下面是一个用openssl 实现获取https 网页内容的demo，整个流程比较简单，主要封装的API如下
static int https_init(https_context_t *context,const char* url); static int https_uninit(https_context_t *context); static int https_read(https_context_t *context,void* buff,int len); static int https_write(https_context_t *context,const void* buff,int len); static int https_get_status_code(https_context_t *context); static int https_read_content(https_context_t *context,char *resp_contet,int max_len);
通信流程：
1、初始化，解析url资源，创建socket 连接，绑定ssl
2、发送http 请求
3、获取请求返回的状态码
4、获取请求返回的数据
5、销毁动态申请的内存资源
我就把整个代码贴在下面
#include <stdio.h> #include <string.h> #include <stdlib.h> #include <unistd.h> #include <sys/stat.h> #include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> #include <netdb.h> #include <openssl/ssl.h> #include <openssl/bio.h> #define HTTP_REQ_LENGTH 512 #define HTTP_RESP_LENGTH 20480 typedef struct { int sock_fd; SSL_CTX *ssl_ct; SSL *ssl; //url 解析出来的信息 char *host; char *path; int port; } https_context_t; static int https_init(https_context_t *context,const char* url); static int https_uninit(https_context_t *context); static int https_read(https_context_t *context,void* buff,int len); static int https_write(https_context_t *context,const void* buff,int len); static int https_get_status_code(https_context_t *context); static int https_read_content(https_context_t *context,char *resp_contet,int max_len); // http 请求头信息 static char https_header[] = "GET %s HTTP/1.1\r\n" "Host: %s:%d\r\n" "Connection: Close\r\n" "Accept: */*\r\n" "\r\n"; static char http_req_content[HTTP_REQ_LENGTH] = {0}; static char https_resp_content[HTTP_RESP_LENGTH+1] = {0}; static int create_request_socket(const char* host,const int port) { int sockfd; struct hostent *server; struct sockaddr_in serv_addr; sockfd = socket(AF_INET, SOCK_STREAM, 0); if (sockfd < 0) { printf("[http_demo] create_request_socket create socket fail.\n"); return -1; } /* lookup the ip address */ server = gethostbyname(host); if(server == NULL) { printf("[http_demo] create_request_socket gethostbyname fail.\n"); close(sockfd); return -1; } memset(&serv_addr,0,sizeof(serv_addr)); serv_addr.sin_family = AF_INET; serv_addr.sin_port = htons(port); memcpy(&serv_addr.sin_addr.s_addr,server->h_addr,server->h_length); if (connect(sockfd,(struct sockaddr *)&serv_addr,sizeof(serv_addr)) < 0) { printf("[http_demo] create_request_socket connect fail.\n"); close(sockfd); return -1; } return sockfd; } /** * @brief https_parser_url 解析出https 中的域名、端口和路径 * @param url 需要解析的url * @param host 解析出来的域名或者ip * @param port 端口，没有时默认返回443 * @param path 路径，指的是域名后面的位置 * @return */ static int https_parser_url(const char* url,char **host,int *port,char **path) { if(url == NULL || strlen(url) < 9 || host == NULL || path == NULL) { printf("[https_demo] url or host or path is null.\n"); return -1; } //判断是不是 https:// int i = 0; char https_prefix[] = "https://"; for(i=0;i<8;i++) { if(url[i] != https_prefix[i]) { printf("[https_demo] illegal url = %s.\n",url); return -1; } } const char *temp = url+i; while(*temp != '/') //next / { if(*temp == '\0') // { printf("[https_demo] illegal url = %s.\n",url); return -1; } temp++; } const char *host_port = url+i; while(*host_port != ':' && *host_port != '/') //找到 :或者 / 结束 { host_port ++; } int host_len = host_port-url-i; //减掉https:// int path_len = strlen(temp); char *host_temp = (char *)malloc(host_len + 1); //多一个字符串结束标识 \0 if(host_temp == NULL) { printf("[https_demo] malloc host fail.\n"); return -1; } if(*host_port++ == ':') //url 中有端口 { *port = 0; while(*host_port !='/' && *host_port !='\0') //十进制字符串转成数字 { *port *= 10; *port += (*host_port - '0'); host_port ++; } } else { *port = 443; } char *path_temp = (char *)malloc(path_len + 1); //多一个字符串结束标识 \0 if(path_temp == NULL) { printf("[https_demo] malloc path fail.\n"); free(host_temp); return -1; } memcpy(host_temp,url+i,host_len); memcpy(path_temp,temp,path_len); host_temp[host_len] = '\0'; path_temp[path_len] = '\0'; *host = host_temp; *path = path_temp; return 0; } static int https_init(https_context_t *context,const char* url) { if(context == NULL) { printf("[https_demo] init https_context_t is null.