Add a function for finding the HTTP proxy server from environment variables

R=ager@google.com

BUG=https://code.google.com/p/dart/issues/detail?id=5468

Review URL: https://codereview.chromium.org//12866005

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@20202 260f80e4-7a28-3924-810f-c04153c831b5

sdk/lib/io/http.dart

@@ -866,9 +866,63 @@ abstract class HttpClient {
    * separated by semicolons, e.g.
    *
    *   "PROXY host:port; PROXY host2:port2; DIRECT"
+   *
+   * The static function [findProxyFromEnvironment] on this class can
+   * be used to implement proxy server resolving based on environment
+   * variables.
    */
   set findProxy(String f(Uri url));
 
+  /**
+   * Function for resolving the proxy server to be used for a HTTP
+   * connection from the proxy configuration specified through
+   * environment variables.
+   *
+   * The following environment variables are taken into account:
+   *
+   *  * http_proxy
+   *  * https_proxy
+   *  * no_proxy
+   *  * HTTP_PROXY
+   *  * HTTPS_PROXY
+   *  * NO_PROXY
+   *
+   * [:http_proxy:] and [:HTTP_PROXY:] specify the proxy server to use for
+   * http:// urls. Use the format [:hostname:port:]. If no port is used a
+   * default of 1080 will be used. If both are set the lower case one takes
+   * precedence.
+   *
+   * [:https_proxy:] and [:HTTPS_PROXY:] specify the proxy server to use for
+   * https:// urls. Use the format [:hostname:port:]. If no port is used a
+   * default of 1080 will be used. If both are set the lower case one takes
+   * precedence.
+   *
+   * [:no_proxy:] and [:NO_PROXY:] specify a comma separated list of
+   * postfixes of hostnames for which not to use the proxy
+   * server. E.g. the value "localhost,127.0.0.1" will make requests
+   * to both "localhost" and "127.0.0.1" not use a proxy. If both are set
+   * the lower case one takes precedence.
+   *
+   * To activate this way of resolving proxies assign this function to
+   * the [findProxy] property on the [HttpClient].
+   *
+   *   HttpClient client = new HttpClient();
+   *   client.findProxy = HttpClient.findProxyFromEnvironment;
+   *
+   * If you don't want to use the system environment you can use a
+   * different one by wrapping the function.
+   *
+   *   HttpClient client = new HttpClient();
+   *   client.findProxy = (url) {
+   *     return HttpClient.findProxyFromEnvironment(
+   *         url, {"http_proxy": ..., "no_proxy": ...});
+   *   }
+   */
+  static String findProxyFromEnvironment(Uri url,
+                                         {Map<String, String> environment}) {
+    return _HttpClient._findProxyFromEnvironment(url, environment);
+  }
+
   /**
    * Shutdown the HTTP client. If [force] is [:false:] (the default)
    * the [:HttpClient:] will be kept alive until all active

sdk/lib/io/http_impl.dart

@@ -1258,6 +1258,56 @@ class _HttpClient implements HttpClient {
       _credentials.removeAt(index);
     }
   }
+
+  static String _findProxyFromEnvironment(Uri url,
+                                          Map<String, String> environment) {
+    checkNoProxy(String option) {
+      if (option == null) return null;
+      Iterator<String> names = option.split(",").map((s) => s.trim()).iterator;
+      while (names.moveNext()) {
+        if (url.domain.endsWith(names.current)) {
+          return "DIRECT";
+        }
+      }
+      return null;
+    }
+
+    checkProxy(String option) {
+      if (option == null) return null;
+      int pos = option.indexOf("://");
+      if (pos >= 0) {
+        option = option.substring(pos + 3);
+      }
+      if (option.indexOf(":") == -1) option = "$option:1080";
+      return "PROXY $option";
+    }
+
+    // Default to using the process current environment.
+    if (environment == null) environment = Platform.environment;
+
+    String proxyCfg;
+
+    String noProxy = environment["no_proxy"];
+    if (noProxy == null) noProxy = environment["NO_PROXY"];
+    if ((proxyCfg = checkNoProxy(noProxy)) != null) {
+      return proxyCfg;
+    }
+
+    if (url.scheme == "http") {
+      String proxy = environment["http_proxy"];
+      if (proxy == null) proxy = environment["HTTP_PROXY"];
+      if ((proxyCfg = checkProxy(proxy)) != null) {
+        return proxyCfg;
+      }
+    } else if (url.scheme == "https") {
+      String proxy = environment["https_proxy"];
+      if (proxy == null) proxy = environment["HTTPS_PROXY"];
+      if ((proxyCfg = checkProxy(proxy)) != null) {
+        return proxyCfg;
+      }
+    }
+    return "DIRECT";
+  }
 }
 
