Add Calendaring support for Asterisk

This commit add Calendaring support to Asterisk for iCalendar, CalDAV, and MS
Exchange calendars. Exchange support has only been tested on Exchange Server 2k3
and does not support forms-based authentication at this time (patches *very*
welcome). Exchange support is also currently missing the ability to return a
list of a meting's attendees (again, patches are very, very welcome).

Features include:
  Querying a calendar for events over a specific time range
  Checking a calendar's busy status via the dialplan
  Writing calendar events via the dialplan (CalDAV and Exchange only)
  Handling calendar event notifications through the dialplan

(closes issue #14771)
Tested by: lmadsen, twilson, Shivaprakash

Review: https://reviewboard.asterisk.org/r/58


git-svn-id: http://svn.digium.com/svn/asterisk/trunk@197738 f38db490-d61c-443f-a65b-d21fe96a405b

1 files changed, 675 insertions, 0 deletions

diff --git a/res/res_calendar_caldav.c b/res/res_calendar_caldav.c
new file mode 100644
index 000000000..57e2575d0
--- /dev/null
+++ b/res/res_calendar_caldav.c
@@ -0,0 +1,675 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2008 - 2009, Digium, Inc.
+ *
+ * Terry Wilson <twilson@digium.com>
+ *
+ * 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 iCalnedar calendars
+ */
+
+/*** MODULEINFO
+	<depend>neon</depend>
+	<depend>ical</depend>
+	<depend>libxml2</depend>
+***/
+#include "asterisk.h"
+
+ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
+
+#include <libical/ical.h>
+#include <neon/ne_session.h>
+#include <neon/ne_uri.h>
+#include <neon/ne_request.h>
+#include <neon/ne_auth.h>
+#include <libxml/xmlmemory.h>
+#include <libxml/parser.h>
+
+#include "asterisk/module.h"
+#include "asterisk/calendar.h"
+#include "asterisk/lock.h"
+#include "asterisk/config.h"
+#include "asterisk/astobj2.h"
+
+static void *caldav_load_calendar(void *data);
+static void *unref_caldav(void *obj);
+static int caldav_write_event(struct ast_calendar_event *event);
+
+static struct ast_calendar_tech caldav_tech = {
+	.type = "caldav",
+	.description = "CalDAV calendars",
+	.module = AST_MODULE,
+	.load_calendar = caldav_load_calendar,
+	.unref_calendar = unref_caldav,
+	.write_event = caldav_write_event,
+};
+
+struct caldav_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;
+	struct ao2_container *events;
+};
+
+static int cb_true(void *user_data, void *arg, int flags)
+{
+	return CMP_MATCH;
+}
+
+static void caldav_destructor(void *obj)
+{
+	struct caldav_pvt *pvt = obj;
+
+	ast_debug(1, "Destroying pvt for CalDAV calendar %s\n", pvt->owner->name);
+	if (pvt->session) {
+		ne_session_destroy(pvt->session);
+	}
+	ast_string_field_free_memory(pvt);
+
+	ao2_callback(pvt->events, OBJ_UNLINK | OBJ_NODATA | OBJ_MULTIPLE, cb_true, NULL);
+
+	ao2_ref(pvt->events, -1);
+}
+
+static void *unref_caldav(void *obj)
+{
+	struct caldav_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 caldav_pvt *pvt = userdata;
+
+	if (attempts > 1) {
+		ast_log(LOG_WARNING, "Invalid username or password for CalDAV calendar '%s'\n", pvt->owner->name);
+		return -1;
+	}
+
+	ne_strnzcpy(username, pvt->user, NE_ABUFSIZ);
+	ne_strnzcpy(secret, pvt->secret, NE_ABUFSIZ);
+
+	return 0;
+}
+
+static struct ast_str *caldav_request(struct caldav_pvt *pvt, const char *method, struct ast_str *req_body, struct ast_str *subdir, const char *content_type)
+{
+	struct ast_str *response;
+	ne_request *req;
+	int ret;
+	char buf[1000];
+
+	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;
+	}
+
+	snprintf(buf, sizeof(buf), "%s%s", pvt->uri.path, subdir ? ast_str_buffer(subdir) : "");
+
+	req = ne_request_create(pvt->session, method, buf);
+	ne_add_response_body_reader(req, ne_accept_2xx, fetch_response_reader, &response);
