1 // This file contains functions which handle all of the CalDAV "REPORT" queries specified in RFC4791 section 7.
2 // Copyright (c) 2023-2024 by the citadel.org team
3 // This program is open source software. Use, duplication, or disclosure is subject to the GNU General Public License v3.
7 #define CALDAV "urn:ietf:params:xml:ns:caldav:" // Shorthand for the XML namespace of CalDAV
8 #define CALDAVLEN sizeof(CALDAV)-1 // And the length of that string
10 const char *the_beginning_of_time = "19010101T010101Z";
11 const char *the_end_of_time = "99991231T235959Z";
13 // A CalDAV REPORT can only be one type. This is stored in the report_type member.
20 // Data type for CalDAV Report Parameters.
21 // As we slog our way through the XML we learn what the client is asking for
22 // and build up the contents of this data type.
24 int comp_filter_nesting_level;
25 enum cr_type report_type; // which RFC4791 section 7 REPORT are we generating
26 StrBuf *Chardata; // XML chardata in between tags is built up here
27 StrBuf *Hrefs; // list of items requested by a `calendar-multiget` REPORT
28 Array *filters; // If the query contains a FILTER stanza, the filter criteria are populated here
29 int filter_nest; // tag nesting level where a FILTER stanza begins
33 // XML parser callback
34 void caldav_xml_start(void *data, const char *el, const char **attr) {
35 struct cr_params *crp = (struct cr_params *) data;
37 #ifdef DEBUG_XML_PARSE
39 syslog(LOG_DEBUG, "<%s>", el);
40 for (int i = 0; attr[i] != NULL; i += 2) {
41 syslog(LOG_DEBUG, "Attribute '%s' = '%s'", attr[i], attr[i + 1]);
46 // RFC4791 7.8 "calendar-query" REPORT - Client will send a lot of search criteria.
47 if (!strcasecmp(el, CALDAV"calendar-query")) {
48 crp->report_type = cr_calendar_query;
51 // RFC4791 7.9 "calendar-multiget" REPORT - Client will supply a list of specific hrefs.
52 else if (!strcasecmp(el, CALDAV"calendar-multiget")) {
53 crp->report_type = cr_calendar_multiget;
56 // RFC4791 7.10 "free-busy-query" REPORT
57 else if (!strcasecmp(el, CALDAV"free-busy-query")) {
58 crp->report_type = cr_freebusy_query;
61 // RFC4791 9.7 create a filter array if this query contains a "filter" stanza
62 else if (!strcasecmp(el, CALDAV"filter")) {
63 crp->filters = array_new(SIZ);
64 crp->filter_nest = crp->comp_filter_nesting_level;
67 // Handle the filters defined in RFC4791 9.7.1 through 9.7.5
68 else if ( ( (!strcasecmp(el, CALDAV"comp-filter"))
69 || (!strcasecmp(el, CALDAV"prop-filter"))
70 || (!strcasecmp(el, CALDAV"param-filter"))
71 || (!strcasecmp(el, CALDAV"is-not-defined"))
72 || (!strcasecmp(el, CALDAV"text-match"))
73 || (!strcasecmp(el, CALDAV"time-range"))
75 && (crp->filters) // Make sure we actually allocated an array
78 if (!strcasecmp(el, CALDAV"comp-filter")) {
79 ++crp->comp_filter_nesting_level;
84 int len = snprintf(newfilter, SIZ, "%d|", crp->comp_filter_nesting_level - crp->filter_nest - 1);
85 len += snprintf(&newfilter[len], SIZ-len, "%s", &el[CALDAVLEN]); // filter name without the namespace
87 len += snprintf(&newfilter[len], SIZ-len, "|%s", attr[a++]); // now save the attributes
89 array_append(crp->filters, newfilter);
94 // XML parser callback
95 void caldav_xml_end(void *data, const char *el) {
96 struct cr_params *crp = (struct cr_params *) data;
98 #ifdef DEBUG_XML_PARSE
101 syslog(LOG_DEBUG, "</%s>", el);
105 if (!strcasecmp(el, CALDAV"comp-filter")) {
106 --crp->comp_filter_nesting_level;
110 if ((!strcasecmp(el, "DAV::href")) || (!strcasecmp(el, "DAV:href"))) {
111 if (crp->Hrefs == NULL) { // append crp->Chardata to crp->Hrefs
112 crp->Hrefs = NewStrBuf();
115 StrBufAppendBufPlain(crp->Hrefs, HKEY("|"), 0);
117 StrBufAppendBuf(crp->Hrefs, crp->Chardata, 0);
120 if (crp->Chardata != NULL) { // Tag is closed; chardata is now out of scope.
