pkg/shelf: case-insensitive headers, cleaner Request ctor, a lot more tests

pkg/shelf/lib/src/request.dart

 // Copyright (c) 2014, 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.
 
 library shelf.request;
 
 import 'dart:async';
-import 'dart:collection';
 
-// TODO(kevmoo): use UnmodifiableMapView from SDK once 1.4 ships
-import 'package:collection/wrappers.dart' as pc;
 import 'package:http_parser/http_parser.dart';
-import 'package:path/path.dart' as p;
 
 import 'message.dart';
 
 /// Represents an HTTP request to be processed by a Shelf application.
 class Request extends Message {
-  /// The remainder of the [requestedUri] path designating the virtual
+  /// The remainder of the [requestedUri] path and query designating the virtual
   /// "location" of the request's target within the handler.
   ///
-  /// [pathInfo] may be an empty string, if [requestedUri ]targets the handler
+  /// [url] may be an empty, if [requestedUri]targets the handler
   /// root and does not have a trailing slash.
   ///
-  /// [pathInfo] is never null. If it is not empty, it will start with `/`.
+  /// [url] is never null. If it is not empty, it will start with `/`.
   ///
-  /// [scriptName] and [pathInfo] combine to create a valid path that should
+  /// [scriptName] and [url] combine to create a valid path that should
   /// correspond to the [requestedUri] path.
-  final String pathInfo;
-
-  /// The portion of the request URL that follows the "?", if any.
-  final String queryString;
+  final Uri url;
 
   /// The HTTP request method, such as "GET" or "POST".
   final String method;
 
   /// The initial portion of the [requestedUri] path that corresponds to the
   /// handler.
   ///
   /// [scriptName] allows a handler to know its virtual "location".
   ///
   /// If the handler corresponds to the "root" of a server, it will be an
   /// empty string, otherwise it will start with a `/`
   ///
-  /// [scriptName] and [pathInfo] combine to create a valid path that should
+  /// [scriptName] and [url] combine to create a valid path that should
   /// correspond to the [requestedUri] path.
   final String scriptName;
 
   /// The HTTP protocol version used in the request, either "1.0" or "1.1".
   final String protocolVersion;
 
   /// The original [Uri] for the request.
   final Uri requestedUri;
 
   /// If this is non-`null` and the requested resource hasn't been modified
   /// since this date and time, the server should return a 304 Not Modified
   /// response.
   ///
   /// This is parsed from the If-Modified-Since header in [headers]. If
   /// [headers] doesn't have an If-Modified-Since header, this will be `null`.
   DateTime get ifModifiedSince {
     if (_ifModifiedSinceCache != null) return _ifModifiedSinceCache;
     if (!headers.containsKey('if-modified-since')) return null;
     _ifModifiedSinceCache = parseHttpDate(headers['if-modified-since']);
     return _ifModifiedSinceCache;
   }
   DateTime _ifModifiedSinceCache;
 
-  Request(this.pathInfo, String queryString, this.method,
-      this.scriptName, this.protocolVersion, this.requestedUri,
-      Map<String, String> headers, {Stream<List<int>> body})
-      : this.queryString = queryString == null ? '' : queryString,
-        super(new pc.UnmodifiableMapView(new HashMap.from(headers)),
-            body == null ? new Stream.fromIterable([]) : body) {
+  /// Creates a new [Request].
+  ///
+  /// If [url] and [scriptName] are omitted, they are inferred from
+  /// [requestedUri].
+  ///
+  /// Setting one of [url] or [scriptName] and not the other will throw an
+  /// [ArgumentError].
+  ///
+  /// The default value for [protocolVersion] is '1.1'.
+  // TODO(kevmoo) finish documenting the rest of the arguments.
+  Request(this.method, Uri requestedUri, {String protocolVersion,
+    Map<String, String> headers, Uri url, String scriptName,
+    Stream<List<int>> body})
+      : this.requestedUri = requestedUri,
+        this.protocolVersion = protocolVersion == null ?
+            '1.1' : protocolVersion,
+        this.url = _computeUrl(requestedUri, url, scriptName),
+        this.scriptName = _computeScriptName(requestedUri, url, scriptName),
+        super(body == null ? new Stream.fromIterable([]) : body,
+            headers: headers) {
     if (method.isEmpty) throw new ArgumentError('method cannot be empty.');
 
-    if (scriptName.isNotEmpty && !scriptName.startsWith('/')) {
+    // TODO(kevmoo) use isAbsolute property on Uri once Issue 18053 is fixed
+    if (requestedUri.scheme.isEmpty) {
+      throw new ArgumentError('requstedUri must be an absolute URI.');
+    }
+
+    if (this.scriptName.isNotEmpty && !this.scriptName.startsWith('/')) {
       throw new ArgumentError('scriptName must be empty or start with "/".');
     }
 
-    if (scriptName == '/') {
+    if (this.scriptName == '/') {
       throw new ArgumentError(
           'scriptName can never be "/". It should be empty instead.');
     }
 
-    if (scriptName.endsWith('/')) {
+    if (this.scriptName.endsWith('/')) {
       throw new ArgumentError('scriptName must not end with "/".');
     }
 
-    if (pathInfo.isNotEmpty && !pathInfo.startsWith('/')) {
-      throw new ArgumentError('pathInfo must be empty or start with "/".');
+    if (this.url.path.isNotEmpty && !this.url.path.startsWith('/')) {
+      throw new ArgumentError('url must be empty or start with "/".');
     }
 
-    if (scriptName.isEmpty && pathInfo.isEmpty) {
-      throw new ArgumentError('scriptName and pathInfo cannot both be empty.');
+    if (this.scriptName.isEmpty && this.url.path.isEmpty) {
+      throw new ArgumentError('scriptName and url cannot both be empty.');
     }
   }
+}
 
-  /// Convenience property to access [pathInfo] data as a [List].
-  List<String> get pathSegments {
-    var segs = p.url.split(pathInfo);
-    if (segs.length > 0) {
-      assert(segs.first == p.url.separator);
-      segs.removeAt(0);
-    }
-    return segs;
+/// Computes `url` from the provided [Request] constructor arguments.
+///
+/// If [url] and [scriptName] are `null`, infer value from [requestedUrl],
+/// otherwise return [url].
+///
+/// If [url] is provided, but [scriptName] is omitted, throws an
+/// [ArgumentError].
+Uri _computeUrl(Uri requestedUri, Uri url, String scriptName) {
+  if (url == null && scriptName == null) {
+    return new Uri(path: requestedUri.path, query: requestedUri.query,
+        fragment: requestedUri.fragment);
   }
+
+  if (url != null && scriptName != null) {
+    // TODO(kevmoo) use isAbsolute property on Uri once Issue 18053 is fixed
+    if (url.scheme.isNotEmpty) throw new ArgumentError('url must be relative.');
+    return url;
+  }
+
+  throw new ArgumentError(
+      'url and scriptName must both be null or both be set.');
 }
+
+/// Computes `scriptName` from the provided [Request] constructor arguments.
+///
+/// If [url] and [scriptName] are `null` it returns an empty string, otherwise
+/// [scriptName] is returned.
+///
+/// If [script] is provided, but [url] is omitted, throws an
+/// [ArgumentError].
+String _computeScriptName(Uri requstedUri, Uri url, String scriptName) {
+  if (url == null && scriptName == null) {
+    return '';
+  }
+
+  if (url != null && scriptName != null) {
+    return scriptName;
+  }
+
+  throw new ArgumentError(
+      'url and scriptName must both be null or both be set.');
+}