+	ne_set_request_body_buffer(req, ast_str_buffer(req_body), ast_str_strlen(req_body));
+	ne_add_request_header(req, "Content-type", ast_strlen_zero(content_type) ? "text/xml" : content_type);
+
+	ret = ne_request_dispatch(req);
+	ne_request_destroy(req);
+
+	if (ret != NE_OK || !ast_str_strlen(response)) {
+		ast_log(LOG_WARNING, "Unknown response to CalDAV calendar %s, request %s to %s: %s\n", pvt->owner->name, method, pvt->url, ne_get_error(pvt->session));
+		ast_free(response);
+		return NULL;
+	}
+
+	return response;
+}
+
+static int caldav_write_event(struct ast_calendar_event *event)
+{
+	struct ast_str *body = NULL, *response = NULL, *subdir = NULL;
+	icalcomponent *calendar, *icalevent;
+	icaltimezone *utc = icaltimezone_get_utc_timezone();
+	int ret = -1;
+
+	if (!event) {
+		ast_log(LOG_WARNING, "No event passed!\n");
+		return -1;
+	}
+
+	if (!(event->start && event->end)) {
+		ast_log(LOG_WARNING, "The event must contain a start and an end\n");
+		return -1;
+	}
+	if (!(body = ast_str_create(512)) ||
+		!(subdir = ast_str_create(32)) ||
+		!(response = ast_str_create(512))) {
+		ast_log(LOG_ERROR, "Could not allocate memory for request and response!\n");
+		goto write_cleanup;
+	}
+
+	if (ast_strlen_zero(event->uid)) {
+		unsigned short val[8];
+		int x;
+		for (x = 0; x < 8; x++) {
+			val[x] = ast_random();
+		}
+		ast_string_field_build(event, uid, "%04x%04x-%04x-%04x-%04x-%04x%04x%04x", val[0], val[1], val[2], val[3], val[4], val[5], val[6], val[7]);
+	}
+
+	calendar = icalcomponent_new(ICAL_VCALENDAR_COMPONENT);
+	icalcomponent_add_property(calendar, icalproperty_new_version("2.0"));
+	icalcomponent_add_property(calendar, icalproperty_new_prodid("-//Digium, Inc.//res_caldav//EN"));
+
+	icalevent = icalcomponent_new(ICAL_VEVENT_COMPONENT);
+	icalcomponent_add_property(icalevent, icalproperty_new_dtstamp(icaltime_current_time_with_zone(utc)));
+	icalcomponent_add_property(icalevent, icalproperty_new_uid(event->uid));
+	icalcomponent_add_property(icalevent, icalproperty_new_dtstart(icaltime_from_timet_with_zone(event->start, 0, utc)));
+	icalcomponent_add_property(icalevent, icalproperty_new_dtend(icaltime_from_timet_with_zone(event->end, 0, utc)));
+	if (!ast_strlen_zero(event->organizer)) {
+		icalcomponent_add_property(icalevent, icalproperty_new_organizer(event->organizer));
+	}
+	if (!ast_strlen_zero(event->summary)) {
+		icalcomponent_add_property(icalevent, icalproperty_new_summary(event->summary));
+	}
+	if (!ast_strlen_zero(event->description)) {
+		icalcomponent_add_property(icalevent, icalproperty_new_description(event->description));
+	}
+	if (!ast_strlen_zero(event->location)) {
+		icalcomponent_add_property(icalevent, icalproperty_new_location(event->location));
+	}
+
+	switch (event->busy_state) {
+	case AST_CALENDAR_BS_BUSY:
+		icalcomponent_add_property(icalevent, icalproperty_new_status(ICAL_STATUS_CONFIRMED));
+		break;
+
+	case AST_CALENDAR_BS_BUSY_TENTATIVE:
+		icalcomponent_add_property(icalevent, icalproperty_new_status(ICAL_STATUS_TENTATIVE));
+		break;
+
+	default:
+		icalcomponent_add_property(icalevent, icalproperty_new_status(ICAL_STATUS_NONE));
+	}
+
+	icalcomponent_add_component(calendar, icalevent);
+
+	ast_str_append(&body, 0, "%s", icalcomponent_as_ical_string(calendar));
+	ast_str_set(&subdir, 0, "%s%s.ics", ast_str_buffer(body)[ast_str_strlen(body)] == '/' ? "" : "/", event->uid);
+
+	response = caldav_request(event->owner->tech_pvt, "PUT", body, subdir, "text/calendar");
+
+	ret = 0;
+
+write_cleanup:
+	if (body) {
+		ast_free(body);
+	}
+	if (response) {
+		ast_free(response);
+	}
+	if (subdir) {
+		ast_free(subdir);
+	}
+
+	return ret;
+}
+
+static struct ast_str *caldav_get_events_between(struct caldav_pvt *pvt, time_t start_time, time_t end_time)
+{
