fix #279: Revisit Key behavior

src/Microsoft.Framework.Configuration.Abstractions/IConfigurationSection.cs

@@ -7,6 +7,7 @@ namespace Microsoft.Framework.Configuration
     public interface IConfigurationSection : IConfiguration
     {
         string Key { get; }
+        string Path { get; }
         string Value { get; set; }
     }
 }

src/Microsoft.Framework.Configuration.Abstractions/IConfigurationSource.cs

@@ -15,7 +15,7 @@ public interface IConfigurationSource
 
         IEnumerable<string> ProduceConfigurationSections(
             IEnumerable<string> earlierKeys,
-            string prefix,
+            string parentPath,
             string delimiter);
     }
 }

src/Microsoft.Framework.Configuration.Binder/ConfigurationBinder.cs

@@ -155,13 +155,6 @@ private static void BindDictionary(object dictionary, Type dictionaryType, IConf
                 if (item != null)
                 {
                     var key = child.Key;
-                    var section = config as IConfigurationSection;
-                    if (section != null)
-                    {
-                        // Remove the parent key and : delimiter to get the configurationSection's key
-                        key = key.Substring(section.Key.Length + 1);
-                    }
-
                     addMethod.Invoke(dictionary, new[] { key, item });
                 }
             }

src/Microsoft.Framework.Configuration/ConfigurationBase.cs

@@ -21,41 +21,17 @@ public ConfigurationBase(IList<IConfigurationSource> sources)
             _sources = sources;
         }
 
+        public abstract string Path { get; }
+
         public string this[string key]
         {
             get
             {
-                if (string.IsNullOrEmpty(key))
-                {
-                    throw new InvalidOperationException(Resources.Error_EmptyKey);
-                }
-
-                // If a key in the newly added configuration source is identical to a key in a
-                // formerly added configuration source, the new one overrides the former one.
-                // So we search in reverse order, starting with latest configuration source.
-                foreach (var src in _sources.Reverse())
-                {
-                    string value = null;
-
-                    if (src.TryGet(GetPrefix() + key, out value))
-                    {
-                        return value;
-                    }
-                }
-
-                return null;
+                return GetSection(key).Value;
             }
             set
             {
-                if (!Sources.Any())
-                {
-                    throw new InvalidOperationException(Resources.Error_NoSources);
-                }
-
-                foreach (var src in Sources)
-                {
-                    src.Set(GetPrefix() + key, value);
-                }
+                GetSection(key).Value = value;
             }
         }
 
@@ -69,29 +45,20 @@ public IList<IConfigurationSource> Sources
 
         public IEnumerable<IConfigurationSection> GetChildren()
         {
-            var prefix = GetPrefix();
-
             var segments = Sources.Aggregate(
                 Enumerable.Empty<string>(),
-                (seed, source) => source.ProduceConfigurationSections(seed, prefix, Constants.KeyDelimiter));
+                (seed, source) => source.ProduceConfigurationSections(seed, Path, Constants.KeyDelimiter));
 
             var distinctSegments = segments.Distinct();
             return distinctSegments.Select(segment =>
             {
-                return new ConfigurationSection(Sources, prefix + segment);
+                return new ConfigurationSection(Sources, Path, segment);
             });
         }
 
         public IConfigurationSection GetSection(string key)
         {
-            if (string.IsNullOrEmpty(key))
-            {
-                throw new InvalidOperationException(Resources.Error_EmptyKey);
-            }
-
-            return new ConfigurationSection(Sources, GetPrefix() + key);
+            return new ConfigurationSection(Sources, Path, key);
         }
-
-        protected abstract string GetPrefix();
     }
 }

src/Microsoft.Framework.Configuration/ConfigurationRoot.cs

@@ -17,17 +17,20 @@ public ConfigurationRoot(IList<IConfigurationSource> sources)
             }
         }
 
-        public void Reload()
+        public override string Path
         {
-            foreach (var src in Sources)
+            get
             {
-                src.Load();
+                return string.Empty;
             }
         }
 
-        protected override string GetPrefix()
+        public void Reload()
         {
-            return string.Empty;
+            foreach (var src in Sources)
+            {
+                src.Load();
+            }
         }
     }
 }

src/Microsoft.Framework.Configuration/ConfigurationSection.cs

@@ -10,26 +10,30 @@ namespace Microsoft.Framework.Configuration
     public class ConfigurationSection : ConfigurationBase, IConfigurationSection
     {
         private readonly string _key;
+        private readonly string _path;
 
