res_calendar_icalendar.c

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/*
 * 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",
);