121 FreeStrBuf(&crp->Chardata); // Free the buffer.
122 crp->Chardata = NULL;
127 // XML parser callback
128 void caldav_xml_chardata(void *data, const XML_Char *s, int len) {
129 struct cr_params *crp = (struct cr_params *) data;
131 char *app = malloc(len+1);
138 if (crp->Chardata == NULL) {
139 crp->Chardata = NewStrBuf();
142 StrBufAppendBufPlain(crp->Chardata, app, len, 0);
144 #ifdef DEBUG_XML_PARSE
146 string_trim(app); // remove leading/trailing whitespace. ok to mangle it because we've already appended.
147 if (!IsEmptyStr(app)) {
149 syslog(LOG_DEBUG, "%s", app, len);
159 // Called by caldav_report_one_item() to fetch a message (by number) in the current room,
160 // and return only the icalendar data as a StrBuf. Returns NULL if not found.
162 // NOTE: this function expects that "MSGP text/calendar" was issued at the beginning
163 // of a REPORT operation to set our preferred MIME type to calendar data.
164 StrBuf *fetch_ical(struct ctdlsession *c, long msgnum) {
168 ctdl_printf(c, "MSG4 %ld", msgnum);
169 ctdl_readline(c, buf, sizeof(buf));
174 while (ctdl_readline(c, buf, sizeof(buf)), strcmp(buf, "000")) {
175 if (Buf != NULL) { // already in body
176 StrBufAppendPrintf(Buf, "%s\n", buf);
178 else if (IsEmptyStr(buf)) { // beginning of body
187 // Called by multiple REPORT types to actually perform the output in "multiget" format.
188 // We need to already know the source message number and the href, but also already have the output data.
189 void cal_multiget_out(long msgnum, StrBuf *ThisHref, StrBuf *Caldata, StrBuf *ReportOut) {
191 StrBufAppendPrintf(ReportOut, "<D:response>");
192 StrBufAppendPrintf(ReportOut, "<D:href>");
193 StrBufXMLEscAppend(ReportOut, ThisHref, NULL, 0, 0);
194 StrBufAppendPrintf(ReportOut, "</D:href>");
195 StrBufAppendPrintf(ReportOut, "<D:propstat>");
197 if (Caldata != NULL) {
198 // syslog(LOG_DEBUG, "caldav_report_one_item(%s) 200 OK", ChrPtr(ThisHref));
199 StrBufAppendPrintf(ReportOut, "<D:status>");
200 StrBufAppendPrintf(ReportOut, "HTTP/1.1 200 OK");
201 StrBufAppendPrintf(ReportOut, "</D:status>");
202 StrBufAppendPrintf(ReportOut, "<D:prop>");
203 StrBufAppendPrintf(ReportOut, "<D:getetag>");
204 StrBufAppendPrintf(ReportOut, "%ld", msgnum);
205 StrBufAppendPrintf(ReportOut, "</D:getetag>");
206 StrBufAppendPrintf(ReportOut, "<C:calendar-data>");
207 StrBufXMLEscAppend(ReportOut, Caldata, NULL, 0, 0);
208 StrBufAppendPrintf(ReportOut, "</C:calendar-data>");
209 StrBufAppendPrintf(ReportOut, "</D:prop>");
212 // syslog(LOG_DEBUG, "caldav_report_one_item(%s) 404 not found", ChrPtr(ThisHref));
213 StrBufAppendPrintf(ReportOut, "<D:status>");
214 StrBufAppendPrintf(ReportOut, "HTTP/1.1 404 not found");
215 StrBufAppendPrintf(ReportOut, "</D:status>");
218 StrBufAppendPrintf(ReportOut, "</D:propstat>");
219 StrBufAppendPrintf(ReportOut, "</D:response>");
223 // Called by caldav_report() to output a single item.
224 // Our policy is to throw away the list of properties the client asked for, and just send everything.
