Connector for SAP Commerce Cloud Manual / Version 2010
Table Of ContentsWhen the commerce system has to deliver the end user's web pages, CoreMedia Content Cloud offers a way to enrich those web pages with content from the CoreMedia CMS; the fragment connector.
Integrating content from the CoreMedia system into the shop pages presents a challenge due to the same-origin policy:
The image above shows a typical situation when a user requests a shop page that includes CoreMedia fragments.
The page request from the end user is sent to the commerce server.
While rendering the page, the commerce server requests a fragment from the CAE.
The returned fragment contains itself parts that must be delivered dynamically. Take the login button. It is user specific, hence it must not be cached. The CoreMedia LiveContext Blueprint may include such parts via Ajax requests or as ESI tags, depending on the capabilities of the component which sent the request.
The commerce server returns the complete page, including the fragment that was rendered by the CAE.
Because it is assumed that the CoreMedia LiveContext fragment contains a dynamic part, which must not be cached, the browser tries to trigger an Ajax request to the CAE. But this breaks the same-origin policy and will not succeed.
Solution 1: Access-Control-Allow-Origin
The first solution is built into the CoreMedia Blueprint workspace, so you may use it out of the
box. The idea is to customize the same origin policy by setting the
Access-Control-Allow-Origin HTTP header accordingly. The allowed origins can be
configured via the property livecontext.crossdomain.whitelist.
livecontext.crossdomain.whitelist=http://my.shop.domain1,http://my.shop.domain2
If you do not want to override but to append allowed origins or to fine-tune the configuration for
Cross-Origin Resource Sharing (CORS) you can customize the bean
caeCorsConfiguration. The bean is of type
org.springframework.web.cors.CorsConfiguration and it is defined in the module
cae-handlerservices.
<customize:append id="customCaeCorsConfiguration" bean="caeCorsConfiguration" property="allowedOrigins" custom-value="customOrigins"/>
Solution 2: The Proxy
To solve this problem the classical way, the Ajax request needs to be sent to the same origin than the whole page request in step 1 was. The next image shows the solution to this problem: A reverse proxy needs to be put in front of both the CAE and the commerce server.
Actually, you may use any proxy you feel comfortable with. The following snippet shows the
configuration for a Varnish. Two back ends were defined, one for the CoreMedia LiveContext CAE
named blueprint and another one for the commerce server named
commerce.
The vcl_recv subroutine is called for every request that reaches the Varnish
instance. Inside of it the request object req is examined that represents the
current request. If its url property starts with /blueprint/, it will
be sent to the CoreMedia LiveContext CAE. Any other request will be sent to the commerce system.
(~ means "contains" and the argument is a regular expression)
Now, if you request a shop URL through Varnish and the resulting page contains a CoreMedia LiveContext fragment including a dynamic part that must not be cached, like the sign in button, the Ajax request will work as expected.
backend commerce {
.host = "ham-its0484-v";
.port = "80";
}
backend blueprint {
.host = "ham-its0484";
.port = "40081";
}
sub vcl_recv {
if (req.url ~ "^/blueprint/") {
set req.backend = blueprint;
} else {
set req.backend = commerce;
}
}