Add a small proxy example

Received very little testing though :-)

Author: helje5

Package.swift

@@ -14,6 +14,7 @@ let package = Package(
     .executable(name: "httpd-helloworld", targets: [ "httpd-helloworld" ]),
     .executable(name: "connect-static",   targets: [ "connect-static"   ]),
     .executable(name: "express-simple",   targets: [ "express-simple"   ]),
+    .executable(name: "httpproxy",        targets: [ "httpproxy"        ]),
     .executable(name: "servedocc",        targets: [ "servedocc"        ]),
     .executable(name: "todomvc",          targets: [ "todomvc"          ]),
     .executable(name    :   "express-simple-lambda",
@@ -24,7 +25,7 @@ let package = Package(
     // A lot of packages for demonstration purposes, only add what you
     // actually need in your own project.
     .package(url: "https://github.com/Macro-swift/Macro.git",
-             from: "0.8.8"),
+             from: "0.8.10"),
     .package(url: "https://github.com/Macro-swift/MacroExpress.git",
              from: "0.8.6"),
     .package(url: "https://github.com/Macro-swift/MacroLambda.git",
@@ -35,6 +36,7 @@ let package = Package(
 
   targets: [
     .target(name: "httpd-helloworld", dependencies: [ "Macro"        ]),
+    .target(name: "httpproxy",        dependencies: [ "Macro"        ]),
     .target(name: "connect-static",   dependencies: [ "MacroExpress" ]),
     .target(name: "express-simple",   dependencies: [ "MacroExpress", "cows" ]),
     .target(name: "servedocc",        dependencies: [ "MacroExpress" ]),

Sources/httpproxy/main.swift

@@ -0,0 +1,49 @@
+#!/usr/bin/swift sh
+
+import Macro // @Macro-swift
+import Foundation
+
+http.createServer { req, res in
+  // log request
+  req.log.log("\(req.method) \(req.url)")
+
+  guard let url = URL(string: req.url),
+        let scheme = url.scheme, let host = url.host else
+  {
+    req.log.error("Invalid URL:", req.url)
+    res.writeHead(400)
+    res.end()
+    return
+  }
+  
+  let options = http.ClientRequestOptions(
+    headers  : req.headers, // TODO: Add 'Via' and such, drop the proper ones
+    protocol : "\(scheme):",
+    host     : host,
+    method   : req.method,
+    path     : url.path
+  )
+  
+  let proxiedRequest = http.request(options) { proxiedResponse in
+    res.writeHead(proxiedResponse.status,
+                  headers: proxiedResponse.headers)
+    
+    // send proxied response body to the original client
+    proxiedResponse
+      .pipe(res)
+      .onError { error in
+        req.log.error("proxy response delivery failed:", error)
+      }
+  }
+  .onError { error in
+    req.log.error("proxy request delivery failed:", error)
+    res.writeHead(500)
+    res.end()
+  }
+
+  // Send the request body to the target server
+  _ = req.pipe(proxiedRequest)
+}
+.listen(1337) { server in
+  console.log("Server listening on http://0.0.0.0:1337/")
+}