225 void caldav_report_one_item(struct http_transaction *h, struct ctdlsession *c, StrBuf *ReportOut, StrBuf *ThisHref) {
227 StrBuf *Caldata = NULL;
230 euid = strrchr(ChrPtr(ThisHref), '/');
235 euid = (char *) ChrPtr(ThisHref);
238 char *unescaped_euid = strdup(euid);
239 if (!unescaped_euid) {
242 unescape_input(unescaped_euid);
244 msgnum = locate_message_by_uid(c, unescaped_euid);
245 free(unescaped_euid);
247 Caldata = fetch_ical(c, msgnum);
253 cal_multiget_out(msgnum, ThisHref, Caldata, ReportOut);
255 if (Caldata != NULL) {
256 FreeStrBuf(&Caldata);
261 // Compare function for "time-range" tests (RFC4791 section 9.9)
262 // Returns nonzero if the supplied icalcomponent occurs within the specified time range
264 // IMPLEMENTATION NOTE:
265 // ical_ctdl_is_overlap() works because icaltime_compare() is really smart.
266 // It looks at the time zone of the dtstart/dtend and can apparently go back up the icalcomponent
267 // hierarchy to find its time zone data. I tested this by creating an event with a fictional
268 // time zone and it did the right thing. It even showed the fictional name to me. This saves us
269 // from having to convert everything to UTC before comparing. Nice!
271 int caldav_time_range_filter_matches(icalcomponent *cal, char *start_str, char *end_str) {
273 struct icaltimetype search_start = icaltime_from_string(start_str); // time range being searched
274 struct icaltimetype search_end = icaltime_from_string(end_str);
276 struct icaltimetype dtstart = icalcomponent_get_dtstart(cal); // time of event
277 struct icaltimetype dtend = icalcomponent_get_dtend(cal);
278 if (icaltime_is_null_time(dtend)) {
282 // If it is a recurring event, RRULE is available at this level. We can handle it here.
283 icalproperty *rrule = icalcomponent_get_first_property(cal, ICAL_RRULE_PROPERTY);
285 struct icaldurationtype dur = icaltime_subtract(dtend, dtstart); // recurrences need duration to find dtend
286 struct icalrecurrencetype recur = icalproperty_get_rrule(rrule);
287 icalrecur_iterator *ritr = icalrecur_iterator_new(recur, dtstart); // iterate through recurrences
288 while (dtstart = icalrecur_iterator_next(ritr), !icaltime_is_null_time(dtstart)) {
289 dtend = icaltime_add(dtstart, dur);
291 // Does THIS recurrence match the query? If so, free the memory we used and stop iterating.
292 if (ical_ctdl_is_overlap(dtstart, dtend, search_start, search_end)) {
293 icalrecur_iterator_free(ritr);
298 icalrecur_iterator_free(ritr);
299 return(0); // compared all recurrences, no match was found for any of them
302 // For non recurring events, do a simple time range compare.
303 return(ical_ctdl_is_overlap(dtstart, dtend, search_start, search_end)); // We have a convenience function for this.
307 // Recursive function to apply CalDAV FILTERS to a calendar item.
308 // Returns zero if the calendar item was disqualified by a filter, nonzero if the calendar item still qualifies.
309 int caldav_apply_filters(void *cal, Array *filters, int apply_at_level) {
311 int f = 0; // filter number iterator
312 int qual = 1; // 0 for disqualify, 1 for qualify
313 int previous_level = -1;
314 int disregard_further_comp_filters = 0;
316 while ( (f<array_len(filters)) && (qual) ) {
318 // Tokenize the filter (a future performance hack would be to pre-tokenize instead of storing delimited strings)
319 char this_filter[SIZ];
320 safestrncpy(this_filter, array_get_element_at(filters, f), sizeof(this_filter));
321 char *t[10] = { NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL } ;
322 char *ft = this_filter;
324 while ( (t[num_tokens]=strtok_r(ft, "|", &ft)) && (num_tokens<10) ) {
327 int this_rule_level = atoi(t[0]);
328 syslog(LOG_DEBUG, "caldav_apply_filters() filter=%d, level=%d, <%s>", f, this_rule_level, array_get_element_at(filters, f) );
330 // Handle the individual filters defined in RFC4791 9.7.1 through 9.7.5
332 if (apply_at_level < previous_level) {
333 syslog(LOG_DEBUG, "caldav: walking back down");
337 else if (this_rule_level != apply_at_level) {
338 syslog(LOG_DEBUG, "caldav: apply_at_level=%d, this_rule_level=%d, skipping this rule", apply_at_level, this_rule_level);
341 else if ( (!strcasecmp(t[1], "comp-filter")) // RFC4791 9.7.1 - filter by component
342 && (!disregard_further_comp_filters) // one is enough to succeed
344 syslog(LOG_DEBUG, "component filter at level %d", this_rule_level);
346 // comp-filter requires exactly one parameter (name="VXXXX")
347 if (num_tokens < 4) {
348 syslog(LOG_DEBUG, "caldav: comp-filter has no parameters - rejecting");
352 // Root element is NOT a component, but the root filter is "comp-filter" -- reject!
