C语言 HTTP协议下载文件,实现断点续传,socket通讯,目前只支持ip和port方式连接,有兴趣的读者可完善域名方式。
代码分为 http.c: 实现http协议下载文件 ,socket.c: 封装linux socket函数,移植时只需修改socket.c中的函数即可。
希望对大家有帮助,本人亲测可用!
http.c
- //http.c
- //作者:王振
- #include <stdio.h>
- #include <stdlib.h>
- #include <errno.h>
- #include <string.h>
- #include <sys/types.h>
- #include <sys/stat.h>
- #include <fcntl.h>
- #include "socket.h"
- #include "http.h"
- #define MAX_RECV_SIZE 1440//硬件单包最大的接收字节数
- char g_host[URL_LEN];
- char g_ip[URL_LEN+1];//ip/域名
- char g_port[5+1];
- char g_buf_send[4*1024];//发送数据暂存区
- char g_buf_recv[10*1024];//接收数据暂存区
- BreakPoint_ST g_break_point;
- /*
- 功能:判断断点有效性,现在校验url是否一致
- 参数:
- 返回:
- >0---------有效,已下载文件大小
- -1----------无效
- */
- int Get_Breakpoint_Available(BreakPoint_ST *breakpoint,char *url,char *file_crc)
- {
-
- //判断断点是否有效,后续加入文件校验码
- if((memcmp(breakpoint->url,url,strlen(url))== 0)&&(breakpoint->recv_size== MAX_RECV_SIZE))
- return breakpoint->download_size;
- else
- {
- return -1;
- }
-
- }
- /*
- 功能:判断要下载文件是否存在断点
- 参数:
- filename---要下载的文件名
- file_crc----服务器返回下载文件的校验码
- 返回:
- 0---------无断点
- >0--------有断点,已下载文件大小
- */
- int Get_Breakpoint(char *url,char *filename,char *file_crc)
- {
- char filename_bp[64];
- int fd = -1;
- int ret;
- BreakPoint_ST break_point;
-
- //断点文件名 filename+bp
- sprintf(filename_bp,"%s.bp",filename);
- //检测是否存在filename断点文件
- fd = open(filename_bp,O_RDONLY,S_IRUSR|S_IWUSR);
- if(fd == -1)
- {
- #ifdef DEBUG_HTTP
- printf("no exsit %s\n",filename_bp);
- #endif
- return 0;
- }
- //存在断点
- ret = read(fd,&break_point,sizeof(break_point));
- if(ret != sizeof(break_point))
- {
- perror("ERR:Get_Breakpoint read");
- exit(-1);
- }
- close(fd);
- //判断断点是否有效
- ret = Get_Breakpoint_Available(&break_point,url,file_crc);
- if(ret > 0)
- return ret;
- else
- {
-
- printf("%s not available\n",filename_bp);
- remove(filename);
- remove(filename_bp);
- return 0;
-
- }
- }
- /*
- 功能:保存断点信息,文件名filename.bp
- 参数:
- filename---要下载的文件名
- file_crc----服务器返回下载文件的校验码
- 返回:
- 0---------成功
- >0--------有断点,已下载文件大小
- */
- int Save_Breakpoint(char *url,char *filename,int download_size,char *file_crc)
- {
- int fd;
- BreakPoint_ST breakpoint;
- char filename_bp[128];//断点信息文件名,包含路径
- sprintf(filename_bp,"%s.bp",filename);
- /* 创建目的文件 */
- if((fd=open(filename_bp,O_WRONLY|O_CREAT,S_IRUSR|S_IWUSR))==-1)
- {
- fprintf(stderr,"Open %s Error:%s\n",filename_bp,strerror(errno));
- exit(1);
- }
- memset(&breakpoint,0x0,sizeof(breakpoint));
- strcpy(breakpoint.url,url);
- //strcpy(breakpoint.crc,file_crc);
- strcpy(breakpoint.filename,filename);
- breakpoint.download_size = download_size;
- breakpoint.recv_size= MAX_RECV_SIZE;
-
- //xu tioa zheng wei fen ci xie ru
- if(write(fd,&breakpoint,sizeof(breakpoint)) != sizeof(breakpoint))
- {
- perror("ERR:Save_Breakpoint");
