Twig fixes. (#348)

Author: pmelab

.travis.yml

@@ -10,6 +10,7 @@ env:
   global:
     - DRUPAL_BUILD_DIR=$TRAVIS_BUILD_DIR/../drupal
     - SIMPLETEST_DB=mysql://root:@127.0.0.1/graphql
+    - TRAVIS=true
   matrix:
     - DRUPAL_CORE=8.2.x
     - DRUPAL_CORE=8.3.x

modules/graphql_twig/graphql_twig.module

@@ -5,7 +5,112 @@
  * GraphQL Twig hook implementations.
  */
 
-use Drupal\graphql_twig\GraphQLNodeVisitor;
+use Youshido\GraphQL\Parser\Parser;
+use Youshido\GraphQL\Parser\Ast\ArgumentValue\Variable;
+use Drupal\Core\Entity\EntityInterface;
+use Drupal\graphql_twig\GraphQLTwigEnvironment;
+
+/**
+ * Implements hook_theme_registry_alter().
+ *
+ * Search for GraphQL enhanced templates in the theme registry and append
+ * the GraphQL preprocessor.
+ */
+function graphql_twig_theme_registry_alter(&$theme_registry) {
+  /** @var \Drupal\Core\Template\TwigEnvironment $twig */
+  $twig = Drupal::service('twig');
+  foreach ($theme_registry as $hook => $info) {
+    $file = $info['path'] . '/' . $info['template'] . '.html.twig';
+    if ($query = graphql_twig_get_query($file)) {
+      $theme_registry[$hook]['graphql_enabled'] = TRUE;
+      $theme_registry[$hook]['graphql_variables'] = graphql_twig_get_query_variables($query);
+      $theme_registry[$hook]['preprocess functions'][] = 'graphql_twig_process_query';
+    }
+  }
+}
+
+/**
+ * Get the query string for a given template file.
+ *
+ * Checks for an annotation, a `*.gql` sibling file or returns NULL if nothing
+ * is found.
+ *
+ * @param string $file
+ *   The template file path.
+ *
+ * @return string|null
+ *   The GraphQL query string or NULL.
+ */
+function graphql_twig_get_query($file) {
+  if (file_exists($file)) {
+
+    $graphqlFile = str_replace('.html.twig', '.gql', $file);
+    if (file_exists($graphqlFile)) {
+      return file_get_contents($graphqlFile);
+    }
+
+    preg_match(GraphQLTwigEnvironment::$GRAPHQL_ANNOTATION_REGEX, file_get_contents($file), $matches);
+    if (array_key_exists('query', $matches)) {
+      $source = (new Parser())->parse($matches['query']);
+      if ($source['queries']) {
+        return $matches['query'];
+      }
+    }
+  }
+
+  return NULL;
+}
+
+/**
+ * Get the declared variables in a GraphQL query string.
+ *
+ * @param $query
+ *   The query string.
+ *
+ * @return array
+ *   A list of variable names.
+ */
+function graphql_twig_get_query_variables($query) {
+  $source = (new Parser())->parse($query);
+  return array_map(function (Variable $var) {
+    return $var->getName();
+  }, $source['variables']);
+}
+
+/**
+ * Implements hook_preprocess().
+ *
+ * Execute the GraphQL query if the theme hook is GraphQL enhanced and add
+ * the query result as well as cache metadata.
+ */
+function graphql_twig_process_query(&$variables, $hook, $info) {
+  if (isset($info['graphql_enabled']) && $info['graphql_enabled']) {
+    /** @var \Drupal\graphql\QueryProcessor $processor */
+    $processor = Drupal::service('graphql.query_processor');
+
+    /** @var \Drupal\Core\Template\TwigEnvironment $twig */
+    $twig = Drupal::service('twig');
+
+    $file = $info['path'] . '/' . $info['template'] . '.html.twig';
+
+    $query = $twig->loadTemplate($file)->getGraphQLQuery();
+
+    $arguments = [];
+    foreach ($info['graphql_variables'] as $var) {
+      if (isset($variables[$var])) {
+        $arguments[$var] = $variables[$var] instanceof EntityInterface ? $variables[$var]->id() : $variables[$var];
+      }
+    }
+
+    $queryResult = $processor->processQuery($query, $arguments);
+
+    $variables['graphql_result'] = $queryResult->getData();
+
+    $variables['#cache']['contexts'] = $queryResult->getCacheContexts();
+    $variables['#cache']['tags'] = $queryResult->getCacheTags();
+    $variables['#cache']['max-age'] = $queryResult->getCacheMaxAge();
+  }
+}
 
