(core) Adding /webhooks endpoint

Summary:
- New /webhooks event that lists all webhooks in a document (available for owners),
- Monitoring webhooks usage and saving it in memory or Redis,
- Loosening _usubscribe API endpoint, so that the information returned from the /webhook endpoint is enough to unsubscribe,
- Owners can remove webhook without the unsubscribe key.

The endpoint lists all webhooks that are registered in a document, not just webhooks from a single table.
There are two status fields. First for the webhook, second for the last request attempt.
Webhook can have 5 statuses: 'idle', 'sending', 'retrying', 'postponed', 'error', which roughly describes what the
sendLoop is currently doing. The 'error' status describes a situation when all request attempts failed and the queue needs
to be drained, so some requests were dropped.

The last request status can only be: 'success', 'failure' or 'rejected'. Rejected means that the last batch was dropped because the
queue was too long.

Test Plan: New and updated tests

Reviewers: paulfitz

Reviewed By: paulfitz

Differential Revision: https://phab.getgrist.com/D3727

app/server/lib/DocApi.ts

@@ -589,31 +589,32 @@ export class DocWorkerApi {
       withDoc(async (activeDoc, req, res) => {
         const metaTables = await getMetaTables(activeDoc, req);
         const tableRef = tableIdToRef(metaTables, req.params.tableId);
-        const {triggerId, unsubscribeKey, webhookId} = req.body;
+        const {unsubscribeKey, webhookId} = req.body as WebhookSubscription;
 
         // Validate combination of triggerId, webhookId, and tableRef.
         // This is overly strict, webhookId should be enough,
         // but it should be easy to relax that later if we want.
         const [, , triggerRowIds, triggerColData] = metaTables._grist_Triggers;
-        const triggerRowIndex = triggerRowIds.indexOf(triggerId);
+        const triggerRowIndex = triggerColData.actions.findIndex(a => {
+          const actions: any[] = JSON.parse((a || '[]') as string);
+          return actions.some(action => action.id === webhookId && action?.type === "webhook");
+        });
         if (triggerRowIndex === -1) {
-          throw new ApiError(`Trigger not found "${triggerId}"`, 404);
+          throw new ApiError(`Webhook not found "${webhookId || ''}"`, 404);
         }
         if (triggerColData.tableRef[triggerRowIndex] !== tableRef) {
           throw new ApiError(`Wrong table`, 400);
         }
-        const actions = JSON.parse(triggerColData.actions[triggerRowIndex] as string);
-        if (!_.find(actions, {type: "webhook", id: webhookId})) {
-          throw new ApiError(`Webhook not found "${webhookId}"`, 404);
-        }
+        const triggerRowId = triggerRowIds[triggerRowIndex];
 
+        const checkKey = !(await this._isOwner(req));
         // Validate unsubscribeKey before deleting trigger from document
-        await this._dbManager.removeWebhook(webhookId, activeDoc.docName, unsubscribeKey);
+        await this._dbManager.removeWebhook(webhookId, activeDoc.docName, unsubscribeKey, checkKey);
 
         // TODO handle trigger containing other actions when that becomes possible
         await handleSandboxError("_grist_Triggers", [], activeDoc.applyUserActions(
           docSessionFromRequest(req),
-          [['RemoveRecord', "_grist_Triggers", triggerId]]));
+          [['RemoveRecord', "_grist_Triggers", triggerRowId]]));
 
         res.json({success: true});
       })
@@ -627,6 +628,13 @@ export class DocWorkerApi {
       })
     );
 
+    // Lists all webhooks and their current status in the document.
+    this._app.get('/api/docs/:docId/webhooks', isOwner,
+      withDoc(async (activeDoc, req, res) => {
+        res.json(await activeDoc.webhooksSummary());
+      })
+    );
+
     // Reload a document forcibly (in fact this closes the doc, it will be automatically
     // reopened on use).
     this._app.post('/api/docs/:docId/force-reload', canEdit, throttled(async (req, res) => {
@@ -1429,3 +1437,8 @@ export function getDocApiUsageKeysToIncr(
   }
   // Usage exceeded all the time buckets, so return undefined to reject the request.
 }
+
+export interface WebhookSubscription {
+  unsubscribeKey: string;
+  webhookId: string;
+}