Initial commit

CalDAV and CardDAV checkers sharing a single Go module. Discovery follows
RFC 6764 (/.well-known + SRV/TXT), authenticated probes cover principal,
home-set, collections and a minimal REPORT query on top of go-webdav.
Common shape in internal/dav/; CalDAV adds a scheduling rule.

Surfaces its context URL (and each secure-SRV target) as TLS endpoints via
the EndpointDiscoverer interface, so the dedicated TLS checker can pick
them up without re-parsing observations.

HTML report foregrounds common misconfigs (well-known returning 200,
missing SRV, plaintext-only SRV, missing DAV capability, skipped auth
phase) as action-item callouts before the full phase breakdown.

carddav/collect.go

@@ -0,0 +1,125 @@
+package carddav
+
+import (
+	"context"
+	"net/http"
+	"time"
+
+	"git.happydns.org/checker-dav/internal/dav"
+	sdk "git.happydns.org/checker-sdk-go/checker"
+	webdav "github.com/emersion/go-webdav"
+	"github.com/emersion/go-webdav/carddav"
+)
+
+func (p *carddavProvider) Collect(ctx context.Context, opts sdk.CheckerOptions) (any, error) {
+	domain, _ := sdk.GetOption[string](opts, "domain_name")
+	user, _ := sdk.GetOption[string](opts, "username")
+	pass, _ := sdk.GetOption[string](opts, "password")
+	explicit, _ := sdk.GetOption[string](opts, "context_url")
+	timeoutSec := sdk.GetFloatOption(opts, "timeout_seconds", 10)
+
+	timeout := time.Duration(timeoutSec * float64(time.Second))
+	if timeout <= 0 {
+		timeout = 10 * time.Second
+	}
+
+	obs := &dav.Observation{
+		Kind:           dav.KindCardDAV,
+		Domain:         domain,
+		HasCredentials: user != "" && pass != "",
+		CollectedAt:    time.Now(),
+	}
+
+	anonClient := dav.NewHTTPClient(timeout)
+
+	// Phase 1: Discovery
+	obs.Discovery = dav.Discover(ctx, anonClient, dav.KindCardDAV, domain, explicit)
+	if obs.Discovery.ContextURL == "" {
+		return obs, nil
+	}
+
+	// Phase 2: OPTIONS
+	optsRes, err := dav.ProbeOptions(ctx, anonClient, obs.Discovery.ContextURL)
+	obs.Options = optsRes
+	if err != nil {
+		obs.Transport = dav.TransportResult{Error: err.Error()}
+		return obs, nil
+	}
+	obs.Transport = dav.TransportResult{Reached: true}
+
+	// Phase 3: Authenticated
+	if !obs.HasCredentials {
+		obs.Principal.Skipped = true
+		obs.HomeSet.Skipped = true
+		obs.Collections.Skipped = true
+		obs.Report.Skipped = true
+		return obs, nil
+	}
+
+	authClient := dav.WithBasicAuth(anonClient, obs.Discovery.ContextURL, user, pass)
+
+	principal, err := dav.FindPrincipal(ctx, authClient, obs.Discovery.ContextURL)
+	if err != nil {
+		obs.Principal.Error = err.Error()
+		obs.HomeSet.Skipped = true
+		obs.Collections.Skipped = true
+		obs.Report.Skipped = true
+		return obs, nil
+	}
+	obs.Principal.URL = principal
+
+	card, err := carddav.NewClient(asHTTPClient(authClient), obs.Discovery.ContextURL)
+	if err != nil {
+		obs.HomeSet.Error = err.Error()
+		obs.Collections.Skipped = true
+		obs.Report.Skipped = true
+		return obs, nil
+	}
+	home, err := card.FindAddressBookHomeSet(ctx, principal)
+	if err != nil {
+		obs.HomeSet.Error = err.Error()
+		obs.Collections.Skipped = true
+		obs.Report.Skipped = true
+		return obs, nil
+	}
+	obs.HomeSet.URL = home
+
+	books, err := card.FindAddressBooks(ctx, home)
+	if err != nil {
+		obs.Collections.Error = err.Error()
+		obs.Report.Skipped = true
+	} else {
+		for _, b := range books {
+			item := dav.CollectionInfo{
+				Path:            b.Path,
+				Name:            b.Name,
+				Description:     b.Description,
+				MaxResourceSize: b.MaxResourceSize,
+			}
+			for _, d := range b.SupportedAddressData {
+				item.SupportedAddressData = append(item.SupportedAddressData, d.ContentType+";"+d.Version)
+			}
+			obs.Collections.Items = append(obs.Collections.Items, item)
+		}
+	}
+
+	if len(obs.Collections.Items) > 0 {
+		first := obs.Collections.Items[0].Path
+		obs.Report.ProbePath = first
+		q := &carddav.AddressBookQuery{
+			DataRequest: carddav.AddressDataRequest{AllProp: true},
+			Limit:       1,
+		}
+		if _, err := card.QueryAddressBook(ctx, first, q); err != nil {
+			obs.Report.Error = err.Error()
+		} else {
+			obs.Report.QueryOK = true
+		}
+	} else {
+		obs.Report.Skipped = true
+	}
+
+	return obs, nil
+}
+
+func asHTTPClient(c *http.Client) webdav.HTTPClient { return c }

