## Problem We are inconsistent about how we use URLs (absolute vs relative) in GitLab and it causes a few different problems: 1. URLs constructed on the frontend that do not take `relative_url_root` into account break functionality for customers using [`relative_url_root` setting](https://docs.gitlab.com/install/relative_url/) 1. Some customers have [reverse proxies](https://gitlab.com/gitlab-org/gitlab/-/issues/547602#note_2554801970) set up where they have a different URL than what was set in the `external_url` in their `gitlab.rb`. This means that using absolute URLs does not work. 2. [Geo customers with Secondary site](https://gitlab.com/gitlab-org/gitlab/-/issues/541974) have issues with absolute URLs. We have some guidance in https://docs.gitlab.com/development/fe_guide/frontend_faq/#5-should-one-use-a-full-url-or-a-full-path-when-referencing-backend-endpoints. But this guidance is hard to find in our docs and there is no tooling to enforce it so there are a lot of instances that slip through the cracks. ## Proposal ### Standardize `web_url` and `web_path` methods on models 1. Create a new concern that has a `web_url` and `web_path` method 2. Add that concern to all models that are listed in [lib/gitlab/url_builder.rb](https://gitlab.com/gitlab-org/gitlab/-/blob/master/lib/gitlab/url_builder.rb) 3. Remove direct usages of `Gitlab::UrlBuilder#build` ### Make `webPath` available in APIs Any API that exposes `webUrl` should also expose `webPath`. Search through the following directories: - `app/graphql/types` - `app/graphql/types` - `/app/serializers` - `/ee/app/serializers` - `/lib/api/entities` - `/ee/lib/api/entities` ### Linting 1. Add ESLint rule to prevent `webUrl` in Vue and JS code. `webPath` should be used instead. 2. Add ESLint rule for usages of "`/${}`" or `base: '/'` 3. Add RoboCop rule to prevent usage of `*_url` in HAML files and controllers (e.g. `dashboard_projects_url`) and instead use `*_path` (e.g. `dashboard_projects_path`) - This one could be tricky. I am not sure if we can lint for just Rails URL helpers. Also there may be instances where we need to use `*_url` (emails?). 5. Add RoboCop rule for direct usages of `Gitlab::UrlBuilder#build`. 6. Add RoboCop rule for APIs that expose `webUrl` but not `webPath` ### Documentation Add documentation to the following locations about how to use URLs - https://docs.gitlab.com/development/fe_guide/haml/ - https://docs.gitlab.com/development/fe_guide/vue/ - https://docs.gitlab.com/development/fe_guide/graphql/ - https://docs.gitlab.com/development/fe_guide/frontend_faq/#5-should-one-use-a-full-url-or-a-full-path-when-referencing-backend-endpoints - https://docs.gitlab.com/development/backend/ruby_style_guide/