Allow multiple meta headers (#103)

Author: flobernd

src/Elastic.Transport/Components/TransportClient/HttpTransportClient.cs

@@ -380,10 +380,13 @@ private static HttpRequestMessage CreateRequestMessage(RequestData requestData)
 
 		if (requestData.MetaHeaderProvider is not null)
 		{
-			var value = requestData.MetaHeaderProvider.ProduceHeaderValue(requestData);
+			foreach (var producer in requestData.MetaHeaderProvider.Producers)
+			{
+				var value = producer.ProduceHeaderValue(requestData);
 
-			if (!string.IsNullOrEmpty(value))
-				requestMessage.Headers.TryAddWithoutValidation(requestData.MetaHeaderProvider.HeaderName, value);
+				if (!string.IsNullOrEmpty(value))
+					requestMessage.Headers.TryAddWithoutValidation(producer.HeaderName, value);
+			}
 		}
 
 		return requestMessage;

src/Elastic.Transport/Components/TransportClient/HttpWebRequestTransportClient.cs

@@ -325,12 +325,15 @@ private static HttpWebRequest CreateWebRequest(RequestData requestData)
 		if (requestData.Headers != null && requestData.Headers.HasKeys())
 			request.Headers.Add(requestData.Headers);
 
-		if (requestData.MetaHeaderProvider is object)
+		if (requestData.MetaHeaderProvider is not null)
 		{
-			var value = requestData.MetaHeaderProvider.ProduceHeaderValue(requestData);
+			foreach (var producer in requestData.MetaHeaderProvider.Producers)
+			{
+				var value = producer.ProduceHeaderValue(requestData);
 
-			if (!string.IsNullOrEmpty(value))
-				request.Headers.Add(requestData.MetaHeaderProvider.HeaderName, requestData.MetaHeaderProvider.ProduceHeaderValue(requestData));
+				if (!string.IsNullOrEmpty(value))
+					request.Headers.Add(producer.HeaderName, value);
+			}
 		}
 
 		var timeout = (int)requestData.RequestTimeout.TotalMilliseconds;

src/Elastic.Transport/Requests/MetaData/DefaultMetaHeaderProvider.cs

@@ -7,41 +7,64 @@
 namespace Elastic.Transport;
 
 /// <summary>
-/// 
+///
 /// </summary>
 public sealed class DefaultMetaHeaderProvider : MetaHeaderProvider
+{
+	private readonly MetaHeaderProducer[] _producers;
+
+	/// <inheritdoc cref="MetaHeaderProvider.Producers"/>
+	public override MetaHeaderProducer[] Producers => _producers;
+
+	/// <summary>
+	///
+	/// </summary>
+	public DefaultMetaHeaderProvider(Type clientType, string serviceIdentifier) =>
+		_producers = new MetaHeaderProducer[] { new DefaultMetaHeaderProducer(clientType, serviceIdentifier) };
+
+	/// <summary>
+	///
+	/// </summary>
+	public DefaultMetaHeaderProvider(VersionInfo versionInfo, string serviceIdentifier) =>
+		_producers = new MetaHeaderProducer[] { new DefaultMetaHeaderProducer(versionInfo, serviceIdentifier) };
+}
+
+/// <summary>
+///
+/// </summary>
+public sealed class DefaultMetaHeaderProducer : MetaHeaderProducer
 {
 	private const string MetaHeaderName = "x-elastic-client-meta";
 
 	private readonly MetaDataHeader _asyncMetaDataHeader;
 	private readonly MetaDataHeader _syncMetaDataHeader;
 
 	/// <summary>
-	/// 
+	///
 	/// </summary>
-	public DefaultMetaHeaderProvider(Type clientType, string serviceIdentifier)
+	public DefaultMetaHeaderProducer(Type clientType, string serviceIdentifier)
 	{
 		var clientVersionInfo = ReflectionVersionInfo.Create(clientType);
 		_asyncMetaDataHeader = new MetaDataHeader(clientVersionInfo, serviceIdentifier, true);
 		_syncMetaDataHeader = new MetaDataHeader(clientVersionInfo, serviceIdentifier, false);
 	}
 
