Generate random webhook_id and add copy button

src/panels/config/automation/trigger/ha-automation-trigger-row.ts

@@ -61,7 +61,7 @@ export const handleChangeEvent = (element: TriggerElement, ev: CustomEvent) => {
   if (!name) {
     return;
   }
-  const newVal = ev.detail.value;
+  const newVal = (ev.target as any)?.value;
 
   if ((element.trigger[name] || "") === newVal) {
     return;

src/panels/config/automation/trigger/types/ha-automation-trigger-webhook.ts

@@ -1,39 +1,133 @@
-import "@polymer/paper-input/paper-input";
-import { html, LitElement } from "lit";
-import { customElement, property } from "lit/decorators";
-import { WebhookTrigger } from "../../../../../data/automation";
+import "../../../../../components/ha-icon-button";
+import "../../../../../components/ha-textfield";
+import { UnsubscribeFunc } from "home-assistant-js-websocket";
+import { mdiContentCopy } from "@mdi/js";
+import { css, html, LitElement, PropertyValues } from "lit";
+import { customElement, property, state } from "lit/decorators";
+import { fireEvent } from "../../../../../common/dom/fire_event";
+import { slugify } from "../../../../../common/string/slugify";
+import { copyToClipboard } from "../../../../../common/util/copy-clipboard";
+import type { HaTextField } from "../../../../../components/ha-textfield";
+import { showToast } from "../../../../../util/toast";
+import {
+  WebhookTrigger,
+  AutomationConfig,
+} from "../../../../../data/automation";
 import { HomeAssistant } from "../../../../../types";
 import { handleChangeEvent } from "../ha-automation-trigger-row";
 
+const DEFAULT_WEBHOOK_ID = "";
+
 @customElement("ha-automation-trigger-webhook")
 export class HaWebhookTrigger extends LitElement {
   @property({ attribute: false }) public hass!: HomeAssistant;
 
   @property() public trigger!: WebhookTrigger;
 
+  @state() private _config?: AutomationConfig;
+
+  private _unsub?: UnsubscribeFunc;
+
   public static get defaultConfig() {
     return {
-      webhook_id: "",
+      webhook_id: DEFAULT_WEBHOOK_ID,
+    };
+  }
+
+  connectedCallback() {
+    super.connectedCallback();
+    const details = {
+      callback: (config) => {
+        this._config = config;
+      },
     };
+    fireEvent(this, "subscribe-automation-config", details);
+    this._unsub = (details as any).unsub;
+  }
+
+  disconnectedCallback() {
+    super.disconnectedCallback();
+    if (this._unsub) {
+      this._unsub();
+    }
+  }
+
+  private _generateWebhookId(): string {
+    // The webhook_id should be treated like a password. Generate a default
+    // value that would be hard for someone to guess. This generates a
+    // 144-bit random value. The output is a 24 character url-safe string.
+    const randomBytes = crypto.getRandomValues(new Uint8Array(18));
+    const base64Str = btoa(String.fromCharCode(...randomBytes));
+    const urlSafeId = base64Str.replace(/\+/g, "-").replace(/\//g, "_");
+
+    // Include the automation name to give the user context about what the
+    // webhook_id is used for.
+    const urlSafeAlias = slugify(this._config?.alias || "", "-");
+
+    return `${urlSafeAlias}-${urlSafeId}`;
+  }
+
+  public willUpdate(changedProperties: PropertyValues) {
+    super.willUpdate(changedProperties);
+    if (changedProperties.has("trigger")) {
+      if (this.trigger.webhook_id === DEFAULT_WEBHOOK_ID) {
+        this.trigger.webhook_id = this._generateWebhookId();
+      }
+    }
   }
 
   protected render() {
     const { webhook_id: webhookId } = this.trigger;
+
     return html`
-      <paper-input
+      <ha-textfield
+        name="webhook_id"
         .label=${this.hass.localize(
           "ui.panel.config.automation.editor.triggers.type.webhook.webhook_id"
         )}
-        name="webhook_id"
-        .value=${webhookId}
-        @value-changed=${this._valueChanged}
-      ></paper-input>
+        .helper=${this.hass.localize(
+          "ui.panel.config.automation.editor.triggers.type.webhook.webhook_id_helper"
+        )}
+        .iconTrailing=${true}
+        .value=${webhookId || ""}
+        @input=${this._valueChanged}
+      >
+        <ha-icon-button
+          @click=${this._copyUrl}
+          slot="trailingIcon"
+          .label=${this.hass.localize(
+            "ui.panel.config.automation.editor.triggers.type.webhook.copy_url"
+          )}
+          .path=${mdiContentCopy}
+        ></ha-icon-button>
+      </ha-textfield>
     `;
   }
 
   private _valueChanged(ev: CustomEvent): void {
     handleChangeEvent(this, ev);
   }
+
+  private async _copyUrl(ev): Promise<void> {
+    const inputElement = ev.target.parentElement as HaTextField;
+    const url = this.hass.hassUrl(`/api/webhook/${inputElement.value}`);
+
+    await copyToClipboard(url);
+    showToast(this, {
+      message: this.hass.localize("ui.common.copied_clipboard"),
+    });
+  }
+
+  static styles = css`
+    ha-textfield {
+      display: block;
+    }
+
+    ha-textfield > ha-icon-button {
+      --mdc-icon-button-size: 24px;
+      --mdc-icon-size: 18px;
+    }
+  `;
 }
 
 declare global {

src/translations/en.json

@@ -1668,8 +1668,10 @@
                   "seconds": "Seconds"
                 },
                 "webhook": {
+                  "copy_url": "Copy URL to Clipboard",
                   "label": "Webhook",
-                  "webhook_id": "Webhook ID"
+                  "webhook_id": "Webhook ID",
+                  "webhook_id_helper": "Treat this ID like a password: keep it secret, and make it hard to guess."
                 },
                 "zone": {
                   "label": "Zone",