[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>

/*
 * Declarations
 */

/* Constants */

const ngx_uint_t WEEK_LENGTH = 7;
const char * CLOSED_TOKEN = "closed";
const ngx_str_t TIME_REGEX = ngx_string("([0-9]{1,2})(?:\\:([0-9]{2}))?\\-([0-9]{1,2})(?:\\:([0-9]{2}))?");
const ngx_str_t HEAD_HTML = ngx_string("<!doctype html><html><head><title>This website is currently closed!</title></head><body><h1>This website is currently closed!</h1><p>This website has closed for the day, please check our office hours below:</p><ul>");
const ngx_str_t OPEN_SERVER_TIME_HTML = ngx_string("</ul><p><em>Current Server Time is: ");
const ngx_str_t CLOSE_SERVER_TIME_HTML = ngx_string("</em></p>");
const ngx_str_t FOOT_HTML = ngx_string("</body></html>");
const char * DAY_NAMES[7] = {
    "Monday",
    "Tuesday",
    "Wednesday",
    "Thursday",
    "Friday",
    "Saturday",
    "Sunday"
};

/* Main Configuration Structure */

typedef struct {
    ngx_array_t *office_hours;
    ngx_str_t   additional_information;
} ngx_http_office_hours_conf_t;

/* Lifecycle Functions For Module Context */

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);

/* Configuration Handler */

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

/* Filter Storage */

static ngx_http_output_header_filter_pt ngx_http_next_header_filter;
static ngx_http_output_body_filter_pt ngx_http_next_body_filter;

/* Utility Functions */
static ngx_uint_t ** parse_office_hours(ngx_array_t * office_hours);
static ngx_uint_t * parse_office_hours_string(ngx_str_t office_hours);
static ngx_flag_t within_office_hours(ngx_uint_t ** office_hours);
static ngx_uint_t get_day_of_week(time_t time);
static ngx_uint_t get_seconds_of_day(time_t time);
static ngx_uint_t parse_number(ngx_str_t string, ngx_uint_t start, ngx_uint_t end);
static ngx_str_t create_output_html(ngx_http_office_hours_conf_t * conf);
static char * format_hours(ngx_uint_t * seconds, char * day);
static char * format_seconds(ngx_uint_t seconds);
static char * left_pad(unsigned int number);

/* Globals */
ngx_regex_compile_t rc;
ngx_str_t OUTPUT_HTML;

/*
 * Module Definitions
 */

/* Module Directives */

static ngx_command_t ngx_http_office_hours_commands[] = {
    {
        ngx_string("office_hours"),
        NGX_HTTP_MAIN_CONF | NGX_HTTP_SRV_CONF | NGX_HTTP_LOC_CONF | NGX_CONF_TAKE1 | NGX_CONF_TAKE2 | NGX_CONF_TAKE3 | NGX_CONF_TAKE4 | NGX_CONF_TAKE5 | NGX_CONF_TAKE6 | NGX_CONF_TAKE7,
        ngx_http_office_hours,
        NGX_HTTP_LOC_CONF_OFFSET,
        offsetof(ngx_http_office_hours_conf_t, office_hours),
        NULL
    },
    {
        ngx_string("office_hours_additional_information"),
        NGX_HTTP_MAIN_CONF | NGX_HTTP_SRV_CONF | NGX_HTTP_LOC_CONF | NGX_CONF_TAKE1 | NGX_CONF_TAKE2 | NGX_CONF_TAKE3 | NGX_CONF_TAKE4 | NGX_CONF_TAKE5 | NGX_CONF_TAKE6 | NGX_CONF_TAKE7,
        ngx_conf_set_str_slot,
        NGX_HTTP_LOC_CONF_OFFSET,
        offsetof(ngx_http_office_hours_conf_t, additional_information),
        NULL
    },

    ngx_null_command
};

/* 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 */
};

/* Module Definition */

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 Header Filter
 * If the current time is within office hours, it goes to the next
 * handler. Otherwise it sets the headers to 403
 */

static ngx_int_t
ngx_http_office_hours_header_filter(ngx_http_request_t * r)
{

    ngx_uint_t ** parsed_office_hours;
    ngx_http_office_hours_conf_t *conf;

    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,
                      "Office hours disabled");
        return ngx_http_next_header_filter(r);
    }

    parsed_office_hours = parse_office_hours(conf->office_hours);

    if (within_office_hours(parsed_office_hours)) {
        ngx_log_error(NGX_LOG_DEBUG, r->connection->log, 0,
                      "Within office hours");
        return ngx_http_next_header_filter(r);
    }

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

    if (OUTPUT_HTML.data == NULL) {
        OUTPUT_HTML = create_output_html(conf);
    }

    r->headers_out.status = NGX_HTTP_FORBIDDEN;
    r->headers_out.content_length_n = OUTPUT_HTML.len;

    return ngx_http_next_header_filter(r);
}

/*
 * Main Body Filter
 * If the current time is within office hours, it goes to the next
 * handler. Otherwise it replaces the body with the office hours.
 */

