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.