Follow the redirect rules from RFC 2616

tests/standalone/io/http_redirect_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");
 
 HttpServer setupServer() {
   HttpServer server = new HttpServer();
@@ skipping 69 matching lines @@
      }
   );
   server.addRequestHandler(
      (HttpRequest request) => request.path == "/target",
      (HttpRequest request, HttpResponse response) {
        Expect.equals("value", request.headers.value("X-Request-Header"));
        response.outputStream.close();
      }
   );
 
+  // Setup redirect for 301 where POST should not redirect.
+  server.addRequestHandler(
+     (HttpRequest request) => request.path == "/301src",
+     (HttpRequest request, HttpResponse response) {
+       Expect.equals("POST", request.method);
+       response.headers.set(HttpHeaders.LOCATION,
+                            "http://127.0.0.1:${server.port}/301target");
+       response.statusCode = HttpStatus.MOVED_PERMANENTLY;
+       response.outputStream.close();
+     }
+  );
+  server.addRequestHandler(
+     (HttpRequest request) => request.path == "/301target",
+     (HttpRequest request, HttpResponse response) {
+       Expect.fail("Redirect of POST should not happen");
+     }
+  );
+
+  // Setup redirect for 303 where POST should turn into GET.
+  server.addRequestHandler(
+     (HttpRequest request) => request.path == "/303src",
+     (HttpRequest request, HttpResponse response) {
+       Expect.equals("POST", request.method);
+       response.headers.set(HttpHeaders.LOCATION,
+                            "http://127.0.0.1:${server.port}/303target");
+       response.statusCode = HttpStatus.SEE_OTHER;
+       response.outputStream.close();
+     }
+  );
+  server.addRequestHandler(
+     (HttpRequest request) => request.path == "/303target",
+     (HttpRequest request, HttpResponse response) {
+       Expect.equals("GET", request.method);
+       response.outputStream.close();
+     }
+  );
+
   return server;
 }
 
 void checkRedirects(int redirectCount, HttpClientConnection conn) {
   if (redirectCount < 2) {
     Expect.isNull(conn.redirects);
   } else {
     Expect.equals(redirectCount - 1, conn.redirects.length);
     for (int i = 0; i < redirectCount - 2; i++) {
       Expect.equals(conn.redirects[i].location.path, "/${i + 2}");
@@ skipping 105 matching lines @@
     };
   };
 
   HttpClientConnection conn =
       client.getUrl(new Uri.fromString("http://127.0.0.1:${server.port}/src"));
   conn.onRequest = onRequest;
   conn.onResponse = onResponse;
   conn.onError = (e) => Expect.fail("Error not expected ($e)");
 }
 
+void testAutoRedirect301POST() {
+  HttpServer server = setupServer();
+  HttpClient client = new HttpClient();
+
+  var requestCount = 0;
+
+  void onRequest(HttpClientRequest request) {
+    requestCount++;
+    request.outputStream.close();
+  };
+
+  void onResponse(HttpClientResponse response) {
+    Expect.equals(HttpStatus.MOVED_PERMANENTLY, response.statusCode);
+    response.inputStream.onData =
+        () => Expect.fail("Response data not expected");
+    response.inputStream.onClosed = () {
+      Expect.equals(1, requestCount);
+      server.close();
+      client.shutdown();
+    };
+  };
+
+  HttpClientConnection conn =
+      client.postUrl(
+          new Uri.fromString("http://127.0.0.1:${server.port}/301src"));
+  conn.onRequest = onRequest;
+  conn.onResponse = onResponse;
+  conn.onError = (e) => Expect.fail("Error not expected ($e)");
+}
+
+void testAutoRedirect303POST() {
+  HttpServer server = setupServer();
+  HttpClient client = new HttpClient();
+
+  var requestCount = 0;
+
+  void onRequest(HttpClientRequest request) {
+    requestCount++;
+    request.outputStream.close();
+  };
+
+  void onResponse(HttpClientResponse response) {
+    Expect.equals(HttpStatus.OK, response.statusCode);
+    response.inputStream.onData =
+        () => Expect.fail("Response data not expected");
+    response.inputStream.onClosed = () {
+      Expect.equals(1, requestCount);
+      server.close();
+      client.shutdown();
+    };
+  };
+
+  HttpClientConnection conn =
+      client.postUrl(
+          new Uri.fromString("http://127.0.0.1:${server.port}/303src"));
+  conn.onRequest = onRequest;
+  conn.onResponse = onResponse;
+  conn.onError = (e) => Expect.fail("Error not expected ($e)");
+}
+
 void testAutoRedirectLimit() {
   HttpServer server = setupServer();
   HttpClient client = new HttpClient();
 
   HttpClientConnection conn =
       client.getUrl(new Uri.fromString("http://127.0.0.1:${server.port}/1"));
   conn.onResponse = (HttpClientResponse response) {
     response.inputStream.onData = () => Expect.fail("Response not expected");
     response.inputStream.onClosed = () => Expect.fail("Response not expected");
   };
@@ skipping 22 matching lines @@
     server.close();
     client.shutdown();
   };
 }
 
 main() {
   testManualRedirect();
   testManualRedirectWithHeaders();
   testAutoRedirect();
   testAutoRedirectWithHeaders();
+  testAutoRedirect301POST();
+  testAutoRedirect303POST();
   testAutoRedirectLimit();
   testRedirectLoop();
 }