Dynamically generate graphql schema, resolve using services

api/src/services/graphql.ts

@@ -0,0 +1,129 @@
+import Knex from 'knex';
+import database from '../database';
+import { AbstractServiceOptions, Accountability, Collection, Field, Relation, Query } from '../types';
+import { GraphQLSchema, GraphQLObjectType, GraphQLList, GraphQLScalarType, GraphQLResolveInfo, SelectionNode, FieldNode } from 'graphql';
+import { CollectionsService } from './collections';
+import { FieldsService } from './fields';
+import { getGraphQLType } from '../utils/get-graphql-type';
+import { RelationsService } from './relations';
+import { ItemsService } from './items';
+
+type SchemaStructure = {
+	[collection: string]: {
+		name: string,
+		fields: Record<string, {
+			name: string,
+			type: GraphQLScalarType,
+		}>
+		$meta?: {
+			single: boolean,
+			relations: {
+				collection: string;
+				field: string;
+				m2o: boolean;
+			}[]
+		},
+	}
+}
+
+export class GraphQLService {
+	accountability: Accountability | null;
+	knex: Knex;
+	fieldsService: FieldsService;
+	collectionsService: CollectionsService;
+	relationsService: RelationsService;
+
+	constructor(options?: AbstractServiceOptions) {
+		this.accountability = options?.accountability || null;
+		this.knex = options?.knex || database;
+		this.fieldsService = new FieldsService(options);
+		this.collectionsService = new CollectionsService(options);
+		this.relationsService = new RelationsService(options);
+	}
+
+	async getSchema() {
+		const collectionsInSystem = await this.collectionsService.readByQuery();
+		const fieldsInSystem = await this.fieldsService.readAll();
+		const relationsInSystem = await this.relationsService.readByQuery({}) as Relation[];
+
+		const schemaStructure = this.generateSchemaStructure(collectionsInSystem, fieldsInSystem, relationsInSystem);
+
+		const schema = this.getGraphQLSchema(schemaStructure);
+
+		return schema;
+	}
+
+	generateSchemaStructure(collections: Collection[], fields: Field[], relations: Relation[]) {
+		const schemaStructure: SchemaStructure = {};
+
+		for (const collection of collections) {
+			schemaStructure[collection.collection] = {
+				name: collection.collection,
+				fields: {},
+				$meta: {
+					single: collection.meta?.single === true,
+					relations: [],
+				}
+			}
+		}
+
+		for (const field of fields) {
+			schemaStructure[field.collection].fields[field.field] = {
+				name: field.field,
+				type: getGraphQLType(field.type),
+			}
+		}
+
+		for (const relation of relations) {}
+
+		return schemaStructure;
+	}
+
+	getGraphQLSchema(structure: SchemaStructure) {
+		const rootFields: any = {};
+
+		for (const [collection, value] of Object.entries(structure)) {
+			const meta = value.$meta;
+			delete value.$meta;
+
+			const object = new GraphQLObjectType(value);
+
+			if (meta?.single === true) {
+				rootFields[collection] = {
+					type: object,
+					resolve: (source: any, args: any, context: any, info: GraphQLResolveInfo) => this.resolve(info),
+				};
+			} else {
+				rootFields[collection] = {
+					type: new GraphQLList(object),
+					resolve: (source: any, args: any, context: any, info: GraphQLResolveInfo) => this.resolve(info),
+				};
+			}
+		}
+
+		return new GraphQLSchema({
+			query: new GraphQLObjectType({
+				name: 'Directus',
+				fields: rootFields,
+			}),
+		});
+	}
+
+	async resolve(info: GraphQLResolveInfo) {
+		const collection = info.fieldName;
+		const query: Query = {};
+
+		const selections = info.fieldNodes[0]?.selectionSet?.selections;
+		if (!selections) return null;
+
+		query.fields = selections
+			.filter((selection) => selection.kind === 'Field')
+			.map((selection) => {
+				return (selection as FieldNode).name.value;
+			});
+
+		const service = new ItemsService(collection, { knex: this.knex, accountability: this.accountability });
+		const result = await service.readByQuery(query);
+		return result;
+	}
+}

api/src/services/index.ts

@@ -5,6 +5,7 @@ export * from './collections';
 export * from './fields';
 export * from './files';
 export * from './folders';
+export * from './graphql';
 export * from './items';
 export * from './meta';
 export * from './payload';