client metadata caching

packages/api/src/controllers/connections.js

@@ -39,14 +39,14 @@ module.exports = {
     } else {
       res = await this.datastore.insert(connection);
     }
-    socket.emit('connection-list-changed');
+    socket.emitChanged('connection-list-changed');
     return res;
   },
 
   delete_meta: 'post',
   async delete(connection) {
     const res = await this.datastore.remove(_.pick(connection, '_id'));
-    socket.emit('connection-list-changed');
+    socket.emitChanged('connection-list-changed');
     return res;
   },
 

packages/api/src/controllers/databaseConnections.js

@@ -13,7 +13,7 @@ module.exports = {
     const existing = this.opened.find((x) => x.conid == conid && x.database == database);
     if (!existing) return;
     existing.structure = structure;
-    socket.emit(`database-structure-changed-${conid}-${database}`);
+    socket.emitChanged(`database-structure-changed-${conid}-${database}`);
   },
   handle_error(conid, database, props) {
     const { error } = props;

packages/api/src/controllers/serverConnections.js

@@ -9,7 +9,7 @@ module.exports = {
     const existing = this.opened.find(x => x.conid == conid);
     if (!existing) return;
     existing.databases = databases;
-    socket.emit(`database-list-changed-${conid}`);
+    socket.emitChanged(`database-list-changed-${conid}`);
   },
   handle_error(conid, { error }) {
     console.log(`Error in server connection ${conid}: ${error}`);

packages/api/src/utility/socket.js

@@ -11,4 +11,9 @@ module.exports = {
     console.log('EMIT:', message, data);
     socket.emit(message, data);
   },
+  emitChanged(key) {
+    console.log('EMIT_CHANGED:', key);
+    socket.emit(key);
+    socket.emit('clean-cache', key);
+  }
 };

packages/web/src/utility/SocketProvider.js

@@ -1,6 +1,7 @@
 import io from 'socket.io-client';
 import React from 'react';
 import resolveApi from './resolveApi';
+import { cacheClean } from './cache';
 
 const SocketContext = React.createContext(null);
 
@@ -10,6 +11,7 @@ export function SocketProvider({ children }) {
     // const newSocket = io('http://localhost:3000', { transports: ['websocket'] });
     const newSocket = io(resolveApi());
     setSocket(newSocket);
+    newSocket.on('clean-cache', (reloadTrigger) => cacheClean(reloadTrigger));
   }, []);
   return <SocketContext.Provider value={socket}>{children}</SocketContext.Provider>;
 }

packages/web/src/utility/cache.js

@@ -0,0 +1,33 @@
+let cachedByKey = {};
+let cachedPromisesByKey = {};
+const cachedKeysByReloadTrigger = {};
+
+export function cacheGet(key) {
+  return cachedByKey[key];
+}
+
+export function cacheSet(key, value, reloadTrigger) {
+  cachedByKey[key] = value;
+  if (!(reloadTrigger in cachedKeysByReloadTrigger)) {
+    cachedKeysByReloadTrigger[reloadTrigger] = [];
+  }
+  cachedKeysByReloadTrigger[reloadTrigger].push(key);
+}
+
+export function cacheClean(reloadTrigger) {
+  const keys = cachedKeysByReloadTrigger[reloadTrigger];
+  if (keys) {
+    for (const key of keys) {
+      delete cachedByKey[key];
+      delete cachedPromisesByKey[key];
+    }
+  }
+  delete cachedKeysByReloadTrigger[reloadTrigger];
+}
+
+export function getCachedPromise(key, func) {
+  if (key in cachedPromisesByKey) return cachedPromisesByKey[key];
+  const promise = func();
+  cachedPromisesByKey[key] = promise;
+  return promise;
+}

packages/web/src/utility/metadataLoaders.js

@@ -1,5 +1,7 @@
 import useFetch from './useFetch';
 import axios from './axios';
+import { cacheGet, cacheSet, getCachedPromise } from './cache';
+import stableStringify from 'json-stable-stringify';
 
 const tableInfoLoader = ({ conid, database, schemaName, pureName }) => ({
   url: 'metadata/table-info',
@@ -9,21 +11,34 @@ const tableInfoLoader = ({ conid, database, schemaName, pureName }) => ({
 
 async function getCore(loader, args) {
   const { url, params, reloadTrigger } = loader(args);
-  const resp = await axios.request({
+  const key = stableStringify({ url, ...params });
-    method: 'get',
+
-    url,
+  async function doLoad() {
-    params,
+    const resp = await axios.request({
-  });
+      method: 'get',
-  return resp.data;
+      url,
+      params,
+    });
+    return resp.data;
+  }
+
+  const fromCache = cacheGet(key);
+  if (fromCache) return fromCache;
+  const res = getCachedPromise(key, doLoad);
+
+  cacheSet(key, res, reloadTrigger);
+  return res;
 }
 
 function useCore(loader, args) {
   const { url, params, reloadTrigger } = loader(args);
+  const cacheKey = stableStringify({ url, ...params });
 
   const res = useFetch({
     url,
     params,
     reloadTrigger,
+    cacheKey,
   });
 
   return res;

packages/web/src/utility/useFetch.js

@@ -3,6 +3,7 @@ import _ from 'lodash';
 import axios from './axios';
 import useSocket from './SocketProvider';
 import stableStringify from 'json-stable-stringify';
+import { getCachedPromise, cacheGet, cacheSet } from './cache';
 
 export default function useFetch({
   url,
@@ -10,6 +11,7 @@ export default function useFetch({
   params = undefined,
   defaultValue = undefined,
   reloadTrigger = undefined,
+  cacheKey = undefined,
   ...config
 }) {
   const [value, setValue] = React.useState([defaultValue, []]);
@@ -23,14 +25,27 @@ export default function useFetch({
   const indicators = [url, stableStringify(data), stableStringify(params), loadCounter];
 
   async function loadValue(loadedIndicators) {
-    const resp = await axios.request({
+    async function doLoad() {
-      method: 'get',
+      const resp = await axios.request({
-      params,
+        method: 'get',
-      url,
+        params,
-      data,
+        url,
-      ...config,
+        data,
-    });
+        ...config,
-    setValue([resp.data, loadedIndicators]);
+      });
+      return resp.data;
+    }
+
+    if (cacheKey) {
+      const fromCache = cacheGet(cacheKey);
+      if (fromCache) return fromCache;
+      const res = await getCachedPromise(cacheKey, doLoad);
+      setValue([res, loadedIndicators]);
+      cacheSet(cacheKey, res, reloadTrigger);
+    } else {
+      const res = await doLoad();
+      setValue([res, loadedIndicators]);
+    }
   }
 
   // React.useEffect(() => {