GQLSwiftQuery

A simple GraphQL query constructor for iOS, written in Swift.

Installation

GQLSwiftQuery is fully contained in one file, so if you're not on the Cocoapods train, feel free to simply drag GQLSwiftQueryTests.swift into your Xcode project. Otherwise, add the following to your Podfile:

pod 'GQLSwiftQuery', :git => 'https://github.com/worthbak/GQLSwiftQuery'

Usage

In GQLSwiftQuery, GraphQL queries are defined primarily through objects that conform to the GQLQueryItemType protocol, namely the GQLQueryItem struct, but also simple Swift Strings. GQLQueryItems are appropriate to use when creating a nested query, but a simple String type will do if a single parameter is being defined.

This may sound more complex than it is. Consider this example:

import GQLSwiftQuery

let pointsSubquery = GQLQueryItem(withKeyDesignation: "points", andSubqueryFields: ["id", "value"])
    
let userQueryItem = GQLQueryItem(
  withKeyDesignation: "user",
  andSubqueryFields: [
    "username",
    "email",
    pointsSubquery
  ]
)

userQueryItem defines the fields of a GraphQL query that seeks to fetch user data from a server, including a username, email, as well as information about a user's points (including the point value and its unique identifier).

In order to turn this GQLQueryItem into a full query, simply pass it in to an instance of GQLQuery (along with any required query arguments):

let args = [
  "userId": 1,
  "authToken": "123456abcd"
]

let userQuery = GQLQuery(
	withSchemaType: .Query, 
	withQueryTitle: "users", 
	withQueryArguments: args, 
	withQuery: userQueryItem
)

Once defined, you can simply access the queryString property of userQuery to access a full GraphQL query, suitable for use in a GET request to your server:

print(userQuery.queryString)
// {users(userId:1,token:"123456abcd"){user{username,email,points{id,value}}}}

Finally, if you're building a mutation query, simply pass in .Mutation for the GQLSchemaType:

let userQuery = GQLQuery(
	withSchemaType: .Mutation, 
	withQueryTitle: "users", 
	withQueryArguments: args, 
	withQuery: userQueryItem
)

print(userQuery.queryString)
// mutation{users(userId:1,token:"123456abcd"){user{username,email,points{id,value}}}}

Full Example Usage (w/ NSURLSession)

In this example, we're constructing a mutation query for creating a Facebook user on a hypothetical social media platform. Upon a successful creation, we're requestion some user data and an API token.

let userDataQuery = GQLQueryItem(
  withKeyDesignation: "user",
  andSubqueryFields: ["id", "username", "email", "facebookId"]
)

let fullQuery = GQLQuery(
  withSchemaType: .Mutation,
  withQueryTitle: "createFacebookUser",
  withQueryArguments: ["facebookToken": facebookTokenString, "username": "worthbak"],
  withQueryItems: [userDataQuery, "apiToken"]
)

let components = NSURLComponents()
components.scheme = "http"
components.host = "localhost"
components.port = 3000
components.path = "/graphql"

components.query = fullQuery.queryString
guard let url = components.URL else { return }

let request = NSMutableURLRequest(URL: url)
request.HTTPMethod = "POST"

let session = NSURLSession.sharedSession()
let dataTask = session.dataTaskWithRequest(request, completionHandler: { (data, response, error) -> Void in
  if (error != nil) {
    print(error)
  } else {
    guard let data = data else { return }
    
    do {
      let dict = try NSJSONSerialization.JSONObjectWithData(data, options: .AllowFragments) as? NSDictionary
      
      if let dict = dict {
        print(dict)
      }
      
    } catch (let error) {
      print(error)
    }
    
  }
})

dataTask.resume()

To-Do

• Expand unit tests
• Add proper integration with Alamofire, Maya, etc.