Handle polymorphic types & relations, clean relational attributes code

packages/plugins/graphql/services/schema/builders/generic-morph.js

@@ -0,0 +1,26 @@
+'use strict';
+
+const { unionType } = require('nexus');
+const { prop } = require('lodash/fp');
+
+const {
+  constants: { GENERIC_MORPH_TYPENAME },
+} = require('../../types');
+
+module.exports = ({ registry }) => ({
+  buildGenericMorphDefinition() {
+    return unionType({
+      name: GENERIC_MORPH_TYPENAME,
+
+      resolveType: prop('__typename'),
+
+      definition(t) {
+        const members = registry
+          .where(({ config }) => ['types', 'components'].includes(config.kind))
+          .map(prop('name'));
+
+        t.members(...members);
+      },
+    });
+  },
+});

packages/plugins/graphql/services/schema/builders/index.js

@@ -18,6 +18,8 @@ const mutations = require('./mutations');
 const filters = require('./filters');
 const inputs = require('./input');
 
+const genericMorph = require('./generic-morph');
+
 const buildersFactories = [
   enums,
   dynamicZone,
@@ -30,6 +32,7 @@ const buildersFactories = [
   mutations,
   filters,
   inputs,
+  genericMorph,
 ];
 
 /**

packages/plugins/graphql/services/schema/builders/type.js

@@ -1,11 +1,11 @@
 'use strict';
 
-const { isArray } = require('lodash/fp');
+const { isArray, isString, isUndefined } = require('lodash/fp');
 const { objectType } = require('nexus');
 
 const { contentTypes } = require('@strapi/utils');
 
-const { mappers, utils: typeUtils } = require('../../types');
+const { mappers, utils: typeUtils, constants } = require('../../types');
 const { buildAssociationResolver } = require('../resolvers');
 
 /**
@@ -62,7 +62,9 @@ module.exports = context => ({
          * - Component
          * - Dynamic Zone
          * - Enum
-         * - Relation
+         * - Media
+         * - Polymorphic Relations
+         * - Regular Relations
          *
          * Here, we iterate over each non-private attribute
          * and add it to the type definition based on its type
@@ -107,9 +109,19 @@ module.exports = context => ({
               addEnumAttribute(options);
             }
 
-            // Relations
+            // Media
+            else if (typeUtils.isMedia(attribute)) {
+              addMediaAttribute(options);
+            }
+
+            // Polymorphic Relations
+            else if (typeUtils.isMorphRelation(attribute)) {
+              addPolymorphicRelationalAttribute(options);
+            }
+
+            // Regular Relations
             else if (typeUtils.isRelation(attribute) || typeUtils.isMedia(attribute)) {
-              addRelationalAttribute(options);
+              addRegularRelationalAttribute(options);
             }
           });
       },
@@ -178,10 +190,10 @@ const addEnumAttribute = ({ builder, attributeName, contentType }) => {
 };
 
 /**
- * Add a relational attribute to the type definition
+ * Add a media attribute to the type definition
  * @param {TypeBuildersOptions} options
  */
-const addRelationalAttribute = options => {
+const addMediaAttribute = options => {
   let { builder } = options;
   const {
     attributeName,
@@ -190,10 +202,37 @@ const addRelationalAttribute = options => {
     context: { strapi },
   } = options;
 
-  // todo[V4]: Clean the logic below
+  if (attribute.multiple) {
+    builder = builder.list;
+  }
 
-  const isMorphLike = typeUtils.isMorphRelation(attribute);
-  const isToManyRelation = typeUtils.isRelation(attribute) && attribute.relation.endsWith('Many');
+  const fileContentType = strapi.getModel('plugins::upload.file');
+  const type = typeUtils.getTypeName(fileContentType);
+
+  const associationResolver = buildAssociationResolver({
+    contentTypeUID: contentType.uid,
+    attributeName,
+    strapi,
+  });
+
+  builder.field(attributeName, { type, resolve: associationResolver });
+};
+
+/**
+ * Add a polymorphic relational attribute to the type definition
+ * @param {TypeBuildersOptions} options
+ */
+const addPolymorphicRelationalAttribute = options => {
+  let { builder } = options;
+  const {
+    attributeName,
+    attribute,
+    contentType,
+    context: { strapi },
+  } = options;
+
+  const { target } = attribute;
+  const isToManyRelation = attribute.relation.endsWith('Many');
 
   if (isToManyRelation) {
     builder = builder.list;
@@ -205,34 +244,53 @@ const addRelationalAttribute = options => {
     strapi,
   });
 
-  if (typeUtils.isMedia(attribute)) {
-    const fileContentType = strapi.getModel('plugins::upload.file');
-    const type = typeUtils.getTypeName(fileContentType);
+  // If there is no specific target specified, then use the GenericMorph type
+  if (isUndefined(target)) {
+    builder.field(attributeName, {
+      type: constants.GENERIC_MORPH_TYPENAME,
+      resolve: associationResolver,
+    });
+  }
 
