Add method getFieldSelectionWithAliases to class ResolveInfo

src/Type/Definition/ResolveInfo.php

@@ -4,12 +4,14 @@
 
 use GraphQL\Error\Error;
 use GraphQL\Error\InvariantViolation;
+use GraphQL\Executor\Values;
 use GraphQL\Language\AST\FieldNode;
 use GraphQL\Language\AST\FragmentDefinitionNode;
 use GraphQL\Language\AST\FragmentSpreadNode;
 use GraphQL\Language\AST\InlineFragmentNode;
 use GraphQL\Language\AST\OperationDefinitionNode;
 use GraphQL\Language\AST\SelectionSetNode;
+use GraphQL\Type\Introspection;
 use GraphQL\Type\Schema;
 
 /**
@@ -214,6 +216,126 @@
         return $fields;
     }
 
+    /**
+     * Helper method that returns names of all fields selected in query for
+     * $this->fieldName up to $depth levels.
+     * For each field there is an "aliases" key regrouping all aliases of this field
+     * (if a field is not aliased, its name is present here as a key)
+     * For each of those "alias" you can find "args" key containing the arguments of the alias and the "fields" key
+     * containing the subfield of this field/alias. Each of those field have the same structure as described above.
+     *
+     * Example:
+     * query MyQuery{
+     * {
+     *   root {
+     *     id,
+     *     nested {
+     *      nested1(myArg:1)
+     *      nested1Bis:nested1
+     *     }
+     *     alias1:nested {
+     *       nested1(myArg:2, mySecondAg:"test")
+     *     }
+     *   }
+     * }
+     *
+     * Given this ResolveInfo instance is a part of "root" field resolution, and $depth === 1,
+     * method will return:
+     * [
+     *     'id' => [
+     *          'aliases' => [
+     *              'id' => [
+     *                  [args] => []
+     *              ]
+     *          ]
+     *      ],
+     *      'nested' => [
+     *           'aliases' => [
+     *               'nested' => [
+     *                  ['args'] => [],
+     *                  ['fields'] => [
+     *                      'nested1' => [
+     *                          'aliases' => [
+     *                              'nested1' => [
+     *                                  ['args'] => [
+     *                                      'myArg' => 1
+     *                                  ]
+     *                              ],
+     *                              'nested1Bis' => [
+     *                                  ['args'] => []
+     *                              ]
+     *                          ]
+     *                      ]
+     *                  ]
+     *               ],
+     *               'alias1' => [
+     *                  ['args'] => [],
+     *                  ['fields'] => [
+     *                       'nested1' => [
+     *                           'aliases' => [
+     *                               'nested1' => [
+     *                                   ['args'] => [
+     *                                       'myArg' => 2,
+     *                                       'mySecondAg' => "test"
+     *                                   ]
+     *                               ]
+     *                           ]
+     *                       ]
+     *                   ]
+     *               ]
+     *           ]
+     *       ]
+     * ]
+     *
+     * Warning: this method it is a naive implementation which does not take into account
+     * conditional typed fragments. So use it with care for fields of interface and union types.
+     * You still can alias the union type fields with the same name in order to extract their corresponding args.
+     *
+     * Example:
+     *  query MyQuery{
+     *  {
+     *    root {
+     *      id,
+     *      unionPerson {
+     *        ...on Child {
+     *          name
+     *          birthdate(format:"d/m/Y")
+     *        }
+     *        ...on Adult {
+     *          adultName:name
+     *          adultBirthDate:birthdate(format:"Y-m-d")
+     *          job
+     *        }
+     *      }
+     *    }
+     *  }
+     *
+     * @param int $depth How many levels to include in output
+     *
+     * @throws \Exception
+     * @throws Error
+     * @throws InvariantViolation
+     *
+     * @return array<string, mixed>
+     *
+     * @api
+     */
+    public function getFieldSelectionWithAlias(int $depth = 0): array
+    {
+        $fields = [];
+
+        foreach ($this->fieldNodes as $fieldNode) {
+            if (isset($fieldNode->selectionSet)) {
+                $fields = \array_merge_recursive(
+                    $fields,
+                    $this->foldSelectionWithAlias($fieldNode->selectionSet, $depth, $this->parentType->getField($fieldNode->name->value)->getType())
+                );
+            }
+        }
+
+        return $fields;
+    }
+
     /**
      * @param QueryPlanOptions $options
      *
@@ -266,4 +388,61 @@
 
         return $fields;
     }
+
+    /**
+     * @throws InvariantViolation|Error|\Exception
+     *
+     * @return array<string>
+     */
+    private function foldSelectionWithAlias(SelectionSetNode $selectionSet, int $descend, Type $parentType): array
+    {
+        /** @var array<string, bool> $fields */
+        $fields = [];
+
+        foreach ($selectionSet->selections as $selectionNode) {
+            if ($selectionNode instanceof FieldNode) {
+                $fieldName = $selectionNode->name->value;
+                $aliasName = $selectionNode->alias->value ?? $fieldName;
+
+                if ($fieldName === Introspection::TYPE_NAME_FIELD_NAME) {
+                    continue;
+                }
+
+                assert($parentType instanceof HasFieldsType, 'ensured by query validation and the check above which excludes union types');
+
+                $fieldDef = $parentType->getField($fieldName);
+                $fieldType = Type::getNamedType($fieldDef->getType());
+                $fields[$fieldName]['aliases'][$aliasName]['args'] = Values::getArgumentValues($fieldDef, $selectionNode, $this->variableValues);
+
+                if ($descend > 0 && $selectionNode->selectionSet !== null) {
+                    $fields[$fieldName]['aliases'][$aliasName]['fields'] = $this->foldSelectionWithAlias($selectionNode->selectionSet, $descend - 1, $fieldType);
+                }
+            } elseif ($selectionNode instanceof FragmentSpreadNode) {
+                $spreadName = $selectionNode->name->value;
+                if (isset($this->fragments[$spreadName])) {
+                    $fragment = $this->fragments[$spreadName];
+                    $fieldType = $this->schema->getType($fragment->typeCondition->name->value);
+                    assert($fieldType instanceof Type, 'ensured by query validation');
+
+                    $fields = \array_merge_recursive(
+                        $this->foldSelectionWithAlias($fragment->selectionSet, $descend, $fieldType),
+                        $fields
+                    );
+                }
+            } elseif ($selectionNode instanceof InlineFragmentNode) {
+                $typeCondition = $selectionNode->typeCondition;
+                $fieldType = $typeCondition === null
+                    ? $parentType
+                    : $this->schema->getType($typeCondition->name->value);
+                assert($fieldType instanceof Type, 'ensured by query validation');
+
+                $fields = \array_merge_recursive(
+                    $this->foldSelectionWithAlias($selectionNode->selectionSet, $descend, $fieldType),
+                    $fields
+                );
+            }
+        }
+
+        return $fields;
+    }
 }