initial commit to fix issue prebid#2291 (prebid#2308)

Author: jsnellbaker

modules/dfpAdServerVideo.js

@@ -70,7 +70,7 @@ export default function buildDfpVideoUrl(options) {
   if (options.url) {
     // when both `url` and `params` are given, parsed url will be overwriten
     // with any matching param components
-    urlComponents = parse(options.url);
+    urlComponents = parse(options.url, {noDecodeWholeURL: true});
 
     if (isEmpty(options.params)) {
       return buildUrlFromAdserverUrlComponents(urlComponents, bid);
@@ -126,7 +126,8 @@ function buildUrlFromAdserverUrlComponents(components, bid) {
   const customParams = Object.assign({},
     adserverTargeting,
   );
-  components.search.cust_params = encodeURIComponent(formatQS(customParams));
+  const encodedCustomParams = encodeURIComponent(formatQS(customParams));
+  components.search.cust_params = (components.search.cust_params) ? components.search.cust_params + '%26' + encodedCustomParams : encodedCustomParams;
 
   return buildUrl(components);
 }

test/spec/modules/dfpAdServerVideo_spec.js

@@ -130,6 +130,26 @@ describe('The DFP video support module', () => {
     expect(customParams).to.have.property('my_targeting', 'foo');
   });
 
+  it('should merge the user-provided cust-params with the default ones when using url object', () => {
+    const bidCopy = Object.assign({ }, bid);
+    bidCopy.adserverTargeting = {
+      hb_adid: 'ad_id',
+    };
+
+    const url = parse(buildDfpVideoUrl({
+      adUnit: adUnit,
+      bid: bidCopy,
+      url: 'https://video.adserver.example/ads?sz=640x480&iu=/123/aduniturl&impl=s&cust_params=section%3dblog%26mykey%3dmyvalue'
+    }));
+
+    const queryObject = parseQS(url.query);
+    const customParams = parseQS('?' + decodeURIComponent(queryObject.cust_params));
+
+    expect(customParams).to.have.property('hb_adid', 'ad_id');
+    expect(customParams).to.have.property('section', 'blog');
+    expect(customParams).to.have.property('mykey', 'myvalue');
+  });
+
   it('should not overwrite an existing description_url for object input and cache disabled', () => {
     const bidCopy = Object.assign({}, bid);
     bidCopy.vastUrl = 'vastUrl.example';