mix phx.gen.json (Phoenix v1.8.0-rc.0)

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Generates controller, JSON view, and context for a JSON resource.

$ mix phx.gen.json Accounts User users name:string age:integer

The first argument is the context module followed by the schema module and its plural name (used as the schema table name).

The context is an Elixir module that serves as an API boundary for the given resource. A context often holds many related resources. Therefore, if the context already exists, it will be augmented with functions for the given resource.

Note: A resource may also be split over distinct contexts (such as Accounts.User and Payments.User).

The schema is responsible for mapping the database fields into an Elixir struct. It is followed by an optional list of attributes, with their respective names and types. See mix phx.gen.schema for more information on attributes.

Overall, this generator will add the following files to lib/:

  • a context module in lib/app/accounts.ex for the accounts API
  • a schema in lib/app/accounts/user.ex, with an users table
  • a controller in lib/app_web/controllers/user_controller.ex
  • a JSON view collocated with the controller in lib/app_web/controllers/user_json.ex

A migration file for the repository and test files for the context and controller features will also be generated.

API Prefix

By default, the prefix "/api" will be generated for API route paths. This can be customized via the :api_prefix generators configuration:

config :your_app, :generators,
  api_prefix: "/api/v1"

Scopes

If your application configures its own default scope, then this generator will automatically make sure all of your context operations are correctly scoped. You can pass the --no-scope flag to disable the scoping.

Umbrella app configuration

By default, Phoenix injects both web and domain specific functionality into the same application. When using umbrella applications, those concerns are typically broken into two separate apps, your context application - let's call it my_app - and its web layer, which Phoenix assumes to be my_app_web.

You can teach Phoenix to use this style via the :context_app configuration option in your my_app_umbrella/config/config.exs:

config :my_app_web,
  ecto_repos: [Stuff.Repo],
  generators: [context_app: :my_app]

Alternatively, the --context-app option may be supplied to the generator:

$ mix phx.gen.html Sales User users --context-app my_app

Web namespace

By default, the controller and JSON view will be namespaced by the schema name. You can customize the web module namespace by passing the --web flag with a module name, for example:

$ mix phx.gen.json Sales User users --web Sales

Which would generate a lib/app_web/controllers/sales/user_controller.ex and lib/app_web/controller/sales/user_json.ex.

Customizing the context, schema, tables and migrations

In some cases, you may wish to bootstrap JSON views, controllers, and controller tests, but leave internal implementation of the context or schema to yourself. You can use the --no-context and --no-schema flags for file generation control. Note --no-context implies --no-schema:

$ mix phx.gen.live Accounts User users --no-context name:string

In the cases above, tests are still generated, but they will all fail.

You can also change the table name or configure the migrations to use binary ids for primary keys, see mix phx.gen.schema for more information.