Frigate event runtime & static validation via zod.

package.json

@@ -18,7 +18,8 @@
     "custom-card-helpers": "^1.7.1",
     "home-assistant-js-websocket": "^5.11.1",
     "lit-element": "^2.5.1",
-    "lit-html": "^1.4.1"
+    "lit-html": "^1.4.1",
+    "zod": "^3.7.1"
   },
   "devDependencies": {
     "@babel/core": "^7.15.0",

src/frigate-card.ts

@@ -1,12 +1,12 @@
-// TODO: Can I use ajv (https://ajv.js.org/guide/typescript.html) to verify
-// event return matches the TS interface?
-
-// TODO Does each event contain thumbnail?
-
 // TODO Check for HA state presence and validity before using it, otherwise warn.
 
 // TODO Add material tooltips
 
+// TODO Action handlers.
+
+// TODO _getEvents may throw errors, catch them when called.
+
+// TODO Can I use Zod for FrigateCardConfig validation?
 
 /* eslint-disable @typescript-eslint/no-explicit-any */
 import {
@@ -34,7 +34,8 @@ import './editor';
 
 import style from './frigate-card.scss'
 
-import type { FrigateCardConfig, FrigateEvent, GetEventsParameters, ControlVideosParameters } from './types';
+import { frigateEventSchema, frigateGetEventsResponseSchema } from './types';
+import type { FrigateCardConfig, FrigateEvent, FrigateGetEventsResponse, GetEventsParameters, ControlVideosParameters } from './types';
 import { actionHandler } from './action-handler-directive';
 import { CARD_VERSION } from './const';
 import { localize } from './localize/localize';
@@ -205,7 +206,7 @@ export class FrigateCard extends LitElement {
     has_clip = false,
     has_snapshot = false,
     limit = 100,
-  }: GetEventsParameters): Promise<FrigateEvent[]> {
+  }: GetEventsParameters): Promise<FrigateGetEventsResponse> {
     let url = `${this.config.frigate_url}/api/events?camera=${this.config.frigate_camera_name}`;
     if (has_clip) {
       url += `&has_clip=1`
@@ -223,7 +224,17 @@ export class FrigateCard extends LitElement {
 
     const response = await fetch(url);
     if (response.ok) {
-      return await response.json();
+      let raw_json;
+      try {
+        raw_json = await response.json();
+      } catch(e) {
+        throw new Error(`Could not JSON decode Frigate API response: ${e}`);
+      }
+      try {
+        return frigateGetEventsResponseSchema.parse(raw_json);
+      } catch(e) {
+        throw new Error(`Frigate events were malformed: ${e}`);
+      }
     } else {
       // TODO: Catch when json decoding fails.
       throw new Error(`Frigate API request failed with status: ${response.status}`);

src/types.ts

@@ -1,4 +1,5 @@
 import { ActionConfig, LovelaceCard, LovelaceCardConfig, LovelaceCardEditor } from 'custom-card-helpers';
+import { z } from "zod";
 declare global {
   interface HTMLElementTagNameMap {
     'frigate-card-editor': LovelaceCardEditor;
@@ -6,6 +7,9 @@ declare global {
   }
 }
 
+/**
+ * Internal types.
+ */
 export interface FrigateCardConfig extends LovelaceCardConfig {
   type: string;
   name?: string;
@@ -25,20 +29,6 @@ export interface FrigateCardConfig extends LovelaceCardConfig {
   double_tap_action?: ActionConfig;
 }
 
-export interface FrigateEvent {
-  camera: string;
-  end_time: number;
-  false_positive: boolean;
-  has_clip: boolean;
-  has_snapshot: boolean;
-  id: string;
-  label: string;
-  start_time: number;
-  thumbnail: string;
-  top_score: number;
-  zones: string[];
-}
-
 export interface GetEventsParameters {
   has_clip?: boolean;
   has_snapshot?: boolean;
@@ -49,4 +39,26 @@ export interface ControlVideosParameters {
   stop: boolean;
   control_live?: boolean;
   control_clip?: boolean;
-}
+}
+
+/**
+ * Frigate API types.
+ */
+
+export const frigateEventSchema = z.object({
+  camera: z.string(),
+  end_time: z.number(),
+  false_positive: z.boolean(),
+  has_clip: z.boolean(),
+  has_snapshot: z.boolean(),
+  id: z.string(),
+  label: z.string(),
+  start_time: z.number(),
+  thumbnail: z.string(),
+  top_score: z.number(),
+  zones: z.string().array(),
+})
+export type FrigateEvent = z.infer<typeof frigateEventSchema>;
+
+export const frigateGetEventsResponseSchema = z.array(frigateEventSchema);
+export type FrigateGetEventsResponse = z.infer<typeof frigateGetEventsResponseSchema>;