Import an iCal file into a calendar

An .ics reaches you by ways that are not your mailbox -- a ticketing
system a customer invited, a colleague's export, a booking confirmation
forwarded on -- and until now the only events ihasmail could take were the
ones attached to a message it had received.

The calendar's own menu now offers "Import iCAL file…", which files
everything in the file into that calendar. No global button: the issue is
right that this is not a frequent enough thing to earn one.

The parsing is the server's, through the same CalendarEvent/parse an
emailed invitation already goes through. An .ics is not a format worth
reimplementing in a browser, and Stalwart's reader handles what a
hand-rolled one would not.

Every event goes out in a single CalendarEvent/set. The round trips are
the smaller half of the reason: createEvent invalidates on the way out and
invalidating refetches every cached range, so a year of events imported
one at a time would refetch the calendar a few hundred times.

Nothing is mailed to anyone named in the file. Importing is filing
something you already have, and scheduling messages would be a surprise to
its participants.

The mock's parser read the whole file with one regex and returned one
event, which is all an invitation ever needed. It now reads per VEVENT, so
a multi-event file can be tested against it, and it invents an organiser
and an attendee only for events that carry a METHOD -- a plain export is
not addressed to anyone.

Closes #173

server/src/mock/index.ts

@@ -476,6 +476,60 @@ function genericSet(list: Obj[], prefix: string, onCreate?: (o: Obj) => void) {
  *   still saying the update succeeded. A mock that applied them would let a
  *   client that sends them look correct everywhere except a real server.
  */
+/**
+ * Enough of an iCalendar reader to stand in for Stalwart's.
+ *
+ * It reads per VEVENT rather than across the whole file, because a file is the
+ * case an emailed invitation never was: an export carries a year of them, and a
+ * regex over the whole text would find the first DTSTART and call that the
+ * answer. One event still comes back as a bare object, the shape this returned
+ * when an invitation was all it had to handle.
+ *
+ * The synthetic organiser and attendee only go on events that arrived with a
+ * METHOD. Those are scheduling messages, which is what the invitation fixtures
+ * are; a plain export is not addressed to anyone, and inventing participants
+ * for it would make imported events look like invitations nobody sent.
+ */
+function calendarEventParse(a: Obj) {
+  const parsed: Obj = {};
+  const notParsable: string[] = [];
+  for (const b of a.blobIds as string[]) {
+    const blob = blobs.get(b);
+    if (!blob) { notParsable.push(b); continue; }
+    const text = blob.data.toString();
+    const field = (src: string, k: string) => new RegExp(`^${k}[^:\r\n]*:(.*)$`, "m").exec(src)?.[1]?.trim();
+    const method = field(text, "METHOD");
+    const bodies = text.match(/BEGIN:VEVENT[\s\S]*?END:VEVENT/g) ?? [];
+    const events = bodies.map((body) => {
+      const g = (k: string) => field(body, k);
+      const ds = g("DTSTART") ?? "20260101T000000Z";
+      const de = g("DTEND") ?? ds;
+      const toLocal = (s: string) => `${s.slice(0, 4)}-${s.slice(4, 6)}-${s.slice(6, 8)}T${s.slice(9, 11)}:${s.slice(11, 13)}:00`;
+      const start = new Date(`${toLocal(ds)}Z`);
+      const end = new Date(`${toLocal(de)}Z`);
+      return {
+        "@type": "Event",
+        uid: g("UID"),
+        title: g("SUMMARY"),
+        start: toLocal(ds),
+        timeZone: "Etc/UTC",
+        duration: `PT${Math.round((end.getTime() - start.getTime()) / 60000)}M`,
+        method,
+        locations: g("LOCATION") ? { l: { name: g("LOCATION") } } : undefined,
+        participants: method
+          ? {
+              org: { name: "Ada Lovelace", calendarAddress: "mailto:[email protected]", roles: { owner: true } },
+              me: { name: "Demo User", calendarAddress: `mailto:${USER}`, roles: { attendee: true, required: true }, participationStatus: "needs-action" },
+            }
+          : undefined,
+      };
+    });
+    if (!events.length) { notParsable.push(b); continue; }
+    parsed[b] = events.length === 1 ? events[0] : events;
+  }
+  return { accountId: ACCOUNT, parsed, notParsable };
+}
+
 function calendarEventSet(a: Obj) {
   const created: Obj = {};
   const updated: Obj = {};
@@ -961,7 +1015,7 @@ const handlers: Record<string, Handler> = {
   // participants addressed the RFC 8984 way. The mock did neither, which is how
   // #26 and #30 reached a live server unnoticed — so it now does both.
   "CalendarEvent/set": (a) => calendarEventSet(a),
-  "CalendarEvent/parse": (a) => { const parsed: Obj = {}; for (const b of a.blobIds as string[]) { const blob = blobs.get(b); if (!blob) continue; const t = blob.data.toString(); const g = (k: string) => new RegExp(`^${k}[^:]*:(.*)$`, "m").exec(t)?.[1]?.trim(); const ds = g("DTSTART") ?? "20260101T000000Z"; const de = g("DTEND") ?? ds; const toLocal = (s: string) => `${s.slice(0, 4)}-${s.slice(4, 6)}-${s.slice(6, 8)}T${s.slice(9, 11)}:${s.slice(11, 13)}:00`; const start = new Date(`${toLocal(ds)}Z`); const end = new Date(`${toLocal(de)}Z`); parsed[b] = { "@type": "Event", uid: g("UID"), title: g("SUMMARY"), start: toLocal(ds), timeZone: "Etc/UTC", duration: `PT${Math.round((end.getTime() - start.getTime()) / 60000)}M`, method: g("METHOD"), locations: g("LOCATION") ? { l: { name: g("LOCATION") } } : undefined, participants: { org: { name: "Ada Lovelace", calendarAddress: "mailto:[email protected]", roles: { owner: true } }, me: { name: "Demo User", calendarAddress: `mailto:${USER}`, roles: { attendee: true, required: true }, participationStatus: "needs-action" } } }; } return { accountId: ACCOUNT, parsed, notParsable: [] }; },
+  "CalendarEvent/parse": (a) => calendarEventParse(a),
   "ParticipantIdentity/get": genericGet(participantIdentities),
   "Principal/query": () => ({ accountId: ACCOUNT, queryState: "1", canCalculateChanges: false, position: 0, ids: principals.map((p) => p.id) }),
   "Principal/get": genericGet(principals),