Apollo GraphQL Websocket: Everything You Need to Know

GraphQL has gained popularity in recent years because of its ability to simplify API development and resolve over-fetching and under-fetching issues. Apollo GraphQL is one of the most popular GraphQL implementations that offers many features, including Apollo GraphQL Websocket. This article will cover all the essential details about Apollo GraphQL Websocket and how you can use it to build real-time applications.

What is Apollo GraphQL Websocket?

Apollo GraphQL Websocket is a protocol that enables real-time communication between the client and server. It allows the server to push updates to the client instead of the client having to make continuous requests to the server to retrieve data. Apollo GraphQL Websocket is built on top of the WebSocket protocol, which provides a full-duplex communication channel over a single TCP connection.

Apollo GraphQL Websocket provides many benefits over traditional HTTP-based APIs, including:

• Reduced Latency: Apollo GraphQL Websocket allows the server to push data to the client as soon as it becomes available, reducing the latency between updates.
• Improved Scalability: With HTTP-based APIs, the server has to handle multiple requests for the same data, which can be resource-intensive. Apollo GraphQL Websocket reduces the number of requests the server needs to handle by pushing updates to clients.
• Less Network Traffic: Apollo GraphQL Websocket transfers data only when there is new data available, reducing the amount of unnecessary network traffic.

How does Apollo GraphQL Websocket work?

Apollo GraphQL Websocket works by establishing a WebSocket connection between the client and server. Once the connection is established, the client sends a GraphQL subscription query to the server. The server uses this query to determine which data the client is interested in and starts sending updates to the client whenever the data changes.

Here’s an example of how Apollo GraphQL Websocket works:

1. The client sends a GraphQL subscription query to the server over a WebSocket connection.
2. The server receives the query and subscribes to the relevant data sources.
3. Whenever the data changes, the server sends an update to all subscribed clients over the WebSocket connection.
4. The client receives the update and updates the UI accordingly.

How to use Apollo GraphQL Websocket?

To use Apollo GraphQL Websocket, you need to have a server that supports GraphQL subscriptions and a client that can establish a WebSocket connection. Apollo Client is a popular choice for building GraphQL clients, and it provides built-in support for Apollo GraphQL Websocket.

Here’s how to use Apollo GraphQL Websocket with Apollo Client:

Step 1: Install the required dependencies

You will need to install the following dependencies:

• apollo-client: The Apollo Client library
• subscriptions-transport-ws: The WebSocket transport for GraphQL subscriptions

You can install these dependencies using npm:

npm install apollo-client subscriptions-transport-ws

Step 2: Create an Apollo Client instance

You can create an Apollo Client instance using the WebSocketLink class from the subscriptions-transport-ws package. Here’s an example:

import { ApolloClient } from 'apollo-client';import { WebSocketLink } from 'subscriptions-transport-ws';import { InMemoryCache } from 'apollo-cache-inmemory';
const link = new WebSocketLink({uri: 'ws://localhost:4000/graphql',options: {reconnect: true}});
const cache = new InMemoryCache();
const client = new ApolloClient({link,cache});

This code creates an Apollo Client instance with a WebSocket link that connects to a GraphQL server running at ws://localhost:4000/graphql.

Step 3: Create a subscription query

Next, you need to create a subscription query that specifies the data you want to receive updates for. Here’s an example:

import gql from 'graphql-tag';
const SUBSCRIPTION_QUERY = gql`subscription {newMessage {idtextcreatedAt}}`;

This code creates a subscription query that listens for new messages and returns their IDs, text, and creation timestamps.

Step 4: Subscribe to the query

Finally, you can subscribe to the query using the subscribe method of the Apollo Client instance. Here’s an example:

client.subscribe({query: SUBSCRIPTION_QUERY}).subscribe({next: (data) => {console.log(data);},error: (err) => {console.error(err);}});

This code subscribes to the SUBSCRIPTION_QUERY and logs any updates to the console.

Conclusion

Apollo GraphQL Websocket is a powerful tool for building real-time applications that require fast, scalable, and efficient data transfer. By using Apollo GraphQL Websocket, you can reduce latency, improve scalability, and reduce network traffic, making your applications more responsive and efficient. With the help of this article, you can now use Apollo GraphQL Websocket to build real-time applications with ease.

FAQ

What is GraphQL?

GraphQL is a query language and runtime for APIs that enables clients to request only the data they need and nothing more. It was developed by Facebook and released as an open-source project in 2015.

What is Apollo GraphQL?

Apollo GraphQL is a collection of open-source libraries and tools for building GraphQL APIs and clients. It provides many features, including caching, error handling, and real-time updates, making it one of the most popular GraphQL implementations.

What is WebSocket?

WebSocket is a protocol that provides a full-duplex communication channel over a single TCP connection. It enables real-time communication between the client and server and is often used for building real-time applications.

What is a GraphQL subscription?

A GraphQL subscription is a query that listens for updates to a specific set of data and returns those updates as soon as they become available. Subscriptions enable real-time communication between the client and server and are often used for building real-time applications.

What is Apollo Client?

Apollo Client is a powerful JavaScript library for managing GraphQL data in the client. It provides many features, including caching, error handling, and real-time updates, making it one of the most popular GraphQL clients.