Append a value (Cookie Header)

[swiffer]

It would be great to be able to append a value within a header (Cookie / XDEBUG_SESSION) instead of replacing the header value.

https://xdebug.org/docs/step_debug#cookie-init

[rickardandersson]

Apologies for not responding until now. I must have forgotten to update my notification settings for this repo.

I'm afraid declarativeNetRequest that Rubric uses to add rules does not support appending to an existing header value. It does support the append operation, but I'm not entirely sure what that does. I believe it just adds a second header. There's also an allowlist of a particular set of headers where the append operation is allowed, so it'll be tricky to do the UI for this.

Here's the list of request headers that Chrome supports appending to:

{"accept", ", "}, {"accept-encoding", ", "}, {"accept-language", ", "}, {"access-control-request-headers", ", "}, {"cache-control", ", "}, {"connection", ", "}, {"content-language", ", "}, {"cookie", "; "}, {"forwarded", ", "}, {"if-match", ", "}, {"if-none-match", ", "}, {"keep-alive", ", "}, {"range", ", "}, {"te", ", "}, {"trailer", ""}, {"transfer-encoding", ", "}, {"upgrade", ", "}, {"user-agent", " "}, {"via", ", "}, {"want-digest", ", "}, {"x-forwarded-for", ", "}