+	struct ast_str *body, *response;
+	icaltimezone *utc = icaltimezone_get_utc_timezone();
+	icaltimetype start, end;
+	const char *start_str, *end_str;
+
+	if (!(body = ast_str_create(512))) {
+		ast_log(LOG_ERROR, "Could not allocate memory for body of request!\n");
+		return NULL;
+	}
+
+	start = icaltime_from_timet_with_zone(start_time, 0, utc);
+	end = icaltime_from_timet_with_zone(end_time, 0, utc);
+	start_str = icaltime_as_ical_string(start);
+	end_str = icaltime_as_ical_string(end);
+
+	/* If I was really being efficient, I would store a collection of event URIs and etags,
+	 * first doing a query of just the etag and seeing if anything had changed.  If it had,
+	 * then I would do a request for each of the events that had changed, and only bother
+	 * updating those.  Oh well. */
+	ast_str_append(&body, 0,
+		"<?xml version=\"1.0\" encoding=\"utf-8\" ?>\n"
+		"<C:calendar-query xmlns:D=\"DAV:\" xmlns:C=\"urn:ietf:params:xml:ns:caldav\">\n"
+		"  <D:prop>\n"
+		"    <C:calendar-data>\n"
+		"      <C:expand start=\"%s\" end=\"%s\"/>\n"
+		"    </C:calendar-data>\n"
+		"  </D:prop>\n"
+		"  <C:filter>\n"
+		"    <C:comp-filter name=\"VCALENDAR\">\n"
+		"      <C:comp-filter name=\"VEVENT\">\n"
+		"        <C:time-range start=\"%s\" end=\"%s\"/>\n"
+		"      </C:comp-filter>\n"
+		"    </C:comp-filter>\n"
+		"  </C:filter>\n"
+		"</C:calendar-query>\n", start_str, end_str, start_str, end_str);
+
+	response = caldav_request(pvt, "REPORT", body, NULL, NULL);
+	ast_free(body);
+
+	return response;
+}
+
+static void caldav_add_event(icalcomponent *comp, struct icaltime_span *span, void *data)
+{
+	struct caldav_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 owner\n");
+		return;
+	}
+
+	if (!(event = ast_calendar_event_alloc(pvt->owner))) {
+		ast_log(LOG_ERROR, "Could not allocate an event!\n");
+		return;
+	}
+
+	start = icaltime_from_timet_with_zone(span->start, 0, utc);
+	end = icaltime_from_timet_with_zone(span->end, 0, utc);
+	event->start = span->start;
+	event->end = span->end;
+
+	switch(icalcomponent_get_status(comp)) {
+	case ICAL_STATUS_CONFIRMED:
+		event->busy_state = AST_CALENDAR_BS_BUSY;
+		break;
+
+	case ICAL_STATUS_TENTATIVE:
+		event->busy_state = AST_CALENDAR_BS_BUSY_TENTATIVE;
+		break;
+
+	default:
+		event->busy_state = 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_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), "%lu", event->start);
+			ast_string_field_set(event, uid, tmp);
+		}
+	}
+
+	/* 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)) {
+			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, utc);
+	}
+
+	ao2_link(pvt->events, event);
+	event = ast_calendar_unref_event(event);
+
+	return;
+}
+
+struct xmlstate {
+	int in_caldata;
+	struct caldav_pvt *pvt;
+	struct ast_str *cdata;
+	time_t start;
+	time_t end;
+};
+
+static void handle_start_element(void *data, const xmlChar *fullname, const xmlChar **atts)
+{
+	struct xmlstate *state = data;
+
+	if (!xmlStrcasecmp(fullname, BAD_CAST "C:calendar-data")) {
+		state->in_caldata = 1;
+		ast_str_reset(state->cdata);
+	}
+}
+
+static void handle_end_element(void *data, const xmlChar *name)
+{
+	struct xmlstate *state = data;
+	struct icaltimetype start, end;
+	icaltimezone *utc = icaltimezone_get_utc_timezone();
+	icalcomponent *iter;
+	icalcomponent *comp;
+
+	if (xmlStrcasecmp(name, BAD_CAST "C:calendar-data")) {
+		return;
+	}
+
+	state->in_caldata = 0;
+	if (!(state->cdata && ast_str_strlen(state->cdata))) {
+		return;
+	}
+	/* XXX Parse the calendar blurb for recurrence events in the time range,
+	 * create an event, and add it to pvt->events */
+	start = icaltime_from_timet_with_zone(state->start, 0, utc);
+	end = icaltime_from_timet_with_zone(state->end, 0, utc);