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

    ngx_buf_t    *b;
    ngx_uint_t ** parsed_office_hours;
    ngx_chain_t   out;
    ngx_http_office_hours_conf_t *conf;

    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,
                      "Office hours disabled");
        return ngx_http_next_body_filter(r, in);
    }

    parsed_office_hours = parse_office_hours(conf->office_hours);

    if (within_office_hours(parsed_office_hours)) {
        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");

    if (OUTPUT_HTML.data == NULL) {
        OUTPUT_HTML = create_output_html(conf);
    }

    b = ngx_pcalloc(r->pool, sizeof(ngx_buf_t));
    if (b == NULL) {
        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "Failed to allocate response buffer.");
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }

    out.buf = b;
    out.next = NULL;

    b->start = OUTPUT_HTML.data;
    b->pos = b->start;
    b->end = OUTPUT_HTML.data + OUTPUT_HTML.len;
    b->last = b->end;

    b->memory = 1;
    b->last_buf = 1;

    return ngx_http_next_body_filter(r, &out);
}

/*
 * Callback for `office_hours ` directive
 * Reads the configuration loaded from the config file(cf)
 * And writes it to the right place in the module configuration(conf)
 */

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

    char *conf_structure = conf;

    ngx_str_t *hours, *value;
    ngx_array_t **office_hours;
    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;
}

/*
 * Config Creator
 * Initializes the configuration structure
 */

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
 * Sets the defaults for the configuration and merges
 * with other configurations
 */

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;
}

/*
 * Parse the office hour strings in the configuration file
 * to fill out the hours array (in seconds)
 */

static ngx_uint_t ** parse_office_hours(ngx_array_t * office_hours)
{

    ngx_str_t *hours;
    ngx_uint_t ** parsed_office_hours;
    ngx_uint_t i, j;

    parsed_office_hours = malloc(7 * sizeof(ngx_uint_t *));

    hours = office_hours->elts;

    /*
     * On the configuration file, the leftmost element
     * always applies to all remaining days, all others
     * are read from right to left. So first we will apply
     * the initial override, and then iterate based on the
     * number of overrides
     */

    for (i = 0; i < WEEK_LENGTH + 1 - office_hours->nelts; ++i) {
        parsed_office_hours[i] = parse_office_hours_string(hours[0]);
    }

    for (i = 1; i < office_hours->nelts; ++i) {
        j = WEEK_LENGTH - office_hours->nelts + i;
        parsed_office_hours[j] = parse_office_hours_string(hours[i]);
    }

    return parsed_office_hours;
}

/*
 * Given a time string or the closed token, return a tuple
 * of numbers representing opening and closing hours
 */

static ngx_uint_t * parse_office_hours_string(ngx_str_t office_hours)
{

    int captures[(1 + 4) * 3];
    ngx_int_t n;
    ngx_uint_t * parsed_hours;

    parsed_hours = malloc(2 * sizeof(ngx_uint_t));

    if(ngx_strcmp(office_hours.data, CLOSED_TOKEN) == 0) {
        parsed_hours[0] = 0;
        parsed_hours[1] = 0;
        return parsed_hours;
    }

    n = ngx_regex_exec(rc.regex, &office_hours, captures, (1 + 4) * 3);

    if (n >= 0) {
        /* Opening Hours */

        parsed_hours[0] = 60 * 60 * parse_number(office_hours, captures[2], captures[3]);
        parsed_hours[0] = parsed_hours[0] + 60 * parse_number(office_hours, captures[4], captures[5]);

        parsed_hours[1] = 60 * 60 * parse_number(office_hours, captures[6], captures[7]);
        parsed_hours[1] = parsed_hours[1] + 60 * parse_number(office_hours, captures[8], captures[9]);

        return parsed_hours;
    }

    /* Non-matching strings count as open */

    parsed_hours[0] = 0;
    parsed_hours[1] = 86400;
    return parsed_hours;
}

/*
 * Given an office hours array, it returns whether or not
 * it is currently within office hours.
 */

static ngx_flag_t within_office_hours(ngx_uint_t ** office_hours)
{

    time_t now;
    ngx_uint_t day_of_week, seconds_of_day;
    ngx_uint_t * current_hours;

    ngx_time_update();
    now = ngx_time();
    day_of_week = get_day_of_week(now);
    seconds_of_day = get_seconds_of_day(now);
    current_hours = office_hours[day_of_week];

    return seconds_of_day >= current_hours[0] && seconds_of_day <= current_hours[1];
}

/*
 * Calculate the day of the week given a timestamp
 */

static ngx_uint_t get_day_of_week(time_t time)
{

    /* Epoch was thursday, so add 3 so we start on monday */
    return (time / 86400 + 3) % 7;
}

