Add support for HTTP proxy in the HTTP client

tests/standalone/io/http_proxy_test.dart

+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+#import("dart:io");
+#import("dart:uri");
+
+class Server {
+  HttpServer server;
+  int proxyHops;
+  int requestCount = 0;
+
+  Server(this.proxyHops) : server = new HttpServer();
+
+  void start() {
+    server.listen("127.0.0.1", 0, 5);

[Mads Ager (google), 2012/10/08 16:59:39]

Maybe leave out the backlog parameter and just use the default one (which is
higher)?

[Søren Gjesse, 2012/10/09 14:05:22]

Done.

+    server.defaultRequestHandler =
+        (HttpRequest request, HttpResponse response) {

[Mads Ager (google), 2012/10/08 16:59:39]

Funky indentation. See the

   if (...) {
} else {
}

below.

[Søren Gjesse, 2012/10/09 14:05:22]

Done.

+          requestCount++;
+          if (proxyHops > 0) {
+            Expect.isNotNull(request.headers[HttpHeaders.VIA]);
+            Expect.equals(1, request.headers[HttpHeaders.VIA].length);
+            Expect.equals(
+                proxyHops,
+                request.headers[HttpHeaders.VIA][0].split(",").length);
+        } else {
+          Expect.isNull(request.headers[HttpHeaders.VIA]);
+        }
+        StringInputStream stream = new StringInputStream(request.inputStream);
+        StringBuffer body = new StringBuffer();
+        stream.onData = () => body.add(stream.read());
+        stream.onClosed = () {
+          String path = request.path.substring(1);
+          String content = "$path$path$path";
+          Expect.equals(content, body.toString());
+          response.outputStream.writeString(request.path);
+          response.outputStream.close();
+       };
+     };
+  }
+
+  void shutdown() {
+    server.close();
+  }
+
+  int get port => server.port;
+}
+
+Server setupServer(int proxyHops) {
+  Server server = new Server(proxyHops);
+  server.start();
+  return server;
+}
+
+class ProxyServer {
+  HttpServer server;
+  HttpClient client;
+  int requestCount = 0;
+
+  ProxyServer() : server = new HttpServer(), client = new HttpClient();
+
+  void start() {
+    server.listen("127.0.0.1", 0, 5);

[Mads Ager (google), 2012/10/08 16:59:39]

Ditto for the backlog param?

[Søren Gjesse, 2012/10/09 14:05:22]

Done.