-        public ConfigurationSection(IList<IConfigurationSource> sources, string key)
+        public ConfigurationSection(IList<IConfigurationSource> sources, string parentPath, string key)
             : base(sources)
         {
-            if (sources == null)
+            if (parentPath == null)
             {
-                throw new ArgumentNullException(nameof(sources));
-            }
-
-            if (key == null)
-            {
-                throw new ArgumentNullException(nameof(key));
+                throw new ArgumentNullException(nameof(parentPath));
             }
 
             if (string.IsNullOrEmpty(key))
             {
-                throw new InvalidOperationException(Resources.Error_EmptyKey);
+                throw new ArgumentException(Resources.Error_EmptyKey);
             }
 
             _key = key;
+            if (!string.Equals(parentPath, string.Empty))
+            {
+                _path = parentPath + Constants.KeyDelimiter + key;
+            }
+            else
+            {
+                _path = key;
+            }
         }
 
         public string Key
@@ -40,6 +44,14 @@ public string Key
             }
         }
 
+        public override string Path
+        {
+            get
+            {
+                return _path;
+            }
+        }
+
         public string Value
         {
             get
@@ -48,7 +60,7 @@ public string Value
                 {
                     string value = null;
 
-                    if (src.TryGet(_key, out value))
+                    if (src.TryGet(Path, out value))
                     {
                         return value;
                     }
@@ -65,14 +77,9 @@ public string Value
 
                 foreach (var src in Sources)
                 {
-                    src.Set(Key, value);
+                    src.Set(Path, value);
                 }
             }
         }
-
-        protected override string GetPrefix()
-        {
-            return _key + Constants.KeyDelimiter;
-        }
     }
 }

src/Microsoft.Framework.Configuration/ConfigurationSource.cs

@@ -32,20 +32,22 @@ public virtual void Load()
 
         public virtual IEnumerable<string> ProduceConfigurationSections(
             IEnumerable<string> earlierKeys,
-            string prefix,
+            string parentPath,
             string delimiter)
         {
+            parentPath = parentPath + delimiter;
+
             return Data
-                .Where(kv => kv.Key.StartsWith(prefix, StringComparison.OrdinalIgnoreCase))
-                .Select(kv => Segment(kv.Key, prefix, delimiter))
+                .Where(kv => kv.Key.StartsWith(parentPath, StringComparison.OrdinalIgnoreCase))
+                .Select(kv => Segment(kv.Key, parentPath, delimiter))
                 .Concat(earlierKeys)
                 .OrderBy(k => k, ConfigurationKeyComparer.Instance);
         }
 
-        private static string Segment(string key, string prefix, string delimiter)
+        private static string Segment(string key, string parentPath, string delimiter)
         {
-            var indexOf = key.IndexOf(delimiter, prefix.Length, StringComparison.OrdinalIgnoreCase);
-            return indexOf < 0 ? key.Substring(prefix.Length) : key.Substring(prefix.Length, indexOf - prefix.Length);
+            var indexOf = key.IndexOf(delimiter, parentPath.Length, StringComparison.OrdinalIgnoreCase);
+            return indexOf < 0 ? key.Substring(parentPath.Length) : key.Substring(parentPath.Length, indexOf - parentPath.Length);
         }
     }
 }

src/Microsoft.Framework.Configuration/Resources.resx

@@ -118,7 +118,7 @@
     <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
   </resheader>
   <data name="Error_EmptyKey" xml:space="preserve">
-    <value>Empty key is not allowed. </value>
+    <value>Empty or null key is not allowed. </value>
   </data>
   <data name="Error_InvalidReload" xml:space="preserve">
     <value>Reload can only be called on top-level configuration element</value>

test/Microsoft.Framework.Configuration.FunctionalTests/ArrayTests.cs

@@ -62,14 +62,23 @@ public void DifferentConfigSources_Merged_KeysAreSorted()
             var indexConfigurationSections = configurationSection.GetChildren().ToArray();
 
