diff options
Diffstat (limited to 'src/csharp/Grpc.Core/Metadata.cs')
| -rw-r--r-- | src/csharp/Grpc.Core/Metadata.cs | 130 |
1 files changed, 109 insertions, 21 deletions
diff --git a/src/csharp/Grpc.Core/Metadata.cs b/src/csharp/Grpc.Core/Metadata.cs index 9db2abf46e..99fe0b5478 100644 --- a/src/csharp/Grpc.Core/Metadata.cs +++ b/src/csharp/Grpc.Core/Metadata.cs @@ -41,11 +41,22 @@ using Grpc.Core.Utils; namespace Grpc.Core { /// <summary> - /// Provides access to read and write metadata values to be exchanged during a call. + /// A collection of metadata entries that can be exchanged during a call. + /// gRPC supports these types of metadata: + /// <list type="bullet"> + /// <item><term>Request headers</term><description>are sent by the client at the beginning of a remote call before any request messages are sent.</description></item> + /// <item><term>Response headers</term><description>are sent by the server at the beginning of a remote call handler before any response messages are sent.</description></item> + /// <item><term>Response trailers</term><description>are sent by the server at the end of a remote call along with resulting call status.</description></item> + /// </list> /// </summary> public sealed class Metadata : IList<Metadata.Entry> { /// <summary> + /// All binary headers should have this suffix. + /// </summary> + public const string BinaryHeaderSuffix = "-bin"; + + /// <summary> /// An read-only instance of metadata containing no entries. /// </summary> public static readonly Metadata Empty = new Metadata().Freeze(); @@ -53,21 +64,19 @@ namespace Grpc.Core readonly List<Entry> entries; bool readOnly; + /// <summary> + /// Initializes a new instance of <c>Metadata</c>. + /// </summary> public Metadata() { this.entries = new List<Entry>(); } - public Metadata(ICollection<Entry> entries) - { - this.entries = new List<Entry>(entries); - } - /// <summary> /// Makes this object read-only. /// </summary> /// <returns>this object</returns> - public Metadata Freeze() + internal Metadata Freeze() { this.readOnly = true; return this; @@ -181,23 +190,49 @@ namespace Grpc.Core private static readonly Encoding Encoding = Encoding.ASCII; readonly string key; - string value; - byte[] valueBytes; + readonly string value; + readonly byte[] valueBytes; + + private Entry(string key, string value, byte[] valueBytes) + { + this.key = key; + this.value = value; + this.valueBytes = valueBytes; + } + /// <summary> + /// Initializes a new instance of the <see cref="Grpc.Core.Metadata.Entry"/> struct with a binary value. + /// </summary> + /// <param name="key">Metadata key, needs to have suffix indicating a binary valued metadata entry.</param> + /// <param name="valueBytes">Value bytes.</param> public Entry(string key, byte[] valueBytes) { - this.key = Preconditions.CheckNotNull(key, "key"); + this.key = NormalizeKey(key); + Preconditions.CheckArgument(this.key.EndsWith(BinaryHeaderSuffix), + "Key for binary valued metadata entry needs to have suffix indicating binary value."); this.value = null; - this.valueBytes = Preconditions.CheckNotNull(valueBytes, "valueBytes"); + Preconditions.CheckNotNull(valueBytes, "valueBytes"); + this.valueBytes = new byte[valueBytes.Length]; + Buffer.BlockCopy(valueBytes, 0, this.valueBytes, 0, valueBytes.Length); // defensive copy to guarantee immutability } + /// <summary> + /// Initializes a new instance of the <see cref="Grpc.Core.Metadata.Entry"/> struct holding an ASCII value. + /// </summary> + /// <param name="key">Metadata key, must not use suffix indicating a binary valued metadata entry.</param> + /// <param name="value">Value string. Only ASCII characters are allowed.</param> public Entry(string key, string value) { - this.key = Preconditions.CheckNotNull(key, "key"); + this.key = NormalizeKey(key); + Preconditions.CheckArgument(!this.key.EndsWith(BinaryHeaderSuffix), + "Key for ASCII valued metadata entry cannot have suffix indicating binary value."); this.value = Preconditions.CheckNotNull(value, "value"); this.valueBytes = null; } + /// <summary> + /// Gets the metadata entry key. + /// </summary> public string Key { get @@ -206,33 +241,86 @@ namespace Grpc.Core } } + /// <summary> + /// Gets the binary value of this metadata entry. + /// </summary> public byte[] ValueBytes { get { if (valueBytes == null) { - valueBytes = Encoding.GetBytes(value); + return Encoding.GetBytes(value); } - return valueBytes; + + // defensive copy to guarantee immutability + var bytes = new byte[valueBytes.Length]; + Buffer.BlockCopy(valueBytes, 0, bytes, 0, valueBytes.Length); + return bytes; } } + /// <summary> + /// Gets the string value of this metadata entry. + /// </summary> public string Value { get { - if (value == null) - { - value = Encoding.GetString(valueBytes); - } - return value; + Preconditions.CheckState(!IsBinary, "Cannot access string value of a binary metadata entry"); + return value ?? Encoding.GetString(valueBytes); } } - + + /// <summary> + /// Returns <c>true</c> if this entry is a binary-value entry. + /// </summary> + public bool IsBinary + { + get + { + return value == null; + } + } + + /// <summary> + /// Returns a <see cref="System.String"/> that represents the current <see cref="Grpc.Core.Metadata.Entry"/>. + /// </summary> public override string ToString() { - return string.Format("[Entry: key={0}, value={1}]", Key, Value); + if (IsBinary) + { + return string.Format("[Entry: key={0}, valueBytes={1}]", key, valueBytes); + } + + return string.Format("[Entry: key={0}, value={1}]", key, value); + } + + /// <summary> + /// Gets the serialized value for this entry. For binary metadata entries, this leaks + /// the internal <c>valueBytes</c> byte array and caller must not change contents of it. + /// </summary> + internal byte[] GetSerializedValueUnsafe() + { + return valueBytes ?? Encoding.GetBytes(value); + } + + /// <summary> + /// Creates a binary value or ascii value metadata entry from data received from the native layer. + /// We trust C core to give us well-formed data, so we don't perform any checks or defensive copying. + /// </summary> + internal static Entry CreateUnsafe(string key, byte[] valueBytes) + { + if (key.EndsWith(BinaryHeaderSuffix)) + { + return new Entry(key, null, valueBytes); + } + return new Entry(key, Encoding.GetString(valueBytes), null); + } + + private static string NormalizeKey(string key) + { + return Preconditions.CheckNotNull(key, "key").ToLower(); } } } |