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);
95 // XML parser callback
96 void caldav_xml_end(void *data, const char *el) {
97 struct cr_params *crp = (struct cr_params *) data;
99 #ifdef DEBUG_XML_PARSE
102 syslog(LOG_DEBUG, "</%s>", el);
106 if (!strcasecmp(el, CALDAV"comp-filter")) {
107 --crp->comp_filter_nesting_level;
111 if ((!strcasecmp(el, "DAV::href")) || (!strcasecmp(el, "DAV:href"))) {
112 if (crp->Hrefs == NULL) { // append crp->Chardata to crp->Hrefs
113 crp->Hrefs = NewStrBuf();
116 StrBufAppendBufPlain(crp->Hrefs, HKEY("|"), 0);
118 StrBufAppendBuf(crp->Hrefs, crp->Chardata, 0);
121 if (crp->Chardata != NULL) { // Tag is closed; chardata is now out of scope.
122 FreeStrBuf(&crp->Chardata); // Free the buffer.
123 crp->Chardata = NULL;
128 // XML parser callback
129 void caldav_xml_chardata(void *data, const XML_Char *s, int len) {
130 struct cr_params *crp = (struct cr_params *) data;
132 char *app = malloc(len+1);
139 if (crp->Chardata == NULL) {
140 crp->Chardata = NewStrBuf();
143 StrBufAppendBufPlain(crp->Chardata, app, len, 0);
145 #ifdef DEBUG_XML_PARSE
147 string_trim(app); // remove leading/trailing whitespace. ok to mangle it because we've already appended.
148 if (!IsEmptyStr(app)) {
150 syslog(LOG_DEBUG, "%s", app, len);
160 // Called by caldav_report_one_item() to fetch a message (by number) in the current room,
161 // and return only the icalendar data as a StrBuf. Returns NULL if not found.
163 // NOTE: this function expects that "MSGP text/calendar" was issued at the beginning
164 // of a REPORT operation to set our preferred MIME type to calendar data.
165 StrBuf *fetch_ical(struct ctdlsession *c, long msgnum) {
169 ctdl_printf(c, "MSG4 %ld", msgnum);
170 ctdl_readline(c, buf, sizeof(buf));
175 while (ctdl_readline(c, buf, sizeof(buf)), strcmp(buf, "000")) {
176 if (Buf != NULL) { // already in body
177 StrBufAppendPrintf(Buf, "%s\n", buf);
179 else if (IsEmptyStr(buf)) { // beginning of body
188 // Called by multiple REPORT types to actually perform the output in "multiget" format.
189 // We need to already know the source message number and the href, but also already have the output data.
190 void cal_multiget_out(long msgnum, StrBuf *ThisHref, StrBuf *Caldata, StrBuf *ReportOut) {
192 StrBufAppendPrintf(ReportOut, "<D:response>");
193 StrBufAppendPrintf(ReportOut, "<D:href>");
194 StrBufXMLEscAppend(ReportOut, ThisHref, NULL, 0, 0);
195 StrBufAppendPrintf(ReportOut, "</D:href>");
196 StrBufAppendPrintf(ReportOut, "<D:propstat>");
198 if (Caldata != NULL) {
199 // syslog(LOG_DEBUG, "caldav_report_one_item(%s) 200 OK", ChrPtr(ThisHref));
200 StrBufAppendPrintf(ReportOut, "<D:status>");
201 StrBufAppendPrintf(ReportOut, "HTTP/1.1 200 OK");
202 StrBufAppendPrintf(ReportOut, "</D:status>");
203 StrBufAppendPrintf(ReportOut, "<D:prop>");
204 StrBufAppendPrintf(ReportOut, "<D:getetag>");
205 StrBufAppendPrintf(ReportOut, "%ld", msgnum);
206 StrBufAppendPrintf(ReportOut, "</D:getetag>");
207 StrBufAppendPrintf(ReportOut, "<C:calendar-data>");
208 StrBufXMLEscAppend(ReportOut, Caldata, NULL, 0, 0);
209 StrBufAppendPrintf(ReportOut, "</C:calendar-data>");
210 StrBufAppendPrintf(ReportOut, "</D:prop>");
213 // syslog(LOG_DEBUG, "caldav_report_one_item(%s) 404 not found", ChrPtr(ThisHref));
214 StrBufAppendPrintf(ReportOut, "<D:status>");
215 StrBufAppendPrintf(ReportOut, "HTTP/1.1 404 not found");
216 StrBufAppendPrintf(ReportOut, "</D:status>");
219 StrBufAppendPrintf(ReportOut, "</D:propstat>");
220 StrBufAppendPrintf(ReportOut, "</D:response>");
224 // Called by caldav_report() to output a single item.
