Reference

PONAPI::Client(3pm)

Client to a {JSON:API} service (http://jsonapi.org/) v1.0

NAME

PONAPI::Client - Client to a {JSON:API} service (http://jsonapi.org/) v1.0

VERSION

version 0.002012

SYNOPSIS

    use PONAPI::Client;
    my $client = PONAPI::Client->new(
        host => $host,
        port => $port,
    );
    $client->retrieve_all( type => $type );
    $client->retrieve(
        type => $type,
        id   => $id,
    );
    $client->retrieve_relationships(
        type     => $type,
        id       => $id,
        rel_type => $rel_type,
    );
    $client->retrieve_by_relationship(
        type     => $type,
        id       => $id,
        rel_type => $rel_type,
    );
    $client->create(
        type => $type,
        data => {
            attributes    => { ... },
            relationships => { ... },
        },
    );
    $client->delete(
        type => $type,
        id   => $id,
    );
    $client->update(
        type => $type,
        id   => $id,
        data => {
            type => $type,
            id   => $id,
            attributes    => { ... },
            relationships => { ... },
        }
    );
    $client->delete_relationships(
        type => $type,
        id   => $id,
        rel_type => $rel_type,
        data => [
            { type => $rel_type, id => $rel_id },
            ...
        ],
    );
    $client->create_relationships(
        type => $type,
        id   => $id,
        rel_type => $rel_type,
        data => [
            { type => $rel_type, id => $rel_id },
            ...
        ],
    );
    $client->update_relationships(
        type => $type,
        id   => $id,
        rel_type => $rel_type,
        # for a one-to-one:
        data => { type => $rel_type, id => $rel_id },
        # or for a one-to-many:
        data => [
            { type => $rel_type, id => $rel_id },
            ...
        ],
    );
    # If the endpoint uses an uncommon url format:
    $client->retrieve(
        type => 'foo',
        id   => 43,
        # Will generate a request to
        # host:port/type_foo_id_43
        uri_template => "type_{type}_id_{id}",
    );

DESCRIPTION

"PONAPI::Client" is a {JSON:API} <http://jsonapi.org/> compliant client; it should be able to communicate with any API-compliant service.

The client does a handful of checks required by the spec, then uses Hijk to communicate with the service.

In most cases, all API methods return a response document:

    my $response = $client->retrieve(...);

In list context however, all api methods will return the request status and the document:

    my ($status, $response) = $client->retrieve(...)

Response documents will look something like these:

    # Successful retrieve(type => 'articles', id => 2)
    {
        jsonapi  => { version => "1.0"         },
        links    => { self    => "/articles/2" },
        data     => { ... },
        meta     => { ... }, # May not be there
        included => [ ... ], # May not be there, see C<include>
    }
    # Successful retrieve_all( type => 'articles' )
    {
        jsonapi => { version => "1.0"       },
        links   => { self    => "/articles" }, # May include pagination links
        data    => [
            { ... },
            { ... },
            ...
        ],
        meta     => { ... }, # May not be there
        included => [ ... ], # May not be there, see C<include>
    }
    # Successful create(type => 'foo', data => { ... })
    {
        jsonapi => { version => "1.0"                 },
        links   => { self => "/foo/$created_id"       },
        data    => { type => 'foo', id => $created_id },
    }
    # Successful update(type => 'foo', id => 2, data => { ... })
    {
        jsonapi => { version => "1.0" },
        links   => { self => "/foo/2" }, # may not be there
        meta    => { ...              }, # may not be there
    }
    # Error, see http://jsonapi.org/format/#error-objects
    {
        jsonapi => { version => "1.0" },
        errors  => [
            { ... }, # error 1
            ...      # potentially others
        ],
    }

However, there are situations where the server may respond with a "204 No Content" and no response document; depending on the situation, it might be worth checking the status.

METHODS

new

Creates a new "PONAPI::Client" object. Takes a couple of attributes:

host

The hostname (or IP address) of the service. Defaults to localhost.

port

Port of the service. Defaults to 5000.

send_version_header

Sends a "X-PONAPI-Client-Version" header set to the {JSON:API} version the client supports. Defaults to true.

retrieve_all

    retrieve_all( type => $type, %optional_arguments )

Retrieves all resources of the given type. In SQL, this is similar to "SELECT * FROM $type".

