How does the HTTP params Hash work?

Rails
1

I am working on a Rails engine. When I go from a Main Application route
to
an Engine route, I think I lose a HTTP param, which I need for a db
query.

My questions are,
*
*
1) When and how is the HTTP params Hash modified?
*
*
2) Is it possible that switching between a application route and engine
route effects the params Hash?

2

Weston P. wrote in post #1073624:

I am working on a Rails engine. When I go from a Main Application route
to
an Engine route, I think I lose a HTTP param, which I need for a db
query.

My questions are,
*
*
1) When and how is the HTTP params Hash modified?

AFAIK that all happens here in the Rails/Rack middleware stack.

The middleware that parses the user’s data into the params hash is:
ActionDispatch::ParamsParser

At least as I understand it.

2) Is it possible that switching between a application route and engine
route effects the params Hash?

Sorry, I’ve not yet created a Rails engine so I don’t know the answer to
this part.