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https://github.com/graphql-perl/graphql-perl

GraphQL in Perl 5
https://github.com/graphql-perl/graphql-perl

graphql graphql-perl moo perl

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GraphQL in Perl 5

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README 

        
# NAME



GraphQL - Perl implementation of GraphQL



# PROJECT STATUS



| OS      |  Build status |

|:-------:|--------------:|

| Linux   | [![Build Status](https://travis-ci.org/graphql-perl/graphql-perl.svg?branch=master)](https://travis-ci.org/graphql-perl/graphql-perl) |



[![CPAN version](https://badge.fury.io/pl/GraphQL.svg)](https://metacpan.org/pod/GraphQL) [![Coverage Status](https://coveralls.io/repos/github/graphql-perl/graphql-perl/badge.svg?branch=master)](https://coveralls.io/github/graphql-perl/graphql-perl?branch=master)



# SYNOPSIS



    use GraphQL::Schema;

    use GraphQL::Type::Object;

    use GraphQL::Type::Scalar qw($String);

    use GraphQL::Execution qw(execute);



    my $schema = GraphQL::Schema->from_doc(<<'EOF');

    type Query {

      helloWorld: String

    }

    EOF

    post '/graphql' => sub {

      send_as JSON => execute(

        $schema,

        body_parameters->{query},

        { helloWorld => 'Hello world!' },

        undef,

        body_parameters->{variables},

        body_parameters->{operationName},

        undef,

      );

    };



The above is from [the sample Dancer 2 applet](https://github.com/graphql-perl/sample-dancer2).



# DESCRIPTION



This module is a port of the GraphQL reference implementation,

[graphql-js](https://github.com/graphql/graphql-js), to Perl 5.



It now supports Promises, allowing asynchronous operation. See

[Mojolicious::Plugin::GraphQL](https://metacpan.org/pod/Mojolicious%3A%3APlugin%3A%3AGraphQL) for an example of how to take advantage

of this.



As of 0.39, supports GraphQL subscriptions.



See [GraphQL::Type](https://metacpan.org/pod/GraphQL%3A%3AType) for description of how to create GraphQL types.



## Introduction to GraphQL



GraphQL is a technology that lets clients talk to APIs via a single

endpoint, which acts as a single "source of the truth". This means clients

do not need to seek the whole picture from several APIs. Additionally,

it makes this efficient in network traffic, time, and programming effort:



- Network traffic



    The request asks for exactly what it wants, which it gets, and no

    more. No wasted traffic.



- Time



    It gets all the things it needs in one go, including any connected

    resources, so it does not need to make several requests to fill its

    information requirement.



- Programming effort



    With "fragments" that can be attached to user-interface components,

    keeping track of what information a whole page needs to request can be

    automated. See [Relay](https://facebook.github.io/relay/) or

    [Apollo](http://dev.apollodata.com/) for more on this.



## Basic concepts



GraphQL implements a system featuring a [schema](https://metacpan.org/pod/GraphQL%3A%3ASchema),

which features various classes of [types](https://metacpan.org/pod/GraphQL%3A%3AType), some of which

are [objects](https://metacpan.org/pod/GraphQL%3A%3AType%3A%3AObject). Special objects provide the roots

of queries (mandatory), and mutations and subscriptions (both optional).



Objects have fields, each of which can be specified to take arguments,

and which have a return type. These are effectively the properties and/or

methods on the type. If they return an object, then a query can specify

subfields of that object, and so on - as alluded to in the "time-saving"

point above.



For more, see the JavaScript tutorial in ["SEE ALSO"](#see-also).



## Hooking your system up to GraphQL



You will need to decide how to model your system in GraphQL terms. This

will involve deciding on what [output object types](https://metacpan.org/pod/GraphQL%3A%3AType%3A%3AObject)

you have, what fields they have, and what arguments and return-types

those fields have.



Additionally, you will need to design mutations if you want to be able

to update/create/delete data. This requires some thought for return types,

to ensure you can get all the information you need to proceed to avoid

extra round-trips.