/*
 * Calculate the number of seconds elapsed today
 */

static ngx_uint_t get_seconds_of_day(time_t time)
{

    return time - (time / 86400) * 86400;
}

/*
 * Parses a string, returns 0 if match was not found
 */

static ngx_uint_t parse_number(ngx_str_t string, ngx_uint_t start, ngx_uint_t end)
{

    if (end - start == 0) {
        return 0;
    }

    return ngx_atoi(&string.data[start], end - start);
}

/*
 * Given the current office hours configuration it creates the custom
 * HTML
 */

static ngx_str_t create_output_html(ngx_http_office_hours_conf_t * conf)
{

    char * output_buffer;
    time_t now;
    ngx_str_t output_html;
    ngx_uint_t i, seconds_of_day;
    ngx_uint_t ** parsed_office_hours;

    size_t base_size = 1024;
    size_t additional_info_size = conf->additional_information.len;
    size_t buffer_size = base_size + additional_info_size + 1;
    output_buffer = malloc(buffer_size * sizeof(char));

    /* UH-OH we couldn't allocate the bufer */
    if (!output_buffer) {
        output_html.data = NULL;
        output_html.len = 0;
        return output_html;
    }

    parsed_office_hours = parse_office_hours(conf->office_hours);
    now = ngx_time();
    seconds_of_day = get_seconds_of_day(now);

    int written = 0;

    written += snprintf(output_buffer + written, buffer_size - written, "%s", (char *) HEAD_HTML.data);

    for (i = 0; i < 7; ++i) {
        written +=  snprintf(output_buffer + written, buffer_size - written, "%s", format_hours(parsed_office_hours[i], (char *) DAY_NAMES[i]));
    }

    written += snprintf(output_buffer + written, buffer_size - written, "%s", (char *) OPEN_SERVER_TIME_HTML.data);
    written += snprintf(output_buffer + written, buffer_size - written, "%s", format_seconds(seconds_of_day));
    written += snprintf(output_buffer + written, buffer_size - written, "%s", (char *) CLOSE_SERVER_TIME_HTML.data);

    if (conf->additional_information.len > 0) {
        char additional_info[conf->additional_information.len + 1];
        ngx_memcpy(additional_info, conf->additional_information.data, conf->additional_information.len);
        additional_info[conf->additional_information.len] = '\0';
        written += snprintf(output_buffer + written, buffer_size - written, "%s", additional_info);
    }

    snprintf(output_buffer + written, buffer_size - written, "%s", (char *) FOOT_HTML.data);

    output_html.data = (unsigned char *) output_buffer;
    output_html.len = strlen(output_buffer);

    return output_html;
}

/*
 * Given a tuple of seconds and a day name, outputs an HTML
 * string containing the formatted data as a list item
 */

static char * format_hours(ngx_uint_t * hours, char * day)
{

    char * output_html;

    output_html = malloc(64 * sizeof(char));
    if (hours[0] == hours[1]) {
        sprintf(output_html, "<li><strong>%s</strong>: CLOSED</li>",
                day
               );
        return output_html;
    }

    sprintf(output_html, "<li><strong>%s</strong>: %s - %s</li>",
            day,
            (char *) format_seconds(hours[0]),
            (char *) format_seconds(hours[1])
           );

    return output_html;
}

/*
 * Given seconds of the day, it returns a string showing
 * HH:MM in 24 hour format
 */

static char * format_seconds(ngx_uint_t seconds)
{

    char * output_html;
    unsigned int hours, minutes;

    output_html = malloc(6 * sizeof(char));

    hours = seconds / 60 / 60;
    minutes = (seconds / 60) % 60;

    sprintf(output_html, "%s:%s",
            left_pad(hours),
            left_pad(minutes)
           );

    return output_html;
}

/*
 * Returns a number as a string adding 0 if < 10
 */

static char * left_pad(unsigned int number)
{

    char * output_string;
    char * padding;

    padding = "";
    output_string = malloc(4 * sizeof(char));

    if (number < 10) {
        padding = "0";
    }

    snprintf(output_string, 4, "%s%u", padding, number);

    return output_string;
}

/*
 * 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_header_filter = ngx_http_top_header_filter;
    ngx_http_top_header_filter = ngx_http_office_hours_header_filter;

    ngx_http_next_body_filter = ngx_http_top_body_filter;
    ngx_http_top_body_filter = ngx_http_office_hours_body_filter;

    rc.pattern = TIME_REGEX;
    rc.pool = cf->pool;
    if (ngx_regex_compile(&rc) != NGX_OK) {
        return NGX_ERROR;
    }

