res_calendar_icalendar.c

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/*
 * 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 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));
        if (!comp) {
            ast_debug(3, "iCalendar response data: %s\n", ast_str_buffer(response));
            ast_log(LOG_WARNING, "Failed to parse iCalendar data: %s\n", icalerror_perror());
        }
    }
    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 owner\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 accurate\n");
        if (!ast_strlen_zero(event->summary)) {
            ast_string_field_set(event, uid, event->summary);
        } else {
            char tmp[AST_TIME_T_LEN];
            ast_time_t_to_string(event->start, tmp, sizeof(tmp));
            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);
    ne_set_useragent(pvt->session, "Asterisk");
    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",
);