collectVars API in url replacements (#3178)

* collectVars API in url replacements * minor fixes
ampproject · May 10, 2016 · 2afa6d2 · 2afa6d2
1 parent bbc75d5
commit 2afa6d2
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diff --git a/src/service/url-replacements-impl.js b/src/service/url-replacements-impl.js
@@ -434,6 +434,17 @@ class UrlReplacements {
    * @return {!Promise<string>}
    */
   expand(url, opt_bindings) {
+    return this.expand_(url, opt_bindings);
+  }
+
+  /**
+   * @param {string} url
+   * @param {!Object<string, *>=} opt_bindings
+   * @param {!Object<string, *>=} opt_collectVars
+   * @return {!Promise<string>}
+   * @private
+   */
+  expand_(url, opt_bindings, opt_collectVars) {
     const expr = this.getExpr_(opt_bindings);
     let replacementPromise;
     const encodeValue = val => {
@@ -467,6 +478,9 @@ class UrlReplacements {
           rethrowAsync(err);
         }).then(v => {
           url = url.replace(match, encodeValue(v));
+          if (opt_collectVars) {
+            opt_collectVars[match] = v;
+          }
         });
         if (replacementPromise) {
           replacementPromise = replacementPromise.then(() => p);
@@ -475,6 +489,9 @@ class UrlReplacements {
         }
         return match;
       }
+      if (opt_collectVars) {
+        opt_collectVars[match] = val;
+      }
       return encodeValue(val);
     });
 
@@ -485,6 +502,19 @@ class UrlReplacements {
     return replacementPromise || Promise.resolve(url);
   }
 
+  /**
+   * Collects all substitutions in the provided URL and expands them to the
+   * values for known variables. Optional `opt_bindings` can be used to add
+   * new variables or override existing ones.
+   * @param {string} url
+   * @param {!Object<string, *>=} opt_bindings
+   * @return {!Promise<!Object<string, *>>}
+   */
+  collectVars(url, opt_bindings) {
+    const vars = Object.create(null);
+    return this.expand_(url, opt_bindings, vars).then(() => vars);
+  }
+
   /**
    * @param {string} name
    * @return {function(*):*}

diff --git a/test/functional/test-url-replacements.js b/test/functional/test-url-replacements.js
@@ -615,6 +615,26 @@ describe('UrlReplacements', () => {
       });
   });
 
+  it('should collect vars', () => {
+    const win = getFakeWindow();
+    win.location = parseUrl('https://example.com?p1=foo');
+    return installUrlReplacementsService(win)
+        .collectVars('?SOURCE_HOST&QUERY_PARAM(p1)&SIMPLE&FUNC&PROMISE', {
+          'SIMPLE': 21,
+          'FUNC': () => 22,
+          'PROMISE': () => Promise.resolve(23),
+        })
+        .then(res => {
+          expect(res).to.deep.equal({
+            'SOURCE_HOST': 'example.com',
+            'QUERY_PARAM(p1)': 'foo',
+            'SIMPLE': 21,
+            'FUNC': 22,
+            'PROMISE': 23,
+          });
+        });
+  });
+
   describe('access values', () => {
 
     let accessService;