Oak-GraphQL

A simple graphql middleware for oak deno framework.

! Make sure your playground endpoint indicates same as your URL http://localhost:8080/graphql

Simple example

import { Application, Router, RouterContext } from "https://deno.land/x/oak@v6.2.0/mod.ts";
import { applyGraphQL, gql, GQLError } from "https://deno.land/x/oak_graphql/mod.ts";

const app = new Application();

app.use(async (ctx, next) => {
  await next();
  const rt = ctx.response.headers.get("X-Response-Time");
  console.log(`${ctx.request.method} ${ctx.request.url} - ${rt}`);
});

app.use(async (ctx, next) => {
  const start = Date.now();
  await next();
  const ms = Date.now() - start;
  ctx.response.headers.set("X-Response-Time", `${ms}ms`);
});

const types = gql`
type User {
  firstName: String
  lastName: String
}

input UserInput {
  firstName: String
  lastName: String
}

type ResolveType {
  done: Boolean
}

type Query {
  getUser(id: String): User 
}

type Mutation {
  setUser(input: UserInput!): ResolveType!
}
`;

const resolvers = {
  Query: {
    getUser: (parent: any, { id }: any, context: any, info: any) => {
      console.log("id", id, context);
      if(context.user === "Aaron") {
        throw new GQLError({ type: "auth error in context" })
      }
      return {
        firstName: "wooseok",
        lastName: "lee",
      };
    },
  },
  Mutation: {
    setUser: (parent: any, { input: { firstName, lastName } }: any, context: any, info: any) => {
      console.log("input:", firstName, lastName);
      return {
        done: true,
      };
    },
  },
};

const GraphQLService = await applyGraphQL<Router>({
  Router,
  typeDefs: types,
  resolvers: resolvers,
  context: (ctx: RouterContext) => {
    return { user: "Aaron" };
  }
})


app.use(GraphQLService.routes(), GraphQLService.allowedMethods());

console.log("Server start at http://localhost:8080");
await app.listen({ port: 8080 });

TODO

• Add cache
• Enable the upload
• Enable the JSON scalar

Method

gql

GraphQL-tag Parsing GraphQL queries

• gql A JavaScript template literal tag that parses GraphQL query strings into the standard GraphQL AST.

GQLError

An error handler

Example

throw new GQLError("string");
or
throw new GQLError({type: "General error", detail: "somthing critical!"});

applyGraphQL

A Generator which based Attain Router class creates some middlewares for supporting the GraphQL.

Options

• Router: oak Router module
  Due to the version incompatible issue mentioned by (avalero)[https://github.com/avalero], I've decoupled the Router. Thanks :)
• path?: string
  A target path that handles the GraphQL post request (*optional: default as /graphql)
• typeDefs: any
  generated type tags by the gql
• resolvers: any
  An object that handles the queries and mutations

const resolvers = {
  Query: {
    getUser: (parent: any, {id}: any, context: any, info: any) => {
      // ...query handling function here
    },
  },
  Mutation: {
    addUser: (parent: any, {firstName, lastName}: any, context: any, info: any) => {
      // ...add user codes here
    },
  }
}

The resolvers will be received these four parameters

• parents: The return value of the resolver for this field's parent
• args: An object that contains all GraphQL arguments provided for this field.
• context: An object shared across all resolvers that are executing for a particular operation.
• info: Contains information about the operation's execution state, including the field name, the path to the field from the root, and more.

• context?: (ctx) => any
  Send any objects to each resolver (*optional)
• usePlayground?: boolean;
  enable the playground at get method (*optional: default as true)