Add support for netstandard 2.0

Features that are used in the project and not available on NS2 (and not covered by PolySharp) have been added to the Compatibility folder.
Parallel Upsert and Fetch are currently disabled on NS2, everything else should work.

Fixes #116

src/Compatibility/ExtensionMethods.cs

@@ -0,0 +1,13 @@
+namespace System.Linq
+{
+#if NETSTANDARD2_0
+    public static class ExtensionMethods
+    {
+        public static void Deconstruct<T1, T2>(this KeyValuePair<T1, T2> tuple, out T1 key, out T2 value)
+        {
+            key = tuple.Key;
+            value = tuple.Value;
+        }
+    }
+#endif
+}

src/Compatibility/RuntimeHelpers.cs

@@ -0,0 +1,35 @@
+namespace System.Runtime.CompilerServices
+{
+#if NETSTANDARD2_0
+    internal static class RuntimeHelpers
+    {
+        public static T[] GetSubArray<T>(T[] array, Range range)
+        {
+            if (array == null)
+            {
+                throw new ArgumentNullException();
+            }
+
+            (int offset, int length) = range.GetOffsetAndLength(array.Length);
+
+            if (default(T)! != null || typeof(T[]) == array.GetType())
+            {
+                if (length == 0)
+                {
+                    return Array.Empty<T>();
+                }
+
+                var dest = new T[length];
+                Array.Copy(array, offset, dest, 0, length);
+                return dest;
+            }
+            else
+            {
+                T[] dest = (T[])Array.CreateInstance(array.GetType().GetElementType()!, length);
+                Array.Copy(array, offset, dest, 0, length);
+                return dest;
+            }
+        }
+    }
+#endif
+}

src/Extensions.cs

@@ -10,14 +10,23 @@ internal static class Extensions
     internal static ValueTask CheckStatusCode(
         this HttpResponseMessage response, CancellationToken ct, [CallerMemberName] string requestName = "")
     {
+#if NETSTANDARD2_0
+        return response.IsSuccessStatusCode ? default : ThrowOnFailedResponse(response, requestName, ct);
+#else
         return response.IsSuccessStatusCode ? ValueTask.CompletedTask : ThrowOnFailedResponse(response, requestName, ct);
+#endif
 
         [DoesNotReturn, StackTraceHidden]
         static async ValueTask ThrowOnFailedResponse(
             HttpResponseMessage response, string requestName, CancellationToken ct)
         {
+
             throw new HttpRequestException($"{requestName} request has failed. " +
+#if NETSTANDARD2_0
+                $"Code: {response.StatusCode}. Message: {await response.Content.ReadAsStringAsync().ConfigureAwait(false)}");
+#else
                 $"Code: {response.StatusCode}. Message: {await response.Content.ReadAsStringAsync(ct).ConfigureAwait(false)}");
+#endif
         }
     }
 }

src/ITransport.cs

@@ -13,7 +13,7 @@ public interface ITransport<
 {
 #if NET7_0_OR_GREATER
     static abstract T Create(string host, string apiKey);
-#else
+#elif !NETSTANDARD2_0
     static T Create(string host, string apiKey)
     {
         if (typeof(T) == typeof(GrpcTransport))

src/Index.cs

@@ -148,6 +148,7 @@ public Task<uint> Upsert(
         string? indexNamespace = null,
         CancellationToken ct = default)
     {
+#if !NETSTANDARD2_0
         const int batchSize = 100;
         const int parallelism = 20;
         const int threshold = 400;
@@ -156,10 +157,12 @@ public Task<uint> Upsert(
         {
             return Upsert(vectors, batchSize, parallelism, indexNamespace, ct);
         }
+#endif
 
         return Transport.Upsert(vectors, indexNamespace, ct);
     }
 
+#if !NETSTANDARD2_0
     /// <summary>
     /// Writes vectors into the index as batches in parallel. If a new value is provided for an existing vector ID, it will overwrite the previous value.
     /// </summary>
@@ -200,6 +203,7 @@ await Parallel.ForEachAsync(batches, options, async (batch, ct) =>
 
         return upserted;
     }
+#endif
 
     /// <summary>
     /// Updates a vector using the <see cref="Vector"/> object.
@@ -242,6 +246,7 @@ public Task Update(
     /// <returns>A dictionary containing vector IDs and the corresponding <see cref="Vector"/> objects containing the vector information.</returns>
     public Task<Dictionary<string, Vector>> Fetch(IEnumerable<string> ids, string? indexNamespace = null, CancellationToken ct = default)
     {
+#if !NETSTANDARD2_0
         const int batchSize = 200;
         const int parallelism = 20;
         const int threshold = 600;
@@ -250,10 +255,12 @@ public Task<Dictionary<string, Vector>> Fetch(IEnumerable<string> ids, string? i
         {
             return Fetch(ids, batchSize, parallelism, indexNamespace, ct);
         }
+#endif
 
         return Transport.Fetch(ids, indexNamespace, ct);
     }
 
+#if !NETSTANDARD2_0
     /// <summary>
     /// Looks up and returns vectors by ID as batches in parallel.
     /// </summary>
@@ -292,6 +299,7 @@ await Parallel.ForEachAsync(batches, options, async (batch, ct) =>
 
         return new(fetched.SelectMany(batch => batch));
     }
+#endif
 
     /// <summary>
     /// Deletes vectors with specified ids.

