@graphql-toolkit/url-loader NPM

tool

A set of utils for faster development of GraphQL tools. Use these utils if you are creating a tool that loads schema/documents, merges schemas, scan for schema/documents/resolvers files.

Included tools:

Schema Loading

These utils are useful for scanning, loading and building a GraphQL schema from any input.

You can specify a GraphQL endpoint, local introspection JSON file, code file that exports a GraphQLSchema, AST string and .graphql files (with support for glob expression).

All found schema files can be merged into a complete schema. There is support for #import syntax (using graphql-import).

The user is given the option of implementing their own loader (implement the interface SchemaLoader).

The schema loading util is using loaders, and implemented using chain-of-responsibility pattern.

Specifiying the loader is not necessary. The user need only provide the inputs. The utils will detect it automatically.

Usage:

import { loadSchema } from 'graphql-toolkit';

const schema1 = loadSchema('type A { foo: String }'); // load from string
const schema2 = loadSchema('http://localhost:3000/graphql'); // load from endpoint
const schema3 = loadSchema('./schema.json'); // load from local json file
const schema4 = loadSchema('schema.graphql'); // load from a single schema file
const schema5 = loadSchema('./src/**/*.graphql'); // load from multiple files using glob

Documents Loading

Similar to schema loading - but meant to use for GraphQL documents (query/mutation/subscription/fragment).

Any input provided as a source will be recognized by utils automatically.

It also extracts usages of gql from code files using graphql-tag-pluck.

Usage:

import { loadDocuments } from 'graphql-toolkit';

const document1 = loadDocuments('query { f }'); // load from string
const document2 = loadDocuments('./users.query.graphql'); // load from a single file 
const document3 = loadDocuments('./src/**/*.graphql'); // load from multiple files using glob
const document4 = loadDocuments('./src/my-component.ts'); // load from code file

Epoxy

Originally implemented in graphql-modules. This tools merged GraphQL type definitions and schema. It aims to merge all possible types, interfaces, enums and unions, without conflicts.

Resolvers are merged using deep-merge. Resolver implementations can be separated across multiple objects and then merged into a single resolvers object.

# a1.graphql
type A {
    f1: String
}

# a2.graphql
type A {
    f2: String
}

Will result:

type A {
    f1: String
    f2: String
}

Sonar

Sonar is a small util that scans you file-system and find GraphQL files (.graphql) and resolvers files (.js/.ts) and loads them (using readFile for GraphQL files and require for resolvers files).

Other Utils

There are some more utils under utils directory:

`validateGraphQlDocuments`

A tool for validating GraphQL documents (query/mutation/subscription/fragment) against the schema.

It uses the original validation logic from graphql package, but suspressing some validation rules, and focuses on validating the fields and the structure of the documents.

`extractDocumentStringFromCodeFile`

This method gets a source code file, and using graphql-tag-pluck tries to extract GraphQL AST from it.

`getDirectives`

This method accepts GraphQLSchema and any AST node, and tries to extract the GraphQL directives of the AST node.

It returnes a Map of the directive name and the arguments of it.

`getFieldsWithDirectives`

This method accepts a GraphQL DocumentNode of a GraphQL types definition and creates a map between GraphQL type.field and the directives it has.

It's useful for getting an easy-to-use structure of the directives that are decorating the schema.

`getImplementingTypes`

This method accepts GraphQLSchema object and a name of a GraphQL interface, and returns an array of all the GraphQL types that are implementing the GraphQL interface.

`getSchemaDirectiveFromDirectiveResolver`

This method accepts a name of a GraphQL Directive and its resolver function; using this method you can easily generate SchemaDirective with a single resolver function.

`composeResolvers`

This method accepts IResolvers object and mappings for composition functions that would be run before resolver itself.

Instead of doing this,

const resolvers ={
    Query: {
        myQuery: (root, args, context) => {
            // Make sure that the user is authenticated
            if (!context.currentUser) {
                throw new Error('You are not authenticated!');
            }

            // Make sure that the user has the correct roles
            if (!context.currentUser.roles || context.currentUser.roles.includes('EDITOR')) {
                throw new Error('You are not authorized!');
            }

            // Business logic
            if (args.something === '1') {
                return true;
            }

            return false;
        },
    },
};

You can do;

const resolvers ={
    Query: {
        myQuery: (root, args, context) => {
            if (args.something === '1') {
                return true;
            }

            return false;
        },
    },
};

const isAuthenticated = () => next => async (root, args, context, info) => {
    if (!context.currentUser) {
        throw new Error('You are not authenticated!');
    }

    return next(root, args, context, info);
};

const hasRole = (role: string) => next => async (root, args, context, info) => {
    if (!context.currentUser.roles || context.currentUser.roles.includes(role)) {
        throw new Error('You are not authorized!');
    }

    return next(root, args, context, info);
};

const resolversComposition = {
    'Query.myQuery': [isAuthenticated(), hasRole('EDITOR')],
};

const composedResolvers = composeResolvers(resolvers, resolversComposition);

`extractResolversFromSchema`

This methods accepts GraphQLSchema object, and returns a map with field resolver functions of all types inside the schema as in IResolvers interface of graphql-tools.

Schema Loading

Documents Loading

Epoxy

Sonar

Other Utils

validateGraphQlDocuments

extractDocumentStringFromCodeFile

getDirectives

getFieldsWithDirectives

getImplementingTypes

getSchemaDirectiveFromDirectiveResolver

composeResolvers

extractResolversFromSchema

extractFieldResolversFromObjectType