refactor: remove moonrope but maintain legacy API actions (#2889)

app/controllers/legacy_api/base_controller.rb

@@ -0,0 +1,133 @@
+# frozen_string_literal: true
+
+module LegacyAPI
+  # The Legacy API is the Postal v1 API which existed from the start with main
+  # aim of allowing e-mails to sent over HTTP rather than SMTP. The API itself
+  # did not feature much functionality. This API was implemented using Moonrope
+  # which was a self documenting API tool, however, is now no longer maintained.
+  # In light of that, these controllers now implement the same functionality as
+  # the original Moonrope API without the actual requirement to use any of the
+  # Moonrope components.
+  #
+  # Important things to note about the API:
+  #
+  #   * Moonrope allow params to be provided as JSON in the body of the request
+  #     along with the application/json content type. It also allowed for params
+  #     to be sent in the 'params' parameter when using the
+  #     application/x-www-form-urlencoded content type. Both methods are supported.
+  #
+  #   * Authentication is performed using a X-Server-API-Key variable.
+  #
+  #   * The method used to make the request is not important. Most clients use POST
+  #     but other methods should be supported. The routing for this legacvy
+  #     API supports GET, POST, PUT and PATCH.
+  #
+  #   * The status code for responses will always be 200 OK. The actual status of
+  #     a request is determined by the value of the 'status' attribute in the
+  #     returned JSON.
+  class BaseController < ActionController::Base
+
+    skip_before_action :set_browser_id
+    skip_before_action :verify_authenticity_token
+
+    before_action :start_timer
+    before_action :authenticate_as_server
+
+    private
+
+    # The Moonrope API spec allows for parameters to be provided in the body
+    # along with the application/json content type or they can be provided,
+    # as JSON, in the 'params' parameter when used with the
+    # application/x-www-form-urlencoded content type. This legacy API needs
+    # support both options for maximum compatibility.
+    #
+    # @return [Hash]
+    def api_params
+      if request.headers["content-type"] =~ /\Aapplication\/json/
+        return params.to_unsafe_hash
+      end
+
+      if params["params"].present?
+        return JSON.parse(params["params"])
+      end
+
+      {}
+    end
+
+    # The API returns a length of time to complete a request. We'll start
+    # a timer when the request starts and then use this method to calculate
+    # the time taken to complete the request.
+    #
+    # @return [void]
+    def start_timer
+      @start_time = Time.now.to_f
+    end
+
+    # The only method available to authenticate to the legacy API is using a
+    # credential from the server itself. This method will attempt to find
+    # that credential from the X-Server-API-Key header and will set the
+    # current_credential instance variable if a token is valid. Otherwise it
+    # will render an error to halt execution.
+    #
+    # @return [void]
+    def authenticate_as_server
+      key = request.headers["X-Server-API-Key"]
+      if key.blank?
+        render_error "AccessDenied",
+                     message: "Must be authenticated as a server."
+        return
+      end
+
+      credential = Credential.where(type: "API", key: key).first
+      if credential.nil?
+        render_error "InvalidServerAPIKey",
+                     message: "The API token provided in X-Server-API-Key was not valid.",
+                     token: key
+        return
+      end
+
+      if credential.server.suspended?
+        render_error "ServerSuspended"
+        return
+      end
+
+      credential.use
+      @current_credential = credential
+    end
+
+    # Render a successful response to the client
+    #
+    # @param [Hash] data
+    # @return [void]
+    def render_success(data)
+      render json: { status: "success",
+                     time: (Time.now.to_f - @start_time).round(3),
+                     flags: {},
+                     data: data }
+    end
+
+    # Render an error response to the client
+    #
+    # @param [String] code
+    # @param [Hash] data
+    # @return [void]
+    def render_error(code, data = {})
+      render json: { status: "error",
+                     time: (Time.now.to_f - @start_time).round(3),
+                     flags: {},
+                     data: data.merge(code: code) }
+    end
+
+    # Render a parameter error response to the client
+    #
+    # @param [String] message
+    # @return [void]
+    def render_parameter_error(message)
+      render json: { status: "parameter-error",
+                     time: (Time.now.to_f - @start_time).round(3),
+                     flags: {},
+                     data: { message: message } }
+    end
+
+  end
+end