ConfigOverlays.md

Connection setting overlays

There may be cases where you want to use a different set of connection settings depending on context, or simply change the connection settings over time. For example, if you want to use username and password provided by the user in a web application, or if you're connecting using an expiring Claris ID token. Since .fmrest_config is set at the class level, changing the username/password for the model in one context would also change it in all other contexts, leading to security issues.

fmrest-ruby solves this scenario with the following methods:

FmRest::Layout.fmrest_config_overlay=

.fmrest_config_overlay= allows you to override some settings in a thread-local and reversible manner. That way, using the same scenario as above, you could connect to the Data API with user-provided credentials without having them leak into other users of your web app.

E.g.:

class BeeBase < FmRest::Layout
  # Host and database provided as base settings
  self.fmrest_config = {
    host:     "example.com",
    database: "My Database"
  }
end

# Example context: a controller action of a Rails application

# User-provided credentials
BeeBase.fmrest_config_overlay = {
  username: params[:username],
  password: params[:password]
}

# Perform some Data API requests ...

FmRest::Layout.clear_fmrest_config_overlay

Clears the thread-local settings provided to .fmrest_config_overaly=.

FmRest::Layout.with_overlay

Runs a block with the given settings overlay, resetting them after the block finishes running. It wraps execution in its own fiber, so it doesn't affect the overlay of the currently-running thread.

Honeybee.with_overlay(username: "...", password: "...") do
  Honeybee.query(...)
end