initial work on fastmail calendar access

fmc/main.go

@@ -0,0 +1,180 @@
+//
+// Demonstrates connecting to fastmail via caldev
+//
+// Influential env variables:
+//
+// - USERNAME: e.g. [email protected]
+// - PASSWORD: an app-specific password with access to the calendar
+// - CALENDAR_PATH: /dav/calendars/user/[email protected]/DEADBEEF
+//
+// you can get the link to the calendar from settings/calendars/export.
+//
+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"net/http"
+	"os"
+	"os/signal"
+	"sort"
+	"time"
+
+	ical "github.com/emersion/go-ical"
+	webdav "github.com/emersion/go-webdav"
+	"github.com/emersion/go-webdav/caldav"
+)
+
+type Event struct {
+	Start time.Time
+	Title string
+}
+
+func discover(ctx context.Context, client *caldav.Client, path string) ([]caldav.Calendar, error) {
+	// curl -X PROPFIND -u USERNAME:PASSWORD https://caldav.fastmail.com/dav/principals/user/USERNAME
+	homeSet, err := client.FindCalendarHomeSet(ctx, path)
+	if err != nil {
+		return []caldav.Calendar{}, err
+	}
+
+	fmt.Println(homeSet)
+
+	calendars, err := client.FindCalendars(ctx, homeSet)
+	if err != nil {
+		return []caldav.Calendar{}, err
+	}
+
+	return calendars, nil
+}
+
+func query(
+	ctx context.Context,
+	client *caldav.Client,
+	calendarPath string,
+	start time.Time,
+	end time.Time,
+) (events []Event, err error) {
+	calendarQuery := caldav.CalendarQuery{
+		CompRequest: caldav.CalendarCompRequest{
+			Name:  "VCALENDAR",
+			Props: []string{"VERSION"},
+			Comps: []caldav.CalendarCompRequest{{
+				Name: "VEVENT",
+				Props: []string{
+					"SUMMARY",
+					"UID",
+					"DTSTART",
+					"DTEND",
+					"DURATION",
+				},
+			}},
+		},
+		CompFilter: caldav.CompFilter{
+			Name: "VCALENDAR",
+			Comps: []caldav.CompFilter{{
+				Name:  "VEVENT",
+				Start: start,
+				End:   end,
+			}},
+		},
+	}
+
+	objects, err := client.QueryCalendar(ctx, calendarPath, &calendarQuery)
+	if err != nil {
+		return events, err
+	}
+
+	for _, obj := range objects {
+		// fmt.Printf("%d %s\n", i, obj.Path)
+		// printComponent(obj.Data.Component, 0)
+
+		summary := obj.Data.Children[0].Props.Get("SUMMARY")
+		dtstart := obj.Data.Children[0].Props.Get("DTSTART")
+		tzid := dtstart.Params.Get("TZID")
+
+		// fmt.Printf("\t\t%s = %s\n", summary.Name, summary.Value)
+		// fmt.Printf("\t\t%s = %s\n", dtstart.Name, dtstart.Value)
+		// fmt.Printf("\t\t%s = %s\n", "TZID", tzid)
+
+		location, err := time.LoadLocation(tzid)
+		if err != nil {
+			// log.Fatal(err)
+			continue
+		}
+
+		startTime, err := time.ParseInLocation("20060102T150405", dtstart.Value, location)
+		if err != nil {
+			// log.Fatal(err)
+			continue
+		}
+
+		event := Event{startTime, summary.Value}
+		events = append(events, event)
+	}
+
+	return events, nil
+}
+
+func main() {
+	httpClient := &http.Client{}
+	username := os.ExpandEnv("$USERNAME")
+	password := os.ExpandEnv("$PASSWORD")
+	calendarPath := os.ExpandEnv("$CALENDAR_PATH")
+
+	authorizedClient := webdav.HTTPClientWithBasicAuth(httpClient, username, password)
+
+	caldavClient, err := caldav.NewClient(authorizedClient, "https://caldav.fastmail.com/dav/calendars/user/"+username)
+	if err != nil {
+		log.Fatalf("NewClient: %s", err)
+	}
+
+	gctx := context.Background()
+	gctx, _ = signal.NotifyContext(gctx, os.Interrupt)
+
+	if calendarPath == "" {
+		path := "/dav/principals/user/" + username
+		calendars, err := discover(gctx, caldavClient, path)
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		for i, calendar := range calendars {
+			fmt.Printf("cal %d: %s %s\n", i, calendar.Name, calendar.Path)
+		}
+
+		calendarPath = calendars[0].Path
+	}
+
+	log.Printf("calendar.Path: %q\n", calendarPath)
+
+	today := time.Now()
+	start := today.AddDate(0, -1, 0)
+	end := today.AddDate(0, 7, 0)
+
+	events, err := query(gctx, caldavClient, calendarPath, start, end)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	sort.Slice(
+		events,
+		func(i, j int) bool { return events[i].Start.Sub(events[j].Start).Seconds() > 0 },
+	)
+
+	for _, evt := range events {
+		fmt.Printf("%s\t%s\n", evt.Start.Format(time.DateTime), evt.Title)
+	}
+}
+
+func printComponent(cal *ical.Component, level int) {
+	for i := 0; i < level; i++ {
+		fmt.Printf("\t")
+	}
+	fmt.Printf("%q %q ", cal.Name, cal.Props)
+	fmt.Println()
+	for _, child := range cal.Children {
+		printComponent(child, level+1)
+	}
+	fmt.Println()
+}