REST API: Put Redis cache in front of CouchDB.

Use master version of Node Redis client for now, because TLS support is
not yet officially released:

redis/node-redis#1268
redis/node-redis#1282

api/package.json

@@ -13,13 +13,17 @@
   },
   "dependencies": {
     "express": "^4.16.3",
+    "express-redis-cache": "^1.1.3",
     "lodash": "^4.17.10",
+    "redis": "https://github.com/NodeRedis/node_redis",
     "request": "^2.87.0",
     "request-promise-native": "^1.0.5"
   },
   "devDependencies": {
     "@types/express": "^4.16.0",
+    "@types/express-redis-cache": "^1.1.0",
     "@types/lodash": "^4.14.115",
+    "@types/redis": "^2.8.6",
     "@types/request": "^2.47.1",
     "@types/request-promise-native": "^1.0.15",
     "typescript": "^3.0.1"

api/src/config.ts

@@ -9,3 +9,6 @@ export const dbUrl = `${couchUrl}/${dbName}`;
 
 export const appDbName = 'data-science-ontology-webapp';
 export const appDbUrl = `${couchUrl}/${appDbName}`;
+
+// Redis
+export const redisUrl = process.env.REDIS_URL || "redis://localhost:6379";

api/src/main.ts

@@ -1,18 +1,20 @@
-import express from "express";
+import Express from "express";
+import ExpressRedisCache from "express-redis-cache";
+import Redis from "redis";
 
 import * as Config from "./config";
 import * as Methods from "./methods";
 
 // Helper functions.
 
-const sendJSON = (res: express.Response, data: object | string) => {
+const sendJSON = (res: Express.Response, data: object | string) => {
   if (typeof data === 'object')
     data = JSON.stringify(data);
   res.set('Content-Type', 'application/json');
   res.send(data);
 }
 
-const handleGetError = (res: express.Response, next: express.NextFunction, error: any) => {
+const handleGetError = (res: Express.Response, next: Express.NextFunction, error: any) => {
   if (error.statusCode == 404) {
     res.status(404);
     sendJSON(res, { error: 'not_found' });
@@ -21,9 +23,21 @@ const handleGetError = (res: express.Response, next: express.NextFunction, error
   }
 }
 
-// Create and set up Express.js app.
+// Create Express.js app.
 
-const app = express();
+const app = Express();
+
+// Set up Redis caching on all routes.
+
+const redis = Redis.createClient(Config.redisUrl);
+const cache = ExpressRedisCache({
+  client: redis,
+  prefix: 'dso',
+  expire: 60*60*24, // Cache entries expire after one day.
+})
+app.use(cache.route());
+
+// Define routes for REST API.
 
 app.get('/', (req, res) => res.send('Data Science Ontology API'));
 

api/yarn.lock

@@ -23,6 +23,14 @@
   version "1.2.0"
   resolved "https://registry.yarnpkg.com/@types/events/-/events-1.2.0.tgz#81a6731ce4df43619e5c8c945383b3e62a89ea86"
 
+"@types/express-redis-cache@^1.1.0":
+  version "1.1.0"
+  resolved "https://registry.yarnpkg.com/@types/express-redis-cache/-/express-redis-cache-1.1.0.tgz#b0b0742c56c1de2672ad6873e8074a6c930afe0d"
+  dependencies:
+    "@types/events" "*"
+    "@types/express" "*"
+    "@types/redis" "*"
+
 "@types/express-serve-static-core@*":
   version "4.16.0"
   resolved "https://registry.yarnpkg.com/@types/express-serve-static-core/-/express-serve-static-core-4.16.0.tgz#fdfe777594ddc1fe8eb8eccce52e261b496e43e7"
@@ -31,7 +39,7 @@
     "@types/node" "*"
     "@types/range-parser" "*"
 
-"@types/express@^4.16.0":
+"@types/express@*", "@types/express@^4.16.0":
   version "4.16.0"
   resolved "https://registry.yarnpkg.com/@types/express/-/express-4.16.0.tgz#6d8bc42ccaa6f35cf29a2b7c3333cb47b5a32a19"
   dependencies:
@@ -61,6 +69,13 @@
   version "1.2.2"
   resolved "https://registry.yarnpkg.com/@types/range-parser/-/range-parser-1.2.2.tgz#fa8e1ad1d474688a757140c91de6dace6f4abc8d"
 