\n"); return -1; } if(https_parser_url(url,&(context->host),&(context->port),&(context->path))) { printf("[https_demo] https_parser_url fail.\n"); return -1; } context->sock_fd = create_request_socket(context->host,context->port); if(context->sock_fd < 0) { printf("[https_demo] create_request_socket fail.\n"); goto https_init_fail; } context->ssl_ct = SSL_CTX_new(SSLv23_method()); if(context->ssl_ct == NULL) { printf("[https_demo] SSL_CTX_new fail.\n"); goto https_init_fail; } context->ssl = SSL_new(context->ssl_ct); if(context->ssl == NULL) { printf("[https_demo] SSL_new fail.\n"); goto https_init_fail; } if(SSL_set_fd(context->ssl,context->sock_fd)<0) { printf("[https_demo] SSL_set_fd fail \n"); } if(SSL_connect(context->ssl) == -1) { printf("[https_demo] SSL_connect fail.\n"); goto https_init_fail; } return 0; https_init_fail: https_uninit(context); return -1; } static int https_read(https_context_t *context,void* buff,int len) { if(context == NULL || context->ssl == NULL) { printf("[https_demo] read https_context_t or ssl is null.\n"); return -1; } return SSL_read(context->ssl,buff,len); } static int https_write(https_context_t *context,const void* buff,int len) { if(context == NULL || context->ssl == NULL) { printf("[https_demo] write https_context_t or ssl is null.\n"); return -1; } return SSL_write(context->ssl,buff,len); } static int https_get_status_code(https_context_t *context) { if(context == NULL || context->ssl == NULL) { printf("[https_demo] get status https_context_t or ssl is null.\n"); return -1; } int ret; int flag =0; int recv_len = 0; char res_header[1024] = {0}; while(recv_len<1023) { ret = SSL_read(context->ssl, res_header+recv_len, 1); if(ret<1) // recv fail { break; } //找到响应头的头部信息, 两个"\r\n"为分割点 if((res_header[recv_len]=='\r'&&(flag==0||flag==2))||(res_header[recv_len]=='\n'&&(flag==1||flag==3))) { flag++; } else { flag = 0; } recv_len+=ret; if(flag==4) { break; } } //printf("[http_demo] recv_len=%d res_header = %s.\n",recv_len,res_header); /*获取响应头的信息*/ int status_code = -1; char *pos = strstr(res_header, "HTTP/"); if(pos) { sscanf(pos, "%*s %d", &status_code);//返回状态码 } return status_code; } static int https_read_content(https_context_t *context,char *resp_contet,int max_len) { if(context == NULL || context->ssl == NULL) { printf("[https_demo] read content https_context_t or ssl is null.\n"); return -1; } int ret ; int recv_size = 0; while(recv_size < max_len) { ret = SSL_read(context->ssl,resp_contet + recv_size,max_len-recv_size); if(ret < 1) { break; } recv_size += ret; } return recv_size; } static int https_uninit(https_context_t *context) { if(context == NULL) { printf("[https_demo] uninit https_context_t is null.\n"); return -1; } if(context->host != NULL) { free(context->host); context->host = NULL; } if(context->path != NULL) { free(context->path); context->path = NULL; } if(context->ssl != NULL) { SSL_shutdown(context->ssl); //SSl_free(context->ssl); context->ssl = NULL; } if(context->ssl_ct != NULL) { SSL_CTX_free(context->ssl_ct); context->ssl_ct = NULL; } if(context->sock_fd > 0) { close(context->sock_fd); context->sock_fd = -1; } return 0; } int main() { https_context_t https_ct = {0}; int ret = SSL_library_init(); printf("[https_demo] SSL_library_init ret = %d.\n",ret); https_init(&https_ct,"https://www.baidu.com/"); ret = snprintf(http_req_content,HTTP_REQ_LENGTH,https_header,https_ct.path,https_ct.host,https_ct.port); ret = https_write(&https_ct,http_req_content,ret); printf("[https_demo] https_write ret = %d.\n",ret); if(https_get_status_code(&https_ct) == 200) { ret = https_read_content(&https_ct,https_resp_content,HTTP_RESP_LENGTH); if(ret > 0) { https_resp_content[ret] = '\0'; //字符串结束标识 printf("[https_demo] https_write https_resp_content = \n %s.\n",https_resp_content); } } https_uninit(&https_ct); return 0; }
