add new example that uses an async lambda handler

Author: tonisuter

Examples/RESTCountries/.gitignore

@@ -0,0 +1,4 @@
+.DS_Store
+/.build
+/Packages
+/*.xcodeproj

Examples/RESTCountries/Package.resolved

@@ -0,0 +1,8 @@
+{
+  "object": {
+    "pins": [
+
+    ]
+  },
+  "version": 1
+}

Examples/RESTCountries/Package.swift

@@ -0,0 +1,16 @@
+// swift-tools-version:4.2
+
+import PackageDescription
+
+let package = Package(
+    name: "RESTCountries",
+    dependencies: [
+        .package(path: "../../"),
+    ],
+    targets: [
+        .target(
+            name: "RESTCountries",
+            dependencies: ["AWSLambdaSwift"]
+        ),
+    ]
+)

Examples/RESTCountries/Sources/RESTCountries/main.swift

@@ -0,0 +1,44 @@
+import AWSLambdaSwift
+import Foundation
+
+struct Input: Codable {
+    let countryCode: String
+}
+
+struct Country: Codable {
+    let name: String
+    let capital: String
+    let population: Int
+}
+
+struct Output: Codable {
+    let country: Country?
+}
+
+func fetchCountry(input: Input, context: Context, completionHandler: @escaping (Output) -> Void) {
+    guard let url = URL(string: "http://restcountries.eu/rest/v2/alpha/\(input.countryCode)") else {
+        completionHandler(Output(country: nil))
+        return
+    }
+
+    let session = URLSession(configuration: .default)
+    let dataTask = session.dataTask(with: url) { data, _, error in
+        guard error == nil, let data = data else {
+            completionHandler(Output(country: nil))
+            return
+        }
+
+        let jsonDecoder = JSONDecoder()
+        guard let country = try? jsonDecoder.decode(Country.self, from: data) else {
+            completionHandler(Output(country: nil))
+            return
+        }
+
+        completionHandler(Output(country: country))
+    }
+    dataTask.resume()
+}
+
+let runtime = try Runtime()
+runtime.registerLambda("fetchCountry", handlerFunction: fetchCountry)
+try runtime.start()

Makefile

@@ -4,6 +4,9 @@ EXAMPLE_PROJECT_PATH=Examples/SquareNumber
 # EXAMPLE_LAMBDA=SyntaxHighlighter
 # EXAMPLE_EXECUTABLE=SyntaxHighlighter
 # EXAMPLE_PROJECT_PATH=Examples/SyntaxHighlighter
+# EXAMPLE_LAMBDA=RESTCountries
+# EXAMPLE_EXECUTABLE=RESTCountries
+# EXAMPLE_PROJECT_PATH=Examples/RESTCountries
 LAMBDA_ZIP=lambda.zip
 SHARED_LIBS_FOLDER=swift-shared-libs
 LAYER_ZIP=swift-lambda-runtime.zip