- exit(1);
- }
- close(fd);
- return 0;
- }
- /*
- 功能:保存文件,追加写
- 参数:
- 返回:
- 0---------成功
- */
- int Save_File(char *filebuf,int filelength,char *filename)
- {
- int fd;
- /* 创建目的文件追加写 */
- if((fd=open(filename,O_WRONLY|O_CREAT|O_APPEND,S_IRUSR|S_IWUSR))==-1)
- {
- fprintf(stderr,"Open %s Error:%s\n",filename,strerror(errno));
- exit(1);
- }
- //xu tioa zheng wei fen ci xie ru
- if(write(fd,filebuf,filelength) != filelength)
- {
- perror("ERR:Save_File");
- exit(1);
- }
- close(fd);
- return 0;
- }
-
- int HTTP_GetResponseCode(void)
- {
-
-
- }
- /*
- 功能:读取http返回的协议实体主体长度
- 参数:
- revbuf--------接收到的返回值
- 返回值:
- >=0---------内容(实体主体)的长度
- -1-----------数据返回错误
- */
- int HTTP_GetRecvLength(char *revbuf)
- {
- char *p1 = NULL;
- int HTTP_Body = 0;//内容体长度
- int HTTP_Head = 0;//HTTP 协议头长度
- HTTP_Body = HTTP_GetContentLength(revbuf);
- if(HTTP_Body == -1)
- return -1;
- p1=strstr(revbuf,"\r\n\r\n");
- if(p1==NULL)
- return -1;
- else
- {
- HTTP_Head = p1- revbuf +4;// 4是\r\n\r\n的长度
- return HTTP_Body+HTTP_Head;
- }
- }
- /*
- 功能:读取http返回的Content-Length长度
- 参数:
- revbuf--------接收到的数据
- 返回值:
- >=0---------Content-Length长度
- -1-----------数据返回错误
- */
- int HTTP_GetContentLength(char *revbuf)
- {
- char *p1 = NULL, *p2 = NULL;
- int HTTP_Body = 0;//内容体长度
- p1 = strstr(revbuf,"Content-Length");
- if(p1 == NULL)
- return -1;
- else
- {
- p2 = p1+strlen("Content-Length")+ 2;
- HTTP_Body = atoi(p2);
- return HTTP_Body;
- }
- }
- /*
- 功能:
- 参数:
- sockfd--------接收到的返回值
- 返回值:
- >0---------接收到长度
- -1----------失败
- =0---------服务端断开连接
- 注:内部接收缓冲10k
- */
- int HTTP_Recv(int sockfd,char *buf_recv)
- {
- int ret;
- int recvlen=0;
- int downloadlen = 0;
- //int contentlen=0;
- char buf_recv_tmp[10*1024+1];
-
- memset(buf_recv_tmp,0x0,sizeof(buf_recv_tmp));
- while(1)
- {
- ret = Recv(sockfd,buf_recv_tmp+recvlen,sizeof(buf_recv_tmp)-1,0);
- if(ret <= 0)//下载失败
- {
- perror("ERR:recv fail");
- return ret;
- }
-
-
- if(recvlen == 0)
- {
- #ifdef DEBUG_HTTP_RECV
- printf("recv len = %d\n", ret);
- printf("recv = %s\n", buf_recv_tmp);
- #endif
- //获取需要下载长度;
- downloadlen = HTTP_GetRecvLength(buf_recv_tmp);
- #ifdef DEBUG_HTTP_RECV
- printf("downloadlen = %d\n",downloadlen);
- #endif
- }
- recvlen += ret;
- #ifdef DEBUG_HTTP_RECV
- printf("total recvlen = %d\n",recvlen);
- #endif
- if(downloadlen == recvlen)//下载完成
- break;
- }
- memcpy(buf_recv,buf_recv_tmp,downloadlen);
- return recvlen;
- }
- /*
- 功能:获取下载url中的文件名,最后一个/后的字符
- 参数:
- 返回值:
- 0-----------成功
- -1----------失败
- 注:内部接收缓冲10k
- */
- int HTTP_GetFileName(char *url,char *filename)
- {
- //提取url中最后一个/后的内容
- int len;
- int i;
- len = strlen(url);
- for(i=len-1;i>0;i--)
- {
- if(url[i] == '/')
- break;
- }
- if(i == 0)//下载地址错误
- {
- printf("url not contain '/'\n");
- return -1;
