I created an app in Java in Eclipse on Google App Engine. For about a year now, I've had that app embedded in a google site iframe as a gadget. I added it using the "add gadget by URL" option and put in the URL of the app: https://mycompany-helpdesk.appspot.com (where mycompany is my company's actual name).
This has been working flawlessly for about a year. Recently I made a small change to the Java code, and it seemed like about a week after that change, the app will not display in Google sites anymore.
The app works just fine if I navigate straight to its URL https://mycompany-helpdesk.appspot.com.
I removed the gadget iframe on my google site and then tried to add it back, but the error I'm getting now is:
The gadget you added is not valid
Unsupported feature: org.apache.shindig.common.xml.XmlException: The markup in the document preceding the root element must be well-formed. At: (1,3)
I have a couple of these apps and I tried using the other one, but I get the same error. I've tried to add them on other google sites and even created a fresh one and still get the same error. I've spent days googling this but I don't think I've found anything that applies to my situation.
Did something change where suddenly it is not possible to do this anymore? If I can't embed the app this way any more, does anyone know of another way that I might be able to do this?
UPDATE: When I am editing the site, under Insert > More gadgets, if, instead of using the "Add Gadget by URL" link (which is what I've been using to insert this gadget) I use the "Include gadget (iframe)" gadget developed by Scott Johnston, then my apps will appear in Firefox and Safari, but not Chrome. This is not useful to me as our employees primarily use Chrome.
I think I'm just going to abandon Google Sites and redo the page in GAE. Hope this helps someone else who has been banging their head against their desk as I have been.
Update: I noticed that suddenly all the embedded apps on my test pages were working, so I reverted to an old version of the google site where the app was still embedded. Voila, it works again. Now if I can just figure out how to add in another embedded app I'll be good to go. It had been working in Safari and Firefox but that doesn't seem to be working now...