This handles several arguments:

fields

Spec <http://jsonapi.org/format/#fetching-sparse-fieldsets>.

Instead of returning every attribute and relationship from a given resource, "fields" can be used to specify exactly what is returned.

This excepts a hashref of arrayrefs, where the keys are types, and the values are either attribute names, or relationship names.

    $client->retrieve_all(
        type   => 'people',
        fields => { people => [ 'name', 'age' ] }
    )

Note that an attribute not being in fields means the opposite to an attribute having empty fields:

    # No attributes or relationships for both people and comments
    $client->retrieve_all(
        type   => 'people',
        fields => { people => [], comments => [] },
    );
    # No attributes or relationships for comments, but
    # ALL attributes and relationships for people
    $client->retrieve_all(
        type   => 'people',
        fields => { comments => [] },
    );
include

Spec <http://jsonapi.org/format/#fetching-includes>.

"include" can be used to fetch related resources. The example below is fetching both all the people, and all comments made by those people:

    my $response = $client->retrieve_all(
        type   => 'people',
        include => ['comments']
    );

"include" expects an arrayref of relationship names. In the response, the resources fetched will be in an arrayref under the top-level "included" key:

    say $_->{attributes}{body} for @{ $response->{included} }
page

Spec <http://jsonapi.org/format/#fetching-pagination>.

Requests that the server paginate the results. Each endpoint may have different pagination rules.

sort

Spec <http://jsonapi.org/format/#fetching-sorting>.

Requests that the server sort the results in a given way:

    $client->retrieve_all(
        type => 'people',
        sort => [qw/ age  /], # sort by age, ascending
    );
    $client->retrieve_all(
        type => 'people',
        sort => [qw/ -age /], # sort by age, descending
    );

Although not all endpoints will support this, it may be possible to sort by a relationship's attribute:

    $client->retrieve_all(
        type => 'people',
        sort => [qw/ -comments.created_date /],
    );
filter

Spec <http://jsonapi.org/format/#fetching-filtering>.

This one is entirely dependent on the endpoint. It's usually employed to act as a "WHERE" clause:

    $client->retrieve_all(
        type   => 'people',
        filter => {
            id  => [ 1, 2, 3, 4, 6 ], # IN ( 1, 2, ... )
            age => 34,                # age = 34
        },
    );

Sadly, more complex filters are currently not available.

retrieve

    retrieve( type => $type, id => $id, %optional_arguments )

Similar to "retrieve_all", but retrieves a single resource.

retrieve_relationships

    retrieve_relationships( type => $type, id => $id, rel_type => $rel_type, %optional_arguments )

Retrieves all of $id's relationships to $rel_type as resource identifiers; that is, as hashrefs that contain only "type" and "id":

    # retrieve_relationships(type=>'people', id=>2, rel_type=>'comments')
    {
        jsonapi => { version => "1.0" },
        data    => [
            { type => 'comments', id => 4  },
            { type => 'comments', id => 9  },
            { type => 'comments', id => 14 },
        ]
    }

These two do roughly the same thing:

    my $response      = $client->retrieve( type => $type, id => $id );
    my $relationships = $response->{data}{relationships}{$rel_type};
    say join ", ", map $_->{id}, @$relationships;
    my $response = $client->retrieve_relationships(
        type     => $type,
        id       => $id,
        rel_type => $rel_type,
    );
    my $relationships = $response->{data};
    say join ", ", map $_->{id}, @$relationships;

However, "retrieve_relationships" also allows you to page those relationships, which may be quite useful.

