Rails engines and path helpers

When extending Avo or writing code that runs inside the Avo engine (e.g. custom tools, breadcrumbs, or controller overrides), you need to be aware of how Rails treats engines and their routes.

The rule

Rails engines have isolated routes. When your code runs inside an engine, path helpers are resolved in that engine's context by default. To reference routes from another engine or the main application, you must use the appropriate routing proxy.

Inside the Avo engine

When your code executes within Avo—for example in Avo::ToolsController, Avo::ResourcesController, or when configuring breadcrumbs in avo.rb—you're inside the Avo engine.

Linking to Avo pages

Use the avo prefix for Avo's internal routes:

avo.root_path
avo.resources_users_path
avo.custom_tool_path
avo.resource_path(resource: UserResource, record: @user)

Linking to your main application

Use the main_app prefix for your application's routes:

main_app.root_path
main_app.posts_path
main_app.user_path(@user)

Why this matters

Without the prefix, Rails resolves helpers in the current context. Calling posts_path from inside Avo could fail (undefined method) or resolve to the wrong route if both Avo and your app define it. The avo and main_app proxies explicitly tell Rails which route set to use.

Quick reference

You want to link to…	Use this prefix
Avo pages (resources, tools, dashboards, etc.)	avo.
Your main application routes	main_app.

Learn more

For the full picture on how Rails engines handle routing, see the Rails Engines guide.