I have custom HTML in WA calling a Google Web App via an GET request. It works. The Google App is doing a lot of WA API calls I don't want to expose in WA Client Code. This is my architecture to work around WA not being server side extensible.

But the Google App redirects to a temp page in the domain script.googleusercontent.com when it is done executing. This is unavoidable in the Google WebApp architecture. I am attempting to make that results page a redirect back to WA. However; this fails only due to the default cross site security.

The recommended workaround is to enable this specific cross site access with Meta tags in the client HTML header which would be WA. I cannot quite seem to find an example of doing this.

Is this possible in my custom WA HTML? Is there some sample code someone could point me to? Thanks.