res_calendar_icalendar.c

Go to the documentation of this file.

/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2008 - 2009, Digium, Inc.
 *
 * Terry Wilson <[email protected]>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 * \brief Resource for handling iCalendar calendars
 */

/*** MODULEINFO
 <depend>res_calendar</depend>
 <depend>neon</depend>
 <depend>ical</depend>
 <support_level>extended</support_level>
***/

#include "asterisk.h"

#include <libical/ical.h>
#include <ne_session.h>
#include <ne_uri.h>
#include <ne_request.h>
#include <ne_auth.h>
#include <ne_redirect.h>

#include "asterisk/module.h"
#include "asterisk/channel.h"
#include "asterisk/calendar.h"
#include "asterisk/lock.h"
#include "asterisk/config.h"
#include "asterisk/astobj2.h"

static void *ical_load_calendar(void *data);
static void *unref_icalendar(void *obj);

static struct ast_calendar_tech ical_tech = {
 .type = "ical",
 .module = AST_MODULE,
 .description = "iCalendar .ics calendars",
 .load_calendar = ical_load_calendar,
 .unref_calendar = unref_icalendar,
};

struct icalendar_pvt {
 AST_DECLARE_STRING_FIELDS(
 AST_STRING_FIELD(url);
 AST_STRING_FIELD(user);
 AST_STRING_FIELD(secret);
 );
 struct ast_calendar *owner;
 ne_uri uri;
 ne_session *session;
 icalcomponent *data;
 struct ao2_container *events;
};

static void icalendar_destructor(void *obj)
{
 struct icalendar_pvt *pvt = obj;

 ast_debug(1, "Destroying pvt for iCalendar %s\n", pvt->owner->name);
 if (pvt->session) {
 ne_session_destroy(pvt->session);
 }
 if (pvt->data) {
 icalcomponent_free(pvt->data);
 }
 ne_uri_free(&pvt->uri);
 ast_string_field_free_memory(pvt);

 ao2_callback(pvt->events, OBJ_UNLINK | OBJ_NODATA | OBJ_MULTIPLE, NULL, NULL);

 ao2_ref(pvt->events, -1);
}

static void *unref_icalendar(void *obj)
{
 struct icalendar_pvt *pvt = obj;

 ao2_ref(pvt, -1);
 return NULL;
}

static int fetch_response_reader(void *data, const char *block, size_t len)
{
 struct ast_str **response = data;
 unsigned char *tmp;

 if (!(tmp = ast_malloc(len + 1))) {
 return -1;
 }
 memcpy(tmp, block, len);
 tmp[len] = '\0';
 ast_str_append(response, 0, "%s", tmp);
 ast_free(tmp);

 return 0;
}

static int auth_credentials(void *userdata, const char *realm, int attempts, char *username, char *secret)
{
 struct icalendar_pvt *pvt = userdata;

 if (attempts > 1) {
 ast_log(LOG_WARNING, "Invalid username or password for iCalendar '%s'\n", pvt->owner->name);
 return -1;
 }

 ne_strnzcpy(username, pvt->user, NE_ABUFSIZ);
 ne_strnzcpy(secret, pvt->secret, NE_ABUFSIZ);

 return 0;
}

static icalcomponent *fetch_icalendar(struct icalendar_pvt *pvt)
{
 int ret;
 struct ast_str *response;
 ne_request *req;
 icalcomponent *comp = NULL;

 if (!pvt) {
 ast_log(LOG_ERROR, "There is no private!\n");
 return NULL;
 }

 if (!(response = ast_str_create(512))) {
 ast_log(LOG_ERROR, "Could not allocate memory for response.\n");
 return NULL;
 }

 req = ne_request_create(pvt->session, "GET", pvt->uri.path);
 ne_add_response_body_reader(req, ne_accept_2xx, fetch_response_reader, &response);

