Allow for IDocumentStore to provide document hash.

src/HotChocolate/Core/src/Abstractions/Execution/IOperationDocumentHashProvider.cs

@@ -0,0 +1,12 @@
+namespace HotChocolate.Execution;
+
+/// <summary>
+/// Provides the hash of an operation document.
+/// </summary>
+public interface IOperationDocumentHashProvider
+{
+    /// <summary>
+    /// Gets the hash of the operation document.
+    /// </summary>
+    OperationDocumentHash Hash { get; }
+}

src/HotChocolate/Core/src/Abstractions/Execution/IOperationDocumentNodeProvider.cs

@@ -0,0 +1,14 @@
+using HotChocolate.Language;
+
+namespace HotChocolate.Execution;
+
+/// <summary>
+/// Provides the document syntax node of an operation document.
+/// </summary>
+public interface IOperationDocumentNodeProvider
+{
+    /// <summary>
+    /// Gets the document syntax node of the operation document.
+    /// </summary>
+    DocumentNode Document { get; }
+}

src/HotChocolate/Core/src/Abstractions/Execution/OperationDocumentHash.cs

@@ -0,0 +1,46 @@
+using HotChocolate.Language;
+
+namespace HotChocolate.Execution;
+
+/// <summary>
+/// Represents the hash of an operation document.
+/// </summary>
+public readonly struct OperationDocumentHash
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="OperationDocumentHash"/> struct.
+    /// </summary>
+    /// <param name="hash">
+    /// The hash of the operation document.
+    /// </param>
+    /// <param name="algorithm">
+    /// The algorithm used to compute the hash.
+    /// </param>
+    /// <param name="format">
+    /// The format of the hash.
+    /// </param>
+    /// <exception cref="ArgumentNullException">
+    /// Thrown when <paramref name="hash"/> or <paramref name="algorithm"/> is <c>null</c>.
+    /// </exception>
+    public OperationDocumentHash(string hash, string algorithm, HashFormat format)
+    {
+        Hash = hash ?? throw new ArgumentNullException(nameof(hash));
+        AlgorithmName = algorithm ?? throw new ArgumentNullException(nameof(algorithm));
+        Format = format;
+    }
+
+    /// <summary>
+    /// Gets the hash of the operation document.
+    /// </summary>
+    public string Hash { get; }
+
+    /// <summary>
+    /// Gets the algorithm used to compute the hash.
+    /// </summary>
+    public string AlgorithmName { get; }
+
+    /// <summary>
+    /// Gets the format of the hash.
+    /// </summary>
+    public HashFormat Format { get; }
+}

src/HotChocolate/Core/src/Execution/Pipeline/DocumentCacheMiddleware.cs

@@ -38,6 +38,7 @@ public async ValueTask InvokeAsync(IRequestContext context)
                 _documentCache.TryGetDocument(request.DocumentId.Value.Value, out var document))
             {
                 context.DocumentId = request.DocumentId;
+                context.DocumentHash = document.Hash;
                 context.Document = document.Body;
                 context.ValidationResult = DocumentValidatorResult.Ok;
                 context.IsCachedDocument = true;
@@ -49,6 +50,7 @@ public async ValueTask InvokeAsync(IRequestContext context)
                 _documentCache.TryGetDocument(request.DocumentHash, out document))
             {
                 context.DocumentId = request.DocumentHash;
+                context.DocumentHash = document.Hash;
                 context.Document = document.Body;
                 context.ValidationResult = DocumentValidatorResult.Ok;
                 context.IsCachedDocument = true;
@@ -81,7 +83,18 @@ public async ValueTask InvokeAsync(IRequestContext context)
         {
             _documentCache.TryAddDocument(
                 context.DocumentId.Value.Value,
-                new CachedDocument(context.Document, context.IsPersistedDocument));
+                new CachedDocument(context.Document, context.DocumentHash, context.IsPersistedDocument));
+
+            // The hash and the documentId can differ if the id is not a hash or
+            // if the hash algorithm is different from the one that Hot Chocolate uses internally.
+            // In the case they differ we just add another lookup to the cache.
+            if(context.DocumentHash is not null)
+            {
+                _documentCache.TryAddDocument(
+                    context.DocumentHash,
+                    new CachedDocument(context.Document, context.DocumentHash, context.IsPersistedDocument));
+            }
+
             _diagnosticEvents.AddedDocumentToCache(context);
         }
     }

src/HotChocolate/Core/src/Execution/Pipeline/ReadPersistedOperationMiddleware.cs

@@ -11,12 +11,14 @@ internal sealed class ReadPersistedOperationMiddleware
     private readonly RequestDelegate _next;
     private readonly IExecutionDiagnosticEvents _diagnosticEvents;
     private readonly IOperationDocumentStorage _operationDocumentStorage;
+    private readonly IDocumentHashProvider _documentHashAlgorithm;
     private readonly PersistedOperationOptions _options;
 
     private ReadPersistedOperationMiddleware(
         RequestDelegate next,
         [SchemaService] IExecutionDiagnosticEvents diagnosticEvents,
         [SchemaService] IOperationDocumentStorage operationDocumentStorage,
+        IDocumentHashProvider documentHashAlgorithm,
         PersistedOperationOptions options)
     {
         _next = next ??
@@ -25,6 +27,8 @@ private ReadPersistedOperationMiddleware(
             throw new ArgumentNullException(nameof(diagnosticEvents));
         _operationDocumentStorage = operationDocumentStorage ??
             throw new ArgumentNullException(nameof(operationDocumentStorage));
+        _documentHashAlgorithm = documentHashAlgorithm ??
+            throw new ArgumentNullException(nameof(documentHashAlgorithm));
         _options = options;
     }
 