    return NGX_OK;
}
Commit	Line	Data
e4db4a20 BB	1	/*
e4db4a20 BB	2	* Copyright 2018 Rubén Beltrán del Río
af4b488f	3	*
e4db4a20 BB	4	* Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the
e4db4a20 BB	5	* License. You may obtain a copy of the License at
af4b488f	6	*
e4db4a20	7	* http://www.apache.org/licenses/LICENSE-2.0
af4b488f	8	*
e4db4a20 BB	9	* Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an
	10	* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
	11	* specific language governing permissions and limitations under the License.
	12	*/
	13
e4db4a20 BB	14	#include <ngx_config.h>
	15	#include <ngx_core.h>
	16	#include <ngx_http.h>
	17
fa2b280d BB	18	/*
	19	* Declarations
	20	*/
	21
fbdf81df BB	22	/* Constants */
	23
	24	const ngx_uint_t WEEK_LENGTH = 7;
	25	const char * CLOSED_TOKEN = "closed";
80c4c3cc	26	const ngx_str_t TIME_REGEX = ngx_string("([0-9]{1,2})(?:\\:([0-9]{2}))?\\-([0-9]{1,2})(?:\\:([0-9]{2}))?");
8b830d84 RBR	27	const ngx_str_t HEAD_HTML = ngx_string("<!doctype html><html><head><title>This website is currently closed!</title></head><body><h1>This website is currently closed!</h1><p>This website has closed for the day, please check our office hours below:</p><ul>");
	28	const ngx_str_t OPEN_SERVER_TIME_HTML = ngx_string("</ul><p><em>Current Server Time is: ");
	29	const ngx_str_t CLOSE_SERVER_TIME_HTML = ngx_string("</em></p>");
	30	const ngx_str_t FOOT_HTML = ngx_string("</body></html>");
61fca89b BB	31	const char * DAY_NAMES[7] = {
	32	"Monday",
	33	"Tuesday",
	34	"Wednesday",
	35	"Thursday",
	36	"Friday",
	37	"Saturday",
	38	"Sunday"
	39	};
fbdf81df	40
fa2b280d	41	/* Main Configuration Structure */
e4db4a20 BB	42
e4db4a20 BB	43	typedef struct {
af4b488f	44	ngx_array_t *office_hours;
8b830d84	45	ngx_str_t additional_information;
af4b488f	46	} ngx_http_office_hours_conf_t;
e4db4a20	47
fa2b280d BB	48	/* Lifecycle Functions For Module Context */
fa2b280d BB	49
af4b488f	50	static void ngx_http_office_hours_create_conf(ngx_conf_t cf);
fa2b280d	51	static char ngx_http_office_hours_merge_conf(ngx_conf_t cf,
f34685bb	52	void parent, void child);
e4db4a20 BB	53	static ngx_int_t ngx_http_office_hours_init(ngx_conf_t * cf);
e4db4a20 BB	54
fa2b280d BB	55	/* Configuration Handler */
	56
	57	static char ngx_http_office_hours(ngx_conf_t cf, ngx_command_t * cmd,
	58	void *conf);
	59
67206816	60	/* Filter Storage */
fa2b280d	61
67206816	62	static ngx_http_output_header_filter_pt ngx_http_next_header_filter;
fa2b280d BB	63	static ngx_http_output_body_filter_pt ngx_http_next_body_filter;
fa2b280d BB	64
fbdf81df BB	65	/* Utility Functions */
	66	static ngx_uint_t ** parse_office_hours(ngx_array_t * office_hours);
	67	static ngx_uint_t * parse_office_hours_string(ngx_str_t office_hours);
	68	static ngx_flag_t within_office_hours(ngx_uint_t ** office_hours);
	69	static ngx_uint_t get_day_of_week(time_t time);
	70	static ngx_uint_t get_seconds_of_day(time_t time);
bbe15175	71	static ngx_uint_t parse_number(ngx_str_t string, ngx_uint_t start, ngx_uint_t end);
61fca89b BB	72	static ngx_str_t create_output_html(ngx_http_office_hours_conf_t * conf);
	73	static char * format_hours(ngx_uint_t * seconds, char * day);
	74	static char * format_seconds(ngx_uint_t seconds);
	75	static char * left_pad(unsigned int number);
fbdf81df	76
61fca89b	77	/* Globals */
80c4c3cc	78	ngx_regex_compile_t rc;
61fca89b	79	ngx_str_t OUTPUT_HTML;
80c4c3cc	80
fa2b280d BB	81	/*
	82	* Module Definitions
	83	*/
e4db4a20	84
fa2b280d	85	/* Module Directives */
e4db4a20 BB	86
	87	static ngx_command_t ngx_http_office_hours_commands[] = {
	88	{
fa2b280d	89	ngx_string("office_hours"),
fbdf81df	90	NGX_HTTP_MAIN_CONF \| NGX_HTTP_SRV_CONF \| NGX_HTTP_LOC_CONF \| NGX_CONF_TAKE1 \| NGX_CONF_TAKE2 \| NGX_CONF_TAKE3 \| NGX_CONF_TAKE4 \| NGX_CONF_TAKE5 \| NGX_CONF_TAKE6 \| NGX_CONF_TAKE7,
fa2b280d BB	91	ngx_http_office_hours,
	92	NGX_HTTP_LOC_CONF_OFFSET,
	93	offsetof(ngx_http_office_hours_conf_t, office_hours),
	94	NULL
e4db4a20	95	},
