NAME
GraphQL::Plugin::Convert::DBIC - convert DBIx::Class schema to GraphQL schema
SYNOPSIS
use GraphQL::Plugin::Convert::DBIC;
use My::Local::Schema;
my $converted = GraphQL::Plugin::Convert::DBIC->to_graphql(My::Local::Schema->connect);
print $converted->{schema}->to_doc;
DESCRIPTION
This module implements the GraphQL::Plugin::Convert API to convert a DBIx::Class::Schema to GraphQL::Schema etc.
Its Query
type represents a guess at what fields are suitable, based on providing a lookup for each type (a DBIx::Class::ResultSource).
Example
Consider this minimal data model:
blog:
id # primary key
articles # has_many
title # non null
language # nullable
article:
id # primary key
blog # foreign key to Blog
title # non null
content # nullable
Generated Output Types
These GraphQL::Type::Object types will be generated:
type Blog {
id: Int!
articles: [Article]
title: String!
language: String
}
type Article {
id: Int!
blog: Blog
title: String!
content: String
}
type Query {
blog(id: [Int!]!): [Blog]
article(id: [Int!]!): [Blog]
}
Note that while the queries take a list, the return order is undefined. This also applies to the mutations. If this matters, request the primary key fields and use those to sort.
Generated Input Types
Different input types are needed for each of CRUD (Create, Read, Update, Delete).
The create one needs to have non-null fields be non-null, for idiomatic GraphQL-level error-catching. The read one needs all fields nullable, since this will be how searches are implemented, allowing fields to be left un-searched-for. Both need to omit primary key fields. The read one also needs to omit foreign key fields, since the idiomatic GraphQL way for this is to request the other object, with this as a field on it, then request any required fields of this.
Meanwhile, the update and delete ones need to include the primary key fields, to indicate what to mutate, and also all non-primary key fields as nullable, which for update will mean leaving them unchanged, and for delete is to be ignored. These input types are split into one input for the primary keys, which is a full input type to allow for multiple primary keys, then a wrapper input for updates, that takes one ID input, and a payload that due to the same requirements, is just the search input.
Therefore, for the above, these input types (and an updated Query, and Mutation) are created:
input BlogCreateInput {
title: String!
language: String
}
input BlogSearchInput {
title: String
language: String
}
input BlogIDInput {
id: Int!
}
input BlogUpdateInput {
id: BlogIDInput!
payload: BlogSearchInput!
}
input ArticleCreateInput {
blog_id: Int!
title: String!
content: String
}
input ArticleSearchInput {
title: String
content: String
}
input ArticleIDInput {
id: Int!
}
input ArticleUpdateInput {
id: ArticleIDInput!
payload: ArticleSearchInput!
}
type Mutation {
createBlog(input: [BlogCreateInput!]!): [Blog]
createArticle(input: [ArticleCreateInput!]!): [Article]
deleteBlog(input: [BlogIDInput!]!): [Boolean]
deleteArticle(input: [ArticleIDInput!]!): [Boolean]
updateBlog(input: [BlogUpdateInput!]!): [Blog]
updateArticle(input: [ArticleUpdateInput!]!): [Article]
}
extends type Query {
searchBlog(input: BlogSearchInput!): [Blog]
searchArticle(input: ArticleSearchInput!): [Article]
}
ARGUMENTS
To the to_graphql
method: a DBIx::Class::Schema object.
PACKAGE FUNCTIONS
field_resolver
This is available as \&GraphQL::Plugin::Convert::DBIC::field_resolver
in case it is wanted for use outside of the "bundle" of the to_graphql
method.
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.