225 // Our policy is to throw away the list of properties the client asked for, and just send everything.
226 void caldav_report_one_item(struct http_transaction *h, struct ctdlsession *c, StrBuf *ReportOut, StrBuf *ThisHref) {
228 StrBuf *Caldata = NULL;
231 euid = strrchr(ChrPtr(ThisHref), '/');
236 euid = (char *) ChrPtr(ThisHref);
239 char *unescaped_euid = strdup(euid);
240 if (!unescaped_euid) {
243 unescape_input(unescaped_euid);
245 msgnum = locate_message_by_uid(c, unescaped_euid);
246 free(unescaped_euid);
248 Caldata = fetch_ical(c, msgnum);
254 cal_multiget_out(msgnum, ThisHref, Caldata, ReportOut);
256 if (Caldata != NULL) {
257 FreeStrBuf(&Caldata);
262 // Compare function for "time-range" tests (RFC4791 section 9.9)
263 // Returns nonzero if the supplied icalcomponent occurs within the specified time range
264 int caldav_time_range_filter_matches(icalcomponent *cal, char *start_str, char *end_str) {
266 struct icaltimetype start = icaltime_from_string(start_str);
267 syslog(LOG_DEBUG, " search start: \033[36m%-16s\033[0m (%s)", icaltime_as_ical_string_r(start), icaltime_get_tzid(start));
269 struct icaltimetype end = icaltime_from_string(end_str);
270 syslog(LOG_DEBUG, " search end: \033[36m%-16s\033[0m (%s)", icaltime_as_ical_string_r(end), icaltime_get_tzid(end));
272 // IMPLEMENTATION NOTE:
273 // ical_ctdl_is_overlap() works because icaltime_compare() is really smart.
274 // It looks at the time zone of the dtstart/dtend and can apparently go back up the icalcomponent
275 // hierarchy to find its time zone data. I tested this by creating an event with a fictional
276 // time zone and it did the right thing. It even showed the fictional name to me. This saves us
277 // from having to convert everything to UTC before comparing. Nice!
279 icaltimetype dts = icalcomponent_get_dtstart(cal);
280 syslog(LOG_DEBUG, "component start: \033[36m%-16s\033[0m (%s)", icaltime_as_ical_string_r(dts), icaltime_get_tzid(dts));
282 icaltimetype dte = icalcomponent_get_dtend(cal);
283 syslog(LOG_DEBUG, "component end: \033[36m%-16s\033[0m (%s)", icaltime_as_ical_string_r(dte), icaltime_get_tzid(dte));
285 return(ical_ctdl_is_overlap(dts, dte, start, end)); // We have a convenience function for this.
289 // Recursive function to apply CalDAV FILTERS to a calendar item.
290 // Returns zero if the calendar item was disqualified by a filter, nonzero if the calendar item still qualifies.
291 int caldav_apply_filters(void *cal, Array *filters, int apply_at_level) {
293 int f = 0; // filter number iterator
294 int qual = 1; // 0 for disqualify, 1 for qualify
295 int previous_level = -1;
296 int disregard_further_comp_filters = 0;
298 while ( (f<array_len(filters)) && (qual) ) {
300 // Tokenize the filter (a future performance hack would be to pre-tokenize instead of storing delimited strings)
301 char this_filter[SIZ];
302 safestrncpy(this_filter, array_get_element_at(filters, f), sizeof(this_filter));
303 char *t[10] = { NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL } ;
304 char *ft = this_filter;
306 while ( (t[num_tokens]=strtok_r(ft, "|", &ft)) && (num_tokens<10) ) {
309 int this_rule_level = atoi(t[0]);
310 syslog(LOG_DEBUG, "caldav_apply_filters() filter=%d, level=%d, <%s>", f, this_rule_level, array_get_element_at(filters, f) );
312 // Handle the individual filters defined in RFC4791 9.7.1 through 9.7.5
314 if (apply_at_level < previous_level) {
315 syslog(LOG_DEBUG, "caldav: walking back down");
319 else if (this_rule_level != apply_at_level) {
320 syslog(LOG_DEBUG, "caldav: apply_at_level=%d, this_rule_level=%d, skipping this rule", apply_at_level, this_rule_level);
323 else if ( (!strcasecmp(t[1], "comp-filter")) // RFC4791 9.7.1 - filter by component
324 && (!disregard_further_comp_filters) // one is enough to succeed
326 syslog(LOG_DEBUG, "component filter at level %d", this_rule_level);
328 // comp-filter requires exactly one parameter (name="VXXXX")
329 if (num_tokens < 4) {
330 syslog(LOG_DEBUG, "caldav: comp-filter has no parameters - rejecting");
334 // Root element is NOT a component, but the root filter is "comp-filter" -- reject!