- }
- else
- {
-
- strcpy(filename,url+i+1);
- #ifdef DEBUG_HTTP
- printf("filename=%s\n",filename);
- #endif
- return 0;
- }
- }
- /*
- 功能:获取下载url中的路径,第一个/后的字符
- 参数:
- 返回值:
- 0-----------成功
- -1----------失败
- 注:url ex ""
- */
- int HTTP_GetPath(char *url,char *path)
- {
- char *p;
- p = strstr(url,"http://");
- if(p == NULL)
- {
- p = strchr(url,'/');
- if(p == NULL)
- return -1;
- else
- {
- strcpy(path,p);
- return 0;
- }
- }
- else
- {
- p = strchr(url+strlen("http://"),'/');
- if(p == NULL)
- return -1;
- else
- {
- strcpy(path,p);
- return 0;
- }
- }
- }
- /*
- 功能:获取下载url中的ip和port,ip支持域名,端口默认为80
- 参数:
- 返回值:
- 1-----------域名式
- 2-----------ip port式
- -1----------失败
- 注:url ex ""
- */
- int HTTP_Get_IP_PORT(char *url,char *ip,char *port)
- {
- char *p = NULL;
- int offset = 0;
- char DOMAIN_NAME[128];
- p = strstr(url,"http://");
- if(p == NULL)
- {
- offset = 0;
- }
- else
- {
- offset = strlen("http://");
- }
- p = strchr(url+offset,'/');
- if(p == NULL)
- {
- printf("url:%s format error\n",url);
- return -1;
-
- }
- else
- {
- memset(DOMAIN_NAME,0x0,sizeof(DOMAIN_NAME));
- memcpy(DOMAIN_NAME,url+offset,(p-url-offset));
- p = strchr(DOMAIN_NAME,':');
- if(p == NULL)
- {
- strcpy(ip,DOMAIN_NAME);
- strcpy(port,"80");
- //printf("ip %p,port %p\n",ip,port);
-
- #ifdef DEBUG_HTTP
- printf("ip=%s,port=%s\n",ip,port);//debug info
- #endif
- return 1;
- }
- else
- {
- *p = '\0';
- strcpy(ip,DOMAIN_NAME);
- strcpy(port,p+1);
-
- #ifdef DEBUG_HTTP
- printf("ip=%s,port=%s\n",ip,port);//debug info
- #endif
- return 2;
- }
- return 0;
- }
-
- }
- void Package_Url_Get_File(char *path, char *range)
- {
- char buf[64];
- memset(g_buf_send,0x0,sizeof(g_buf_send));
- sprintf(g_buf_send, "GET %s",path);
-
- //HTTP/1.1\r\n 前面需要一个空格
- strcat(g_buf_send," HTTP/1.1\r\n");
- strcat(g_buf_send, "Host: ");
- strcat(g_buf_send, g_host);
- //strcat(g_buf_send, ":");
- //strcat(g_buf_send, PORT);
-
- sprintf(buf, "\r\nRange: bytes=%s",range);
- strcat(g_buf_send,buf);
- strcat(g_buf_send, "\r\nKeep-Alive: 200");
- strcat(g_buf_send,"\r\nConnection: Keep-Alive\r\n\r\n");
-
- }
- int Package_Url_Get_FileSize(char *url)
- {
-
- memset(g_buf_send,0x0,sizeof(g_buf_send));
- sprintf(g_buf_send, "HEAD %s",url);
- //HTTP/1.1\r\n 前面需要一个空格
- strcat(g_buf_send," HTTP/1.1\r\n");
- strcat(g_buf_send, "Host: ");
- strcat(g_buf_send, g_host);
- //strcat(g_buf_send, ":");
- //strcat(g_buf_send, PORT);
- strcat(g_buf_send,"\r\nConnection: Keep-Alive\r\n\r\n");
- return 0;
- }
- int HTTP_GetFileSize(int sockfd,char *path)
- {
- int ret = -1;
- char buf_recv_tmp[10*1024+1];
- Package_Url_Get_FileSize(path);
- #ifdef DEBUG_HTTP
- printf("send = %s \n",g_buf_send);
- #endif
- Send(sockfd, g_buf_send, strlen(g_buf_send), 0);