 ret = ne_request_dispatch(req);
 ne_request_destroy(req);
 if (ret != NE_OK || !ast_str_strlen(response)) {
 ast_log(LOG_WARNING, "Unable to retrieve iCalendar '%s' from '%s': %s\n", pvt->owner->name, pvt->url, ne_get_error(pvt->session));
 ast_free(response);
 return NULL;
 }

 if (!ast_strlen_zero(ast_str_buffer(response))) {
 comp = icalparser_parse_string(ast_str_buffer(response));
 }
 ast_free(response);

 return comp;
}

static time_t icalfloat_to_timet(icaltimetype time)
{
 struct ast_tm tm = {0,};
 struct timeval tv;

 tm.tm_mday = time.day;
 tm.tm_mon = time.month - 1;
 tm.tm_year = time.year - 1900;
 tm.tm_hour = time.hour;
 tm.tm_min = time.minute;
 tm.tm_sec = time.second;
 tm.tm_isdst = -1;
 tv = ast_mktime(&tm, NULL);

 return tv.tv_sec;
}

/* span->start & span->end may be dates or floating times which have no timezone,
 * which would mean that they should apply to the local timezone for all recipients.
 * For example, if a meeting was set for 1PM-2PM floating time, people in different time
 * zones would not be scheduled at the same local times. Dates are often treated as
 * floating times, so all day events will need to be converted--so we can trust the
 * span here, and instead will grab the start and end from the component, which will
 * allow us to test for floating times or dates.
 */

static void icalendar_add_event(icalcomponent *comp, struct icaltime_span *span, void *data)
{
 struct icalendar_pvt *pvt = data;
 struct ast_calendar_event *event;
 icaltimezone *utc = icaltimezone_get_utc_timezone();
 icaltimetype start, end, tmp;
 icalcomponent *valarm;
 icalproperty *prop;
 struct icaltriggertype trigger;

 if (!(pvt && pvt->owner)) {
 ast_log(LOG_ERROR, "Require a private structure with an ownenr\n");
 return;
 }

 if (!(event = ast_calendar_event_alloc(pvt->owner))) {
 ast_log(LOG_ERROR, "Could not allocate an event!\n");
 return;
 }

 start = icalcomponent_get_dtstart(comp);
 end = icalcomponent_get_dtend(comp);

 event->start = icaltime_get_tzid(start) ? span->start : icalfloat_to_timet(start);
 event->end = icaltime_get_tzid(end) ? span->end : icalfloat_to_timet(end);
 event->busy_state = span->is_busy ? AST_CALENDAR_BS_BUSY : AST_CALENDAR_BS_FREE;

 if ((prop = icalcomponent_get_first_property(comp, ICAL_SUMMARY_PROPERTY))) {
 ast_string_field_set(event, summary, icalproperty_get_value_as_string(prop));
 }

 if ((prop = icalcomponent_get_first_property(comp, ICAL_DESCRIPTION_PROPERTY))) {
 ast_string_field_set(event, description, icalproperty_get_value_as_string(prop));
 }

 if ((prop = icalcomponent_get_first_property(comp, ICAL_ORGANIZER_PROPERTY))) {
 ast_string_field_set(event, organizer, icalproperty_get_value_as_string(prop));
 }

 if ((prop = icalcomponent_get_first_property(comp, ICAL_LOCATION_PROPERTY))) {
 ast_string_field_set(event, location, icalproperty_get_value_as_string(prop));
 }

 if ((prop = icalcomponent_get_first_property(comp, ICAL_CATEGORIES_PROPERTY))) {
 ast_string_field_set(event, categories, icalproperty_get_value_as_string(prop));
 }

 if ((prop = icalcomponent_get_first_property(comp, ICAL_PRIORITY_PROPERTY))) {
 event->priority = icalvalue_get_integer(icalproperty_get_value(prop));
 }

 if ((prop = icalcomponent_get_first_property(comp, ICAL_UID_PROPERTY))) {
 ast_string_field_set(event, uid, icalproperty_get_value_as_string(prop));
 } else {
 ast_log(LOG_WARNING, "No UID found, but one is required. Generating, but updates may not be acurate\n");
 if (!ast_strlen_zero(event->summary)) {
 ast_string_field_set(event, uid, event->summary);
 } else {
 char tmp[100];
 snprintf(tmp, sizeof(tmp), "%ld", event->start);
 ast_string_field_set(event, uid, tmp);
 }
 }

