feat: implement Pluggable Abstraction Layer for Data Retrieval (PALDRA) - #19

- Create ArrRetriever abstract base class defining pluggable interface
- Implement PollingSonarrRetriever and PollingRadarrRetriever with HTTP polling
- Add ArrRetrieverRegistry for managing retriever instances
- Refactor poller.js to use retriever registry instead of direct Axios calls
- Update historyFetcher.js to use retriever registry
- Preserve all cache keys, TTLs, timing logs, SSE broadcasts, error handling
- Enable future webhook listeners without touching poller logic

server/utils/poller.js

@@ -2,6 +2,7 @@
 const axios = require('axios');
 const cache = require('./cache');
 const { initializeClients, getAllDownloads, getDownloadsByClientType } = require('./downloadClients');
+const { initializeRetrievers, getTagsByType, getQueuesByType, getHistoryByType } = require('./arrRetrievers');
 const {
   getSonarrInstances,
   getRadarrInstances
@@ -38,8 +39,9 @@ async function pollAllServices() {
   const start = Date.now();
 
   try {
-    // Ensure download clients are initialized
+    // Ensure download clients and *arr retrievers are initialized
     await initializeClients();
+    await initializeRetrievers();
 
     const sonarrInstances = getSonarrInstances();
     const radarrInstances = getRadarrInstances();
@@ -50,58 +52,30 @@ async function pollAllServices() {
         const downloadsByType = await getDownloadsByClientType();
         return downloadsByType;
       }),
-      timed('Sonarr Tags', () => Promise.all(sonarrInstances.map(inst =>
-        axios.get(`${inst.url}/api/v3/tag`, {
-          headers: { 'X-Api-Key': inst.apiKey }
-        }).then(res => ({ instance: inst.id, data: res.data })).catch(err => {
-          console.error(`[Poller] Sonarr ${inst.id} tags error:`, err.message);
-          return { instance: inst.id, data: [] };
-        })
-      ))),
-      timed('Sonarr Queue', () => Promise.all(sonarrInstances.map(inst =>
-        axios.get(`${inst.url}/api/v3/queue`, {
-          headers: { 'X-Api-Key': inst.apiKey },
-          params: { includeSeries: true, includeEpisode: true }
-        }).then(res => ({ instance: inst.id, data: res.data })).catch(err => {
-          console.error(`[Poller] Sonarr ${inst.id} queue error:`, err.message);
-          return { instance: inst.id, data: { records: [] } };
-        })
-      ))),
-      timed('Sonarr History', () => Promise.all(sonarrInstances.map(inst =>
-        axios.get(`${inst.url}/api/v3/history`, {
-          headers: { 'X-Api-Key': inst.apiKey },
-          params: { pageSize: 10, includeEpisode: true }
-        }).then(res => ({ instance: inst.id, data: res.data })).catch(err => {
-          console.error(`[Poller] Sonarr ${inst.id} history error:`, err.message);
-          return { instance: inst.id, data: { records: [] } };
-        })
-      ))),
-      timed('Radarr Queue', () => Promise.all(radarrInstances.map(inst =>
-        axios.get(`${inst.url}/api/v3/queue`, {
-          headers: { 'X-Api-Key': inst.apiKey },
-          params: { includeMovie: true }
-        }).then(res => ({ instance: inst.id, data: res.data })).catch(err => {
-          console.error(`[Poller] Radarr ${inst.id} queue error:`, err.message);
-          return { instance: inst.id, data: { records: [] } };
-        })
-      ))),
-      timed('Radarr History', () => Promise.all(radarrInstances.map(inst =>
-        axios.get(`${inst.url}/api/v3/history`, {
-          headers: { 'X-Api-Key': inst.apiKey },
-          params: { pageSize: 10 }
-        }).then(res => ({ instance: inst.id, data: res.data })).catch(err => {
-          console.error(`[Poller] Radarr ${inst.id} history error:`, err.message);
-          return { instance: inst.id, data: { records: [] } };
-        })
-      ))),
-      timed('Radarr Tags', () => Promise.all(radarrInstances.map(inst =>
-        axios.get(`${inst.url}/api/v3/tag`, {
-          headers: { 'X-Api-Key': inst.apiKey }
-        }).then(res => ({ instance: inst.id, data: res.data })).catch(err => {
-          console.error(`[Poller] Radarr ${inst.id} tags error:`, err.message);
-          return { instance: inst.id, data: [] };
-        })
-      ))),
+      timed('Sonarr Tags', async () => {
+        const tagsByType = await getTagsByType();
+        return tagsByType.sonarr || [];
+      }),
+      timed('Sonarr Queue', async () => {
+        const queuesByType = await getQueuesByType();
+        return queuesByType.sonarr || [];
+      }),
+      timed('Sonarr History', async () => {
+        const historyByType = await getHistoryByType({ pageSize: 10 });
+        return historyByType.sonarr || [];
+      }),
+      timed('Radarr Queue', async () => {
+        const queuesByType = await getQueuesByType();
+        return queuesByType.radarr || [];
+      }),
+      timed('Radarr History', async () => {
+        const historyByType = await getHistoryByType({ pageSize: 10 });
+        return historyByType.radarr || [];
+      }),
+      timed('Radarr Tags', async () => {
+        const tagsByType = await getTagsByType();
+        return tagsByType.radarr || [];
+      }),
     ]);
 
     const [