- memset(buf_recv_tmp,0x0,sizeof(buf_recv_tmp));
- ret = Recv(sockfd,buf_recv_tmp,sizeof(buf_recv_tmp)-1,0);
- #ifdef DEBUG_HTTP
- printf("recv len = %d\n", ret);
- printf("recv = %s\n", buf_recv_tmp);
- #endif
- if(ret <= 0)
- {
- perror("ERR:recv fail GetFileSize()");
- return -1;
- }
- ret = HTTP_GetContentLength(buf_recv_tmp);
- if(ret <= 0)
- return -1;
- else
- return ret;
- }
- /*
- 功能:分段下载文件
- 参数:
- 返回值:
- >0----------已下载文件大小(不包含上次下载)
- -1----------失败
- */
- int HTTP_GetFile(int sockfd,char *path,int filelength,int download_size,char *filebuf)
- {
- int count;
- char range[32];
- int i;
- int j = 0;//成功下载次数
- int ret = -1;
- char *p = NULL;
- int download_index;//下载开始索引
- count = (filelength%MAX_RECV_SIZE)?(filelength/MAX_RECV_SIZE +1):(filelength/MAX_RECV_SIZE);
- download_index = download_size/MAX_RECV_SIZE;
- for(i=download_index;i<count;i++)
- {
- //if(i == 20)//测试断点
- //break;
- if((i == (count-1))&&(filelength%MAX_RECV_SIZE))
- sprintf(range,"%d-%d",i*MAX_RECV_SIZE,filelength-1);
- else
- sprintf(range,"%d-%d",i*MAX_RECV_SIZE,(i+1)*MAX_RECV_SIZE-1);
- Package_Url_Get_File(path,range);
- #ifdef DEBUG_HTTP
- printf("send = %s \n",g_buf_send);
- #endif
- Send(sockfd, g_buf_send, strlen(g_buf_send), 0);
- /*需改为提取http 返回协议头和协议体总长,然后定长接收*/
- memset(g_buf_recv,0x0,sizeof(g_buf_recv));
- ret = HTTP_Recv(sockfd,g_buf_recv);
- if(ret < 0)
- break;
- if(ret == 0 )//服务端断开连接
- {
- sockfd = Socket_Connect(g_ip,g_port);
- i--;
- continue;
- }
- /*提取协议体数据,保存在filebuf中*/
- p = strstr(g_buf_recv,"\r\n\r\n");
- if(p == NULL)//jia ru duan dian baocun
- {
- printf("ERR:g_buf_recv not contain end flag\n");
- break;
- }
- else
- {
- memcpy(filebuf+j*MAX_RECV_SIZE,p+4,MAX_RECV_SIZE);
- j++;
- }
- }
- if(i == count)
- return (filelength-download_size);
- else
- return (i*MAX_RECV_SIZE-download_size);
- }
- /*
- 功能:HTTP下载文件
- 参数:
- 返回值:
- 0----------下载完成
- -1---------失败
- -2---------部分下载完成
- 注:保存文件到bin所在目录
- */
- int HTTP_DownloadFile(char *url,char *save_path)
- {
- int ret;
- int sockfd;
- int filesize;
- int download_size;
- char filename[FILENAME_LEN+1];
- char filename_bp[FILENAME_LEN+3+1];
- char *filebuf;
- char save_file_path[FILENAME_LEN+1];//保存下载文件的路径+文件名
- char path[PATH_LEN+1];//url中的path
- //提取ip和port或url(url 暂不实现,需要gethostbyname linux)
- ret = HTTP_Get_IP_PORT(url,g_ip,g_port);
- if(ret == -1)
- return -1;
- else
- {
- sprintf(g_host,"%s:%s",g_ip,g_port);
- }
- //提取下载文件名
- ret = HTTP_GetFileName(url,filename);
- if(ret == -1)
- return -1;
- ret = HTTP_GetPath(url,path);
- if(ret == -1)
- return -1;
- //sleep(3);//debug info
- //建立连接
- sockfd = Socket_Connect(g_ip,g_port);
- //获取下载文件总大小
- filesize = HTTP_GetFileSize(sockfd,path);
- if(filesize == -1)
- return -1;
- //#ifdef DEBUG_HTTP
- printf("http need download size %d\n",filesize);
