使用nginx如何處理http請求

typedef enum {
 NGX_HTTP_POST_READ_PHASE = 0,
 
 NGX_HTTP_SERVER_REWRITE_PHASE,
 
 NGX_HTTP_FIND_CONFIG_PHASE,
 NGX_HTTP_REWRITE_PHASE,
 NGX_HTTP_POST_REWRITE_PHASE,
 
 NGX_HTTP_PREACCESS_PHASE,
 
 NGX_HTTP_ACCESS_PHASE,
 NGX_HTTP_POST_ACCESS_PHASE,
 
 NGX_HTTP_TRY_FILES_PHASE,
 NGX_HTTP_CONTENT_PHASE,
 
 NGX_HTTP_LOG_PHASE
} ngx_http_phases;

NGX_HTTP_POST_READ_PHASE = 0  //讀取請求階段
NGX_HTTP_SERVER_REWRITE_PHASE //URI轉(zhuǎn)換階段
NGX_HTTP_FIND_CONFIG_PHASE   //查找相應(yīng)的配置來執(zhí)行階段
NGX_HTTP_REWRITE_PHASE    //URI轉(zhuǎn)換階段（不太清楚此處）
NGX_HTTP_POST_REWRITE_PHASE  //對轉(zhuǎn)換后的URL結(jié)果進(jìn)行處理的階段
NGX_HTTP_PREACCESS_PHASE   //權(quán)限檢查準(zhǔn)備階段
NGX_HTTP_ACCESS_PHASE    //權(quán)限檢查階段
NGX_HTTP_POST_ACCESS_PHASE  //對權(quán)限檢查結(jié)果進(jìn)行處理階段
NGX_HTTP_TRY_FILES_PHASE   //處理配置中的try_files階段
NGX_HTTP_CONTENT_PHASE    //處理生成返回?cái)?shù)據(jù)階段(此處認(rèn)為不太細(xì)，當(dāng)然有filter也可以忽略)
NGX_HTTP_LOG_PHASE     //記錄日志處理階段，具體說明應(yīng)當(dāng)是請求完成后，關(guān)閉請求時(shí)處理

static ngx_int_t
ngx_http_xxx_init(ngx_conf_t *cf)
{
 ngx_http_handler_pt  *h;
 ngx_http_core_main_conf_t *cmcf;
 
 cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);
 
 h = ngx_array_push(&cmcf->phases[NGX_HTTP_CONTENT_PHASE].handlers);
 if (h == NULL) {
 return NGX_ERROR;
 }
 
 *h = ngx_http_xxx_handler;
 
 return NGX_OK;
}

NGX_OK        //處理成功，進(jìn)入下一階段
NGX_DECLINED      //放棄處理
NGX_AGAIN || NGX_DONE  //處理完成，返回該值會觸發(fā)請求
NGX_ERROR || NGX_HTTP_.. //處理錯(cuò)誤或者HTTP的其它狀態(tài)值

static char *
ngx_http_xxx_server(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
 ngx_str_t     *value;
 ngx_url_t     u;
 ngx_http_core_loc_conf_t *clcf;
 
 clcf = ngx_http_conf_get_module_loc_conf(cf, ngx_http_core_module);
 
 clcf->handler = ngx_http_xxx_handler;
 
 if (clcf->name.data[clcf->name.len - 1] == '/') {
 clcf->auto_redirect = 1;
 }
 
 return NGX_CONF_OK;
}