NAME

GraphQL::Execution - Execute GraphQL queries

SYNOPSIS

use GraphQL::Execution qw(execute);
my $result = execute($schema, $doc, $root_value);

DESCRIPTION

Executes a GraphQL query, returns results.

METHODS

execute

my $result = execute(
  $schema,
  $doc, # can also be AST
  $root_value,
  $context_value,
  $variable_values,
  $operation_name,
  $field_resolver,
  $promise_code,
);

$schema

A GraphQL::Schema.

$doc

Either a GraphQL query document to be fed in to "parse" in GraphQL::Language::Parser, or a return value from that.

$root_value

A root value that can be used by field-resolvers. The default one needs a code-ref, a hash-ref or an object.

For instance:

my $schema = GraphQL::Schema->from_doc(<<'EOF');
type Query { dateTimeNow: String, hi: String }
EOF
my $root_value = {
  dateTimeNow => sub { DateTime->now->ymd },
  hi => "Bob",
};
my $data = execute($schema, "{ dateTimeNow hi }", $root_value);

will return:

{
  data => {
    dateTimeNow => { ymd => '20190501' },
    hi => 'Bob',
  }
}

Be aware that with the default field-resolver, when it calls a method, that method will get called with "$args" in GraphQL::Type::Library "$context" in GraphQL::Type::Library, "$info" in GraphQL::Type::Library. To override that to pass no parameters, this is suitable as a $field_resolver parameters:

sub {
  my ($root_value, $args, $context, $info) = @_;
  my $field_name = $info->{field_name};
  my $property = ref($root_value) eq 'HASH'
    ? $root_value->{$field_name}
    : $root_value;
  return $property->($args, $context, $info) if ref $property eq 'CODE';
  return $root_value->$field_name if ref $property; # no args
  $property;
}

$context_value

A per-request scalar, that will be passed to field-resolvers.

$variable_values

A hash-ref, typically the decoded JSON object supplied by a client. E.g. for this query:

query q($input: TestInputObject) {
  fieldWithObjectInput(input: $input)
}

The $variable_values will need to be a JSON object with a key input, whose value will need to conform to the input type TestInputObject.

The purpose of this is to avoid needing to hard-code input values in your query. This aids in, among other things, being able to whitelist individual queries as acceptable, non-abusive queries to your system; and being able to generate client-side code for client-side validation rather than including the full GraphQL system in client code.

$operation_name

A string (or undef) that if given will be the name of one of the operations in the query.

$field_resolver

A code-ref to be used instead of the default field-resolver.

$promise_code

If you need to return a promise, supply a hash-ref matching "PromiseCode" in GraphQL::Type::Library.