353 if ( (!icalcomponent_isa_component(cal)) && (this_rule_level == 0) ) {
354 syslog(LOG_DEBUG, "caldav: root element is not a component, rejecting");
358 // Current element is a component and the filter is "comp-filter" -- see if it matches the requested type
359 if ( (icalcomponent_isa_component(cal))
360 && (!strcasecmp(t[2], "name"))
362 if (icalcomponent_isa(cal) == icalcomponent_string_to_kind(t[3]) ) {
363 syslog(LOG_DEBUG, "caldav: component at level %d is <%s>, looking for <%s>, recursing...",
365 icalcomponent_kind_to_string(icalcomponent_isa(cal)), t[3]
368 // We have a match. Drill down into the subcomponents.
370 icalcomponent *c = NULL;
371 int number_of_subcomponents = 0;
372 int number_of_matches = 0;
373 for ( c = icalcomponent_get_first_component(cal, ICAL_ANY_COMPONENT);
375 c = icalcomponent_get_next_component(cal, ICAL_ANY_COMPONENT)
377 ++number_of_subcomponents;
378 if (caldav_apply_filters(c, filters, apply_at_level+1)) {
379 syslog(LOG_DEBUG, "Subcomponent %d might match", number_of_subcomponents);
383 if (number_of_matches > 0) { // something matched
385 disregard_further_comp_filters = 1;
388 else if (number_of_subcomponents > 0) { // nothing matched
389 return(0); // but only fail if there *were* subcomponents.
394 syslog(LOG_DEBUG, "caldav: component at level %d is <%s>, looking for <%s>, rejecting",
396 icalcomponent_kind_to_string(icalcomponent_isa(cal)),
405 else if (!strcasecmp(t[1], "prop-filter")) { // RFC4791 9.7.2 - filter by property
406 syslog(LOG_DEBUG, "property filter at level %d FIXME not implemented yet", this_rule_level);
409 else if (!strcasecmp(t[1], "param-filter")) { // RFC4791 9.7.3 - filter by parameter
410 syslog(LOG_DEBUG, "parameter filter at level %d FIXME not implemented yet", this_rule_level);
413 else if (!strcasecmp(t[1], "is-not-defined")) { // RFC4791 9.7.4
414 syslog(LOG_DEBUG, "is-not-defined filter at level %d FIXME not implemented yet", this_rule_level);
417 else if (!strcasecmp(t[1], "text-match")) { // RFC4791 9.7.5
418 syslog(LOG_DEBUG, "text match filter at level %d FIXME not implemented yet", this_rule_level);
421 else if (!strcasecmp(t[1], "time-range")) { // RFC4791 9.9
422 syslog(LOG_DEBUG, "time range filter at level %d", this_rule_level);
423 char *tr_start = (char *)the_beginning_of_time; // default if not specified
424 char *tr_end = (char *)the_end_of_time; // default if not specified
425 for (int i=2; (i+1)<num_tokens; i+=2) {
426 if (!strcasecmp(t[i], "start")) {
429 else if (!strcasecmp(t[i], "end")) {
433 if (caldav_time_range_filter_matches(cal, tr_start, tr_end)) {
434 syslog(LOG_DEBUG, "time range matches");
437 syslog(LOG_DEBUG, "time range does not match -- rejecting");
445 syslog(LOG_DEBUG, "caldav: we reached the end of level %d , returning %d", apply_at_level, qual);
450 // Called by report_the_room_itself() in room_functions.c when a CalDAV REPORT method
451 // is requested on a calendar room. We fire up an XML Parser to decode the request and
452 // hopefully produce the correct output.