8b830d84 RBR	96	{
	97	ngx_string("office_hours_additional_information"),
	98	NGX_HTTP_MAIN_CONF \| NGX_HTTP_SRV_CONF \| NGX_HTTP_LOC_CONF \| NGX_CONF_TAKE1 \| NGX_CONF_TAKE2 \| NGX_CONF_TAKE3 \| NGX_CONF_TAKE4 \| NGX_CONF_TAKE5 \| NGX_CONF_TAKE6 \| NGX_CONF_TAKE7,
	99	ngx_conf_set_str_slot,
	100	NGX_HTTP_LOC_CONF_OFFSET,
	101	offsetof(ngx_http_office_hours_conf_t, additional_information),
	102	NULL
	103	},
e4db4a20 BB	104
	105	ngx_null_command
	106	};
	107
fa2b280d	108	/* Module Context */
e4db4a20 BB	109
e4db4a20 BB	110	static ngx_http_module_t ngx_http_office_hours_filter_module_ctx = {
fa2b280d BB	111	NULL, /* Preconfiguration */
fa2b280d BB	112	ngx_http_office_hours_init, /* Postconfiguration */
e4db4a20	113
fa2b280d BB	114	NULL, /* Create main configuration */
fa2b280d BB	115	NULL, /* Initialize main configuration */
e4db4a20	116
fa2b280d BB	117	NULL, /* Create server configuration */
	118	NULL, /* Merge server configuration */
	119
	120	ngx_http_office_hours_create_conf, /* Create location configuration */
	121	ngx_http_office_hours_merge_conf /* Merge location configuration */
e4db4a20 BB	122	};
e4db4a20 BB	123
fa2b280d	124	/* Module Definition */
e4db4a20 BB	125
e4db4a20 BB	126	ngx_module_t ngx_http_office_hours_filter_module = {
fa2b280d BB	127	NGX_MODULE_V1, //Module Version
	128	&ngx_http_office_hours_filter_module_ctx, //Module context
	129	ngx_http_office_hours_commands, //Module commands
	130	NGX_HTTP_MODULE, //Module Type
	131	NULL, //Initialize Master
	132	NULL, //Initialize Module
	133	NULL, //Initialize Process
	134	NULL, //Initialize Thread
	135	NULL, //Exit Thread
	136	NULL, //Exit Process
	137	NULL, //Exit Master
	138	NGX_MODULE_V1_PADDING
e4db4a20 BB	139	};
e4db4a20 BB	140
67206816 BB	141	/*
	142	* Main Header Filter
	143	* If the current time is within office hours, it goes to the next
	144	* handler. Otherwise it sets the headers to 403
	145	*/
	146
	147	static ngx_int_t
	148	ngx_http_office_hours_header_filter(ngx_http_request_t * r)
	149	{
	150
	151	ngx_uint_t ** parsed_office_hours;
	152	ngx_http_office_hours_conf_t *conf;
	153
	154	conf =
	155	ngx_http_get_module_loc_conf(r,
	156	ngx_http_office_hours_filter_module);
	157
67206816 BB	158	if (conf->office_hours == NULL) {
	159	ngx_log_error(NGX_LOG_DEBUG, r->connection->log, 0,
	160	"Office hours disabled");
	161	return ngx_http_next_header_filter(r);
	162	}
	163
	164	parsed_office_hours = parse_office_hours(conf->office_hours);
	165
	166	if (within_office_hours(parsed_office_hours)) {
	167	ngx_log_error(NGX_LOG_DEBUG, r->connection->log, 0,
	168	"Within office hours");
	169	return ngx_http_next_header_filter(r);
	170	}
	171
	172	ngx_log_error(NGX_LOG_DEBUG, r->connection->log, 0,
	173	"Outside office hours");
	174
61fca89b BB	175	if (OUTPUT_HTML.data == NULL) {
	176	OUTPUT_HTML = create_output_html(conf);
	177	}
	178
67206816 BB	179	r->headers_out.status = NGX_HTTP_FORBIDDEN;
	180	r->headers_out.content_length_n = OUTPUT_HTML.len;
	181
	182	return ngx_http_next_header_filter(r);
	183	}
	184
fa2b280d BB	185	/*
	186	* Main Body Filter
	187	* If the current time is within office hours, it goes to the next
67206816	188	* handler. Otherwise it replaces the body with the office hours.
fa2b280d	189	*/
e4db4a20	190
af4b488f	191	static ngx_int_t
67206816	192	ngx_http_office_hours_body_filter(ngx_http_request_t * r, ngx_chain_t *in)
af4b488f	193	{
e4db4a20	194
67206816	195	ngx_buf_t *b;
fbdf81df	196	ngx_uint_t ** parsed_office_hours;
67206816	197	ngx_chain_t out;
af4b488f	198	ngx_http_office_hours_conf_t *conf;
e4db4a20	199
fa2b280d BB	200	conf =
	201	ngx_http_get_module_loc_conf(r,
	202	ngx_http_office_hours_filter_module);
e4db4a20 BB	203
e4db4a20 BB	204	if (conf->office_hours == NULL) {
fa2b280d	205	ngx_log_error(NGX_LOG_DEBUG, r->connection->log, 0,
fbdf81df	206	"Office hours disabled");
fa2b280d	207	return ngx_http_next_body_filter(r, in);
e4db4a20	208	}
fa2b280d	209
fbdf81df	210	parsed_office_hours = parse_office_hours(conf->office_hours);