Keep in mind that "retrieve_relationships" will return an arrayref for one-to-many relationships, and a hashref for one-to-ones.

retrieve_by_relationship

    retrieve_by_relationship( type => $type, id => $id, rel_type => $rel_type, %optional_arguments )

"retrieve_relationships" on steroids. It behaves the same way, but will retrieve full resources, not just resource identifiers; because of this, you can also potentially apply more complex filters and sorts.

create

    create( type => $type, data => { ... }, id => $optional )

Create a resource of type $type using $data to populate it. Data must include the type, and may include two other keys: "attributes" and "relationships":

    $client->create(
        type => 'comments',
        data => {
            type          => 'comments',
            attributes    => { body => 'abc' },
            relationships => {
                author   => { type => 'people', id => 55 },
                liked_by => [
                    { type => 'people', id => 55  },
                    { type => 'people', id => 577 },
                ],
            }
        }
    }

An optional "id" may be provided, in which case the server may choose to use it when creating the new resource.

update

    update( type => $type, id => $id, data => { ... } )

Can be used to update the resource. Data must have "type" and "id" keys:

    $client->create(
        type => 'comments',
        id   => 5,
        data => {
            type          => 'comments',
            id            => 5,
            attributes    => { body => 'new body!' },
            relationships => {
                author   => undef, # no author
                liked_by => [
                    { type => 'people', id => 79 },
                ],
            }
        }
    }

An empty arrayref ("[]") can be used to clear one-to-many relationships, and "undef" to clear one-to-one relationships.

A successful "update" will always return a response document; see the spec for more details.

Spec <http://jsonapi.org/format/#crud-updating>.

delete

    delete( type => $type, id => $id )

Deletes the resource.

update_relationships

   update_relationships( type => $type, id => $id, rel_type => $rel_type, data => $data )

Update a resource's relationships. Basically a shortcut to using "update".

For one-to-one relationships, "data" can be either a single hashref, or undef. For one-to-many relationships, "data" can be an arrayref; an empty arrayref means 'clear the relationship'.

create_relationships

   create_relationships( type => $type, id => $id, rel_type => $rel_type, data => [{ ... }] )

Adds to the specified one-to-many relationship.

delete_relationships

   delete_relationships( type => $type, id => $id, rel_type => $rel_type, data => [{ ... }] )

Deletes from the specified one-to-many relationship.

Endpoint URI format

By default, "PONAPI::Client" assumes urls on the endpoint are in this format:

    retrieve_all:               /$type
    retrieve:                   /$type/$id
    retrieve_by_relationships:  /$type/$id/$rel_type
    retrieve_relationships:     /$type/$id/relationships/$rel_type
    create:                     /$type or /$type/$id
    delete:                     /$type/$id
    update:                     /$type/$id
    update_relationships:       /$type/$id/relationships/$rel_type
    create_relationships:       /$type/$id/relationships/$rel_type
    delete_relationships:       /$type/$id/relationships/$rel_type
    # Will generate a request to /foo/99
    $client->retrieve(
        type => 'foo',
        id   => 99,
    );

However, if another format is needed, two approaches are possible:

URI paths have a common prefix

If all the endpoint urls have a common prefix, ala "/v1/articles" instead of simply "/articles", then you can just set "uri_base" as needed:

    $client->retrieve(
        type     => 'foo',
        id       => 99,
        uri_base => '/v1'
    );

We can also set this when creating the client; if done this way, all requests generated from this client will include the base:

    my $new_client = PONAPI::Client->new(
        uri_base => '/v1',
        ...
    );
    # This will generate a request to /v1/foo/99
    $new_client->retrieve(
        type => 'foo',
        id   => 99,
    );

Completely different uris

If the endpoint's expected formats are wildly different, you can specify "uri_template" with your request:

    # Will generate a request to id_here_99_and_type_there/foo
    $client->retrieve(
        type => 'foo',
        id   => 99,
        uri_template => 'id_here_{id}_and_type_there/{type}'
    );

These placeholders are recognized:

•

type

•

id

•

rel_type

This can only be done on a per-request basis.

AUTHORS

•

Mickey Nasriachi <[email protected]>

•

Stevan Little <[email protected]>

•

Brian Fraser <[email protected]>

COPYRIGHT AND LICENSE

This software is copyright (c) 2019 by Mickey Nasriachi, Stevan Little, Brian Fraser.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

History