Apache加载memcached模块的源文件（mod_memcached.c）


/******************************************************************************************************************
Discription: This is a simple memcached module for Apache web server, which can set a picture file into memcached.
*******************************************************************************************************************
made by Reesun Huang at 2010.04
*******************************************************************************************************************
Version: 0.1
******************************************************************************************************************/

#include <httpd.h>
#include <http_protocol.h>
#include <http_config.h>
#include <http_log.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <libmemcached/memcached.h>

//该函数用于设定memcached的key值

char * location(request_rec *r)
{
  char *key;

  key = (char *)rindex(r->uri, '/');

   if (key)
    return key;
  else
    return NULL;
}

static int memcached_handler(request_rec *r)
{
    memcached_st *memc;
    memcached_return rc;
    memcached_server_st *servers;
    char bytebuf[r->finfo.size];
    char *fileName = NULL;
    FILE *fp = NULL;

    apr_file_t *fd;
    apr_size_t sz;
    apr_status_t rv;

    //判断头部，如果头部不是“memcached”则返回。

     if (!r->handler || strcmp(r->handler, "memcached")) {
        return DECLINED;
    }
    
    //判断文件名是否为空，如为空则返回

    if (r->filename == NULL) {
        return DECLINED;
    }
  
    //从文件信息中获取一些有用的头文件定义内容

    if(r->finfo.mtime){
        char *datestring = apr_palloc(r->pool, APR_RFC822_DATE_LEN);
        apr_rfc822_date(datestring, r->finfo.mtime);
        apr_table_setn(r->headers_out, "Last-Modified", datestring);
    }

    /***************************************************************************************************************
    定义memcached的key值，其值为“/$memcached_key”。其中“$memcached_key”为nginx传递给Apache的key值
 ***************************************************************************************************************/
    fileName = location(r);


    //将文件转化为byte数组

    fp = fopen(r->filename, "rb");
    if(!fread(bytebuf, 1, r->finfo.size, fp)) {
        return DECLINED;
    }
    fclose(fp);


    //将相应文件写入memcached缓存

 
    //连接memcached服务器

    memc = memcached_create(NULL);
    servers = memcached_server_list_append(NULL, "localhost", 12000, &rc);
    rc = memcached_server_push(memc, servers);
    memcached_server_free(servers);

    //将相应文件写入memcached缓存

    rc = memcached_set(memc, fileName, strlen(fileName), bytebuf, sizeof(bytebuf), (time_t)0, (uint32_t)0);

    if(rc != MEMCACHED_SUCCESS){
        return DECLINED;
    }//fi


    //断开连接

    memcached_free(memc);


    //写入缓存后，将相应文件输出。这样在html文件嵌入的图片就能输出了


    rv = apr_file_open(&fd, r->filename,
                       APR_READ|APR_SHARELOCK|APR_SENDFILE_ENABLED,
                       APR_OS_DEFAULT, r->pool);
    if(rv != APR_SUCCESS){
        ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
                      "can't open %s", r->filename);
        return HTTP_NOT_FOUND;
    }

    ap_send_fd (fd, r, 0, r->finfo.size, &sz);

    apr_file_close (fd);

    return OK;
}

static void memcached_hooks(apr_pool_t *pool)
{
    ap_hook_handler(memcached_handler, NULL, NULL, APR_HOOK_MIDDLE);
}

module AP_MODULE_DECLARE_DATA memcached_module = {
    STANDARD20_MODULE_STUFF,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    memcached_hooks
};