graphql-subscriptions/README.md

# graphql-subscriptions

GraphQL subscriptions is a simple npm package that lets you wire up GraphQL with a pubsub system (like Redis) to implement subscriptions in GraphQL.

### Installation

`npm install graphql-subscriptions`


### Example usage

```js
import { PubSub, SubscriptionManager } from 'graphql-subscriptions';
import schema from './schema';

// PubSub can be easily replaced, for example with https://github.com/davidyaha/graphql-redis-subscriptions
const pubsub = new PubSub();

const subscriptionManager = new SubscriptionManager({
  schema,
  pubsub,

  // setupFunctions maps from subscription name to a map of channel names and their filter functions
  // in this case it will subscribe to the commentAddedChannel and re-run the subscription query
  // every time a new comment is posted whose repository name matches args.repoFullName.
  setupFunctions: {
    commentAdded: (options, args) => ({
      newCommentsChannel: {
        filter: comment => comment.repository_name === args.repoFullName,
      },
    }),
  },
});

// start a subscription
subscriptionManger.subscribe({
  query: `
    subscription newComments($repoName: String!){
      commentAdded(repoName: $repoName) { # <-- this is the subscription name
        id
        content
        createdBy {
          username
        }
      }
    }
  `,
  variables: {
    repoName: 'apollostack/GitHunt-API',
  },
  context: {},
  callback: (err, data) => console.log(data),
});

// publish to the channel
pubsub.publish('newCommentsChannel', {
  id: 123,
  content: 'Test',
  repoFullName: 'apollostack/GitHunt-API',
  posted_by: 'helfer',
});

// the query will run, and the callback will print
// {
//   data: {
//     commentAdded: {
//       id: 123,
//       content: 'Test',
//       createdBy: {
//         username: 'helfer',
//       }
//     }
//   }
// }

```