Extract AppAPI auth and OCS preferences from CheckDNS.

Publish gonexapp v1 with Credentials, OCSClient, and parameterized
AppAPIPreferences so ExApps share Nextcloud ExApp plumbing per ADR 0013.

Co-authored-by: Cursor <cursoragent@cursor.com>

preferences_test.go

@@ -0,0 +1,126 @@
+package gonexapp_test
+
+import (
+	"encoding/json"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"gitea.neitzel.de/konrad/go-nc-exapp"
+)
+
+func TestOCSCallIncludesFormatJSON(t *testing.T) {
+	var gotPath string
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		gotPath = r.URL.String()
+		_ = json.NewEncoder(w).Encode(map[string]string{"ok": "true"})
+	}))
+	t.Cleanup(srv.Close)
+
+	cred := gonexapp.Credentials{
+		BaseURL: srv.URL, AppID: "app", AppVersion: "0.1.0", AAVersion: "1.0.0", AppSecret: "s", UserID: "alice",
+	}
+	client := gonexapp.OCSClient{Cred: cred, Client: srv.Client()}
+	raw, err := client.Call(http.MethodGet, "apps/app_api/api/v1/ex-app/preference/get-values", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !json.Valid(raw) {
+		t.Fatalf("not json: %s", raw)
+	}
+	if !strings.Contains(gotPath, "format=json") {
+		t.Fatalf("path missing format=json: %s", gotPath)
+	}
+}
+
+func TestOCSCallRejectsNonJSON(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+		_, _ = io.WriteString(w, "<xml/>")
+	}))
+	t.Cleanup(srv.Close)
+
+	cred := gonexapp.Credentials{BaseURL: srv.URL, AppID: "app", AppVersion: "0.1.0", AAVersion: "1.0.0", AppSecret: "s", UserID: "alice"}
+	client := gonexapp.OCSClient{Cred: cred, Client: srv.Client()}
+	_, err := client.Call(http.MethodGet, "apps/example", nil)
+	if err == nil || !strings.Contains(err.Error(), "not JSON") {
+		t.Fatalf("got %v", err)
+	}
+}
+
+func TestOCSCallSurfacesHTTPError(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		http.Error(w, "nope", http.StatusBadRequest)
+	}))
+	t.Cleanup(srv.Close)
+
+	cred := gonexapp.Credentials{BaseURL: srv.URL, AppID: "app", AppVersion: "0.1.0", AAVersion: "1.0.0", AppSecret: "s", UserID: "alice"}
+	client := gonexapp.OCSClient{Cred: cred, Client: srv.Client()}
+	_, err := client.Call(http.MethodPost, "apps/example", []byte(`{}`))
+	if err == nil || !strings.Contains(err.Error(), "400") {
+		t.Fatalf("got %v", err)
+	}
+}
+
+func TestAppAPIPreferencesGetSet(t *testing.T) {
+	const prefKey = "savedDefault"
+	prefsVals := map[string]string{}
+
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		switch {
+		case strings.Contains(r.URL.Path, "ex-app/preference/get-values"):
+			_ = json.NewEncoder(w).Encode(map[string]any{
+				"ocs": map[string]any{
+					"data": []map[string]string{{
+						"configkey":   prefKey,
+						"configvalue": prefsVals[prefKey],
+					}},
+				},
+			})
+		case strings.HasSuffix(r.URL.Path, "ex-app/preference") && r.Method == http.MethodPost:
+			var body struct {
+				ConfigKey   string `json:"configKey"`
+				ConfigValue string `json:"configValue"`
+			}
+			_ = json.NewDecoder(r.Body).Decode(&body)
+			prefsVals[body.ConfigKey] = body.ConfigValue
+			w.WriteHeader(http.StatusOK)
+			_ = json.NewEncoder(w).Encode(map[string]string{"status": "ok"})
+		default:
+			http.Error(w, "unhandled "+r.Method+" "+r.URL.Path, http.StatusInternalServerError)
+		}
+	}))
+	t.Cleanup(srv.Close)
+
+	cred := gonexapp.Credentials{
+		BaseURL: srv.URL, AppID: "myexapp", AppVersion: "0.1.0", AAVersion: "1.0.0", AppSecret: "s", UserID: "alice",
+	}
+	store := gonexapp.NewAppAPIPreferences(cred, "myexapp", prefKey)
+	store.Client = srv.Client()
+	store.OCS.Client = srv.Client()
+
+	got, err := store.Get()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got != "" {
+		t.Fatalf("initial value=%q", got)
+	}
+
+	if err := store.Set("Zones"); err != nil {
+		t.Fatal(err)
+	}
+	if prefsVals[prefKey] != "Zones" {
+		t.Fatalf("prefs not written: %#v", prefsVals)
+	}
+
+	got, err = store.Get()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got != "Zones" {
+		t.Fatalf("got %q", got)
+	}
+}