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Overview

SwiftGraphQL is a GraphQL Client that ships with a type-safe query builder. It lets you perform queries, mutations and listen for subscriptions.

The library is centered around three core principles:

  • 🚀 If your project compiles, your queries work.
  • 🦅 Use Swift in favour of GraphQL wherever possible.
  • 🗝 We don’t lock you into the framework.

You may choose to only use parts of the library (e.g. only the client but not the query builder, or only the websocket client), but you may also choose to use the entire library.

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GraphQL Client

SwiftGraphQLClient is heavily inspired by urql GraphQL client in the JavaScript community. It models the queries as streams of values and lets you create custom operation processors called exchanges.

import SwiftGraphQLClient
import GraphQL

let request = URLRequest(url: URL(string: "http://127.0.0.1:4000/graphql")!)
let client = SwiftGraphQLClient.Client(request: request)

let args = ExecutionArgs(
    query: """
    query HelloWorld {
        hello
    }
    """,
    variables: [:]
)

client.query(args)
    .sink { completion in
        print(completion)
    } receiveValue: { result in
        print(result)
    }

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WebSocket Client

GraphQLWebSocket is an implementation of GraphQL over WebSocket client conforming to the GraphQL over WebSocket protocol specification widely supported by GraphQL servers.

let ws = GraphQLWebSocket(request: API_ENDPOINT)

let args = ExecutionArgs(
    query: """
    subscription Counter {
        count(from: 10, to: 1)
    }
    """,
    variables: [:]
)

client.subscribe(args)
    .sink { completion in
        print(completion)
    } receiveValue: { result in
        print(result)
    }

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Query Builder

The query builder guarantees that every query you can create is valid and complies with the GraphQL spec. Additionally, it lets you write queries as Swift functions and process the data during the selection process.

import SwiftGraphQL

enum Planet: String {
    case earth
}

// Define a Swift model.
struct Human: Identifiable {
    let id: String
    let name: String
    let planet: Planet?
}

// Create a selection.
let human = Selection.Human<Human> {
    // Query
    let id: String = try $0.id()
    let name: String = try $0.name()
    let rawPlanet = try $0.planet()

    // Decode
    guard let homePlanet = Planet(rawValue: rawPlanet) else {
        throw "Invalid planet value"
    }
    return Human(id: id, name: name, homePlanet: homePlanet)
}

let query = Selection.Query<[Human]> {
    try $0.friends(selection: human.list)
}

// Perform a request.
let url = URL(string: "http://localhost:8080/graphql")!
let request = URLRequest(url: url).querying(query)

let task = URLSession.shared.dataTask(with: request) { data, response, error in
    guard let result = try? data?.decode(query) else {
        print("something went wrong")
    }

    print(result)
}
task.resume()

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What Now

Depending on how confident you are about using SwiftGraphQL I recommend reading either

  • Why SwiftGraphQL to learn what pain points it solves, or
  • Installation instructions to start using it.
Why?