 /**
  * Implements hook_theme().
@@ -39,21 +144,15 @@ function graphql_twig_theme($existing, $type, $theme, $path) {
         continue;
       }
 
-      $content = file_get_contents($file->uri);
-
-      preg_match(GraphQLNodeVisitor::$GRAPHQL_TWIG_REGEX, $content, $matches);
-      if (array_key_exists('query', $matches)) {
-        $source = (new \Youshido\GraphQL\Parser\Parser())->parse($matches['query']);
+      if ($query = graphql_twig_get_query($file->uri)) {
         $themeRegistry[$hook] = [
           'template' => $template,
           'path' => dirname($file->uri),
           'theme path' => $path,
           'variables' => [],
         ];
-
-        foreach ($source['variables'] as $variable) {
-          /** @var \Youshido\GraphQL\Parser\Ast\ArgumentValue\Variable $variable */
-          $themeRegistry[$hook]['variables'][$variable->getName()] = null;
+        foreach (graphql_twig_get_query_variables($query) as $var) {
+          $themeRegistry[$hook]['variables'][$var] = NULL;
         }
       }
     }
@@ -64,8 +163,12 @@ function graphql_twig_theme($existing, $type, $theme, $path) {
 
 /**
  * Implements hook_module_implements_alter().
+ *
+ * Make sure graphql_twig_theme runs last to not accidentially override existing
+ * theme hooks.
  */
 function graphql_twig_module_implements_alter(&$implementations, $hook) {
+
   if ($hook == 'theme') {
     unset($implementations['graphql_twig']);
     $implementations['graphql_twig'] = FALSE;

modules/graphql_twig/graphql_twig.services.yml

@@ -1,6 +1,5 @@
 services:
   graphql_twig.twig.embed:
     class: Drupal\graphql_twig\GraphQLTwigExtension
-    arguments: ['@renderer']
     tags:
       - { name: twig.extension }

modules/graphql_twig/src/GraphQLFragmentNode.php

@@ -0,0 +1,38 @@
+<?php
+
+namespace Drupal\graphql_twig;
+
+/**
+ * A Twig node for collecting GraphQL query fragments in twig templates.
+ */
+class GraphQLFragmentNode extends \Twig_Node {
+
+  /**
+   * The fragment string.
+   *
+   * @var string
+   */
+  protected $fragment = "";
+
+  /**
+   * GraphQLFragmentNode constructor.
+   *
+   * @param string $fragment
+   *   The query fragment.
+   */
+  public function __construct($fragment) {
+    $this->fragment = $fragment;
+    parent::__construct();
+  }
+
+  /**
+   * Retrieve the stored query fragment.
+   *
+   * @return string
+   *   The query fragment.
+   */
+  public function getFragment() {
+    return $this->fragment;
+  }
+
+}

modules/graphql_twig/src/GraphQLNode.php

@@ -4,18 +4,44 @@
 
 use Twig_Compiler;
 
+/**
+ * GraphQL meta information Twig node.
+ *
+ * A Twig node that will be attached to templates `class_end` to output the
+ * collected graphql query and inheritance metadata. Not parsed directly but
+ * injected by the `GraphQLNodeVisitor`.
+ */
 class GraphQLNode extends \Twig_Node {
 
+  /**
+   * The modules query string.
+   *
+   * @var string
+   */
   protected $query = "";
+
+  /**
+   * The modules parent class.
+   *
+   * @var string
+   */
   protected $parent = "";
+
+  /**
+   * The modules includes.
+   * @var array
+   */
   protected $includes = [];
 