+    server.defaultRequestHandler =
+        (HttpRequest request, HttpResponse response) {
+          requestCount++;
+          // Open the connection from the proxy.
+          HttpClientConnection conn =
+              client.openUrl(request.method, new Uri.fromString(request.path));
+          conn.onRequest = (HttpClientRequest clientRequest) {
+            // Forward all headers.
+            request.headers.forEach((String name, List<String> values) {
+              values.forEach((String value) {
+                if (name != "content-length" && name != "via") {
+                  clientRequest.headers.add(name, value);
+                }
+              });
+            });
+            // Special handling of Content-Length and Via.
+            clientRequest.contentLength = request.contentLength;
+            List<String> via = request.headers[HttpHeaders.VIA];
+            String viaPrefix = via == null ? "" : "${via[0]}, ";
+            clientRequest.headers.add(
+                HttpHeaders.VIA, "${viaPrefix}1.1 localhost:$port");
+            // Copy all content.
+            request.inputStream.pipe(clientRequest.outputStream);
+          };
+          conn.onResponse = (HttpClientResponse clientResponse) {
+            clientResponse.inputStream.pipe(response.outputStream);
+          };
+        };
+  }
+
+  void shutdown() {
+    server.close();
+    client.shutdown();
+  }
+
+  int get port => server.port;
+}
+
+ProxyServer setupProxyServer() {
+  ProxyServer proxyServer = new ProxyServer();
+  proxyServer.start();
+  return proxyServer;
+}
+
+testInvalidProxy() {
+  HttpClient client = new HttpClient();
+
+  // TODO(sgjesse): This should not throw errors, but call
+  // HttpClientConnection onError.
+  client.findProxy = (Uri uri) => "XXX";
+  Expect.throws(
+      () => client.getUrl(new Uri.fromString("http://www.google.com/test")),
+      (e) => e is HttpException);
+
+  client.findProxy = (Uri uri) => "PROXY www.google.com";
+  Expect.throws(
+      () => client.getUrl(new Uri.fromString("http://www.google.com/test")),
+      (e) => e is HttpException);
+
+  client.findProxy = (Uri uri) => "PROXY www.google.com:http";
+  Expect.throws(
+      () => client.getUrl(new Uri.fromString("http://www.google.com/test")),
+      (e) => e is HttpException);
+}
+
+int testDirectDoneCount = 0;
+void testDirectProxy() {
+  Server server = setupServer(0);
+  HttpClient client = new HttpClient();
+  List<String> proxy =
+      ["DIRECT", " DIRECT ", "DIRECT ;", " DIRECT ; ",
+       ";DIRECT", " ; DIRECT ", ";;DIRECT;;"];
+
+  client.findProxy = (Uri uri) {
+    int index = int.parse(uri.path.substring(1));
+    return proxy[index];
+  };
+
+  for (int i = 0; i < proxy.length; i++) {
+    HttpClientConnection conn =
+        client.getUrl(new Uri.fromString("http://127.0.0.1:${server.port}/$i"));
+    conn.onRequest = (HttpClientRequest clientRequest) {
+      String content = "$i$i$i";
+      clientRequest.contentLength = content.length;
+      clientRequest.outputStream.writeString(content);
+      clientRequest.outputStream.close();
+    };
+    conn.onResponse = (HttpClientResponse response) {
+      response.inputStream.onData = () => response.inputStream.read();
+      response.inputStream.onClosed = () {
+        testDirectDoneCount++;
+        if (testDirectDoneCount == proxy.length) {
+          Expect.equals(proxy.length, server.requestCount);
+          server.shutdown();
+          client.shutdown();
+        }
+      };
+    };
+  }
+}
+
+int testProxyDoneCount = 0;
+void testProxy() {
+  ProxyServer proxyServer = setupProxyServer();
+  Server server = setupServer(1);
+  HttpClient client = new HttpClient();
+
+  List<String> proxy =
+      ["PROXY localhost:${proxyServer.port}",
+       "PROXY localhost:${proxyServer.port}; PROXY hede.hule.hest:8080",
+       "PROXY localhost:${proxyServer.port}; DIRECT"];
+
+  client.findProxy = (Uri uri) {
+    // Pick the proxy configuration based on the request path.
+    int index = int.parse(uri.path.substring(1));
+    return proxy[index];
+  };
+
+  for (int i = 0; i < proxy.length; i++) {
+    HttpClientConnection conn =
+        client.postUrl(
+            new Uri.fromString("http://127.0.0.1:${server.port}/$i"));
+    conn.onRequest = (HttpClientRequest clientRequest) {
+      String content = "$i$i$i";
+      clientRequest.outputStream.writeString(content);
+      clientRequest.outputStream.close();
+    };
+    conn.onResponse = (HttpClientResponse response) {
+      response.inputStream.onData = () => response.inputStream.read();
+      response.inputStream.onClosed = () {
+        testProxyDoneCount++;
+        if (testProxyDoneCount == proxy.length) {
+          Expect.equals(proxy.length, server.requestCount);
+          proxyServer.shutdown();
+          server.shutdown();
+          client.shutdown();
+        }
+      };
+    };
+  }
+}
+
+int testProxyChainDoneCount = 0;
+void testProxyChain() {
+  // Setup two proxy servers having the first using the second as its proxy.
+  ProxyServer proxyServer1 = setupProxyServer();
+  ProxyServer proxyServer2 = setupProxyServer();
+  proxyServer1.client.findProxy = (_) => "PROXY 127.0.0.1:${proxyServer2.port}";
+
+  Server server = setupServer(2);
+  HttpClient client = new HttpClient();
+
+  List<String> proxy =
+      ["PROXY localhost:${proxyServer1.port}",
+       "PROXY localhost:${proxyServer1.port}; PROXY hede.hule.hest:8080",
+       "PROXY localhost:${proxyServer1.port}; DIRECT"];
+
+  client.findProxy = (Uri uri) {
+    // Pick the proxy configuration based on the request path.
+    int index = int.parse(uri.path.substring(1));
+    return proxy[index];
+  };
+
+  for (int i = 0; i < proxy.length; i++) {
+    HttpClientConnection conn =
+        client.getUrl(new Uri.fromString("http://127.0.0.1:${server.port}/$i"));
+    conn.onRequest = (HttpClientRequest clientRequest) {
+      String content = "$i$i$i";
+      clientRequest.contentLength = content.length;
+      clientRequest.outputStream.writeString(content);
+      clientRequest.outputStream.close();
+    };
+    conn.onResponse = (HttpClientResponse response) {
+      response.inputStream.onData = () => response.inputStream.read();
+      response.inputStream.onClosed = () {
+        testProxyChainDoneCount++;
+        if (testProxyChainDoneCount == proxy.length) {
+          Expect.equals(proxy.length, server.requestCount);
+          proxyServer1.shutdown();
+          proxyServer2.shutdown();
+          server.shutdown();
+          client.shutdown();
+        }
+      };
+    };
+  }
+}
+
+int testRealProxyDoneCount = 0;
+void testRealProxy() {
+  Server server = setupServer(1);
+  HttpClient client = new HttpClient();
+
+  List<String> proxy =
+      ["PROXY localhost:8080",
+       "PROXY localhost:8080; PROXY hede.hule.hest:8080",
+       "PROXY localhost:8080; DIRECT"];
+
+  client.findProxy = (Uri uri) {
+    // Pick the proxy configuration based on the request path.
+    int index = int.parse(uri.path.substring(1));
+    return proxy[index];
+  };
+
+  for (int i = 0; i < proxy.length; i++) {
+    HttpClientConnection conn =
+       client.getUrl(new Uri.fromString("http://127.0.0.1:${server.port}/$i"));
+    conn.onRequest = (HttpClientRequest clientRequest) {
+      String content = "$i$i$i";
+      clientRequest.contentLength = content.length;
+      clientRequest.outputStream.writeString(content);
+      clientRequest.outputStream.close();
+    };
+    conn.onResponse = (HttpClientResponse response) {
+      response.inputStream.onData = () => response.inputStream.read();
+      response.inputStream.onClosed = () {
+        testRealProxyDoneCount++;
+        if (testRealProxyDoneCount == proxy.length) {
+          Expect.equals(proxy.length, server.requestCount);
+          server.shutdown();
+          client.shutdown();
+        }
+      };
+    };
+  }
+}
+
+main() {
+  testInvalidProxy();
+  testDirectProxy();
+  testProxy();
+  testProxyChain();
+  // This test is not normally run. It can be used for locally testing
+  // with a real proxy server (e.g. Apache).
+  // testRealProxy();
+}