[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 MIDDLE_HTML = ngx_string("</ul><p><em>Current Server Time is: ");
const ngx_str_t FOOT_HTML = ngx_string("</em></p></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_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_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;


    output_buffer = malloc(1024 * sizeof(char));
    parsed_office_hours = parse_office_hours(conf->office_hours);
    now = ngx_time();
    seconds_of_day = get_seconds_of_day(now);

    sprintf(output_buffer, "%s", (char *) HEAD_HTML.data);

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

    sprintf(output_buffer + strlen(output_buffer), "%s", (char *) MIDDLE_HTML.data);
    sprintf(output_buffer + strlen(output_buffer), "%s", format_seconds(seconds_of_day));
    sprintf(output_buffer + strlen(output_buffer), "%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(3 * sizeof(char));

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

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