carddav/definition.go

@@ -0,0 +1,39 @@
+package carddav
+
+import (
+	"time"
+
+	"git.happydns.org/checker-dav/internal/dav"
+	sdk "git.happydns.org/checker-sdk-go/checker"
+)
+
+var Version = "built-in"
+
+func (p *carddavProvider) Definition() *sdk.CheckerDefinition {
+	return &sdk.CheckerDefinition{
+		ID:      "carddav",
+		Name:    "CardDAV server",
+		Version: Version,
+		Availability: sdk.CheckerAvailability{
+			ApplyToDomain: true,
+			// See caldav/definition.go for the rationale; abstract.CardDAV
+			// isn't in the catalog yet, so this is a no-op until it is.
+			ApplyToService:  true,
+			LimitToServices: []string{"abstract.CardDAV"},
+		},
+		ObservationKeys: []sdk.ObservationKey{ObservationKey},
+		Options: sdk.CheckerOptionsDocumentation{
+			UserOpts:   dav.UserOptions(),
+			DomainOpts: dav.DomainOptions(),
+			RunOpts:    dav.RunOptions(),
+		},
+		Rules:      dav.Rules(dav.KindCardDAV, ObservationKey),
+		Aggregator: dav.WorstStatus{},
+		Interval: &sdk.CheckIntervalSpec{
+			Min:     1 * time.Minute,
+			Max:     1 * time.Hour,
+			Default: 15 * time.Minute,
+		},
+		HasHTMLReport: true,
+	}
+}

carddav/discovery.go

@@ -0,0 +1,16 @@
+package carddav
+
+import (
+	"fmt"
+
+	"git.happydns.org/checker-dav/internal/dav"
+	sdk "git.happydns.org/checker-sdk-go/checker"
+)
+
+func (p *carddavProvider) DiscoverEntries(data any) ([]sdk.DiscoveryEntry, error) {
+	obs, ok := data.(*dav.Observation)
+	if !ok {
+		return nil, fmt.Errorf("unexpected data type %T", data)
+	}
+	return dav.DiscoverEntries(obs), nil
+}

carddav/provider.go

@@ -0,0 +1,20 @@
+package carddav
+
+import (
+	"net/http"
+
+	"git.happydns.org/checker-dav/internal/dav"
+	sdk "git.happydns.org/checker-sdk-go/checker"
+)
+
+func Provider() sdk.ObservationProvider { return &carddavProvider{} }
+
+type carddavProvider struct{}
+
+func (p *carddavProvider) Key() sdk.ObservationKey { return ObservationKey }
+
+func (p *carddavProvider) RenderForm() []sdk.CheckerOptionField { return dav.InteractiveForm() }
+
+func (p *carddavProvider) ParseForm(r *http.Request) (sdk.CheckerOptions, error) {
+	return dav.ParseInteractiveForm(r)
+}

carddav/report.go

@@ -0,0 +1,20 @@
+package carddav
+
+import (
+	"encoding/json"
+	"fmt"
+
+	sdk "git.happydns.org/checker-sdk-go/checker"
+
+	"git.happydns.org/checker-dav/internal/dav"
+)
+
+// GetHTMLReport: see the CalDAV sibling.
+func (p *carddavProvider) GetHTMLReport(ctx sdk.ReportContext) (string, error) {
+	var d dav.Observation
+	if err := json.Unmarshal(ctx.Data(), &d); err != nil {
+		return "", fmt.Errorf("failed to unmarshal carddav report: %w", err)
+	}
+	d.Kind = dav.KindCardDAV
+	return dav.RenderReport(&d, "CardDAV Server", ctx.Related(dav.TLSRelatedKey))
+}

carddav/types.go

@@ -0,0 +1,9 @@
+// Package carddav: see the CalDAV sibling. The two share everything except
+// the protocol-specific home-set and REPORT calls in collect.go.
+package carddav
+
+import "git.happydns.org/checker-dav/internal/dav"
+
+const ObservationKey = "carddav"
+
+type Data = dav.Observation