Changing base must bust cache for OER

mkondel · Oct 27, 2017 · a50edb3 · a50edb3
1 parent 11ce3c5
commit a50edb3
Show file tree

Hide file tree

Showing 2 changed files with 24 additions and 1 deletion.
diff --git a/src/FXService/providers/OpenExchangeProvider.ts b/src/FXService/providers/OpenExchangeProvider.ts
@@ -32,6 +32,7 @@ export default class OpenExchangeProvider extends FXProvider {
     private pending: Promise<Response> = null;
     private cacheDuration: number;
     private cacheTimer: Timer = null;
+    private base: string = null;
 
     constructor(config: OpenExchangeConfig) {
         super(config);
@@ -71,10 +72,11 @@ export default class OpenExchangeProvider extends FXProvider {
             base: pair.from,
             app_id: this.apiKey
         };
-        if (this.pending === null) {
+        if (this.needsRequest(pair.from)) {
             this.pending = request.get(API_URL + '/latest.json')
                 .accept('application/json')
                 .query(query);
+            this.base = pair.from;
         }
         return this.pending.then((res: Response) => {
             const result = res.body;
@@ -96,6 +98,12 @@ export default class OpenExchangeProvider extends FXProvider {
             });
         });
     }
+
+    private needsRequest(from: string): boolean {
+        return (this.pending === null) ||
+            (this.base === null) ||
+            (this.base !== from);
+    }
 }
 
 function isSupported(pair: CurrencyPair): boolean {

diff --git a/test/FXService/OpenExchangeRateTest.ts b/test/FXService/OpenExchangeRateTest.ts
@@ -107,4 +107,19 @@ describe('OpenExchangeProvider', () => {
             assert.ok(err instanceof EFXRateUnavailable);
         });
     });
+
+    it('busts cache for base changes', () => {
+        nock('https://openexchangerates.org/api')
+            .get('/latest.json')
+            .query({ app_id: 'key', base: 'GBP' })
+            .reply(200, {
+                base: 'GBP',
+                rates: { USD: 1.25 }
+            });
+        return provider.fetchCurrentRate({ from: 'GBP', to: 'USD' }).then((result: FXObject) => {
+            assert.equal(result.rate.toNumber(), 1.25);
+            assert.equal(result.from, 'GBP');
+            assert.equal(result.to, 'USD');
+        });
+    });
 });