The easiest way to achieve these things is to make a

[GraphQL::Plugin::Convert](https://metacpan.org/pod/GraphQL%3A%3APlugin%3A%3AConvert) subclass, to encapsulate the specifics of

your system. See the documentation for further information.



Finally, you should consider whether you need "subscriptions". These

are designed to hook into WebSockets. Apollo has a [JavaScript

module](https://github.com/apollographql/graphql-subscriptions) for this.



Specifying types and fields is straightforward. See [the

document](https://metacpan.org/pod/GraphQL%3A%3AType%3A%3ALibrary#FieldMapOutput) for how to make resolvers.



# DEBUGGING



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



# EXPORT



None yet.



# SEE ALSO



[SQL::Translator::Producer::GraphQL](https://metacpan.org/pod/SQL%3A%3ATranslator%3A%3AProducer%3A%3AGraphQL) - produce GraphQL schemas from a [DBIx::Class::Schema](https://metacpan.org/pod/DBIx%3A%3AClass%3A%3ASchema) (or in fact any SQL database)



[GraphQL::Plugin::Convert::DBIC](https://metacpan.org/pod/GraphQL%3A%3APlugin%3A%3AConvert%3A%3ADBIC) - produce working GraphQL schema from

a [DBIx::Class::Schema](https://metacpan.org/pod/DBIx%3A%3AClass%3A%3ASchema)



[GraphQL::Plugin::Convert::OpenAPI](https://metacpan.org/pod/GraphQL%3A%3APlugin%3A%3AConvert%3A%3AOpenAPI) - produce working GraphQL schema

from an OpenAPI specification



[Sample Mojolicious OpenAPI to GraphQL applet](https://github.com/graphql-perl/sample-mojolicious-openapi)



[Sample Dancer 2 applet](https://github.com/graphql-perl/sample-dancer2)



[Sample Mojolicious applet](https://github.com/graphql-perl/sample-mojolicious)



[Dancer2::Plugin::GraphQL](https://metacpan.org/pod/Dancer2%3A%3APlugin%3A%3AGraphQL)



[Mojolicious::Plugin::GraphQL](https://metacpan.org/pod/Mojolicious%3A%3APlugin%3A%3AGraphQL)



[http://facebook.github.io/graphql/](http://facebook.github.io/graphql/) - GraphQL specification



[http://graphql.org/graphql-js/](http://graphql.org/graphql-js/) - Tutorial on the JavaScript version,

highly recommended.

[Translation to

graphql-perl](http://blogs.perl.org/users/ed_j/2017/10/graphql-perl---graphql-js-tutorial-translation-to-graphql-perl-and-mojoliciousplugingraphql.html).



# AUTHOR



Ed J, ``



# BUGS



Please report any bugs or feature requests on

[https://github.com/graphql-perl/graphql-perl/issues](https://github.com/graphql-perl/graphql-perl/issues).



Or, if you prefer email and/or RT: to `bug-graphql

at rt.cpan.org`, or through the web interface at

[http://rt.cpan.org/NoAuth/ReportBug.html?Queue=GraphQL](http://rt.cpan.org/NoAuth/ReportBug.html?Queue=GraphQL). I will be

notified, and then you'll automatically be notified of progress on your

bug as I make changes.



# ACKNOWLEDGEMENTS



The creation of this work has been sponsored by Perl Careers:

[https://perl.careers/](https://perl.careers/).



Artur Khabibullin `` contributed valuable ports

of the JavaScript tests.



The creation of the subscriptions functionality in this work has been

sponsored by Sanctus.app: [https://sanctus.app](https://sanctus.app).



# LICENSE AND COPYRIGHT



Copyright 2017 Ed J.



This program is free software; you can redistribute it and/or modify it

under the terms of the the Artistic License (2.0). You may obtain a

copy of the full license at:



[http://www.perlfoundation.org/artistic\_license\_2\_0](http://www.perlfoundation.org/artistic_license_2_0)