move code for generation of the APQ extension into GraphQLRequest

src/GraphQL.Client.Abstractions/GraphQLClientExtensions.cs

@@ -13,14 +13,12 @@ public static Task<GraphQLResponse<TResponse>> SendQueryAsync<TResponse>(this IG
             cancellationToken: cancellationToken);
     }
 
-#if NET6_0_OR_GREATER
     public static Task<GraphQLResponse<TResponse>> SendQueryAsync<TResponse>(this IGraphQLClient client,
         GraphQLQuery query, object? variables = null,
         string? operationName = null, Func<TResponse>? defineResponseType = null,
         CancellationToken cancellationToken = default)
         => SendQueryAsync(client, query.Text, variables, operationName, defineResponseType,
             cancellationToken);
-#endif
 
     public static Task<GraphQLResponse<TResponse>> SendMutationAsync<TResponse>(this IGraphQLClient client,
         [StringSyntax("GraphQL")] string query, object? variables = null,
@@ -31,13 +29,11 @@ public static Task<GraphQLResponse<TResponse>> SendMutationAsync<TResponse>(this
             cancellationToken: cancellationToken);
     }
 
-#if NET6_0_OR_GREATER
     public static Task<GraphQLResponse<TResponse>> SendMutationAsync<TResponse>(this IGraphQLClient client,
         GraphQLQuery query, object? variables = null, string? operationName = null, Func<TResponse>? defineResponseType = null,
         CancellationToken cancellationToken = default)
         => SendMutationAsync(client, query.Text, variables, operationName, defineResponseType,
             cancellationToken);
-#endif
 
     public static Task<GraphQLResponse<TResponse>> SendQueryAsync<TResponse>(this IGraphQLClient client,
         GraphQLRequest request, Func<TResponse> defineResponseType, CancellationToken cancellationToken = default)

src/GraphQL.Client/GraphQL.Client.csproj

@@ -22,10 +22,6 @@
     <PackageReference Include="System.Net.WebSockets.Client.Managed" Version="1.0.22" />
   </ItemGroup>
 
-  <ItemGroup Condition=" '$(TargetFramework)' == 'netstandard2.0'">
-    <PackageReference Include="System.Memory" Version="4.5.5" />
-  </ItemGroup>
-
   <ItemGroup>
     <ProjectReference Include="..\GraphQL.Client.Abstractions.Websocket\GraphQL.Client.Abstractions.Websocket.csproj" />
     <ProjectReference Include="..\GraphQL.Client.Abstractions\GraphQL.Client.Abstractions.csproj" />

src/GraphQL.Client/GraphQLHttpClient.cs

@@ -96,19 +96,15 @@ public async Task<GraphQLResponse<TResponse>> SendQueryAsync<TResponse>(GraphQLR
     {
         cancellationToken.ThrowIfCancellationRequested();
 
-        string? savedQuery = request.Query;
+        string? savedQuery = null;
         bool useAPQ = false;
 
         if (request.Query != null && !APQDisabledForSession && Options.EnableAutomaticPersistedQueries(request))
         {
             // https://www.apollographql.com/docs/react/api/link/persisted-queries/
             useAPQ = true;
-            request.Extensions ??= new();
-            request.Extensions["persistedQuery"] = new Dictionary<string, object>
-            {
-                ["version"] = APQ_SUPPORTED_VERSION,
-                ["sha256Hash"] = Hash.Compute(request.Query),
-            };
+            request.GeneratePersistedQueryExtension();
+            savedQuery = request.Query;
             request.Query = null;
         }
 

src/GraphQL.Client/GraphQLHttpRequest.cs

@@ -19,13 +19,10 @@ public GraphQLHttpRequest([StringSyntax("GraphQL")] string query, object? variab
         : base(query, variables, operationName, extensions)
     {
     }
-
-#if NET6_0_OR_GREATER
     public GraphQLHttpRequest(GraphQLQuery query, object? variables = null, string? operationName = null, Dictionary<string, object?>? extensions = null)
         : base(query, variables, operationName, extensions)
     {
     }
-#endif
 
     public GraphQLHttpRequest(GraphQLRequest other)
         : base(other)

src/GraphQL.Primitives/GraphQL.Primitives.csproj

@@ -6,4 +6,7 @@
     <TargetFrameworks>netstandard2.0;net6.0;net7.0;net8.0</TargetFrameworks>
   </PropertyGroup>
 
+  <ItemGroup Condition=" '$(TargetFramework)' == 'netstandard2.0'">
+    <PackageReference Include="System.Memory" Version="4.5.5" />
+  </ItemGroup>
 </Project>

src/GraphQL.Primitives/GraphQLQuery.cs

@@ -1,15 +1,34 @@
-#if NET6_0_OR_GREATER
 using System.Diagnostics.CodeAnalysis;
-
 namespace GraphQL;
 
 /// <summary>
-/// Value record for a GraphQL query string
+/// Value object representing a GraphQL query string and storing the corresponding APQ hash. <br />
+/// Use this to hold query strings you want to use more than once.
 /// </summary>
-/// <param name="Text">the actual query string</param>
-public readonly record struct GraphQLQuery([StringSyntax("GraphQL")] string Text)
+public class GraphQLQuery : IEquatable<GraphQLQuery>
 {
+    /// <summary>
+    /// The actual query string
+    /// </summary>
+    public string Text { get; }
+
+    /// <summary>
+    /// The SHA256 hash used for the advanced persisted queries feature (APQ)
+    /// </summary>
+    public string Sha256Hash { get; }
+
+    public GraphQLQuery([StringSyntax("GraphQL")] string text)
+    {
+        Text = text;
+        Sha256Hash = Hash.Compute(Text);
+    }
+
     public static implicit operator string(GraphQLQuery query)
         => query.Text;
-};
-#endif
+
+    public bool Equals(GraphQLQuery other) => Sha256Hash == other.Sha256Hash;
+
+    public override bool Equals(object? obj) => obj is GraphQLQuery other && Equals(other);
+
+    public override int GetHashCode() => Sha256Hash.GetHashCode();
+}