 

tests/standalone/io/http_proxy_configuration_test.dart

@@ -0,0 +1,59 @@
+// Copyright (c) 2013, 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";
+
+expect(expected, String uri, environment) {
+  Expect.equals(expected,
+                HttpClient.findProxyFromEnvironment(Uri.parse(uri),
+                                                    environment: environment));
+}
+
+expectDirect(String uri, environment) {
+  Expect.equals("DIRECT",
+                HttpClient.findProxyFromEnvironment(Uri.parse(uri),
+                                                    environment: environment));
+}
+
+main() {
+  expectDirect("http://www.google.com", {});
+  expect("PROXY www.proxy.com:1080",
+         "http://www.google.com",
+         {"http_proxy": "www.proxy.com"});
+  expect("PROXY www.proxys.com:1080",
+         "https://www.google.com",
+         {"https_proxy": "www.proxys.com"});
+  expect("PROXY www.proxy.com:8080",
+         "http://www.google.com",
+         {"http_proxy": "www.proxy.com:8080"});
+  expect("PROXY www.proxys.com:8080",
+         "https://www.google.com",
+         {"https_proxy": "www.proxys.com:8080"});
+  expect("PROXY www.proxy.com:8080",
+         "http://www.google.com",
+         {"http_proxy": "www.proxy.com:8080",
+          "https_proxy": "www.proxy.com:8080"});
+  expect("PROXY www.proxys.com:8080",
+         "https://www.google.com",
+         {"http_proxy": "www.proxy.com:8080",
+          "https_proxy": "www.proxys.com:8080"});
+  expectDirect("http://www.google.com",
+               {"http_proxy": "www.proxy.com:8080",
+                "no_proxy": "www.google.com"});
+  expectDirect("http://www.google.com",
+               {"http_proxy": "www.proxy.com:8080",
+                "no_proxy": "google.com"});
+  expectDirect("http://www.google.com",
+               {"http_proxy": "www.proxy.com:8080",
+                "no_proxy": ".com"});
+  expectDirect("http://www.google.com",
+               {"http_proxy": "www.proxy.com:8080",
+                "no_proxy": ",,  , www.google.edu,,.com    "});
+  expectDirect("http://www.google.edu",
+               {"http_proxy": "www.proxy.com:8080",
+                "no_proxy": ",,  , www.google.edu,,.com    "});
+  expectDirect("http://www.google.com",
+               {"https_proxy": "www.proxy.com:8080"});
+}

tests/standalone/io/http_proxy_test.dart

@@ -232,6 +232,7 @@ void testProxy() {
               testProxyDoneCount++;
               if (testProxyDoneCount == proxy.length * 2) {
                 Expect.equals(proxy.length, server.requestCount);
+                Expect.equals(proxy.length, secureServer.requestCount);
                 proxyServer.shutdown();
                 server.shutdown();
                 secureServer.shutdown();
@@ -311,6 +312,56 @@ void testProxyChain() {
   });
 }
 
+int testProxyFromEnviromentDoneCount = 0;
+void testProxyFromEnviroment() {
+  setupProxyServer().then((proxyServer) {
+  setupServer(1).then((server) {
+  setupServer(1, secure: true).then((secureServer) {
+    HttpClient client = new HttpClient();
+
+    client.findProxy = (Uri uri) {
+      return HttpClient.findProxyFromEnvironment(
+          uri,
+          environment: {"http_proxy": "localhost:${proxyServer.port}",
+                        "https_proxy": "localhost:${proxyServer.port}"});
+    };
+
+    const int loopCount = 5;
+    for (int i = 0; i < loopCount; i++) {
+      test(bool secure) {
+        String url = secure
+            ? "https://localhost:${secureServer.port}/$i"
+            : "http://127.0.0.1:${server.port}/$i";
+
+        client.postUrl(Uri.parse(url))
+          .then((HttpClientRequest clientRequest) {
+            String content = "$i$i$i";
+            clientRequest.write(content);
+            return clientRequest.close();
+          })
+          .then((HttpClientResponse response) {
+            response.listen((_) {}, onDone: () {
+              testProxyFromEnviromentDoneCount++;
+              if (testProxyFromEnviromentDoneCount == loopCount * 2) {
+                Expect.equals(loopCount, server.requestCount);
+                Expect.equals(loopCount, secureServer.requestCount);
+                proxyServer.shutdown();
+                server.shutdown();
+                secureServer.shutdown();
+                client.close();
+              }
+            });
+          });
+      }
+
+      test(false);
+      test(true);
+    }
+  });
+  });
+  });
+}
+
 int testRealProxyDoneCount = 0;
 void testRealProxy() {
   setupServer(1).then((server) {
@@ -363,6 +414,7 @@ main() {
   testDirectProxy();
   testProxy();
   testProxyChain();
+  testProxyFromEnviroment();
   // This test is not normally run. It can be used for locally testing
   // with a real proxy server (e.g. Apache).
   //testRealProxy();