 /*
 * If comp has an RRULE and/or RDATE property, we need to check whether
 * another vevent component supercedes this span. Such a component would
 * have two characteristics:
 * - its UID is the same as comp
 * - its RECURRENCE-ID property is the same time as span->start
 */
 if (icalcomponent_get_first_property(comp, ICAL_RRULE_PROPERTY)
 || icalcomponent_get_first_property(comp, ICAL_RDATE_PROPERTY)) {
 icalcompiter comp_iter;
 icaltimetype span_start = icaltime_from_timet_with_zone(
 event->start, icaltime_is_date(start), icaltime_get_timezone(start));

 icaltime_set_timezone(&span_start, icaltime_get_timezone(start));
 for (comp_iter = icalcomponent_begin_component(pvt->data, ICAL_VEVENT_COMPONENT);
 icalcompiter_deref(&comp_iter);
 icalcompiter_next(&comp_iter)) {
 icalcomponent *vevent = icalcompiter_deref(&comp_iter);
 icalproperty *uid = icalcomponent_get_first_property(vevent, ICAL_UID_PROPERTY);

 if (uid && !strcmp(icalproperty_get_value_as_string(uid), event->uid)) {
 icaltimetype recurrence_id = icalcomponent_get_recurrenceid(vevent);

 /* Set the same timezone that we want to compare against */
 icaltime_set_timezone(&recurrence_id, icaltime_get_timezone(start));

 if (!icaltime_compare(recurrence_id, span_start)
 && icaltime_is_date(span_start) == icaltime_is_date(recurrence_id)) {
 event = ast_calendar_unref_event(event);
 return;
 }
 }
 }
 }

 /* Get the attendees */
 for (prop = icalcomponent_get_first_property(comp, ICAL_ATTENDEE_PROPERTY);
 prop; prop = icalcomponent_get_next_property(comp, ICAL_ATTENDEE_PROPERTY)) {
 struct ast_calendar_attendee *attendee;
 const char *data;

 if (!(attendee = ast_calloc(1, sizeof(*attendee)))) {
 event = ast_calendar_unref_event(event);
 return;
 }
 data = icalproperty_get_attendee(prop);
 if (ast_strlen_zero(data)) {
 ast_free(attendee);
 continue;
 }
 attendee->data = ast_strdup(data);;
 AST_LIST_INSERT_TAIL(&event->attendees, attendee, next);
 }


 /* Only set values for alarm based on VALARM. Can be overriden in main/calendar.c by autoreminder
 * therefore, go ahead and add events even if their is no VALARM or it is malformed
 * Currently we are only getting the first VALARM and are handling repitition in main/calendar.c from calendar.conf */
 if (!(valarm = icalcomponent_get_first_component(comp, ICAL_VALARM_COMPONENT))) {
 ao2_link(pvt->events, event);
 event = ast_calendar_unref_event(event);
 return;
 }

 if (!(prop = icalcomponent_get_first_property(valarm, ICAL_TRIGGER_PROPERTY))) {
 ast_log(LOG_WARNING, "VALARM has no TRIGGER, skipping!\n");
 ao2_link(pvt->events, event);
 event = ast_calendar_unref_event(event);
 return;
 }

 trigger = icalproperty_get_trigger(prop);

