RPC middlewares

AnyCable Ruby allows to add custom middlewares to the RPC server (both standalone gRPC and embedded HTTP versions).

For example, anycable-rails ships with the middleware that integrate Rails Executor into RPC server.

Exceptions handling is also implemented via AnyCable middleware.

Adding a custom middleware

AnyCable middleware is a class inherited from AnyCable::Middleware and implementing #call method:

class PrintMiddleware < AnyCable::Middleware
  # request - is a request payload (incoming message)
  # handler - is a method (Symbol) of RPC handler which is called
  # meta - is a metadata (Hash) provided along with request
  def call(handler, request, meta)
    p request
    yield
  end
endCopy to clipboardErrorCopied

NOTE: you MUST yield the execution to continue calling middlewares and the RPC handler itself.

Activate your middleware by adding it to the middleware chain:

# anywhere in your app before AnyCable server starts
AnyCable.middleware.use(PrintMiddleware)

# or using instance
AnyCable.middleware.use(ParameterizedMiddleware.new(params))Copy to clipboardErrorCopied