pl-fe: Allow checking whether remote instances support emoji reactions when reacting

Signed-off-by: Nicole Mikołajczyk <git@mkljczk.pl>

packages/pl-fe/src/utils/check-instance-capability.ts

@@ -0,0 +1,83 @@
+import KVStore from 'pl-fe/storage/kv-store';
+
+type DomainCapabilities = {
+  lastChecked: number;
+} & ({
+  failed: true;
+} | {
+  failed: false;
+  emojiReacts: boolean;
+});
+
+interface Capabilities {
+  _version: number;
+  domains: Record<string, DomainCapabilities>;
+}
+
+let capabilities: Capabilities = {
+  _version: 1,
+  domains: {},
+};
+
+const getCapabilitiesFromMemory = () =>
+  KVStore.getItem<Capabilities>('instanceCapabilities').then((capabilitiesFromMemory) => {
+    if (capabilitiesFromMemory) {
+      capabilities = capabilitiesFromMemory;
+    }
+  }).catch(() => { });
+
+const checkEmojiReactsSupport = (instance: Record<string, any>) => instance.configuration?.reactions?.max_reactions > 0 || instance.pleroma?.metadata?.features?.includes('pleroma_emoji_reactions');
+
+const setDomainCapabilities = async (domain: string, domainCapabilities: DomainCapabilities) => {
+  await getCapabilitiesFromMemory();
+  capabilities.domains[domain] = domainCapabilities;
+  await KVStore.setItem('instanceCapabilities', capabilities);
+};
+
+const fetchCapabilities = async (domain: string): Promise<DomainCapabilities> => {
+  try {
+    const response = await fetch(`https://${domain}/api/v1/instance`, {
+      headers: {
+        'Content-Type': 'application/json',
+      },
+    }).then((res) => res.json());
+
+    const emojiReacts = checkEmojiReactsSupport(response);
+
+    const domainCapabilities: DomainCapabilities = {
+      lastChecked: Date.now(),
+      failed: false,
+      emojiReacts,
+    };
+    await setDomainCapabilities(domain, domainCapabilities);
+    return domainCapabilities;
+  } catch (e) {
+    const domainCapabilities: DomainCapabilities = {
+      lastChecked: Date.now(),
+      failed: true,
+    };
+    await setDomainCapabilities(domain, domainCapabilities);
+    return domainCapabilities;
+  }
+};
+
+const supportsEmojiReacts = async (accountUrl: string): Promise<'true' | 'false' | 'unknown'> => {
+  const domain = new URL(accountUrl).hostname;
+  let domainCapabilities = capabilities.domains[domain];
+
+  if (!domainCapabilities || domainCapabilities.lastChecked > Date.now() - 1000 * 60 * 60 * 24 * (domainCapabilities.failed ? 1 : 7)) {
+    domainCapabilities = await fetchCapabilities(domain);
+  }
+
+  if (domainCapabilities.failed) {
+    return 'unknown';
+  }
+  if (domainCapabilities.emojiReacts) {
+    return 'true';
+  }
+  return 'false';
+};
+
+getCapabilitiesFromMemory();
+
+export { supportsEmojiReacts };