char str1[4096], str2[4096], buf[BUFSIZE], *str;socklen_t len;fd_set t_set1;struct timeval tv;if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0 ) {printf("创建网络连接失败,本线程即将终止---socket error!\n");exit(0);};bzero(&servaddr, sizeof(servaddr));servaddr.sin_family = AF_INET;servaddr.sin_port = htons(PORT);if (inet_pton(AF_INET, IPSTR, &servaddr.sin_addr) <= 0 ){printf("创建网络连接失败,本线程即将终止--inet_pton error!\n");exit(0);};if (connect(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) < 0){printf("连接到服务器失败,connect error!\n");exit(0);}printf("与远端建立了连接\n");memset(str2, 0, 4096);strcat(str2, "qqCode=287101329");str=(char *)malloc(128);len = strlen(str2);sprintf(str, "%d", len);memset(str1, 0, 4096);strcat(str1, "POST /webservices/qqOnlineWebService.asmx/qqCheckOnline HTTP/1.1\n");strcat(str1, "Host: \n");strcat(str1, "Content-Type: application/x-www-form-urlencoded\n");strcat(str1, "Content-Length: ");strcat(str1, str);strcat(str1, "\n\n");//str2的值为post的数据strcat(str1, str2);strcat(str1, "\r\n\r\n");printf("%s\n",str1);ret = write(sockfd,str1,strlen(str1));if (ret < 0) {printf("发送失败！错误代码是%d，错误信息是'%s'\n",errno, strerror(errno));exit(0);}else{printf("消息发送成功，共发送了%d个字节！\n\n", ret);}FD_ZERO(&t_set1);FD_SET(sockfd, &t_set1);tv.tv_sec= 0;tv.tv_usec= 0;h= 0;while(1){sleep(2);printf("--------------->1");h = select(sockfd +1, &t_set1, NULL, NULL, &tv);printf("--------------->2");//if (h == 0) continue;if (h == -1) {close(sockfd);printf("在读取数据报文时SELECT检测到异常，该异常导致线程终止！\n");return -1;};if ( FD_ISSET(sockfd, &t_set1) ){memset(buf, 0, 4096);i= read(sockfd, buf, 4095);if (i==0){close(sockfd);printf("读取数据报文时发现远端关闭，该线程终止！\n");return -1;}printf("%s\n", buf);}}close(sockfd);return 0;}
请求一个HTTP服务器的数据， 接收一个参数为请求的服务器IP：
运行下面代码
#include <stdio.h>#include <stdlib.h>#include <string.h>#include <sys/types.h> #include <sys/socket.h>#include <arpa/inet.h>#include <netinet/in.h>#include <unistd.h>int main(int argc, char *argv[]){ if(argc!=2){printf("error usage %s ip\n",argv[0]); return 1;} int sockfd;int len; struct sockaddr_in address; int result; char httpstring[100]; sprintf(httpstring,"GET / HTTP/1.1\r\n""Host: %s\r\n""Connection: Close\r\n\r\n",argv[1]); char ch; sockfd = socket(AF_INET, SOCK_STREAM, 0); address.sin_family = AF_INET; address.sin_addr.s_addr = inet_addr(argv[1]); address.sin_port = htons(80); len = sizeof(address);result = connect(sockfd,(struct sockaddr *)&address,len); if(result == -1){ perror("oops: client"); return 1; }write(sockfd,httpstring,strlen(httpstring)); while(read(sockfd,&ch,1)){ printf("%c", ch); } close(sockfd); printf("\n"); return 0; }
使用gcc编译以后执行：sudo ./req 42.121.252.58
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参考：
Linux下用c语言实现发送http请求 方式可以Get或者Post：/code/snippet_176076_5908/
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