+	comp = icalparser_parse_string(ast_str_buffer(state->cdata));
+
+	for (iter = icalcomponent_get_first_component(comp, ICAL_VEVENT_COMPONENT);
+	     iter;
+	     iter = icalcomponent_get_next_component(comp, ICAL_VEVENT_COMPONENT))
+	{
+		icalcomponent_foreach_recurrence(iter, start, end, caldav_add_event, state->pvt);
+	}
+
+	icalcomponent_free(comp);
+}
+
+static void handle_characters(void *data, const xmlChar *ch, int len)
+{
+	struct xmlstate *state = data;
+	xmlChar *tmp;
+
+	if (!state->in_caldata) {
+		return;
+	}
+
+	tmp = xmlStrndup(ch, len);
+	ast_str_append(&state->cdata, 0, "%s", (char *)tmp);
+	xmlFree(tmp);
+}
+
+static int update_caldav(struct caldav_pvt *pvt)
+{
+	struct timeval now = ast_tvnow();
+	time_t start, end;
+	struct ast_str *response;
+	xmlSAXHandler saxHandler;
+	struct xmlstate state = {
+		.in_caldata = 0,
+		.pvt = pvt
+	};
+
+	start = now.tv_sec;
+	end = now.tv_sec + 60 * pvt->owner->timeframe;
+	if (!(response = caldav_get_events_between(pvt, start, end))) {
+		return -1;
+	}
+
+	if (!(state.cdata = ast_str_create(512))) {
+		ast_free(response);
+		return -1;
+	}
+
+	state.start = start;
+	state.end = end;
+
+	memset(&saxHandler, 0, sizeof(saxHandler));
+	saxHandler.startElement = handle_start_element;
+	saxHandler.endElement = handle_end_element;
+	saxHandler.characters = handle_characters;
+
+	xmlSAXUserParseMemory(&saxHandler, &state, ast_str_buffer(response), ast_str_strlen(response));
+
+	ast_calendar_merge_events(pvt->owner, pvt->events);
+
+	ast_free(response);
+	ast_free(state.cdata);
+
+	return 0;
+}
+
+static int verify_cert(void *userdata, int failures, const ne_ssl_certificate *cert)
+{
+	/* Verify all certs */
+	return 0;
+}
+
+static void *caldav_load_calendar(void *void_data)
+{
+	struct caldav_pvt *pvt;
+	struct ast_variable *v;
+	struct ast_calendar *cal = void_data;
+	ast_mutex_t refreshlock;
+
+	if (!(cal && calendar_config)) {
+		ast_log(LOG_ERROR, "You must enable calendar support for res_caldav 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");
+		}
+		return NULL;
+	}
+
+	if (!(pvt = ao2_alloc(sizeof(*pvt), caldav_destructor))) {
+		ast_log(LOG_ERROR, "Could not allocate caldav_pvt structure for calendar: %s\n", cal->name);
+		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_caldav(pvt);
+		ao2_unlock(cal);
+		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_caldav(pvt);
+		ao2_unlock(cal);
+		return NULL;
+	}
+
+	for (v = ast_variable_browse(calendar_config, 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);
+		}
+	}
+
+	if (ast_strlen_zero(pvt->url)) {
+		ast_log(LOG_WARNING, "No URL was specified for CalDAV calendar '%s' - skipping.\n", cal->name);
+		pvt = unref_caldav(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 CalDAV calendar '%s' - skipping.\n", pvt->url, cal->name);
+		pvt = unref_caldav(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_set_server_auth(pvt->session, auth_credentials, pvt);
+	if (!strncasecmp(pvt->uri.scheme, "https", sizeof(pvt->uri.scheme))) {
+		ne_ssl_trust_default_ca(pvt->session);
+		ne_ssl_set_verify(pvt->session, verify_cert, NULL);
+	}
+
+	cal->tech_pvt = pvt;
+
+	ast_mutex_init(&refreshlock);
+
+	/* Load it the first time */
+	update_caldav(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);
+
+		update_caldav(pvt);
+	}
+
+	return NULL;
+}
+
+static int load_module(void)
+{
+	ne_sock_init();
+	if (ast_calendar_register(&caldav_tech)) {
+		ne_sock_exit();
+		return AST_MODULE_LOAD_DECLINE;
+	}
+
+	return AST_MODULE_LOAD_SUCCESS;
+}
+
+static int unload_module(void)
+{
+	ast_calendar_unregister(&caldav_tech);
+	ne_sock_exit();
+	return 0;
+}
+
+AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_DEFAULT, "Asterisk CalDAV Calendar Integration",
+		.load = load_module,
+		.unload = unload_module,
+	);