Armature

Armature is an HTTP routing framework for Crystal.

Installation

Add the dependency to your shard.yml:

dependencies:
  armature:
    github: jgaskins/armature

Run shards install

Usage

Armature has 2 primary components:

Armature::Route
- Provides a routing graph by allowing a top-level application to delegate to various child routes based on path segments
- Provides an ECR rendering macro to render view templates at compile time. View templates are under the views/ directory in the application root.
- Provides a missed-match handler (r.miss) so you can provide custom 404 handling in a way that's simple and discoverable
Armature::Session
- If you're using cookie-based authentication, you can use Armature sessions to persist session data between requests
- Currently the only supported session adapter is Armature::Session::RedisStore. The value stored in the cookie is the session id and the data stored in Redis will be the session data serialized into a JSON string.

require "armature"
require "armature/redis_session"
require "redis"

class App
  include HTTP::Handler
  include Armature::Route

  def call(context)
    route context do |r, response, session|
      # The `session` can be treated as a key/value object. All JSON-friendly
      # types can be stored and retrieved. The stored session data is saved as
      # JSON and parsed into a `JSON::Any`.
      if current_user_id = session["user_id"]?.try(&.as_i?)
        current_user = UserQuery.new.find_by_id(current_user_id)
      end

      # `render` macro provided by `Armature::Route` renders the given template
      # inside the `views/` directory to the `response` object. This example
      # renders `views/app_header.ecr`.
      #
      # Note: You can render as many templates as you need, allowing for nesting
      # your UI via nested routes.
      render "app_header"
      
      # Root path (all HTTP verbs)
      r.root do
        # Execute the given block only for GET requests
        r.get { render "homepage" }

        # Execute the given block only for POST requests
        r.post do
          # ...
        end
      end

      # Delegate certain paths to other `Armature::Route`s with `on`
      r.on "products" { Products.new.call(context) }

      # Allow for authenticated-only routes
      if current_user
        r.on "notifications" { Notifications.new(current_user).call(context) }
        r.on "cart" { Cart.new(current_user).call(context) }
      end

      # Execute a block if an endpoint has not been reached yet.
      r.miss do
        response.status = :not_found
        render "not_found"
      end

      # Rendering the footer below main app content
      render "app_footer"
    end
  end
end

http = HTTP::Server.new([
  Armature::Session::RedisStore.new(
    # the HTTP cookie name to store the session id in
    key: "app_session",
    # a client for the Redis instance to store session data in
    redis: Redis::Client.from_env("REDIS_URL"),
  ),
  App.new,
])
http.listen 8080