Add dummy filter module.

[rbdr/ngx_http_office_hours_filter_module] / ngx_http_office_hours_filter_module.c

/*
 * Copyright 2018 Rubén Beltrán del Río
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the
 * License. You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations under the License.
 */


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

// Module Config Definitions

typedef struct {
    ngx_array_t    *office_hours;
}               ngx_http_office_hours_conf_t;

static void    *ngx_http_office_hours_create_conf(ngx_conf_t * cf);
static char    *ngx_http_office_hours_merge_conf(ngx_conf_t * cf, void *parent, void *child);
static ngx_int_t ngx_http_office_hours_init(ngx_conf_t * cf);

static char    *ngx_http_office_hours(ngx_conf_t * cf, ngx_command_t * cmd, void *conf);

//Module Directive Definitions

static ngx_command_t ngx_http_office_hours_commands[] = {
    {
        ngx_string("office_hours"),
        NGX_HTTP_SRV_CONF | NGX_HTTP_LOC_CONF | NGX_CONF_1MORE,
        ngx_http_office_hours,
        NGX_HTTP_LOC_CONF_OFFSET,
        offsetof(ngx_http_office_hours_conf_t, office_hours),
        NULL
    },

    ngx_null_command
};

//Define the module context

static ngx_http_module_t ngx_http_office_hours_filter_module_ctx = {
    NULL, //Preconfiguration
    ngx_http_office_hours_init, //Postconfiguration

    NULL, //Create main configuration
    NULL, //Initialize main configuration
    NULL, //Create server configuration
    NULL, //Merge server configuration

    ngx_http_office_hours_create_conf, //Create location configuration
    ngx_http_office_hours_merge_conf // Merge location configuration
};

//Define the module

ngx_module_t ngx_http_office_hours_filter_module = {
    NGX_MODULE_V1, //Module Version
        & ngx_http_office_hours_filter_module_ctx, //Module context
        ngx_http_office_hours_commands, //Module commands
        NGX_HTTP_MODULE, //Module Type
        NULL, //Initialize Master
        NULL, //Initialize Module
        NULL, //Initialize Process
        NULL, //Initialize Thread
        NULL, //Exit Thread
        NULL, //Exit Process
        NULL, //Exit Master
        NGX_MODULE_V1_PADDING
};


//Main Body Filter

static ngx_http_output_body_filter_pt ngx_http_next_body_filter;

static          ngx_int_t
ngx_http_office_hours_body_filter(ngx_http_request_t * r, ngx_chain_t * in) {

ngx_http_office_hours_conf_t *conf;
ngx_uint_t      i;
ngx_str_t      *hours;

    conf = ngx_http_get_module_loc_conf(r, ngx_http_office_hours_filter_module);

    if (conf->office_hours == NULL) {

        ngx_log_error(NGX_LOG_DEBUG, r->connection->log, 0, "Within office hours");

        return ngx_http_next_body_filter(r, in);
    }

    ngx_log_error(NGX_LOG_DEBUG, r->connection->log, 0, "Outside office hours");

    hours = conf->office_hours->elts;

    for (i = 0; i < conf->office_hours->nelts; ++i) {
        ngx_log_error(NGX_LOG_DEBUG, r->connection->log, 0, (const char *)hours[i].data);
    }

    r->keepalive = 0;
    return NGX_HTTP_FORBIDDEN;
}

//Read Arguments from config file

static char    *
ngx_http_office_hours(ngx_conf_t * cf, ngx_command_t * cmd, void *conf) {

char           *conf_structure = conf;

ngx_array_t   **office_hours;
ngx_str_t      *hours;
ngx_str_t      *value;
ngx_uint_t      i;

    //Gets the array from the config structure using the defined
        // offset, and if the
        pointer is unset it creates a new one.
            //
            //(The first element is the directive itself, so we should be
            // offset by 1)
            office_hours = (ngx_array_t **) (conf_structure + cmd->offset);

    if (*office_hours == NGX_CONF_UNSET_PTR) {
        *office_hours = ngx_array_create(cf->pool, cf->args->nelts - 1,
            sizeof(ngx_str_t));

        if (*office_hours == NULL) {
            return NGX_CONF_ERROR;
        }
    }

    value = cf->args->elts;

    for (i = 1; i < cf->args->nelts; ++i) {

        hours = ngx_array_push(*office_hours);
        if (hours == NULL) {
            return NGX_CONF_ERROR;
        }

        *hours = value[i];
    }

    return NGX_CONF_OK;
}


//Initialize the Configuration Object

static void    *
ngx_http_office_hours_create_conf(ngx_conf_t * cf) {

ngx_http_office_hours_conf_t *conf;

    conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_office_hours_conf_t));

    if (conf == NULL) {
        return NULL;
    }

    conf->office_hours = NGX_CONF_UNSET_PTR;

    return conf;
}

//Merge Config Values

static char    *
ngx_http_office_hours_merge_conf(ngx_conf_t * cf, void *parent, void *child) {

ngx_http_office_hours_conf_t *prev = parent;
ngx_http_office_hours_conf_t *conf = child;

    ngx_conf_merge_ptr_value(conf->office_hours, prev->office_hours, NULL);

    return NGX_CONF_OK;
}

//Postconfig Initialization Handler
// Sets the request filter at the top of the chain

static ngx_int_t 
ngx_http_office_hours_init(ngx_conf_t * cf) {

    ngx_http_next_body_filter = ngx_http_top_body_filter;
    ngx_http_top_body_filter = ngx_http_office_hours_body_filter;

    return NGX_OK;
}