Add a minimal GraphQL API

1 files changed, 49 insertions, 0 deletions

diff --git a/app/controllers/graphql_controller.rb b/app/controllers/graphql_controller.rb
new file mode 100644
index 00000000000..ef258bf07cb
--- /dev/null
+++ b/app/controllers/graphql_controller.rb
@@ -0,0 +1,49 @@
+class GraphqlController < ApplicationController
+  # Unauthenticated users have access to the API for public data
+  skip_before_action :authenticate_user!
+
+  before_action :check_graphql_feature_flag!
+
+  def execute
+    variables = ensure_hash(params[:variables])
+    query = params[:query]
+    operation_name = params[:operationName]
+    context = {
+      current_user: current_user
+    }
+    result = GitlabSchema.execute(query, variables: variables, context: context, operation_name: operation_name)
+    render json: result
+  end
+
+  private
+
+  # Overridden from the ApplicationController to make the response look like
+  # a GraphQL response. That is nicely picked up in Graphiql.
+  def render_404
+    error = { errors: [ message: "Not found" ] }
+
+    render json: error, status: :not_found
+  end
+
+  def check_graphql_feature_flag!
+    render_404 unless Feature.enabled?(:graphql)
+  end
+
+  # Handle form data, JSON body, or a blank value
+  def ensure_hash(ambiguous_param)
+    case ambiguous_param
+    when String
+      if ambiguous_param.present?
+        ensure_hash(JSON.parse(ambiguous_param))
+      else
+        {}
+      end
+    when Hash, ActionController::Parameters
+      ambiguous_param
+    when nil
+      {}
+    else
+      raise ArgumentError, "Unexpected parameter: #{ambiguous_param}"
+    end
+  end
+end