-    builder.field(attributeName, { type, resolve: associationResolver });
-  } else if (isMorphLike) {
-    const { target } = attribute;
-
-    if (typeof target === 'string') {
-      const targetContentType = strapi.getModel(target);
-      const type = typeUtils.getTypeName(targetContentType);
-
-      builder.field(attributeName, { type, resolve: associationResolver });
-    } else if (Array.isArray(target)) {
-      const type = typeUtils.getMorphRelationTypeName(contentType, attributeName);
-
-      builder.field(attributeName, { type, resolve: associationResolver });
-    } else if (!target) {
-      builder.field(attributeName, { type: 'GenericMorph', resolve: associationResolver });
-    }
-  } else {
-    const targetContentType = strapi.getModel(attribute.target);
-    const type = typeUtils.getTypeName(targetContentType);
+  // If the target is an array of string, resolve the associated morph type and use it
+  else if (isArray(target) && target.every(isString)) {
+    const type = typeUtils.getMorphRelationTypeName(contentType, attributeName);
 
     builder.field(attributeName, { type, resolve: associationResolver });
   }
 };
 
+/**
+ * Add a regular relational attribute to the type definition
+ * @param {TypeBuildersOptions} options
+ */
+const addRegularRelationalAttribute = options => {
+  let { builder } = options;
+  const {
+    attributeName,
+    attribute,
+    contentType,
+    context: { strapi },
+  } = options;
+
+  const isToManyRelation = attribute.relation.endsWith('Many');
+
+  if (isToManyRelation) {
+    builder = builder.list;
+  }
+
+  const associationResolver = buildAssociationResolver({
+    contentTypeUID: contentType.uid,
+    attributeName,
+    strapi,
+  });
+
+  const targetContentType = strapi.getModel(attribute.target);
+  const type = typeUtils.getTypeName(targetContentType);
+
+  builder.field(attributeName, { type, resolve: associationResolver });
+};
+
 /**
  * Bind a content type on an attribute privacy checker
  *

packages/plugins/graphql/services/schema/generators/content-api.js

@@ -4,7 +4,7 @@ const { prop } = require('lodash/fp');
 const { makeSchema, unionType } = require('nexus');
 
 const createBuilders = require('../builders');
-const { utils, scalars, buildInternals } = require('../../types');
+const { utils, constants, scalars, buildInternals } = require('../../types');
 
 const { create: createTypeRegistry } = require('../../type-registry');
 
@@ -42,56 +42,45 @@ module.exports = strapi => {
 
   const registerMorphTypes = contentTypes => {
     // Create & register a union type that includes every type or component registered
-    registry.register(
-      'GenericMorph',
-
-      unionType({
-        name: 'GenericMorph',
-
-        resolveType(obj) {
-          return obj.__typename;
-        },
-
-        definition(t) {
-          const members = registry
-            .where(({ config: { kind } }) => ['types', 'components'].includes(kind))
-            .map(prop('name'));
-
-          t.members(...members);
-        },
-      }),
-      { kind: 'morphs' }
-    );
+    const genericMorphType = builders.buildGenericMorphDefinition();
+    registry.register(constants.GENERIC_MORPH_TYPENAME, genericMorphType, { kind: 'morphs' });
 
+    // For every content type
     contentTypes.forEach(contentType => {
       const { attributes = {} } = contentType;
 
+      // Isolate its polymorphic attributes
       const morphAttributes = Object.entries(attributes).filter(([, attribute]) =>
         utils.isMorphRelation(attribute)
       );
 
+      // For each one of those polymorphic attribute
       for (const [attributeName, attribute] of morphAttributes) {
         const name = utils.getMorphRelationTypeName(contentType, attributeName);
         const { target } = attribute;
 
+        // Ignore those whose target is not an array
         if (!Array.isArray(target)) {
           continue;
         }
 
+        // Transform target UIDs into types names
+        const members = target
+          // Get content types definitions
+          .map(uid => strapi.getModel(uid))
+          // Resolve types names
+          .map(contentType => utils.getTypeName(contentType));
+
+        // Register the new polymorphic union type
         registry.register(
           name,
 
           unionType({
             name,
 
-            resolveType(obj) {
-              return obj.__typename;
-            },
+            resolveType: prop('__typename'),
 
             definition(t) {
-              // const members = backLinks.map(prop('definition'));
-              const members = target || ['GenericMorph'];
-
               t.members(...members);
             },
           }),

packages/plugins/graphql/services/types/constants.js

@@ -32,10 +32,13 @@ const STRAPI_SCALARS = [
   'timestamp',
 ];
 
+const GENERIC_MORPH_TYPENAME = 'GenericMorph';
+
 module.exports = {
   PAGINATION_TYPE_NAME,
   RESPONSE_COLLECTION_META_TYPE_NAME,
   PUBLICATION_STATE_TYPE_NAME,
   GRAPHQL_SCALARS,
   STRAPI_SCALARS,
+  GENERIC_MORPH_TYPENAME,
 };