Investigate having support for union (#10)

* Investigate having support for union

* Add some extra union<Type> functions

* Update StarWarsTests to include a working Union example

Author: williambailey

Sources/Graphiti/Schema/Schema.swift

@@ -117,6 +117,50 @@ public final class SchemaBuilder<Root, Context> {
         map(Type.self, to: interfaceType)
     }
 
+    public func union<Type>(
+        type: Type.Type,
+        members: [Any.Type]
+        ) throws {
+        let name = fixName(String(describing: Type.self))
+        try union(name: name, type: type, members: members)
+    }
+
+    public func union<Type>(
+        name: String,
+        type: Type.Type,
+        members: [Any.Type]
+    ) throws {
+        try union(name: name, type: type) { builder in
+            builder.types = members
+        }
+    }
+
+    public func union<Type>(
+        type: Type.Type,
+        build: (UnionTypeBuilder<Type>) throws -> Void
+        ) throws {
+        let name = fixName(String(describing: Type.self))
+        try union(name: name, type: type, build: build)
+    }
+
+    public func union<Type>(
+        name: String,
+        type: Type.Type,
+        build: (UnionTypeBuilder<Type>) throws -> Void
+        ) throws {
+        let builder = UnionTypeBuilder<Type>()
+        try build(builder)
+
+        let interfaceType = try GraphQLUnionType(
+            name: name,
+            description: builder.description,
+            resolveType: builder.resolveType,
+            types: builder.types.map { try getObjectType(from: $0) }
+        )
+
+        map(Type.self, to: interfaceType)
+    }
+
     public func `enum`<Type : OutputType>(
         type: Type.Type,
         build: (EnumTypeBuilder<Type>) throws -> Void
@@ -517,3 +561,4 @@ public struct Schema<Root, Context> {
         )
     }
 }
+

Sources/Graphiti/Types/UnionType.swift

@@ -0,0 +1,8 @@
+import GraphQL
+
+public final class UnionTypeBuilder<Type> {
+    public var description: String? = nil
+    public var resolveType: GraphQLTypeResolve? = nil
+    public var types: [Any.Type] = []
+}
+

Tests/GraphitiTests/StarWarsTests/StarWarsData.swift

@@ -60,9 +60,19 @@ struct Droid : Character {
     let primaryFunction: String
 }
 
+protocol SearchResult {}
+extension Planet: SearchResult {}
+extension Human: SearchResult {}
+extension Droid: SearchResult {}
+
 var tatooine = Planet(id:"10001", name: "Tatooine", diameter: 10465, rotationPeriod: 23, orbitalPeriod: 304,residents: [Human]() )
 var alderaan = Planet(id: "10002", name: "Alderaan", diameter: 12500, rotationPeriod: 24, orbitalPeriod: 364, residents: [Human]())
 
+let planetData: [String: Planet] = [
+    "10001": tatooine,
+    "10002": alderaan,
+]
+
 let luke = Human(
     id: "1000",
     name: "Luke Skywalker",
@@ -193,3 +203,30 @@ func getSecretBackStory() throws -> String? {
     throw Secret(description: "secretBackstory is secret.")
 }
 
+/**
+ * Allos us to query for either a Human, Droid, or Planet.
+ */
+func search(for value: String) -> [SearchResult] {
+    let value = value.lowercased()
+    var result: [SearchResult] = []
+
+    result.append(contentsOf: 
+        planetData.filter({
+            return $1.name.lowercased().range(of:value) != nil
+        }).map({ $1 })
+    )
+
+    result.append(contentsOf:
+        humanData.filter({
+            return $1.name.lowercased().range(of:value) != nil
+        }).map({ $1 })
+    )
+
+    result.append(contentsOf:
+        droidData.filter({
+            return $1.name.lowercased().range(of:value) != nil
+        }).map({ $1 })
+    )
+
+    return result
+}

