一个简单的wed服务器SHTTPD（5）————服务器SHTTPD请求方法解析

//start from the very beginning,and to create greatness
//@author: Chuangwei Lin
//@E-mail：979951191@qq.com
//@brief： 服务器SHTTPD请求方法解析
#include "lcw_shttpd.h"
/******************************************************
函数名： Method_DoGet(struct worker_ctl *wctl)
参数：
功能：GET方法
*******************************************************/
static int Method_DoGet(struct worker_ctl *wctl)
{
    DBGPRINT("LCW==>Method_DoGet\n");
    struct conn_response *res = &wctl->conn.con_res;
    struct conn_request *req = &wctl->conn.con_req;
    char path[URI_MAX];
    memset(path, 0, URI_MAX);
    size_t    n;
    unsigned long r1, r2;
    char *fmt = "%a, %d %b %Y %H:%M:%S GMT";//时间格式
    //需要确定的参数
    size_t status = 200;//状态值,已确定
    char *msg = "OK";    //状态信息,已确定
    char date[64] = "";//时间
    char lm[64] = "";    //请求文件最后修改信息
    char etag[64] = "";//etag信息
    big_int_t cl;        //内容长度
    char range[64] = "";//范围    
    struct mine_type *mine = NULL;    
    time_t t = time(NULL);//取得当前时间
    //根据fmt指向字符串的命令将localtime(&t)中的时间信息储存在date中
    (void)strftime(date, sizeof(date),fmt,localtime(&t));
    //最后修改时间
    (void) strftime(lm, sizeof(lm), fmt,localtime(&res->fsate.st_mtime));
    //ETAG 将可变个参数(...)按照"%lx.%lx"格式化成字符串，然后将其复制到etag中
    (void) snprintf(etag, sizeof(etag), "%lx.%lx",(unsigned long)res->fsate.st_mtime,(unsigned long)res->fsate.st_size);    
    //发送的MIME类型
    mine = Mine_Type(req->uri, strlen(req->uri), wctl);
    //内容长度
    cl = (big_int_t) res->fsate.st_size;
    //范围range
    memset(range, 0, sizeof(range));
    n = -1;
    if (req->ch.range.v_vec.len > 0 )//取出请求范围
    {
        printf("request range:%d\n",req->ch.range.v_vec.len);
        //从ptr里读进数据，依照第二个参数的格式将数据写入到后面的参数里
        n = sscanf(req->ch.range.v_vec.ptr,"bytes=%lu-%lu",&r1, &r2);
    }
    printf("n:%d\n",n);
    if(n > 0) 
    {
        status = 206;
        lseek(res->fd, r1, SEEK_SET);
        //n==2取前一个
        cl = n == 2 ? r2 - r1 + 1: cl - r1;
        (void) snprintf(range, sizeof(range),"Content-Range: bytes %lu-%lu/%lu\r\n",r1, r1 + cl - 1, (unsigned long) res->fsate.st_size); 
        msg = "Partial Content";
    }
    //构建输出的头部
    memset(res->res.ptr, 0, sizeof(wctl->conn.dres));
    snprintf(res->res.ptr,//缓冲区
        sizeof(wctl->conn.dres),//缓冲区长度
        "HTTP/1.1 %d %s\r\n" //状态和状态信息
        "Date: %s\r\n"//日期
        "Last-Modified: %s\r\n"//最后修改时间
        "Etag: \"%s\"\r\n"//Web资源标记号
        "Content-Type: %.*s\r\n"//内容类型
        "Content-Length: %lu\r\n"//内容长度
        //"Connection:close\r\n"
        "Accept-Ranges: bytes\r\n"//发送范围        
        "%s\r\n",//范围起始
        status,msg,date,lm,etag,strlen(mine->mime_type),mine->mime_type,cl,range);
    res->cl = cl;
    res->status = status;
    printf("content length:%d, status:%d\n",res->cl, res->status);
    DBGPRINT("LCW<==Method_DoGet\n");
    return 0;
}
/******************************************************
未实现的方法
*******************************************************/
static int Method_DoPost(struct worker_ctl *wctl)
{
    return 0;
}
static int Method_DoHead(struct worker_ctl *wctl)
{
    Method_DoGet(wctl);
    close(wctl->conn.con_res.fd);
    wctl->conn.con_res.fd = -1;
    return 0;
}
static int Method_DoPut(struct worker_ctl *wctl)
{
    return 0;
}
static int Method_DoDelete(struct worker_ctl *wctl)
{
    return 0;
}
static int Method_DoCGI(struct worker_ctl *wctl)
{
    return 0;    
}
static int Method_DoList(struct worker_ctl *wctl)
{
    return 0;
}
/******************************************************
函数名：Method_Do(struct worker_ctl *wctl)
参数：业务和线程状态结构
功能：匹配方法
*******************************************************/
void Method_Do(struct worker_ctl *wctl)
{
    DBGPRINT("LCW==>Method_Do\n");
    if(0)//????什么意思 不执行？
        Method_DoCGI(wctl);
    switch(wctl->conn.con_req.method)//匹配请求类型
    {
        case METHOD_PUT://PUT方法
            Method_DoPut(wctl);
            break;
        case METHOD_DELETE://DELETE方法
            Method_DoDelete(wctl);
            break;
        case METHOD_GET://GET方法(这里只实现GET方法)
            Method_DoGet(wctl);
            break;
        case METHOD_POST://POST方法
            Method_DoPost(wctl);
            break;
        case METHOD_HEAD://HEAD方法
            Method_DoHead(wctl);
            break;
        default:
            Method_DoList(wctl);
    }

    DBGPRINT("LCW<==Method_Do\n");
}