一、介绍
最近做ota升级需要用到http下载，所以写了一下http下载器实现流程1、解析url网址的域名和文件名2、获取ip地址3、构建http请求头发送到服务器4、解析回复5、下载文件
环境ubuntu linuxc语言开源链接
main.c
#include <stdio.h>#include "http_download.h"int main(int argc, char const *argv[]){ if (argc == 1) { printf("Input a valid URL \n"); exit(0); } else { http_download_file(argv[1]); } return 0;}
http_download.c
#include <stdio.h>#include <stdlib.h>#include <string.h>#include <unistd.h>#include <arpa/inet.h>#include <netdb.h>#include <fcntl.h>#include "tcp.h"typedef struct { int status_code;//HTTP/1.1 '200' OK char content_type[128];//Content-Type: application/gzip long content_length;//Content-Length: 11683079 char file_name[256];}resp_header_def;resp_header_def resp;//头信息#if 0下载分为以下几个过程1、解析出下载地址中的域名和文件名2、通过域名获取服务器的IP地址3、与目标服务器建立连接4、构建http请求头并将其发送到服务器5、等待服务器响应然后接收响应头6、解析响应头, 判断返回码, 分离开响应头, 并且响应的正文内容以字节形式写入文件, 正文内容与头部用两个\n\r分开#endif#define print_LOG(format, ...) {\printf(format, ##__VA_ARGS__);}//解析网址//输入url，输出域名、端口、文件名static int Parsing_urls(char *url, char *domain, int *port, char *filename){ int i,j,start; char *patterns[] = {"http://", "https://", NULL}; *port = 80; //解析域名，就是http://或者https://到/的内容 for(i = 0; patterns[i]; i++) { if(strncmp(url, patterns[i], strlen(patterns[i])) == 0) { start = strlen(patterns[i]); } } //复制域名 j = 0; for ( i = start; url[i] != '/' && url[i] != '\0'; i++,j++) { domain[j] = url[i]; } domain[i] = '\0'; //解析端口,冒号后面就是端口 char pos = strstr(domain, ":"); if(pos) { sscanf(pos, ":%d", port); } //如果有端口，需要删掉 for ( i = 0; i < (int)strlen(domain); i++) { if(domain[i] == ':') { domain[i] = '\0'; break; } } //解析下载文件名,/后面就是文件名 j = 0; for ( i = start; url[i] != '\0'; i++) { if(url[i] == '/') { j = i + 1; memcpy(filename, &url[j], strlen(&url[j])); } } i = strlen(&url[j]); filename[i] = '\0'; return 0;}//通过域名获取ipstatic int Domain_to_ip(char *domain, char *ip){ int i; struct hostent *host = gethostbyname(domain); if(host == 0) { *ip = NULL; return -1; } //找到不为空的地址 for ( i = 0; host->h_addr_list[i]; i++) { strcpy(ip, inet_ntoa( * (struct in_addr*) host->h_addr_list[i])); break; } return 0;}//构建请求头信息static int Set_request_headers(char *header, char *url, char *domain){ int ret = 0; sprintf(header, \ "GET %s HTTP/1.1\r\n"\ "Accept:text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8\r\n"\ "User-Agent:Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537(KHTML, like Gecko) Chrome/47.0.2526Safari/537.36\r\n"\ "Host:%s\r\n"\ "Connection:close\r\n"\ "\r\n"\ ,url, domain); ret = strlen(header); return ret;}static char *get_response(){ int len, lencnt = 0,mem_size = 4096; char *rcvbuff = (char *)malloc( mem_size*sizeof(char) ); char *response = (char *)malloc( mem_size*sizeof(char) ); while((len = tcp_client_rcv(rcvbuff, 1)) != 0) { //动态调整缓存大小 if((lencnt + len) > mem_size)//判断缓存是否超限 { //重新分配内存 mem_size *= 2; char *tmp = (char *)realloc(response, mem_size*sizeof(char)); if(tmp == NULL) { printf("realloc fail\n"); exit(-1); } response = tmp; } rcvbuff[len] = '\0'; strcat(response, rcvbuff); //找到响应头的头部信息, 两个"\n\r"为分割点 int flag = 0; int i = strlen(response) - 1; for (; response[i] == '\n' || response[i] == '\r'; i--, flag++); { if (flag == 4)//最多找4次，没找到 break; } lencnt += len; } free(rcvbuff); return response;}//获取回复头的信息static int get_resp_header(const char *response, resp_header_def *resp){ //查找HTTP/ char *pos = strstr(response, "HTTP/"); if (pos) sscanf(pos, "%*s %d", &resp->status_code);//返回状态码 pos = strstr(response, "Content-Type:");//返回内容类型 if (pos) sscanf(pos, "%*s %s", resp->content_type); pos = strstr(response, "Content-Length:");//内容的长度(字节) if (pos) sscanf(pos, "%*s %ld", &resp->content_length); return 0;}//打印进度int progress_bar(int x){ int i; char tmp[100] = {0}; static int x_old = 0; if(x == x_old) { return 0; } x_old = x; i = x/2; if(i > 50) i = 50; memset(tmp, '=', i); printf("\r%d%[%s]", x, tmp); fflush(stdout);//立刻输出 return 0;}static int download_writefile(){ int length = 0; int mem_size = 4096;//mem_size might be enlarge, so reset it int buf_len = mem_size;//read 4k each time int len = 0; int fd = open(resp.file_name, O_CREAT | O_WRONLY, S_IRWXG | S_IRWXO | S_IRWXU); if (fd < 0) { print_LOG("Create file failed\n"); exit(0); } //申请4k缓存 char *buf = (char *)malloc(mem_size * sizeof(char)); //读取文件 while ((len = tcp_client_rcv(buf, buf_len)) != 0 && length < resp.content_length) { write(fd, buf, len); length += len; progress_bar((length*100/resp.content_length)); } if (length == resp.content_length) { print_LOG("\nDownload successful ^_^\n\n"); } else { print_LOG("Finished length:%d,resp.content_length:%d\n", length, resp.content_length); } close(fd); return 0;}//http下载文件函数int http_download_file(char *url){ //char url[2048] = "127.0.0.1"; char domain[64] = {0}; char ip_addr[16] = {0}; int port = 80; char file_name[256] = {0}; char header[2048] = {0}; char *response = 0; //解析域名 Parsing_urls(url, domain, &port, file_name); //解析ip Domain_to_ip(domain, ip_addr); print_LOG("download:\n url:%s\n domain:%s\n ip:%s\n port:%d\n filename:%s\n", url, domain, ip_addr, port, file_name); //发送下载请求 Set_request_headers(header, url, domain); if(tcp_client_init(ip_addr, port) == -1) { print_LOG("connect server fail\n"); return -1; } tcp_client_send(header, strlen(header)); print_LOG("\nsend request\n"); //print_LOG("send request:%s\n", header); //解析回复 response = get_response(); get_resp_header(response, &resp); print_LOG("response:%s\n", response); free(response); strcpy(resp.file_name, file_name); print_LOG("\nres:\n content_length:%d\n file_name:%s\n Content-Type:%s\n", resp.content_length, resp.file_name, resp.content_type); //下载文件 print_LOG("\ndownload %s start ...\n", resp.file_name); download_writefile(); return 0;}
download.h
#ifndef __HTTP_DOWNLOAD_H#define __HTTP_DOWNLOAD_Hint http_download_file(char *url);#endif
tcp.c
//-------tcp相关头文件------#include <sys/socket.h>#include <sys/types.h>#include <netinet/in.h>#include <arpa/inet.h>#include <unistd.h> //close()static int socket_fd = 0;//tcp_client_init()//1、创建socket//2、配置为客户端//3、配置要连接的服务器ip和端口以及协议类型//4、连接服务器//5、收发数据//6、关闭连接int tcp_client_init(char *ip, int port){int ret;//1 2socket_fd = socket(AF_INET, SOCK_STREAM, 0);if(socket_fd == -1){printf("create socket fail\n");return -1;}//3 struct sockaddr_in servaddr;servaddr.sin_family = AF_INET;//IPv4协议servaddr.sin_port = htons(port);//服务器端口号servaddr.sin_addr.s_addr = inet_addr(ip);//设置服务器//4ret = connect(socket_fd, &servaddr, sizeof(servaddr));if(ret == -1){printf("connect %s fail\n", ip);return -1;}}//tcp_client_send()int tcp_client_send(char *buff, int len){int ret = 0;ret = write(socket_fd, buff, len);return ret;}//tcp_client_rcv()int tcp_client_rcv(char *buff, int len){int ret;ret = read(socket_fd, buff, len);return ret;}//tcp_client_close()int tcp_client_close(){close(socket_fd);}#define CLENT_NUM 2struct sockaddr_in sSever_c_sd[CLENT_NUM];static int socket_s_fd = 0;static int socket_c_fd[CLENT_NUM] = {0};//tcp_server_init()#if 01、创建socket2、设置本地ip和端口以及协议类型3、绑定4、监听5、等待客户端连接6、收发数据7、关闭连接#endifint tcp_server_init(int port){int ret;//1 socket_s_fd = socket(AF_INET, SOCK_STREAM, 0);if(socket_s_fd == -1){printf("create socket fail\n");return -1;}else{printf("create socket ok\n");}//2 struct sockaddr_in local_addr,c_addr;local_addr.sin_family = AF_INET;//IPv4协议local_addr.sin_port = htons(port);//服务器端口号local_addr.sin_addr.s_addr = INADDR_ANY;//设置服务器ip//3ret = bind(socket_s_fd, &local_addr, sizeof(local_addr));if(ret == -1){printf("bind fail\n");close(socket_s_fd);return -1;}else{printf("bind ok\n");}//4ret = listen(socket_s_fd, 3);if(ret == -1){printf("listen fail\n");close(socket_s_fd);return -1;}else{printf("listen ok\n");}//5socklen_t addrlen = 0;while(1){printf("wait client conect\n");socket_c_fd[0] = accept(socket_s_fd, &c_addr, &addrlen);if(addrlen != 0)break;sleep(1);}printf("client conect\n");return 0;}//tcp_server_send()int tcp_server_send(char c, char *buff, int len){write(socket_c_fd[c], buff, len);}//tcp_server_rcv()int tcp_server_rcv(char c, char *buff, int len){int ret;ret = read(socket_c_fd[c], buff, len);return ret;}//tcp_server_close()int tcp_server_close(){close(socket_s_fd);}
tcp.h
#ifndef __TCP_H#define __TCP_Hint tcp_client_init(char *ip, int port);int tcp_client_send(unsigned char *buff, int len);int tcp_client_rcv(unsigned char *buff, int len);int tcp_client_close();int tcp_server_init( int port);int tcp_server_send(char c, unsigned char *buff, int len);int tcp_server_rcv(char c, unsigned char *buff, int len);int tcp_server_close();#endif
编译脚本
rm -rf main sscom32.zipgcc main.c http_download.c tcp.c -o main -w./main http://xzd.197946.com/sscom32.zip
测试效果http://xzd.197946.com/sscom32.zip
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