c ngx模块两次请求

Question

#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>

typedef struct {
    ngx_flag_t enable; 
    ngx_uint_t num; 
    ngx_str_t key; 
} ngx_http_sample_loc_conf_t;
static ngx_int_t ngx_http_sample_handler(ngx_http_request_t *r);
static void *ngx_http_sample_create_loc_conf(ngx_conf_t *cf);
static char *ngx_http_sample_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child);
static ngx_int_t ngx_http_sample_init(ngx_conf_t *cf);

static ngx_command_t ngx_http_sample_commands[] = {
    { ngx_string("sample"),
     NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG, 
     ngx_conf_set_flag_slot,
     NGX_HTTP_LOC_CONF_OFFSET,
     offsetof(ngx_http_sample_loc_conf_t, enable), 
     NULL },

    { ngx_string("sample_num"),
     NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1, 
     ngx_conf_set_num_slot, 
     NGX_HTTP_LOC_CONF_OFFSET,
     offsetof(ngx_http_sample_loc_conf_t, num), 
     NULL },         

    { ngx_string("sample_access_key"), 
     NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1, 
     ngx_conf_set_str_slot, 
     NGX_HTTP_LOC_CONF_OFFSET,
     offsetof(ngx_http_sample_loc_conf_t, key),
     NULL },

     ngx_null_command
};
static ngx_http_module_t ngx_http_sample_module_ctx = {
    NULL, /* preconfiguration */
    ngx_http_sample_init, /* postconfiguration */
    NULL, /* create main configuration */
    NULL, /* init main configuration */
    NULL, /* create server configuration */
    NULL, /* merge server configuration */
    ngx_http_sample_create_loc_conf, /* create location configuration */
    ngx_http_sample_merge_loc_conf /* merge location configuration */
};
ngx_module_t ngx_http_sample_module = {
    NGX_MODULE_V1,
    &ngx_http_sample_module_ctx, /* module context */
    ngx_http_sample_commands, /* module directives */
    NGX_HTTP_MODULE,             /* module type */
    NULL,                         /* init master */
    NULL,                         /* init module */
    NULL,                         /* init process */
    NULL,                         /* init thread */
    NULL,                         /* exit thread */
    NULL,                         /* exit process */
    NULL,                         /* exit master */
    NGX_MODULE_V1_PADDING
};

static void *
ngx_http_sample_create_loc_conf(ngx_conf_t *cf)
{
    ngx_http_sample_loc_conf_t *conf;
    conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_sample_loc_conf_t));
    if (conf == NULL) {
        return NGX_CONF_ERROR;
    }        

    conf->enable = NGX_CONF_UNSET;
    conf->num = NGX_CONF_UNSET;
    return conf;
}

static char *
ngx_http_sample_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child)
{
    ngx_http_sample_loc_conf_t *prev = parent;
    ngx_http_sample_loc_conf_t *conf = child;

    ngx_conf_merge_value(conf->enable, prev->enable, 0);
    ngx_conf_merge_uint_value(conf->num, prev->num, 10);
    ngx_conf_merge_str_value(conf->key, prev->key, "key");

    return NGX_CONF_OK;
}

static ngx_int_t
ngx_http_sample_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_ACCESS_PHASE].handlers);
    if (h == NULL) {
        return NGX_ERROR;
    }
    *h = ngx_http_sample_handler;

    return NGX_OK;
}
static ngx_int_t
ngx_http_sample_handler(ngx_http_request_t *r)
{        
    ngx_http_sample_loc_conf_t *alcf;    
    alcf = ngx_http_get_module_loc_conf(r, ngx_http_sample_module);        

    if (!alcf->enable) {
        return NGX_OK;
    }        

    ngx_log_error(NGX_LOG_DEBUG, r->connection->log, 0, "access sample module limit:%d", alcf->num);
    ngx_log_error(NGX_LOG_DEBUG, r->connection->log, 0, "access sample module key:%V", &alcf->key);    

    return NGX_OK;
}

nginx.conf http

    http { 
sample on;
sample 50;
sample_access_key "Symfoware";
}

curl http://127.0.0.1/?asdfadsf

输出的结果为 结果：     2016/09/09 16:19:04 [错误] 5063＃0：* 1访问示例模块限制：50，客户端：127.0.0.1，服务器：localhost，请求：＆＃34; GET /？asdfadsf HTTP / 1.1＆ ＃34;，主持人：＆＃34; 127.0.0.1＆＃34;

2016/09/09 16:19:04 [error] 5063#0: *1 access sample module key:Symfoware, client: 127.0.0.1, server: localhost, request: "GET /?asdfadsf HTTP/1.1", host: "127.0.0.1"

2016/09/09 16:19:04 [error] 5063#0: *1 access sample module limit:50, client: 127.0.0.1, server: localhost, request: "GET /?asdfadsf HTTP/1.1", host: "127.0.0.1"

2016/09/09 16:19:04 [error] 5063#0: *1 access sample module key:Symfoware, client: 127.0.0.1, server: localhost, request: "GET /?asdfadsf HTTP/1.1", host: "127.0.0.1"

问题是一次GET请求，而通过nginx module输出的却是两次请求的处理。