+"@types/redis@*", "@types/redis@^2.8.6":
+  version "2.8.6"
+  resolved "https://registry.yarnpkg.com/@types/redis/-/redis-2.8.6.tgz#3674d07a13ad76bccda4c37dc3909e4e95757e7e"
+  dependencies:
+    "@types/events" "*"
+    "@types/node" "*"
+
 "@types/request-promise-native@^1.0.15":
   version "1.0.15"
   resolved "https://registry.yarnpkg.com/@types/request-promise-native/-/request-promise-native-1.0.15.tgz#5b3369fc6aaf9e7fef7b6b688aef4c5759623e16"
@@ -117,6 +132,12 @@ assert-plus@1.0.0, assert-plus@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/assert-plus/-/assert-plus-1.0.0.tgz#f12e0f3c5d77b0b1cdd9146942e4e96c1e4dd525"
 
+async@^2.6.1:
+  version "2.6.1"
+  resolved "https://registry.yarnpkg.com/async/-/async-2.6.1.tgz#b245a23ca71930044ec53fa46aa00a3e87c6a610"
+  dependencies:
+    lodash "^4.17.10"
+
 asynckit@^0.4.0:
   version "0.4.0"
   resolved "https://registry.yarnpkg.com/asynckit/-/asynckit-0.4.0.tgz#c79ed97f7f34cb8f2ba1bc9790bcc366474b4b79"
@@ -162,6 +183,10 @@ co@^4.6.0:
   version "4.6.0"
   resolved "https://registry.yarnpkg.com/co/-/co-4.6.0.tgz#6ea6bdf3d853ae54ccb8e47bfa0bf3f9031fb184"
 
+colors@^1.3.0:
+  version "1.3.1"
+  resolved "https://registry.yarnpkg.com/colors/-/colors-1.3.1.tgz#4accdb89cf2cabc7f982771925e9468784f32f3d"
+
 combined-stream@1.0.6, combined-stream@~1.0.5:
   version "1.0.6"
   resolved "https://registry.yarnpkg.com/combined-stream/-/combined-stream-1.0.6.tgz#723e7df6e801ac5613113a7e445a9b69cb632818"
@@ -204,6 +229,10 @@ delayed-stream@~1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/delayed-stream/-/delayed-stream-1.0.0.tgz#df3ae199acadfb7d440aaae0b29e2272b24ec619"
 
+denque@^1.2.3:
+  version "1.3.0"
+  resolved "https://registry.yarnpkg.com/denque/-/denque-1.3.0.tgz#681092ef44a630246d3f6edb2a199230eae8e76b"
+
 depd@1.1.1:
   version "1.1.1"
   resolved "https://registry.yarnpkg.com/depd/-/depd-1.1.1.tgz#5783b4e1c459f06fa5ca27f991f3d06e7a310359"
@@ -239,6 +268,14 @@ etag@~1.8.1:
   version "1.8.1"
   resolved "https://registry.yarnpkg.com/etag/-/etag-1.8.1.tgz#41ae2eeb65efa62268aebfea83ac7d79299b0887"
 
+express-redis-cache@^1.1.3:
+  version "1.1.3"
+  resolved "https://registry.yarnpkg.com/express-redis-cache/-/express-redis-cache-1.1.3.tgz#93eb6b09df1ff74a14a7f6caccb5d0d975010c62"
+  dependencies:
+    async "^2.6.1"
+    colors "^1.3.0"
+    redis "^2.4.2"
+
 express@^4.16.3:
   version "4.16.3"
   resolved "https://registry.yarnpkg.com/express/-/express-4.16.3.tgz#6af8a502350db3246ecc4becf6b5a34d22f7ed53"
@@ -510,6 +547,22 @@ raw-body@2.3.2:
     iconv-lite "0.4.19"
     unpipe "1.0.0"
 
+redis-commands@^1.2.0:
+  version "1.3.5"
+  resolved "https://registry.yarnpkg.com/redis-commands/-/redis-commands-1.3.5.tgz#4495889414f1e886261180b1442e7295602d83a2"
+
+redis-parser@^2.6.0:
+  version "2.6.0"
+  resolved "https://registry.yarnpkg.com/redis-parser/-/redis-parser-2.6.0.tgz#52ed09dacac108f1a631c07e9b69941e7a19504b"
+
+redis@^2.4.2, "redis@https://github.com/NodeRedis/node_redis":
+  version "2.8.0"
+  resolved "https://github.com/NodeRedis/node_redis#27bb93ac19157bdc7b7958bef012e4b266d156ae"
+  dependencies:
+    denque "^1.2.3"
+    redis-commands "^1.2.0"
+    redis-parser "^2.6.0"
+
 request-promise-core@1.1.1:
   version "1.1.1"
   resolved "https://registry.yarnpkg.com/request-promise-core/-/request-promise-core-1.1.1.tgz#3eee00b2c5aa83239cfb04c5700da36f81cd08b6"