@@ -53,45 +57,58 @@ await _operationDocumentStorage.TryReadAsync(
                     documentId.Value, context.RequestAborted)
                     .ConfigureAwait(false);
 
-            if (operationDocument is OperationDocument parsedDoc)
+            if (operationDocument is not null)
             {
                 context.DocumentId = documentId;
-                context.Document = parsedDoc.Document;
+                context.Document = GetOrParseDocument(operationDocument);
+                context.DocumentHash = GetDocumentHash(operationDocument);
                 context.ValidationResult = DocumentValidatorResult.Ok;
                 context.IsCachedDocument = true;
                 context.IsPersistedDocument = true;
-                if (_options.SkipPersistedDocumentValidation)
-                {
-                    context.ValidationResult = DocumentValidatorResult.Ok;
-                }
-                _diagnosticEvents.RetrievedDocumentFromStorage(context);
-            }
 
-            if (operationDocument is OperationDocumentSourceText sourceTextDoc)
-            {
-                context.DocumentId = documentId;
-                context.Document = Utf8GraphQLParser.Parse(sourceTextDoc.AsSpan());
-                context.ValidationResult = DocumentValidatorResult.Ok;
-                context.IsCachedDocument = true;
-                context.IsPersistedDocument = true;
                 if (_options.SkipPersistedDocumentValidation)
                 {
                     context.ValidationResult = DocumentValidatorResult.Ok;
                 }
+
                 _diagnosticEvents.RetrievedDocumentFromStorage(context);
             }
         }
     }
 
+    private static DocumentNode GetOrParseDocument(IOperationDocument document)
+    {
+        if (document is IOperationDocumentNodeProvider nodeProvider)
+        {
+            return nodeProvider.Document;
+        }
+
+        return Utf8GraphQLParser.Parse(document.AsSpan());
+    }
+
+    private string? GetDocumentHash(IOperationDocument document)
+    {
+        if (document is IOperationDocumentHashProvider hashProvider
+            && _documentHashAlgorithm.Name.Equals(hashProvider.Hash.AlgorithmName)
+            && _documentHashAlgorithm.Format.Equals(hashProvider.Hash.Format))
+        {
+            return hashProvider.Hash.Hash;
+        }
+
+        return null;
+    }
+
     public static RequestCoreMiddleware Create()
         => (core, next) =>
         {
             var diagnosticEvents = core.SchemaServices.GetRequiredService<IExecutionDiagnosticEvents>();
             var persistedOperationStore = core.SchemaServices.GetRequiredService<IOperationDocumentStorage>();
+            var documentHashAlgorithm = core.Services.GetRequiredService<IDocumentHashProvider>();
             var middleware = new ReadPersistedOperationMiddleware(
                 next,
                 diagnosticEvents,
                 persistedOperationStore,
+                documentHashAlgorithm,
                 core.Options.PersistedOperations);
             return context => middleware.InvokeAsync(context);
         };

src/HotChocolate/Core/test/Execution.Tests/Pipeline/DocumentCacheMiddlewareTests.cs

@@ -25,7 +25,7 @@ public async Task RetrieveItemFromCache_DocumentFoundOnCache()
             .Build();
 
         var document = Utf8GraphQLParser.Parse("{ a }");
-        cache.TryAddDocument("a", new CachedDocument(document, false));
+        cache.TryAddDocument("a", new CachedDocument(document, null, false));
 
         var requestContext = new Mock<IRequestContext>();
         var schema = new Mock<ISchema>();
@@ -63,7 +63,7 @@ public async Task RetrieveItemFromCacheByHash_DocumentFoundOnCache()
             .Build();
 
         var document = Utf8GraphQLParser.Parse("{ a }");
-        cache.TryAddDocument("a", new CachedDocument(document, false));
+        cache.TryAddDocument("a", new CachedDocument(document, null, false));
 
         var requestContext = new Mock<IRequestContext>();
         var schema = new Mock<ISchema>();
@@ -101,7 +101,7 @@ public async Task RetrieveItemFromCache_DocumentNotFoundOnCache()
             .Build();
 
         var document = Utf8GraphQLParser.Parse("{ a }");
-        cache.TryAddDocument("b", new CachedDocument(document, false));
+        cache.TryAddDocument("b", new CachedDocument(document, null, false));
 
         var requestContext = new Mock<IRequestContext>();
         var schema = new Mock<ISchema>();