src/Pinecone.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <PackageId>Pinecone.NET</PackageId>
@@ -13,7 +13,7 @@ In the absence of an official SDK, it provides first-class support for Pinecone
   </PropertyGroup>
 
   <PropertyGroup>
-    <TargetFrameworks>net6.0;net7.0;net8.0</TargetFrameworks>
+    <TargetFrameworks>net6.0;net7.0;net8.0;netstandard2.0</TargetFrameworks>
     <WarningsAsErrors>nullable</WarningsAsErrors>
     <IsAotCompatible>true</IsAotCompatible>
     <ImplicitUsings>enable</ImplicitUsings>
@@ -23,11 +23,11 @@ In the absence of an official SDK, it provides first-class support for Pinecone
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
   </PropertyGroup>
 
-  <PropertyGroup Condition="'$(TargetFramework)' == 'net6.0'">
+  <PropertyGroup Condition="'$(TargetFramework)' == 'net6.0' Or '$(TargetFramework)' == 'netstandard2.0'">
     <PolySharpIncludeRuntimeSupportedAttributes>true</PolySharpIncludeRuntimeSupportedAttributes>
   </PropertyGroup>
 
-  <ItemGroup Condition="'$(TargetFramework)' == 'net7.0' Or '$(TargetFramework)' == 'net6.0'">
+  <ItemGroup Condition="'$(TargetFramework)' == 'net7.0' Or '$(TargetFramework)' == 'net6.0' Or '$(TargetFramework)' == 'netstandard2.0'">
     <PackageReference Include="System.Net.Http.Json" Version="8.0.0" />
     <PackageReference Include="System.Text.Json" Version="8.0.3" />
     <PackageReference Include="PolySharp" Version="1.14.1">

src/PineconeClient.cs

@@ -168,14 +168,36 @@ public async Task<Index<TTransport>> GetIndex<
             Status = response.Status,
 #if NET7_0_OR_GREATER
             Transport = TTransport.Create(host, apiKey)
-#else
+#elif !NETSTANDARD2_0
             Transport = ITransport<TTransport>.Create(host, apiKey)
+#else
+            Transport = Create<TTransport>(host, apiKey)
 #endif
         };
 
         return index;
     }
 
+#if !NET7_0_OR_GREATER
+    private static T Create<T>(string host, string apiKey)
+    {
+        if (typeof(T) == typeof(GrpcTransport))
+        {
+            return (T)(object)new GrpcTransport(host, apiKey);
+        }
+        else if (typeof(T) == typeof(RestTransport))
+        {
+            return (T)(object)new RestTransport(host, apiKey);
+        }
+        else
+        {
+            var instance = (T?)Activator.CreateInstance(typeof(T), host, apiKey);
+
+            return instance ?? throw new InvalidOperationException($"Unable to create instance of {typeof(T)}");
+        }
+    }
+#endif
+
     /// <summary>
     /// Specifies the pod type and number of replicas for an index. It applies to pod-based indexes only. Serverless indexes scale automatically based on usage.
     /// </summary>

src/Rest/Converters.cs

@@ -57,7 +57,11 @@ public override IndexNamespace[] Read(ref Utf8JsonReader reader, Type typeToConv
                     ThrowHelper.ThrowFormatException("Expected number value");
                 }
 
+#if !NETSTANDARD2_0
                 buffer.Add(new() { Name = Encoding.UTF8.GetString(nameSpan), VectorCount = reader.GetUInt32() });
+#else
+                buffer.Add(new() { Name = Encoding.UTF8.GetString(nameSpan.ToArray()), VectorCount = reader.GetUInt32() });
+#endif
             }
         }
 

src/Types/VectorTypes.cs

@@ -91,7 +91,13 @@ public MetadataMap() : base() { }
     /// Creates a new instance of the <see cref="MetadataMap" /> class from an existing collection.
     /// </summary>
     /// <param name="collection"></param>
-    public MetadataMap(IEnumerable<KeyValuePair<string, MetadataValue>> collection) : base(collection) { }
+    public MetadataMap(IEnumerable<KeyValuePair<string, MetadataValue>> collection)
+#if NETSTANDARD2_0
+        : base(collection.ToDictionary(e => e.Key, e => e.Value))
+#else
+        : base(collection)
+#endif
+    { }
 }
 
 /// <summary>