Set Origin header to the request Origin

I want to allow every Origin to use my API, but it seems I can’t do it with the * sign, cause I need to authorize on it, which ends up telling me the following: A wildcard '*' cannot be used in the 'Access-Control-Allow-Origin' header when the credentials flag is true.

So how do I dynamically just send the origin to the request origin?

[szpasztor]

It doesn’t seem to accept the lambda as of version 1.0.0. This is what worked for me:

origins do |source, env|
    true
end

This proc evaluates the given source, always accepting it, and returning the request origin.

[cyu]

Origin can be a proc, so something like this should work:

allow do
  origins ->(origin, env) { origin }
end