 if (icaltriggertype_is_null_trigger(trigger)) {
 ast_log(LOG_WARNING, "Bad TRIGGER for VALARM, skipping!\n");
 ao2_link(pvt->events, event);
 event = ast_calendar_unref_event(event);
 return;
 }

 if (!icaltime_is_null_time(trigger.time)) { /* This is an absolute time */
 tmp = icaltime_convert_to_zone(trigger.time, utc);
 event->alarm = icaltime_as_timet_with_zone(tmp, utc);
 } else { /* Offset from either dtstart or dtend */
 /* XXX Technically you can check RELATED to see if the event fires from the END of the event
 * But, I'm not sure I've ever seen anyone implement it in calendaring software, so I'm ignoring for now */
 tmp = icaltime_add(start, trigger.duration);
 event->alarm = icaltime_as_timet_with_zone(tmp, icaltime_get_timezone(start));
 }

 ao2_link(pvt->events, event);
 event = ast_calendar_unref_event(event);

 return;
}

 static void icalendar_update_events(struct icalendar_pvt *pvt)
{
 struct icaltimetype start_time, end_time;
 icalcomponent *iter;

 if (!pvt) {
 ast_log(LOG_ERROR, "iCalendar is NULL\n");
 return;
 }

 if (!pvt->owner) {
 ast_log(LOG_ERROR, "iCalendar is an orphan!\n");
 return;
 }

 if (!pvt->data) {
 ast_log(LOG_ERROR, "The iCalendar has not been parsed!\n");
 return;
 }

 start_time = icaltime_current_time_with_zone(icaltimezone_get_utc_timezone());
 end_time = icaltime_current_time_with_zone(icaltimezone_get_utc_timezone());
 end_time.second += pvt->owner->timeframe * 60;
 end_time = icaltime_normalize(end_time);

 for (iter = icalcomponent_get_first_component(pvt->data, ICAL_VEVENT_COMPONENT);
 iter;
 iter = icalcomponent_get_next_component(pvt->data, ICAL_VEVENT_COMPONENT))
 {
 icalcomponent_foreach_recurrence(iter, start_time, end_time, icalendar_add_event, pvt);
 }

 ast_calendar_merge_events(pvt->owner, pvt->events);
}

static void *ical_load_calendar(void *void_data)
{
 struct icalendar_pvt *pvt;
 const struct ast_config *cfg;
 struct ast_variable *v;
 struct ast_calendar *cal = void_data;
 ast_mutex_t refreshlock;

 if (!(cal && (cfg = ast_calendar_config_acquire()))) {
 ast_log(LOG_ERROR, "You must enable calendar support for res_icalendar to load\n");
 return NULL;
 }
 if (ao2_trylock(cal)) {
 if (cal->unloading) {
 ast_log(LOG_WARNING, "Unloading module, load_calendar cancelled.\n");
 } else {
 ast_log(LOG_WARNING, "Could not lock calendar, aborting!\n");
 }
 ast_calendar_config_release();
 return NULL;
 }

 if (!(pvt = ao2_alloc(sizeof(*pvt), icalendar_destructor))) {
 ast_log(LOG_ERROR, "Could not allocate icalendar_pvt structure for calendar: %s\n", cal->name);
 ast_calendar_config_release();
 return NULL;
 }

 pvt->owner = cal;

 if (!(pvt->events = ast_calendar_event_container_alloc())) {
 ast_log(LOG_ERROR, "Could not allocate space for fetching events for calendar: %s\n", cal->name);
 pvt = unref_icalendar(pvt);
 ao2_unlock(cal);
 ast_calendar_config_release();
 return NULL;
 }

 if (ast_string_field_init(pvt, 32)) {
 ast_log(LOG_ERROR, "Couldn't allocate string field space for calendar: %s\n", cal->name);
 pvt = unref_icalendar(pvt);
 ao2_unlock(cal);
 ast_calendar_config_release();
 return NULL;
 }