e4db4a20	211
fbdf81df	212	if (within_office_hours(parsed_office_hours)) {
fa2b280d	213	ngx_log_error(NGX_LOG_DEBUG, r->connection->log, 0,
fbdf81df BB	214	"Within office hours");
fbdf81df BB	215	return ngx_http_next_body_filter(r, in);
e4db4a20 BB	216	}
e4db4a20 BB	217
fbdf81df BB	218	ngx_log_error(NGX_LOG_DEBUG, r->connection->log, 0,
	219	"Outside office hours");
	220
61fca89b BB	221	if (OUTPUT_HTML.data == NULL) {
	222	OUTPUT_HTML = create_output_html(conf);
	223	}
	224
67206816 BB	225	b = ngx_pcalloc(r->pool, sizeof(ngx_buf_t));
	226	if (b == NULL) {
	227	ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "Failed to allocate response buffer.");
	228	return NGX_HTTP_INTERNAL_SERVER_ERROR;
	229	}
	230
	231	out.buf = b;
	232	out.next = NULL;
	233
	234	b->start = OUTPUT_HTML.data;
	235	b->pos = b->start;
	236	b->end = OUTPUT_HTML.data + OUTPUT_HTML.len;
	237	b->last = b->end;
	238
	239	b->memory = 1;
	240	b->last_buf = 1;
	241
	242	return ngx_http_next_body_filter(r, &out);
e4db4a20 BB	243	}
e4db4a20 BB	244
fa2b280d BB	245	/*
	246	* Callback for `office_hours ` directive
	247	* Reads the configuration loaded from the config file(cf)
	248	* And writes it to the right place in the module configuration(conf)
	249	*/
e4db4a20	250
fa2b280d BB	251	static char ngx_http_office_hours(ngx_conf_t cf, ngx_command_t * cmd,
fa2b280d BB	252	void *conf)
af4b488f	253	{
e4db4a20	254
af4b488f	255	char *conf_structure = conf;
e4db4a20	256
fbdf81df	257	ngx_str_t hours, value;
af4b488f	258	ngx_array_t **office_hours;
af4b488f	259	ngx_uint_t i;
e4db4a20	260
fa2b280d BB	261	/* Gets the array from the config structure using the defined
	262	* offset, and if the pointer is unset it creates a new one.
	263	* (The first element is the directive itself, so we should be
	264	* offset by 1)
	265	*/
	266	office_hours = (ngx_array_t **) (conf_structure + cmd->offset);
e4db4a20 BB	267
e4db4a20 BB	268	if (*office_hours == NGX_CONF_UNSET_PTR) {
fa2b280d BB	269	*office_hours = ngx_array_create(cf->pool, cf->args->nelts - 1,
fa2b280d BB	270	sizeof(ngx_str_t));
e4db4a20	271
fa2b280d BB	272	if (*office_hours == NULL) {
	273	return NGX_CONF_ERROR;
	274	}
e4db4a20	275	}
e4db4a20 BB	276	value = cf->args->elts;
	277
	278	for (i = 1; i < cf->args->nelts; ++i) {
fa2b280d BB	279	hours = ngx_array_push(*office_hours);
	280	if (hours == NULL) {
	281	return NGX_CONF_ERROR;
	282	}
	283	*hours = value[i];
e4db4a20 BB	284	}
	285
	286	return NGX_CONF_OK;
	287	}
	288
fa2b280d BB	289	/*
	290	* Config Creator
	291	* Initializes the configuration structure
	292	*/
e4db4a20	293
fa2b280d	294	static void ngx_http_office_hours_create_conf(ngx_conf_t cf)
af4b488f	295	{
e4db4a20	296
af4b488f	297	ngx_http_office_hours_conf_t *conf;
e4db4a20 BB	298
	299	conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_office_hours_conf_t));
	300
	301	if (conf == NULL) {
fa2b280d	302	return NULL;
e4db4a20	303	}
e4db4a20 BB	304	conf->office_hours = NGX_CONF_UNSET_PTR;
	305
	306	return conf;
	307	}
	308
fa2b280d BB	309	/*
	310	* Merge Config Values
	311	* Sets the defaults for the configuration and merges
	312	* with other configurations
	313	*/
e4db4a20	314
fa2b280d	315	static char ngx_http_office_hours_merge_conf(ngx_conf_t cf,
f34685bb	316	void parent, void child)
af4b488f	317	{
e4db4a20	318
af4b488f BB	319	ngx_http_office_hours_conf_t *prev = parent;
af4b488f BB	320	ngx_http_office_hours_conf_t *conf = child;
e4db4a20 BB	321
	322	ngx_conf_merge_ptr_value(conf->office_hours, prev->office_hours, NULL);
	323
	324	return NGX_CONF_OK;
	325	}
	326
fbdf81df BB	327	/*
	328	* Parse the office hour strings in the configuration file
	329	* to fill out the hours array (in seconds)
	330	*/
	331
	332	static ngx_uint_t ** parse_office_hours(ngx_array_t * office_hours)
	333	{
	334
	335	ngx_str_t *hours;
	336	ngx_uint_t ** parsed_office_hours;
	337	ngx_uint_t i, j;
	338
	339	parsed_office_hours = malloc(7 * sizeof(ngx_uint_t *));
	340
	341	hours = office_hours->elts;
	342
	343	/*