335 if ( (!icalcomponent_isa_component(cal)) && (this_rule_level == 0) ) {
336 syslog(LOG_DEBUG, "caldav: root element is not a component, rejecting");
340 // Current element is a component and the filter is "comp-filter" -- see if it matches the requested type
341 if ( (icalcomponent_isa_component(cal))
342 && (!strcasecmp(t[2], "name"))
344 if (icalcomponent_isa(cal) == icalcomponent_string_to_kind(t[3]) ) {
345 syslog(LOG_DEBUG, "caldav: component at level %d is <%s>, looking for <%s>, recursing...",
347 icalcomponent_kind_to_string(icalcomponent_isa(cal)), t[3]
350 // We have a match. Drill down into the subcomponents.
352 icalcomponent *c = NULL;
353 int number_of_subcomponents = 0;
354 int number_of_matches = 0;
355 for ( c = icalcomponent_get_first_component(cal, ICAL_ANY_COMPONENT);
357 c = icalcomponent_get_next_component(cal, ICAL_ANY_COMPONENT)
359 ++number_of_subcomponents;
360 if (caldav_apply_filters(c, filters, apply_at_level+1)) {
361 syslog(LOG_DEBUG, "Subcomponent %d might match", number_of_subcomponents);
365 if (number_of_matches > 0) { // something matched
367 disregard_further_comp_filters = 1;
370 else if (number_of_subcomponents > 0) { // nothing matched
371 return(0); // but only fail if there *were* subcomponents.
376 syslog(LOG_DEBUG, "caldav: component at level %d is <%s>, looking for <%s>, rejecting",
378 icalcomponent_kind_to_string(icalcomponent_isa(cal)),
387 else if (!strcasecmp(t[1], "prop-filter")) { // RFC4791 9.7.2 - filter by property
388 syslog(LOG_DEBUG, "property filter at level %d FIXME not implemented yet", this_rule_level);
391 else if (!strcasecmp(t[1], "param-filter")) { // RFC4791 9.7.3 - filter by parameter
392 syslog(LOG_DEBUG, "parameter filter at level %d FIXME not implemented yet", this_rule_level);
395 else if (!strcasecmp(t[1], "is-not-defined")) { // RFC4791 9.7.4
396 syslog(LOG_DEBUG, "is-not-defined filter at level %d FIXME not implemented yet", this_rule_level);
399 else if (!strcasecmp(t[1], "text-match")) { // RFC4791 9.7.5
400 syslog(LOG_DEBUG, "text match filter at level %d FIXME not implemented yet", this_rule_level);
403 else if (!strcasecmp(t[1], "time-range")) { // RFC4791 9.9
404 syslog(LOG_DEBUG, "time range filter at level %d FIXME add recur", this_rule_level);
405 for (int i=2; (i+1)<num_tokens; i+=2) {
406 char *tr_start = (char *)the_beginning_of_time; // default if not specified
407 char *tr_end = (char *)the_end_of_time; // default if not specified
408 if (!strcasecmp(t[i], "start")) {
411 else if (!strcasecmp(t[i], "end")) {
414 if (caldav_time_range_filter_matches(cal, tr_start, tr_end)) {
415 syslog(LOG_DEBUG, "time range matches");
418 syslog(LOG_DEBUG, "time range does not match -- rejecting");
427 syslog(LOG_DEBUG, "caldav: we reached the end of level %d , returning %d", apply_at_level, qual);
432 // Called by report_the_room_itself() in room_functions.c when a CalDAV REPORT method
433 // is requested on a calendar room. We fire up an XML Parser to decode the request and
434 // hopefully produce the correct output.