   /**
    * GraphQLNode constructor.
    *
    * @param string $query
+   *   The query string.
    * @param string $parent
+   *   The parent template identifier.
    * @param array $includes
+   *   Identifiers for any included/referenced templates.
    */
   public function __construct($query, $parent, $includes) {
     $this->query = $query;
@@ -24,9 +50,14 @@ public function __construct($query, $parent, $includes) {
     parent::__construct();
   }
 
+  /**
+   * {@inheritdoc}
+   */
   public function compile(Twig_Compiler $compiler) {
     $compiler
+      // Make the template implement the GraphQLTemplateTrait.
       ->write("\nuse \Drupal\graphql_twig\GraphQLTemplateTrait;\n")
+      // Write metadata properties.
       ->write("\nprotected \$graphqlQuery = ")
       ->string($this->query)
       ->write(";\n")

modules/graphql_twig/src/GraphQLNodeVisitor.php

@@ -5,62 +5,91 @@
 use Twig_Environment;
 use Twig_Node;
 
+/**
+ * Scans a Twig template for query fragments and references to other templates.
+ */
 class GraphQLNodeVisitor extends \Twig_BaseNodeVisitor {
 
-  public static $GRAPHQL_TWIG_REGEX = '/.*\{#graphql\s+(?<query>.*)\s+#\}.*/s';
-
+  /**
+   * The query string.
+   *
+   * @var string
+   */
   protected $query = '';
+
+  /**
+   * The parent template identifier.
+   *
+   * @var string
+   */
   protected $parent = '';
+
+  /**
+   * A list of referenced templates (include, embed).
+   *
+   * @var string[]
+   */
   protected $includes = [];
 
+  /**
+   * {@inheritdoc}
+   */
   public function getPriority() {
     return 0;
   }
 
+  /**
+   * {@inheritdoc}
+   */
   protected function doEnterNode(Twig_Node $node, Twig_Environment $env) {
 
     if ($node instanceof \Twig_Node_Module) {
 
-      if (!$node->hasAttribute('source')) {
-        return $node;
-      }
-
-      $this->query = '';
-      $this->parent = '';
-      $this->includes = [];
-
-      $source = $node->getAttribute('source');
-      preg_match(static::$GRAPHQL_TWIG_REGEX, $source, $matches);
-
-      if (array_key_exists('query', $matches)) {
-        $this->query = $matches['query'];
-      }
-
+      // If there is a parent node (created by `extends` or `embed`),
+      // store it's identifier.
       if ($node->hasNode('parent')) {
         $parent = $node->getNode('parent');
         if ($parent instanceof \Twig_Node_Expression_Constant) {
           $this->parent = $parent->getAttribute('value');
         }
       }
 
+      // Recurse into embedded templates.
       foreach ($node->getAttribute('embedded_templates') as $embed) {
         $this->doEnterNode($embed, $env);
       }
     }
 
+    // Store identifiers of any static includes.
+    // There is no way to make this work for dynamic includes.
     if ($node instanceof \Twig_Node_Include && !($node instanceof \Twig_Node_Embed)) {
       $ref = $node->getNode('expr');
       if ($ref instanceof \Twig_Node_Expression_Constant) {
         $this->includes[] = $ref->getAttribute('value');
       }
     }
 
+    // When encountering a GraphQL fragment, add it to the current query.
+    if ($node instanceof GraphQLFragmentNode) {
+      $this->query .= $node->getFragment();
+    }
+
     return $node;
   }
 
+  /**
+   * {@inheritdoc}
+   */
   protected function doLeaveNode(Twig_Node $node, Twig_Environment $env) {
     if ($node instanceof \Twig_Node_Module) {
+      // Store current query information to be compiled into the templates
+      // `class_end`.
       $node->setNode('class_end', new GraphQLNode($this->query, $this->parent, $this->includes));
+
+      // Reset query information for the next module.
+      $this->query = '';
+      $this->parent = '';
+      $this->includes = [];
     }
     return $node;
   }