	344	* On the configuration file, the leftmost element
	345	* always applies to all remaining days, all others
	346	* are read from right to left. So first we will apply
	347	* the initial override, and then iterate based on the
	348	* number of overrides
	349	*/
	350
	351	for (i = 0; i < WEEK_LENGTH + 1 - office_hours->nelts; ++i) {
	352	parsed_office_hours[i] = parse_office_hours_string(hours[0]);
	353	}
	354
	355	for (i = 1; i < office_hours->nelts; ++i) {
	356	j = WEEK_LENGTH - office_hours->nelts + i;
	357	parsed_office_hours[j] = parse_office_hours_string(hours[i]);
	358	}
	359
	360	return parsed_office_hours;
	361	}
	362
	363	/*
	364	* Given a time string or the closed token, return a tuple
	365	* of numbers representing opening and closing hours
	366	*/
	367
	368	static ngx_uint_t * parse_office_hours_string(ngx_str_t office_hours)
	369	{
	370
80c4c3cc BB	371	int captures[(1 + 4) * 3];
80c4c3cc BB	372	ngx_int_t n;
fbdf81df BB	373	ngx_uint_t * parsed_hours;
	374
	375	parsed_hours = malloc(2 * sizeof(ngx_uint_t));
	376
	377	if(ngx_strcmp(office_hours.data, CLOSED_TOKEN) == 0) {
	378	parsed_hours[0] = 0;
	379	parsed_hours[1] = 0;
	380	return parsed_hours;
	381	}
	382
80c4c3cc BB	383	n = ngx_regex_exec(rc.regex, &office_hours, captures, (1 + 4) * 3);
	384
	385	if (n >= 0) {
	386	/* Opening Hours */
	387
bbe15175 BB	388	parsed_hours[0] = 60 * 60 * parse_number(office_hours, captures[2], captures[3]);
bbe15175 BB	389	parsed_hours[0] = parsed_hours[0] + 60 * parse_number(office_hours, captures[4], captures[5]);
80c4c3cc	390
bbe15175 BB	391	parsed_hours[1] = 60 * 60 * parse_number(office_hours, captures[6], captures[7]);
bbe15175 BB	392	parsed_hours[1] = parsed_hours[1] + 60 * parse_number(office_hours, captures[8], captures[9]);
80c4c3cc BB	393
	394	return parsed_hours;
	395	}
	396
	397	/* Non-matching strings count as open */
	398
fbdf81df BB	399	parsed_hours[0] = 0;
	400	parsed_hours[1] = 86400;
	401	return parsed_hours;
	402	}
	403
	404	/*
	405	* Given an office hours array, it returns whether or not
	406	* it is currently within office hours.
	407	*/
	408
	409	static ngx_flag_t within_office_hours(ngx_uint_t ** office_hours)
	410	{
	411
	412	time_t now;
	413	ngx_uint_t day_of_week, seconds_of_day;
	414	ngx_uint_t * current_hours;
	415
	416	ngx_time_update();
	417	now = ngx_time();
	418	day_of_week = get_day_of_week(now);
	419	seconds_of_day = get_seconds_of_day(now);
	420	current_hours = office_hours[day_of_week];
	421
	422	return seconds_of_day >= current_hours[0] && seconds_of_day <= current_hours[1];
	423	}
	424
	425	/*
	426	* Calculate the day of the week given a timestamp
	427	*/
61fca89b	428
fbdf81df BB	429	static ngx_uint_t get_day_of_week(time_t time)
	430	{
	431
	432	/* Epoch was thursday, so add 3 so we start on monday */
	433	return (time / 86400 + 3) % 7;
	434	}
	435
	436	/*
	437	* Calculate the number of seconds elapsed today
	438	*/
61fca89b	439
fbdf81df BB	440	static ngx_uint_t get_seconds_of_day(time_t time)
	441	{
	442
	443	return time - (time / 86400) * 86400;
	444	}
bbe15175 BB	445
	446	/*
	447	* Parses a string, returns 0 if match was not found
	448	*/
61fca89b	449
bbe15175 BB	450	static ngx_uint_t parse_number(ngx_str_t string, ngx_uint_t start, ngx_uint_t end)
	451	{
	452
	453	if (end - start == 0) {
	454	return 0;
	455	}
	456
	457	return ngx_atoi(&string.data[start], end - start);
	458	}
	459
61fca89b BB	460	/*
	461	* Given the current office hours configuration it creates the custom
	462	* HTML
	463	*/
	464
	465	static ngx_str_t create_output_html(ngx_http_office_hours_conf_t * conf)
	466	{
	467
	468	char * output_buffer;
	469	time_t now;
	470	ngx_str_t output_html;
	471	ngx_uint_t i, seconds_of_day;
	472	ngx_uint_t ** parsed_office_hours;
	473
8b830d84 RBR	474	size_t base_size = 1024;
	475	size_t additional_info_size = conf->additional_information.len;
	476	size_t buffer_size = base_size + additional_info_size + 1;
	477	output_buffer = malloc(buffer_size * sizeof(char));
	478