 	/// <summary>
-	/// 
+	///
 	/// </summary>
-	internal DefaultMetaHeaderProvider(ReflectionVersionInfo reflectionVersionInfo, string serviceIdentifier)
+	public DefaultMetaHeaderProducer(VersionInfo versionInfo, string serviceIdentifier)
 	{
-		_asyncMetaDataHeader = new MetaDataHeader(reflectionVersionInfo, serviceIdentifier, true);
-		_syncMetaDataHeader = new MetaDataHeader(reflectionVersionInfo, serviceIdentifier, false);
+		_asyncMetaDataHeader = new MetaDataHeader(versionInfo, serviceIdentifier, true);
+		_syncMetaDataHeader = new MetaDataHeader(versionInfo, serviceIdentifier, false);
 	}
 
 	/// <summary>
-	/// 
+	///
 	/// </summary>
 	public override string HeaderName => MetaHeaderName;
 
 	/// <summary>
-	/// 
+	///
 	/// </summary>
 	/// <param name="requestData"></param>
 	/// <returns></returns>

src/Elastic.Transport/Requests/MetaData/MetaHeaderProvider.cs

@@ -5,13 +5,28 @@
 namespace Elastic.Transport;
 
 /// <summary>
-/// Injects a metadata header into all outgoing requests
+/// Injects metadata headers into all outgoing requests.
 /// </summary>
 public abstract class MetaHeaderProvider
 {
-	/// <summary>Header name </summary>
+	/// <summary>
+	/// The list of all <see cref="MetaHeaderProducer"/>s for the provider.
+	/// </summary>
+	public abstract MetaHeaderProducer[] Producers { get; }
+}
+
+/// <summary>
+/// Injects a metadata headers into all outgoing requests.
+/// </summary>
+public abstract class MetaHeaderProducer
+{
+	/// <summary>
+	/// The header name.
+	/// </summary>
 	public abstract string HeaderName { get; }
 
-	/// <summary> Produces the header value based on current outgoing <paramref name="requestData"/> </summary>
+	/// <summary>
+	/// Produces the header value based on current outgoing <paramref name="requestData"/>.
+	/// </summary>
 	public abstract string ProduceHeaderValue(RequestData requestData);
 }

src/Elastic.Transport/Requests/MetaData/ReflectionVersionInfo.cs

@@ -11,7 +11,10 @@
 
 namespace Elastic.Transport;
 
-internal sealed class ReflectionVersionInfo : VersionInfo
+/// <summary>
+/// 
+/// </summary>
+public sealed class ReflectionVersionInfo : VersionInfo
 {
 	private static readonly SemVersion Empty = new(0, 0, 0);
 
@@ -20,13 +23,23 @@ private ReflectionVersionInfo(SemVersion version) :
 	{
 	}
 
+	/// <summary>
+	/// 
+	/// </summary>
+	/// <typeparam name="T"></typeparam>
+	/// <returns></returns>
 	public static ReflectionVersionInfo Create<T>()
 	{
 		var version = DetermineVersionFromType(typeof(T));
 		var versionInfo = new ReflectionVersionInfo(version);
 		return versionInfo;
 	}
 
+	/// <summary>
+	/// 
+	/// </summary>
+	/// <param name="type"></param>
+	/// <returns></returns>
 	public static ReflectionVersionInfo Create(Type type)
 	{
 		var version = DetermineVersionFromType(type);

src/Elastic.Transport/Requests/MetaData/VersionInfo.cs

@@ -63,18 +63,7 @@ protected VersionInfo(int major, int minor, int patch, string? prerelease, strin
 	public override string ToString()
 	{
 		var prefix = $"{Major}.{Minor}.{Patch}";
-		var meta = string.Empty;
 
-		if (!string.IsNullOrEmpty(Metadata))
-		{
-			meta = $"+{Metadata}";
-			if (meta.EndsWith("p"))
-			{
-				// Make sure release versions are not accidentally marked as prerelease version
-				meta += "r";
-			}
-		}
-
-		return IsPrerelease ? $"{prefix}{meta}p" : $"{prefix}{meta}";
+		return IsPrerelease ? $"{prefix}p" : $"{prefix}";
 	}
 }