435 void caldav_report(struct http_transaction *h, struct ctdlsession *c) {
436 struct cr_params crp;
439 memset(&crp, 0, sizeof(struct cr_params));
441 XML_Parser xp = XML_ParserCreateNS("UTF-8", ':');
443 syslog(LOG_INFO, "Cannot create XML parser!");
448 XML_SetElementHandler(xp, caldav_xml_start, caldav_xml_end);
449 XML_SetCharacterDataHandler(xp, caldav_xml_chardata);
450 XML_SetUserData(xp, &crp);
451 XML_SetDefaultHandler(xp, NULL); // Disable internal entity expansion to prevent "billion laughs attack"
452 XML_Parse(xp, h->request_body, h->request_body_length, 1);
455 if (crp.Chardata != NULL) { // Discard any trailing chardata ... normally nothing here
456 FreeStrBuf(&crp.Chardata);
460 // We're going to make a lot of MSG4 calls, and the preferred MIME type we want is "text/calendar".
461 // The iCalendar standard is mature now, and we are no longer interested in text/x-vcal or application/ics.
462 ctdl_printf(c, "MSGP text/calendar");
463 ctdl_readline(c, buf, sizeof buf);
465 // Now begin the REPORT.
466 syslog(LOG_DEBUG, "CalDAV REPORT type is: %d", crp.report_type);
467 StrBuf *ReportOut = NewStrBuf();
468 StrBufAppendPrintf(ReportOut,
469 "<?xml version=\"1.0\" encoding=\"utf-8\"?>"
472 "xmlns:C=\"urn:ietf:params:xml:ns:caldav\""
476 // RFC4791 7.8 "calendar-query" REPORT - Client will send a lot of search criteria.
477 if (crp.report_type == cr_calendar_query) {
479 Array *msglist = get_msglist(c, "ALL");
480 if (msglist != NULL) {
481 for (i = 0; i < array_len(msglist); ++i) {
483 memcpy(&m, array_get_element_at(msglist, i), sizeof(long));
485 // load and parse one calendar item
486 StrBuf *one_item = fetch_ical(c, m);
487 icalcomponent *cal = icalcomponent_new_from_string(ChrPtr(one_item));
489 // Does this calendar item qualify for output?
492 // If there was a filter stanza, run this calendar item through the filters.
493 syslog(LOG_DEBUG, "Evaluating message \033[33m%ld\033[0m...", m);
494 qualify = caldav_apply_filters(cal, crp.filters, 0);
495 syslog(LOG_DEBUG, "Message %ld %s\033[0m qualify", m, (qualify ? "\033[32mDOES" : "\033[31mDOES NOT"));
496 syslog(LOG_DEBUG, "");
498 // Did this calendar item match the query? If so, output it.
500 // FIXME need to populate the Href instead of NULL
501 cal_multiget_out(m, NULL, one_item, ReportOut);
504 icalcomponent_free(cal);
505 FreeStrBuf(&one_item);
512 // RFC4791 7.9 "calendar-multiget" REPORT - go get the specific Hrefs the client asked for.
513 // Can we move this back into citserver too?
514 else if ( (crp.report_type == cr_calendar_multiget) && (crp.Hrefs != NULL) ) {
516 StrBuf *ThisHref = NewStrBuf();
517 const char *pvset = NULL;
518 while (StrBufExtract_NextToken(ThisHref, crp.Hrefs, &pvset, '|') >= 0) {
519 StrBufTrim(ThisHref); // remove leading/trailing whitespace from the href
520 caldav_report_one_item(h, c, ReportOut, ThisHref);
522 FreeStrBuf(&ThisHref);
525 // RFC4791 7.10 "free-busy-query" REPORT
526 else if (crp.report_type == cr_freebusy_query) {
527 // FIXME build this REPORT. At the moment we send an empty multistatus.
530 // Free any query parameters that might have been allocated during the xml parse
531 if (crp.Hrefs != NULL) {
532 FreeStrBuf(&crp.Hrefs);
536 array_free(crp.filters);
540 StrBufAppendPrintf(ReportOut, "</D:multistatus>\n"); // End the REPORT.
542 add_response_header(h, strdup("Content-type"), strdup("text/xml"));
543 h->response_code = 207;
544 h->response_string = strdup("Multi-Status");
545 h->response_body_length = StrLength(ReportOut);
546 h->response_body = SmashStrBuf(&ReportOut);