Add an option to gzip compress gql http requests

Package.swift

@@ -36,12 +36,13 @@ let package = Package(
         .package(url: "https://github.com/nicklockwood/SwiftFormat", from: "0.41.2"),
         .package(url: "https://github.com/apple/swift-argument-parser", from: "1.0.0"),
         .package(url: "https://github.com/jpsim/Yams.git", from: "4.0.4"),
+        .package(url: "https://github.com/unstoppablefi/GzipSwift", .upToNextMajor(from: "5.0.0")),
     ],
     targets: [
         /* SwiftGraphQL */
         .target(
             name: "SwiftGraphQL",
-            dependencies: [],
+            dependencies: [.product(name: "Gzip", package: "GzipSwift")],
             path: "Sources/SwiftGraphQL"
         ),
         .target(

Sources/SwiftGraphQL/HTTP.swift

@@ -1,5 +1,6 @@
 //import Combine
 import Foundation
+import Gzip
 
 /*
  SwiftGraphQL has no client as it needs no state. Developers
@@ -25,6 +26,7 @@ public func send<Type, TypeLock>(
     headers: HttpHeaders = [:],
     method: HttpMethod = .post,
     session: URLSession = .shared,
+    compressRequest: Bool = false,
     onComplete completionHandler: @escaping (Response<Type, TypeLock>) -> Void
 ) -> URLSessionDataTask? where TypeLock: GraphQLHttpOperation & Decodable {
     send(
@@ -34,6 +36,7 @@ public func send<Type, TypeLock>(
         headers: headers,
         method: method,
         session: session,
+        compressRequest: compressRequest,
         completionHandler: completionHandler
     )
 }
@@ -59,6 +62,7 @@ public func send<Type, TypeLock>(
     headers: HttpHeaders = [:],
     method: HttpMethod = .post,
     session: URLSession = .shared,
+    compressRequest: Bool = false,
     onComplete completionHandler: @escaping (Response<Type, TypeLock>) -> Void
 ) -> URLSessionDataTask? where TypeLock: GraphQLHttpOperation & Decodable {
     send(
@@ -68,6 +72,7 @@ public func send<Type, TypeLock>(
         headers: headers,
         method: method,
         session: session,
+        compressRequest: compressRequest,
         completionHandler: completionHandler
     )
 }
@@ -81,6 +86,7 @@ private func send<Type, TypeLock>(
     headers: HttpHeaders,
     method: HttpMethod,
     session: URLSession,
+    compressRequest: Bool = false,
     completionHandler: @escaping (Response<Type, TypeLock>) -> Void
 ) -> URLSessionDataTask? where TypeLock: GraphQLOperation & Decodable {
     // Validate that we got a valid url.
@@ -98,6 +104,7 @@ private func send<Type, TypeLock>(
         url: url,
         headers: headers,
         method: method,
+        compressRequest: compressRequest,
         debugTime: debugTime
     )
 
@@ -220,6 +227,7 @@ private func createGraphQLRequest<Type, TypeLock>(
     url: URL,
     headers: HttpHeaders,
     method: HttpMethod,
+    compressRequest: Bool,
     debugTime: UInt64
 ) -> URLRequest where TypeLock: GraphQLOperation & Decodable {
     // Construct a request.
@@ -246,8 +254,12 @@ private func createGraphQLRequest<Type, TypeLock>(
     }
     #endif
     #endif
-    let encoded = try! encoder.encode(payload)
-    request.httpBody = encoded
+    request.httpBody = try? encoder.encode(payload)
+
+    if compressRequest, let gzipped = try? encoder.encode(payload) {
+        request.httpBody = gzipped
+        request.setValue("gzip", forHTTPHeaderField: "Content-Encoding")
+    }
 
     return request
 }