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,
);
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.