 for (v = ast_variable_browse(cfg, cal->name); v; v = v->next) {
 if (!strcasecmp(v->name, "url")) {
 ast_string_field_set(pvt, url, v->value);
 } else if (!strcasecmp(v->name, "user")) {
 ast_string_field_set(pvt, user, v->value);
 } else if (!strcasecmp(v->name, "secret")) {
 ast_string_field_set(pvt, secret, v->value);
 }
 }

 ast_calendar_config_release();

 if (ast_strlen_zero(pvt->url)) {
 ast_log(LOG_WARNING, "No URL was specified for iCalendar '%s' - skipping.\n", cal->name);
 pvt = unref_icalendar(pvt);
 ao2_unlock(cal);
 return NULL;
 }

 if (ne_uri_parse(pvt->url, &pvt->uri) || pvt->uri.host == NULL || pvt->uri.path == NULL) {
 ast_log(LOG_WARNING, "Could not parse url '%s' for iCalendar '%s' - skipping.\n", pvt->url, cal->name);
 pvt = unref_icalendar(pvt);
 ao2_unlock(cal);
 return NULL;
 }

 if (pvt->uri.scheme == NULL) {
 pvt->uri.scheme = "http";
 }

 if (pvt->uri.port == 0) {
 pvt->uri.port = ne_uri_defaultport(pvt->uri.scheme);
 }

 pvt->session = ne_session_create(pvt->uri.scheme, pvt->uri.host, pvt->uri.port);
 ne_redirect_register(pvt->session);
 ne_set_server_auth(pvt->session, auth_credentials, pvt);
 if (!strcasecmp(pvt->uri.scheme, "https")) {
 ne_ssl_trust_default_ca(pvt->session);
 }

 cal->tech_pvt = pvt;

 ast_mutex_init(&refreshlock);

 /* Load it the first time */
 if (!(pvt->data = fetch_icalendar(pvt))) {
 ast_log(LOG_WARNING, "Unable to parse iCalendar '%s'\n", cal->name);
 }

 icalendar_update_events(pvt);

 ao2_unlock(cal);

 /* The only writing from another thread will be if unload is true */
 for(;;) {
 struct timeval tv = ast_tvnow();
 struct timespec ts = {0,};

 ts.tv_sec = tv.tv_sec + (60 * pvt->owner->refresh);

 ast_mutex_lock(&refreshlock);
 while (!pvt->owner->unloading) {
 if (ast_cond_timedwait(&pvt->owner->unload, &refreshlock, &ts) == ETIMEDOUT) {
 break;
 }
 }
 ast_mutex_unlock(&refreshlock);

 if (pvt->owner->unloading) {
 ast_debug(10, "Skipping refresh since we got a shutdown signal\n");
 return NULL;
 }

 ast_debug(10, "Refreshing after %d minute timeout\n", pvt->owner->refresh);

 /* Free the old calendar data */
 if (pvt->data) {
 icalcomponent_free(pvt->data);
 pvt->data = NULL;
 }
 if (!(pvt->data = fetch_icalendar(pvt))) {
 ast_log(LOG_WARNING, "Unable to parse iCalendar '%s'\n", pvt->owner->name);
 continue;
 }

 icalendar_update_events(pvt);
 }

 return NULL;
}

static int load_module(void)
{
 ne_sock_init();
 if (ast_calendar_register(&ical_tech)) {
 ne_sock_exit();
 return AST_MODULE_LOAD_DECLINE;
 }

 return AST_MODULE_LOAD_SUCCESS;
}

static int unload_module(void)
{
 ast_calendar_unregister(&ical_tech);
 ne_sock_exit();
 return 0;
}

AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "Asterisk iCalendar .ics file integration",
 .support_level = AST_MODULE_SUPPORT_EXTENDED,
 .load = load_module,
 .unload = unload_module,
 .load_pri = AST_MODPRI_DEVSTATE_PLUGIN,
 .requires = "res_calendar",
);