Tests/GraphitiTests/StarWarsTests/StarWarsIntrospectionTests.swift

@@ -40,10 +40,12 @@ class StarWarsIntrospectionTests : XCTestCase {
                         [
                             "name": "Query",
                         ],
+                        [
+                            "name": "SearchResult",
+                        ],
                         [
                             "name": "String",
                         ],
-
                         [
                             "name": "__Directive",
                         ],
@@ -125,6 +127,9 @@ class StarWarsIntrospectionTests : XCTestCase {
                         [
                             "name": "Query",
                         ],
+                        [
+                            "name": "SearchResult",
+                        ],
                         [
                             "name": "String",
                         ],
@@ -467,6 +472,24 @@ class StarWarsIntrospectionTests : XCTestCase {
                                     ],
                                 ],
                             ],
+                            [
+                                "name": "search",
+                                "args": [
+                                    [
+                                        "name": "query",
+                                        "description": "text to find",
+                                        "type": [
+                                            "name": nil,
+                                            "kind": "NON_NULL",
+                                            "ofType": [
+                                                "name": "String",
+                                                "kind": "SCALAR",
+                                            ]
+                                        ],
+                                        "defaultValue": nil,
+                                    ],
+                                ],
+                            ],
                         ],
                     ],
                 ],

Tests/GraphitiTests/StarWarsTests/StarWarsQueryTests.swift

@@ -490,6 +490,38 @@ class StarWarsQueryTests : XCTestCase {
         let result = try schema.execute(request: query)
         XCTAssertEqual(result, expected)
     }
+
+    func testSearchQuery() throws {
+        let query = "query {" +
+            "    search(query: \"o\") {" +
+            "        ... on Planet {" +
+            "            name " +
+            "            diameter " +
+            "        }" +
+            "        ... on Human {" +
+            "            name " +
+            "        }" +
+            "        ... on Droid {" +
+            "            name " +
+            "            primaryFunction " +
+            "        }" +
+            "    }" +
+            "}"
+
+        let expected: Map = [
+            "data": [
+                "search": [
+                    [ "name": "Tatooine", "diameter": 10465 ],
+                    [ "name": "Han Solo" ],
+                    [ "name": "Leia Organa" ],
+                    [ "name": "C-3PO", "primaryFunction": "Protocol" ],
+                ],
+            ],
+            ]
+
+        let result = try starWarsSchema.execute(request: query)
+        XCTAssertEqual(result, expected)
+    }
 }
 
 extension StarWarsQueryTests {

Tests/GraphitiTests/StarWarsTests/StarWarsSchema.swift

@@ -252,6 +252,15 @@ let starWarsSchema = try! Schema<NoRoot, NoContext> { schema in
         )
     }
 
+    /**
+     * A search result can be a include a number of different types.
+     *
+     * This implements the following type system shorthand:
+     *
+     * union SearchResult = Planet | Human | Droid
+     */
+    try schema.union(type: SearchResult.self, members: [ Planet.self, Human.self, Droid.self ])
+
     /**
      * This is the type that will be the root of our query, and the
      * entry point into our schema. It gives us the ability to fetch
@@ -264,6 +273,7 @@ let starWarsSchema = try! Schema<NoRoot, NoContext> { schema in
      *         hero(episode: Episode): Character
      *         human(id: String!): Human
      *         droid(id: String!): Droid
+     *         search(query: String!): SearchResult
      *     }
      */
     try schema.query { query in
@@ -298,6 +308,16 @@ let starWarsSchema = try! Schema<NoRoot, NoContext> { schema in
         try query.field(name: "droid") { (_, arguments: DroidArguments, _, _) in
             getDroid(id: arguments.id)
         }
+
+        struct SearchArguments : Arguments {
+            let query: String
+            static let descriptions = ["query": "text to find"]
+        }
+
+        try query.field(name: "search") { (_, arguments: SearchArguments, _, _) in
+            search(for: arguments.query)
+        }
+
     }
 
     schema.types = [Human.self, Droid.self]