✨ [amp-ad smartadserver] Add schain attribute (#37522)

* Update documentation

* Support schain parameter

* Fixing unit tests

* Fix formatting errors in documentation

extensions/amp-ad-network-smartadserver-impl/0.1/amp-ad-network-smartadserver-impl.js

@@ -80,6 +80,11 @@ export class AmpAdNetworkSmartadserverImpl extends AmpA4A {
           urlParams['hb_height'] = this.element.getAttribute('height');
         }
 
+        const schain = this.element.getAttribute('data-schain');
+        if (schain) {
+          urlParams['schain'] = schain;
+        }
+
         const formatId = this.element.getAttribute('data-format');
         const tagId = 'sas_' + formatId;
         return buildUrl(

extensions/amp-ad-network-smartadserver-impl/0.1/test/test-amp-ad-network-smartadserver-impl.js

@@ -295,6 +295,42 @@ describes.realWin('amp-ad-network-smartadserver-impl', realWinConfig, (env) => {
           );
         });
     });
+
+    it('should return proper url with schain value', async () => {
+      element = createElementWithAttributes(doc, 'amp-ad', {
+        'data-site': '1',
+        'data-format': '22',
+        'data-schain': 'some-sco-string',
+      });
+      doc.body.appendChild(element);
+      const viewer = Services.viewerForDoc(element);
+      env.sandbox.stub(viewer, 'getReferrerUrl');
+      return new AmpAdNetworkSmartadserverImpl(element)
+        .getAdUrl({}, null)
+        .then((url) => {
+          expect(url).to.match(
+            /^https:\/\/www\.smartadserver\.com\/ac\?siteid=1&fmtid=22&tag=sas_22&out=amp-hb&schain=some-sco-string&pgDomain=[a-zA-Z0-9.%]+&tmstp=[0-9]+$/
+          );
+        });
+    });
+
+    it('should not return chain parameter in url if empty value', async () => {
+      element = createElementWithAttributes(doc, 'amp-ad', {
+        'data-site': 10,
+        'data-format': '3',
+        'data-schain': '',
+      });
+      doc.body.appendChild(element);
+      const viewer = Services.viewerForDoc(element);
+      env.sandbox.stub(viewer, 'getReferrerUrl');
+      return new AmpAdNetworkSmartadserverImpl(element)
+        .getAdUrl({}, null)
+        .then((url) => {
+          expect(url).to.match(
+            /^https:\/\/www\.smartadserver\.com\/ac\?siteid=10&fmtid=3&tag=sas_3&out=amp-hb&pgDomain=[a-zA-Z0-9.%]+&tmstp=[0-9]+$/
+          );
+        });
+    });
   });
 
   describe('getNonAmpCreativeRenderingMethod', () => {

extensions/amp-ad-network-smartadserver-impl/amp-ad-network-smartadserver-impl-internal.md

@@ -19,10 +19,10 @@ limitations under the License.
 <table>
   <tr>
     <td class="col-fourty"><strong>Description</strong></td>
-    <td>The Smartadserver fast fetch implementation for serving AMP ads, using `<amp-ad>`.</td>
+    <td>The Smartadserver fast fetch implementation for serving AMP ads using <code>&lt;amp-ad&gt;</code></td>
   </tr>
   <tr>
-    <td class="col-fourty" width="40%"><strong>Availability</strong></td>
+    <td class="col-fourty" width="25%"><strong>Availability</strong></td>
     <td>Launched</td>
   </tr>
   <tr>
@@ -31,11 +31,11 @@ limitations under the License.
   </tr>
 </table>
 
-## Behavior
+# Behavior
 
 Smartadserver supports the Real Time Config (RTC) to preload configuration settings for ad placements. The RTC setup is optional.
 
-## Supported parameters
+# Supported parameters
 
 Smartadserver largely uses the same tags as `<amp-ad>`. The following are required tags for special behaviors of existing ones:
 
@@ -47,9 +47,10 @@ Smartadserver largely uses the same tags as `<amp-ad>`. The following are requir
 These attributes are optional:
 
 -   `data-target`: Targeting string
+-   `data-schain`: SupplyChain Object string
 -   `rtc-config`: Please refer to [RTC Documentation](https://github.com/ampproject/amphtml/blob/main/extensions/amp-a4a/rtc-documentation.md) for details
 
-### Example configuration
+## Example configuration
 
 ```html
 <amp-ad width="300" height="250" type="smartadserver"