453 void caldav_report(struct http_transaction *h, struct ctdlsession *c) {
454 struct cr_params crp;
457 memset(&crp, 0, sizeof(struct cr_params));
459 XML_Parser xp = XML_ParserCreateNS("UTF-8", ':');
461 syslog(LOG_INFO, "Cannot create XML parser!");
466 XML_SetElementHandler(xp, caldav_xml_start, caldav_xml_end);
467 XML_SetCharacterDataHandler(xp, caldav_xml_chardata);
468 XML_SetUserData(xp, &crp);
469 XML_SetDefaultHandler(xp, NULL); // Disable internal entity expansion to prevent "billion laughs attack"
470 XML_Parse(xp, h->request_body, h->request_body_length, 1);
473 if (crp.Chardata != NULL) { // Discard any trailing chardata ... normally nothing here
474 FreeStrBuf(&crp.Chardata);
478 // We're going to make a lot of MSG4 calls, and the preferred MIME type we want is "text/calendar".
479 // The iCalendar standard is mature now, and we are no longer interested in text/x-vcal or application/ics.
480 ctdl_printf(c, "MSGP text/calendar");
481 ctdl_readline(c, buf, sizeof buf);
483 // Now begin the REPORT.
484 syslog(LOG_DEBUG, "CalDAV REPORT type is: %d", crp.report_type);
485 StrBuf *ReportOut = NewStrBuf();
486 StrBufAppendPrintf(ReportOut,
487 "<?xml version=\"1.0\" encoding=\"utf-8\"?><D:multistatus xmlns:D=\"DAV:\" xmlns:C=\"%s\">",
491 // RFC4791 7.8 "calendar-query" REPORT - Client will send a lot of search criteria.
492 if (crp.report_type == cr_calendar_query) {
494 Array *msglist = get_msglist(c, "ALL");
495 if (msglist != NULL) {
496 for (i = 0; i < array_len(msglist); ++i) {
498 memcpy(&m, array_get_element_at(msglist, i), sizeof(long));
500 // load and parse one calendar item
501 StrBuf *one_item = fetch_ical(c, m);
502 icalcomponent *cal = icalcomponent_new_from_string(ChrPtr(one_item));
504 // Does this calendar item qualify for output? Run this calendar item through the filters.
505 syslog(LOG_DEBUG, "Evaluating message \033[33m%ld\033[0m...", m);
506 if (caldav_apply_filters(cal, crp.filters, 0)) {
507 syslog(LOG_DEBUG, "Message %ld \033[32mQUALIFIES\033[0m", m);
508 // FIXME need to populate the Href instead of NULL
509 cal_multiget_out(m, NULL, one_item, ReportOut);
512 syslog(LOG_DEBUG, "Message %ld \033[31mDOES NOT QUALIFY\033[0m", m);
514 syslog(LOG_DEBUG, "");
516 icalcomponent_free(cal);
517 FreeStrBuf(&one_item);
524 // RFC4791 7.9 "calendar-multiget" REPORT - go get the specific Hrefs the client asked for.
525 // Can we move this back into citserver too?
526 else if ( (crp.report_type == cr_calendar_multiget) && (crp.Hrefs != NULL) ) {
528 StrBuf *ThisHref = NewStrBuf();
529 const char *pvset = NULL;
530 while (StrBufExtract_NextToken(ThisHref, crp.Hrefs, &pvset, '|') >= 0) {
531 StrBufTrim(ThisHref); // remove leading/trailing whitespace from the href
532 caldav_report_one_item(h, c, ReportOut, ThisHref);
534 FreeStrBuf(&ThisHref);
537 // RFC4791 7.10 "free-busy-query" REPORT
538 else if (crp.report_type == cr_freebusy_query) {
539 // FIXME build this REPORT. At the moment we send an empty multistatus.
542 // Free any query parameters that might have been allocated during the xml parse
543 if (crp.Hrefs != NULL) {
544 FreeStrBuf(&crp.Hrefs);
548 array_free(crp.filters);
552 StrBufAppendPrintf(ReportOut, "</D:multistatus>\n"); // End the REPORT.
554 add_response_header(h, strdup("Content-type"), strdup("text/xml"));
555 h->response_code = 207;
556 h->response_string = strdup("Multi-Status");
557 h->response_body_length = StrLength(ReportOut);
558 h->response_body = SmashStrBuf(&ReportOut);