src/GraphQL.Primitives/GraphQLRequest.cs

@@ -11,19 +11,29 @@ public class GraphQLRequest : Dictionary<string, object>, IEquatable<GraphQLRequ
     public const string QUERY_KEY = "query";
     public const string VARIABLES_KEY = "variables";
     public const string EXTENSIONS_KEY = "extensions";
+    public const string EXTENSIONS_PERSISTED_QUERY_KEY = "persistedQuery";
+    public const int APQ_SUPPORTED_VERSION = 1;
+
+    private string? _sha265Hash;
 
     /// <summary>
-    /// The Query
+    /// The query string
     /// </summary>
     [StringSyntax("GraphQL")]
     public string? Query
     {
         get => TryGetValue(QUERY_KEY, out object value) ? (string)value : null;
-        set => this[QUERY_KEY] = value;
+        set
+        {
+            this[QUERY_KEY] = value;
+            // if the query string gets overwritten, reset the hash value
+            if (_sha265Hash is not null)
+                _sha265Hash = null;
+        }
     }
 
     /// <summary>
-    /// The name of the Operation
+    /// The operation to execute
     /// </summary>
     public string? OperationName
     {
@@ -59,16 +69,28 @@ public GraphQLRequest([StringSyntax("GraphQL")] string query, object? variables
         Extensions = extensions;
     }
 
-#if NET6_0_OR_GREATER
     public GraphQLRequest(GraphQLQuery query, object? variables = null, string? operationName = null,
         Dictionary<string, object?>? extensions = null)
         : this(query.Text, variables, operationName, extensions)
     {
+        _sha265Hash = query.Sha256Hash;
     }
-#endif
 
     public GraphQLRequest(GraphQLRequest other) : base(other) { }
 
+    public void GeneratePersistedQueryExtension()
+    {
+        if (Query is null)
+            throw new InvalidOperationException($"{nameof(Query)} is null");
+
+        Extensions ??= new();
+        Extensions[EXTENSIONS_PERSISTED_QUERY_KEY] = new Dictionary<string, object>
+        {
+            ["version"] = APQ_SUPPORTED_VERSION,
+            ["sha256Hash"] = _sha265Hash ?? Hash.Compute(Query),
+        };
+    }
+
     /// <summary>
     /// Returns a value that indicates whether this instance is equal to a specified object
     /// </summary>

src/GraphQL.Client/Hash.cs → src/GraphQL.Primitives/Hash.cs

@@ -3,18 +3,18 @@
 using System.Security.Cryptography;
 using System.Text;
 
-namespace GraphQL.Client.Http;
+namespace GraphQL;
 
 internal static class Hash
 {
     private static SHA256? _sha256;
 
     internal static string Compute(string query)
     {
-        var expected = Encoding.UTF8.GetByteCount(query);
-        var inputBytes = ArrayPool<byte>.Shared.Rent(expected);
-        var written = Encoding.UTF8.GetBytes(query, 0, query.Length, inputBytes, 0);
-        Debug.Assert(written == expected, $"Encoding.UTF8.GetBytes returned unexpected bytes: {written} instead of {expected}");
+        int expected = Encoding.UTF8.GetByteCount(query);
+        byte[]? inputBytes = ArrayPool<byte>.Shared.Rent(expected);
+        int written = Encoding.UTF8.GetBytes(query, 0, query.Length, inputBytes, 0);
+        Debug.Assert(written == expected, (string)$"Encoding.UTF8.GetBytes returned unexpected bytes: {written} instead of {expected}");
 
         var shaShared = Interlocked.Exchange(ref _sha256, null) ?? SHA256.Create();
 
@@ -33,7 +33,7 @@ internal static string Compute(string query)
         return Convert.ToHexString(bytes);
 #else
         var builder = new StringBuilder(bytes.Length * 2);
-        foreach (var item in bytes)
+        foreach (byte item in bytes)
         {
             builder.Append(item.ToString("x2"));
         }

tests/GraphQL.Integration.Tests/APQ/AdvancedPersistentQueriesTest.cs

@@ -78,4 +78,33 @@ query Human($id: String!){
         Assert.Equal(name, response.Data.Human.Name);
         StarWarsWebsocketClient.APQDisabledForSession.Should().BeFalse("if APQ has worked it won't get disabled");
     }
+
+    [Fact]
+    public void Verify_the_persisted_query_extension_object()
+    {
+        var query = new GraphQLQuery("""
+                                     query Human($id: String!){
+                                     human(id: $id) {
+                                             name
+                                         }
+                                     }
+                                     """);
+        query.Sha256Hash.Should().NotBeNullOrEmpty();
+
+        var request = new GraphQLRequest(query);
+        request.Extensions.Should().BeNull();
+        request.GeneratePersistedQueryExtension();
+        request.Extensions.Should().NotBeNull();
+
+        string expectedKey = "persistedQuery";
+        var expectedExtensionValue = new Dictionary<string, object>
+        {
+            ["version"] = 1,
+            ["sha256Hash"] = query.Sha256Hash,
+        };
+
+        request.Extensions.Should().ContainKey(expectedKey);
+        request.Extensions![expectedKey].As<Dictionary<string, object>>()
+            .Should().NotBeNull().And.BeEquivalentTo(expectedExtensionValue);
+    }
 }