/* * 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 #include #include /* * 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("This website is currently closed!

This website is currently closed!

This website has closed for the day, please check our office hours below:

"); const ngx_str_t OPEN_SERVER_TIME_HTML = ngx_string("

Current Server Time is: "); const ngx_str_t CLOSE_SERVER_TIME_HTML = ngx_string("

"); const ngx_str_t FOOT_HTML = ngx_string(""); 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, "

%s: CLOSED

", day ); return output_html; } sprintf(output_html, "

%s: %s - %s

", 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; }