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executing-queries.md

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Using Facade Method

Query execution is a complex process involving multiple steps, including query parsing, validating and finally executing against your schema.

graphql-php provides a convenient facade for this process in class GraphQL\GraphQL:

<?php
use GraphQL\GraphQL;

$result = GraphQL::executeQuery(
    $schema,
    $queryString,
    $rootValue = null,
    $context = null,
    $variableValues = null,
    $operationName = null,
    $fieldResolver = null,
    $validationRules = null
);

It returns an instance of GraphQL\Executor\ExecutionResult which can be easily converted to array:

$serializableResult = $result->toArray();

Returned array contains data and errors keys, as described by the GraphQL spec. This array is suitable for further serialization (e.g. using json_encode). See also the section on error handling and formatting.

Description of executeQuery method arguments:

Argument Type Notes
schema GraphQL\Type\Schema Required. Instance of your application Schema
queryString string or GraphQL\Language\AST\DocumentNode Required. Actual GraphQL query string to be parsed, validated and executed. If you parse query elsewhere before executing - pass corresponding AST document here to avoid new parsing.
rootValue mixed Any value that represents a root of your data graph. It is passed as the 1st argument to field resolvers of Query type. Can be omitted or set to null if actual root values are fetched by Query type itself.
context mixed Any value that holds information shared between all field resolvers. Most often they use it to pass currently logged in user, locale details, etc.

It will be available as the 3rd argument in all field resolvers. (see section on Field Definitions for reference) graphql-php never modifies this value and passes it as is to all underlying resolvers.
variableValues array Map of variable values passed along with query string. See section on query variables on official GraphQL website. Note that while variableValues must be an associative array, the values inside it can be nested using \stdClass if desired.
operationName string Allows the caller to specify which operation in queryString will be run, in cases where queryString contains multiple top-level operations.
fieldResolver callable A resolver function to use when one is not provided by the schema. If not provided, the default field resolver is used.
validationRules array A set of rules for query validation step. The default value is all available rules. Empty array would allow skipping query validation (may be convenient for persisted queries which are validated before persisting and assumed valid during execution)

Using Server

If you are building HTTP GraphQL API, you may prefer our Standard Server (compatible with express-graphql). It supports more features out of the box, including parsing HTTP requests, producing a spec-compliant response; batched queries; persisted queries.

Usage example (with plain PHP):

<?php
use GraphQL\Server\StandardServer;

$server = new StandardServer([/* server options, see below */]);
$server->handleRequest(); // parses PHP globals and emits response

Server also supports PSR-7 request/response interfaces:

<?php
use GraphQL\Server\StandardServer;
use GraphQL\Executor\ExecutionResult;
use Psr\Http\Message\RequestInterface;
use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\StreamInterface;

/** @var RequestInterface $psrRequest */
/** @var ResponseInterface $psrResponse */
/** @var StreamInterface $psrBodyStream */
$server = new StandardServer([/* server options, see below */]);
$psrResponse = $server->processPsrRequest($psrRequest, $psrResponse, $psrBodyStream);


// Alternatively create PSR-7 response yourself:

/** @var ExecutionResult|ExecutionResult[] $result */
$result = $server->executePsrRequest($psrRequest);
$psrResponse = new SomePsr7ResponseImplementation(json_encode($result));

PSR-7 is useful when you want to integrate the server into existing framework:

Server configuration options

Argument Type Notes
schema Schema Required. Instance of your application Schema
rootValue mixed Any value that represents a root of your data graph. It is passed as the 1st argument to field resolvers of Query type. Can be omitted or set to null if actual root values are fetched by Query type itself.
context mixed Any value that holds information shared between all field resolvers. Most often they use it to pass currently logged in user, locale details, etc.

It will be available as the 3rd argument in all field resolvers. (see section on Field Definitions for reference) graphql-php never modifies this value and passes it as is to all underlying resolvers.
fieldResolver callable A resolver function to use when one is not provided by the schema. If not provided, the default field resolver is used.
validationRules array or callable A set of rules for query validation step. The default value is all available rules. The empty array would allow skipping query validation (may be convenient for persisted queries which are validated before persisting and assumed valid during execution).

Pass callable to return different validation rules for different queries (e.g. empty array for persisted query and a full list of rules for regular queries). When passed, it is expected to have the following signature:

function (OperationParams $params, DocumentNode $node, $operationType): array
queryBatching bool Flag indicating whether this server supports query batching (apollo-style).

Defaults to false
debug int Debug flags. See docs on error debugging (flag values are the same).
persistentQueryLoader callable A function which is called to fetch actual query when server encounters queryId in request vs query.

The server does not implement persistence part (which you will have to build on your own), but it allows you to execute queries which were persisted previously.

Expected function signature:
function ($queryId, OperationParams $params)

Function is expected to return query string or parsed DocumentNode

Read more about persisted queries.
errorFormatter callable Custom error formatter. See error handling docs.
errorsHandler callable Custom errors handler. See error handling docs.
promiseAdapter PromiseAdapter Required for Async PHP only.

Server config instance

If you prefer fluid interface for config with autocomplete in IDE and static time validation, use GraphQL\Server\ServerConfig instead of an array:

<?php
use GraphQL\Server\ServerConfig;
use GraphQL\Server\StandardServer;

$config = ServerConfig::create()
    ->setSchema($schema)
    ->setErrorFormatter($myFormatter)
    ->setDebugFlag($debug)
;

$server = new StandardServer($config);

Query batching

Standard Server supports query batching (apollo-style).

One of the major benefits of Server over a sequence of executeQuery() calls is that Deferred resolvers won't be isolated in queries. So for example following batch will require single DB request (if user field is deferred):

[
  {
    "query": "{user(id: 1) { id }}"
  },
  {
    "query": "{user(id: 2) { id }}"
  },
  {
    "query": "{user(id: 3) { id }}"
  }
]

To enable query batching, pass queryBatching option in server config:

<?php
use GraphQL\Server\StandardServer;

$server = new StandardServer([
    'queryBatching' => true
]);

Custom Validation Rules

Before execution, a query is validated using a set of standard rules defined by the GraphQL spec. It is possible to override standard set of rules globally or per execution.

Add rules globally:

<?php
use GraphQL\Validator\Rules;
use GraphQL\Validator\DocumentValidator;

// Add to standard set of rules globally:
DocumentValidator::addRule(new Rules\DisableIntrospection());

Custom rules per execution:

<?php
use GraphQL\GraphQL;
use GraphQL\Validator\Rules;

$myValiationRules = array_merge(
    GraphQL::getStandardValidationRules(),
    [
        new Rules\QueryComplexity(100),
        new Rules\DisableIntrospection()
    ]
);

$result = GraphQL::executeQuery(
    $schema,
    $queryString,
    $rootValue = null,
    $context = null,
    $variableValues = null,
    $operationName = null,
    $fieldResolver = null,
    $myValiationRules // <-- this will override global validation rules for this request
);

Or with a standard server:

<?php
use GraphQL\Server\StandardServer;

$server = new StandardServer([
    'validationRules' => $myValiationRules
]);