- //#endif
- //malloc分配存储文件空间
- filebuf = (char *)malloc(filesize);
- if(filebuf == NULL)
- {
- perror("malloc filebuf fail");
- return -1;
- }
- else
- memset(filebuf,0x0,filesize);
- download_size = Get_Breakpoint(url,filename,NULL);
- #ifdef DEBUG_HTTP
- printf("breakpoint download_size=%d\n",download_size);//debug info
- sleep(3);//debug info
- #endif
- //分段下载文件
- ret = HTTP_GetFile(sockfd,path,filesize,download_size,filebuf);
- Close(sockfd);
- if(ret < 0)
- {
- free(filebuf);
- return -1;
- }
- else
- {
- sprintf(save_file_path,"%s%s",save_path,filename);
-
- #ifdef DEBUG_HTTP
- printf("save_path=%s\n",save_path);
- printf("filename=%s\n",filename);
- printf("save_file_path=%s\n",save_file_path);
- printf("download_size = %d\n",ret);
- #endif
- Save_File(filebuf,ret,save_file_path);
- free(filebuf);
- if((ret+download_size) == filesize)//全部下载完成
- {
- sprintf(filename_bp,"%s.bp",filename);
- remove(filename_bp);
-
- printf("download success\n");
- return 0;
- }
- else//部分下载完成
- {
- printf("part download success\n");
- //保存断点信息
- Save_Breakpoint(url,save_file_path,ret+download_size,NULL);
- return -2;
- }
- }
- }
socket.c - //socket.c
- //作者:王振
- #include <stdio.h>
- #include <stdlib.h>
- #include <errno.h>
- #include <string.h>
- #include <sys/types.h>
- #include <netinet/in.h>
- #include <sys/socket.h>
- #include <sys/wait.h>
- #include "socket.h"
- int Connect(int fd, struct sockaddr *addr, socklen_t len)
- {
- int result;
- if ((result = connect(fd, addr, len)) == -1) {
- perror("connect");
- exit(EXIT_FAILURE);
- }
- return 0;
- }
- int Socket_Connect(char *ip,char *port)
- {
- struct sockaddr_in addr;
- int sockfd;
- int len;
-
- addr.sin_family = AF_INET;
- addr.sin_addr.s_addr = inet_addr(ip);//127.0.0.1为本机ip
- addr.sin_port = htons(atoi(port));
- len = sizeof(addr);
-
- sockfd = socket(AF_INET, SOCK_STREAM, 0);
- Connect(sockfd, (struct sockaddr*)&addr, len);
- return sockfd;
- }
- /*
- 功能:向socketfd发送数据,内部实现了循环发送len长度
- 参数:
- sockfd 是代表你与远程程序连接的套接字描述符。
- msg 是一个指针,指向你想发送的信息的地址。
- len 是你想发送信息的长度。
- flags 发送标记。一般都设为0
- 返回:
- 0-------- 成功
- 退出---失败
- 修改:
- 备注:
- 王振
- */
- int Send(int sockfd, char *sendbuf, int len, int flags)
- {
- int sendlen = 0;
- int ret = -1;
- while(sendlen < len)
- {
- ret = send(sockfd, sendbuf+sendlen, len-sendlen, flags);
- if(-1 == ret)
- {
- perror("send");
- exit(EXIT_FAILURE);
- }
- else
- sendlen += ret;
- }
- return 0;
- }
- int Close(int sockfd)
- {
- return close(sockfd);
-
- }
- int Recv(int sockfd, char *recvbuf, int len, int flags)
- {
- int recv_len;
- if ((recv_len = recv(sockfd, recvbuf, len, flags)) < 0)
- {
- perror("recv error");
- exit(EXIT_FAILURE);
- }
- return recv_len;
- }
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