NAME

GraphQL::Plugin::Convert::MojoPubSub - convert a Mojo PubSub server to GraphQL schema

SYNOPSIS

  use GraphQL::Plugin::Convert::MojoPubSub;
  use GraphQL::Type::Scalar qw($String);
  my $pg = Mojo::Pg->new('postgresql://postgres@/test');
  my $converted = GraphQL::Plugin::Convert::MojoPubSub->to_graphql(
    {
      username => $String->non_null,
      message => $String->non_null,
    },
    $pg->pubsub,
  );
  print $converted->{schema}->to_doc;

DESCRIPTION

This module implements the GraphQL::Plugin::Convert API to convert a Mojo pub-sub server (currently either Mojo::Pg::PubSub or Mojo::Redis::PubSub) to GraphQL::Schema with publish/subscribe functionality.

ARGUMENTS

To the to_graphql method:

  • a hash-ref of field-names to GraphQL::Type objects. These must be both input and output types, so only scalars or enums. This allows you to pass in programmatically-created scalars or enums.

    This will be used to construct the fields arguments for the GraphQL::Type::InputObject and GraphQL::Type::Object which are the input and output of the mutation and subscription respectively.

  • an object compatible with Mojo::Redis, with a pubsub attribute.

Note the output type will have a dateTime field added to it with type non-null DateTime. Both input and output types will have a non-null channel String added.

E.g. for this input (implementing a trivial chat system):

  {
    username => $String->non_null,
    message => $String->non_null,
  }

The schema will look like:

  scalar DateTime

  input MessageInput {
    channel: String!
    username: String!
    message: String!
  }

  type Message {
    channel: String!
    username: String!
    message: String!
    dateTime: DateTime!
  }

  type Query {
    status: Boolean!
  }

  type Mutation {
    publish(input: [MessageInput!]!): DateTime!
  }

  type Subscription {
    subscribe(channels: [String!]): Message!
  }

The subscribe field takes a list of channels to subscribe to. If the list is null or empty, all channels will be subscribed to - a "firehose", implemented as an actual channel named _firehose.

DEBUGGING

To debug, set environment variable GRAPHQL_DEBUG to a true value.

AUTHOR

Ed J, <etj at cpan.org>

LICENSE

Copyright (C) Ed J

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.