Access-Control-Allow-Origin fails when docker container sends "*" as Header Value

The play-with-docker containers will override the value with the container’s URL. If the project inside the container returns “*”, it will fail in Chrome and Firefox, because sending the header two times with different values is not allowed as per specification.

Example error in Chrome:

XMLHttpRequest cannot load http://pwd10_0_9_3-8080.play-with-docker.com:4848/api/project/index. The 'Access-Control-Allow-Origin' header contains multiple values 'http://pwd10_0_9_3-8080.play-with-docker.com, *', but only one is allowed. Origin 'http://pwd10_0_9_3-8080.play-with-docker.com' is therefore not allowed access.

The header is added by play-with-docker and not overwritten which means there will be two times the Access-Control-Allow-Origin header transmitted over the network. You can see that in Chrome via the Network Tab’s Header Inspector:

[marcosnils]

Was there a change in the NAT behaviour?

Yes, we forgot to add something, just re-applied it and I’m getting the same error as you. I’ll investigate and check what can be done. Thx for reportiing!.

[cookiengineer]

Awesome! Tested and verified, works like a charm!