             Assert.Equal(8, indexConfigurationSections.Length);
-            Assert.Equal("address:0", indexConfigurationSections[0].Key);
-            Assert.Equal("address:1", indexConfigurationSections[1].Key);
-            Assert.Equal("address:2", indexConfigurationSections[2].Key);
-            Assert.Equal("address:3", indexConfigurationSections[3].Key);
-            Assert.Equal("address:4", indexConfigurationSections[4].Key);
-            Assert.Equal("address:i", indexConfigurationSections[5].Key);
-            Assert.Equal("address:j", indexConfigurationSections[6].Key);
-            Assert.Equal("address:x", indexConfigurationSections[7].Key);
+            Assert.Equal("0", indexConfigurationSections[0].Key);
+            Assert.Equal("1", indexConfigurationSections[1].Key);
+            Assert.Equal("2", indexConfigurationSections[2].Key);
+            Assert.Equal("3", indexConfigurationSections[3].Key);
+            Assert.Equal("4", indexConfigurationSections[4].Key);
+            Assert.Equal("i", indexConfigurationSections[5].Key);
+            Assert.Equal("j", indexConfigurationSections[6].Key);
+            Assert.Equal("x", indexConfigurationSections[7].Key);
+
+            Assert.Equal("address:0", indexConfigurationSections[0].Path);
+            Assert.Equal("address:1", indexConfigurationSections[1].Path);
+            Assert.Equal("address:2", indexConfigurationSections[2].Path);
+            Assert.Equal("address:3", indexConfigurationSections[3].Path);
+            Assert.Equal("address:4", indexConfigurationSections[4].Path);
+            Assert.Equal("address:i", indexConfigurationSections[5].Path);
+            Assert.Equal("address:j", indexConfigurationSections[6].Path);
+            Assert.Equal("address:x", indexConfigurationSections[7].Path);
         }
 
         [Fact]

test/Microsoft.Framework.Configuration.Json.Test/ArrayTest.cs

@@ -233,12 +233,12 @@ public void PropertiesAreSortedByNumberOnlyFirst()
             var indexConfigurationSections = configurationSection.GetChildren().ToArray();
 
             Assert.Equal(6, indexConfigurationSections.Count());
-            Assert.Equal("setting:4", indexConfigurationSections[0].Key);
-            Assert.Equal("setting:10", indexConfigurationSections[1].Key);
-            Assert.Equal("setting:42", indexConfigurationSections[2].Key);
-            Assert.Equal("setting:1text", indexConfigurationSections[3].Key);
-            Assert.Equal("setting:bob", indexConfigurationSections[4].Key);
-            Assert.Equal("setting:hello", indexConfigurationSections[5].Key);
+            Assert.Equal("4", indexConfigurationSections[0].Key);
+            Assert.Equal("10", indexConfigurationSections[1].Key);
+            Assert.Equal("42", indexConfigurationSections[2].Key);
+            Assert.Equal("1text", indexConfigurationSections[3].Key);
+            Assert.Equal("bob", indexConfigurationSections[4].Key);
+            Assert.Equal("hello", indexConfigurationSections[5].Key);
         }
     }
 }

test/Microsoft.Framework.Configuration.Test/ConfigurationTest.cs

@@ -189,7 +189,7 @@ public void CanGetConfigurationSection()
         }
 
         [Fact]
-        public void CanGetConfigurationSections()
+        public void CanGetConfigurationChildren()
         {
             // Arrange
             var dic1 = new Dictionary<string, string>()
@@ -221,11 +221,11 @@ public void CanGetConfigurationSections()
 
             // Assert
             Assert.Equal(2, configSections.Count());
-            Assert.Equal("MemVal1", configSections.FirstOrDefault(c => c.Key == "Data:DB1")["Connection1"]);
-            Assert.Equal("MemVal2", configSections.FirstOrDefault(c => c.Key == "Data:DB1")["Connection2"]);
-            Assert.Equal("MemVal3", configSections.FirstOrDefault(c => c.Key == "Data:DB2Connection").Value);
-            Assert.False(configSections.Exists(c => c.Key == "Data:DB3"));
-            Assert.False(configSections.Exists(c => c.Key == "Source:DB3"));
+            Assert.Equal("MemVal1", configSections.FirstOrDefault(c => c.Key == "DB1")["Connection1"]);
+            Assert.Equal("MemVal2", configSections.FirstOrDefault(c => c.Key == "DB1")["Connection2"]);
+            Assert.Equal("MemVal3", configSections.FirstOrDefault(c => c.Key == "DB2Connection").Value);
+            Assert.False(configSections.Exists(c => c.Key == "DB3"));
+            Assert.False(configSections.Exists(c => c.Key == "DB3"));
         }
 
         [Fact]