Parsing Invites

Two entry points read .ics bytes:

• ParseICS(data) (*Event, error) — returns the first VEVENT. This is what mail clients want: invites are overwhelmingly single-event.
• Parse(data) (*Calendar, error) — returns every VEVENT plus the calendar-level method and headers. Use it when a calendar may carry several events. An empty calendar is not an error.

cal, err := icalendar.Parse(data)
if err != nil {
    log.Fatal(err)
}
fmt.Println(cal.Method) // REQUEST, REPLY, CANCEL, PUBLISH, ...
for _, ev := range cal.Events {
    fmt.Println(ev.UID, ev.Summary)
}

The Event struct

Everything is flattened onto one struct, so rendering needs no property lookups:

type Event struct {
    UID         string
    Summary     string
    Description string
    Location    string
    Start, End  time.Time
    AllDay      bool

    Organizer     string
    OrganizerName string
    Attendees     []Attendee

    Status     string // CONFIRMED, TENTATIVE, CANCELLED
    Method     string // mirrors the calendar METHOD
    Sequence   int
    URL        string
    Categories []string

    Stamp, Created, Modified time.Time

    Recurrence       *RRule
    RDates, ExDates  []time.Time
}

Status and Method are plain strings because they come straight off the wire; compare them against the typed constants with a conversion, e.g. ev.Status == string(icalendar.StatusConfirmed).

Timestamps

DTSTART / DTEND are parsed with full RFC 5545 awareness:

When DTEND is absent, the end is derived from a DURATION property (e.g. PT1H30M), or for an all-day event defaults to one day.

ev, _ := icalendar.ParseICS(data)
fmt.Println(ev.Duration())   // End - Start
fmt.Println(ev.IsRecurring())