feature: Add variable validation rule to query save

src/Admin/Editor.php

@@ -46,12 +46,12 @@ public function admin_init() {
 	public function untrashed_post_cb( $post_id, $previous_status ) {
 		// If have errors when validating the post content/data, do not show those in the admin when untrash.
 		$untrashed_post = get_post( $post_id );
-		
+
 		// Bail if the untrashed post is not a GraphQL Document
 		if ( ! isset( $untrashed_post->post_type ) || Document::TYPE_NAME !== $untrashed_post->post_type ) {
 			return;
 		}
-	
+
 		delete_transient( AdminErrors::TRANSIENT_NAME );
 	}
 

src/Document.php

@@ -11,6 +11,7 @@
 use WPGraphQL\SmartCache\Admin\Settings;
 use GraphQL\Error\SyntaxError;
 use GraphQL\Server\RequestError;
+use GraphQL\Validator\DocumentValidator;
 
 class Document {
 
@@ -306,6 +307,15 @@ public function valid_or_throw( $post_content, $post_id ) {
 				throw new RequestError( sprintf( __( 'This query has already been associated with another query "%s"', 'wp-graphql-smart-cache' ), $existing_post->post_title ) );
 			}
 
+			// During save/parse of query string, check for variables of the query string.
+			// "To save this query, arguments should use variables instead of static values."
+			$rules                                = DocumentValidator::defaultRules();
+			$rules['argument_should_be_variable'] = new \WPGraphQL\SmartCache\ValidationRules\ArgShouldBeVariable();
+			$validationErrors                     = DocumentValidator::validate( \WPGraphQL::get_schema(), $ast, $rules );
+			if ( count( $validationErrors ) > 0 ) {
+				throw new RequestError( __( 'Validation Error: ', 'wp-graphql-smart-cache' ) . $validationErrors[0]->getMessage() );
+			}
+
 			// Format the query string and save that
 			return \GraphQL\Language\Printer::doPrint( $ast );
 		} catch ( SyntaxError $e ) {

src/ValidationRules/ArgShouldBeVariable.php

@@ -0,0 +1,52 @@
+<?php
+
+namespace WPGraphQL\SmartCache\ValidationRules;
+
+use GraphQL\Error\Error;
+use GraphQL\Language\AST\NodeKind;
+use GraphQL\Language\AST\ArgumentNode;
+use GraphQL\Validator\Rules\ValidationRule;
+use GraphQL\Validator\ValidationContext;
+
+/**
+ * Class ArgShouldBeVariable
+ *
+ * @package WPGraphQL\SmartCache\Rules
+ */
+class ArgShouldBeVariable extends ValidationRule {
+
+	/**
+	 * Returns structure suitable for GraphQL\Language\Visitor
+	 *
+	 * @see \GraphQL\Language\Visitor
+	 *
+	 * @return mixed[]
+	 */
+	public function getVisitor( ValidationContext $context ) {
+
+		return [
+			NodeKind::ARGUMENT => [
+				'enter' => function ( ArgumentNode $node ) use ( $context ) {
+					// Arguments in operation are process here, ex.  post( id: "1", idType: DATABASE_ID )
+
+					// If this argument should map to a variable
+					// For a string or "idType" enum
+					if ( in_array( $node->value->kind, [ 'StringValue', 'EnumValue' ], true ) ) {
+						$context->reportError(new Error(
+							self::shouldBeVariableMessage( $node->name->value ),
+							$node
+						));
+					}
+				},
+			],
+		];
+	}
+
+	/**
+	 * @param string $varName
+	 * @return string
+	 */
+	public static function shouldBeVariableMessage( $varName ) {
+		return sprintf( __( 'Argument "$%s" should be a variable.', 'wp-graphql-smart-cache' ), $varName );
+	}
+}