	479	/* UH-OH we couldn't allocate the bufer */
	480	if (!output_buffer) {
	481	output_html.data = NULL;
	482	output_html.len = 0;
	483	return output_html;
	484	}
	485
61fca89b BB	486	parsed_office_hours = parse_office_hours(conf->office_hours);
	487	now = ngx_time();
	488	seconds_of_day = get_seconds_of_day(now);
	489
8b830d84 RBR	490	int written = 0;
	491
	492	written += snprintf(output_buffer + written, buffer_size - written, "%s", (char *) HEAD_HTML.data);
61fca89b BB	493
61fca89b BB	494	for (i = 0; i < 7; ++i) {
8b830d84 RBR	495	written += snprintf(output_buffer + written, buffer_size - written, "%s", format_hours(parsed_office_hours[i], (char *) DAY_NAMES[i]));
	496	}
	497
	498	written += snprintf(output_buffer + written, buffer_size - written, "%s", (char *) OPEN_SERVER_TIME_HTML.data);
	499	written += snprintf(output_buffer + written, buffer_size - written, "%s", format_seconds(seconds_of_day));
	500	written += snprintf(output_buffer + written, buffer_size - written, "%s", (char *) CLOSE_SERVER_TIME_HTML.data);
	501
	502	if (conf->additional_information.len > 0) {
	503	char additional_info[conf->additional_information.len + 1];
	504	ngx_memcpy(additional_info, conf->additional_information.data, conf->additional_information.len);
	505	additional_info[conf->additional_information.len] = '\0';
	506	written += snprintf(output_buffer + written, buffer_size - written, "%s", additional_info);
61fca89b BB	507	}
61fca89b BB	508
8b830d84	509	snprintf(output_buffer + written, buffer_size - written, "%s", (char *) FOOT_HTML.data);
61fca89b BB	510
	511	output_html.data = (unsigned char *) output_buffer;
	512	output_html.len = strlen(output_buffer);
	513
	514	return output_html;
	515	}
	516
	517	/*
	518	* Given a tuple of seconds and a day name, outputs an HTML
	519	* string containing the formatted data as a list item
	520	*/
	521
	522	static char * format_hours(ngx_uint_t * hours, char * day)
	523	{
	524
	525	char * output_html;
	526
	527	output_html = malloc(64 * sizeof(char));
	528	if (hours[0] == hours[1]) {
	529	sprintf(output_html, "<li><strong>%s</strong>: CLOSED</li>",
	530	day
	531	);
	532	return output_html;
	533	}
	534
	535	sprintf(output_html, "<li><strong>%s</strong>: %s - %s</li>",
	536	day,
	537	(char *) format_seconds(hours[0]),
	538	(char *) format_seconds(hours[1])
	539	);
	540
	541	return output_html;
	542	}
	543
	544	/*
	545	* Given seconds of the day, it returns a string showing
	546	* HH:MM in 24 hour format
	547	*/
	548
	549	static char * format_seconds(ngx_uint_t seconds)
	550	{
	551
	552	char * output_html;
	553	unsigned int hours, minutes;
	554
	555	output_html = malloc(6 * sizeof(char));
	556
	557	hours = seconds / 60 / 60;
	558	minutes = (seconds / 60) % 60;
	559
	560	sprintf(output_html, "%s:%s",
	561	left_pad(hours),
	562	left_pad(minutes)
	563	);
	564
	565	return output_html;
	566	}
	567
	568	/*
	569	* Returns a number as a string adding 0 if < 10
	570	*/
	571
	572	static char * left_pad(unsigned int number)
	573	{
574
575	char * output_string;
576	char * padding;
577
578	padding = "";
f34685bb	579	output_string = malloc(4 * sizeof(char));
61fca89b BB	580
	581	if (number < 10) {
	582	padding = "0";
	583	}
	584
f34685bb	585	snprintf(output_string, 4, "%s%u", padding, number);
61fca89b BB	586
	587	return output_string;
	588	}
	589
bbe15175 BB	590	/*
	591	* Postconfig Initialization Handler
	592	* Sets the request filter at the top of the chain
	593	*/
	594
	595	static ngx_int_t ngx_http_office_hours_init(ngx_conf_t * cf)
	596	{
	597
67206816 BB	598	ngx_http_next_header_filter = ngx_http_top_header_filter;
	599	ngx_http_top_header_filter = ngx_http_office_hours_header_filter;
	600
bbe15175 BB	601	ngx_http_next_body_filter = ngx_http_top_body_filter;
	602	ngx_http_top_body_filter = ngx_http_office_hours_body_filter;
	603
	604	rc.pattern = TIME_REGEX;
	605	rc.pool = cf->pool;
	606	if (ngx_regex_compile(&rc) != NGX_OK) {
	607	return NGX_ERROR;
	608	}
	609
	610	return NGX_OK;
	611	}