Support skipping output generation based on API specification checksum (

RicoSuter#3404)

.gitignore

@@ -74,4 +74,5 @@ src/packages/**
 /src/NSwag.Console/Properties/launchSettings.json
 
 # Ignore files from JetBrainds Rider
-/src/.idea/
+/src/.idea/
+_ReSharper.Caches/

src/NSwag.AspNetCore/OpenApiDocumentProvider.cs

@@ -28,7 +28,7 @@ public OpenApiDocumentProvider(IServiceProvider serviceProvider, IEnumerable<Ope
             _documents = documents ?? throw new ArgumentNullException(nameof(documents));
         }
 
-        public async Task<OpenApiDocument> GenerateAsync(string documentName)
+        public Task<OpenApiDocument> GenerateAsync(string documentName)
         {
             if (documentName == null)
             {
@@ -53,7 +53,7 @@ public async Task<OpenApiDocument> GenerateAsync(string documentName)
                     $"Add with the AddSwagger()/AddOpenApi() methods in ConfigureServices().");
             }
 
-            return await document.Generator.GenerateAsync(_serviceProvider);
+            return document.Generator.GenerateAsync(_serviceProvider);
         }
 
         // Called by the <c>dotnet-getdocument</c> tool from the Microsoft.Extensions.ApiDescription.Server package.

src/NSwag.CodeGeneration.CSharp/Models/CSharpFileTemplateModel.cs

@@ -48,8 +48,14 @@ public CSharpFileTemplateModel(
             _clientCode = clientTypes.Concatenate();
 
             Classes = dtoTypes.Concatenate();
+            SourceSha = _settings.ChecksumCacheEnabled ? _document.GetChecksum() : "";
         }
 
+        /// <summary>
+        /// Gets the checksum for the document that was used to produce the file.
+        /// </summary>
+        public string SourceSha { get; }
+
         /// <summary>Gets the namespace.</summary>
         public string Namespace => _settings.CSharpGeneratorSettings.Namespace ?? string.Empty;
 

src/NSwag.CodeGeneration.CSharp/Templates/File.liquid

@@ -1,6 +1,9 @@
 //----------------------
 // <auto-generated>
 //     Generated using the NSwag toolchain v{{ ToolchainVersion }} (http://NSwag.org)
+{% if SourceSha != "" -%}
+//     SourceSHA: {{ SourceSha }}
+{% endif -%}
 // </auto-generated>
 //----------------------
 
@@ -22,7 +25,7 @@ using {{ usage }};
 namespace {{ Namespace }}
 {
     using System = global::System;
-    
+
     {{ Clients | tab }}
 
 {% if GenerateContracts -%}
@@ -100,14 +103,14 @@ namespace {{ Namespace }}
         public FileResponse(int statusCode, System.Collections.Generic.IReadOnlyDictionary<string, System.Collections.Generic.IEnumerable<string>> headers, System.IO.Stream stream, System.IDisposable client, System.IDisposable response)
 {%          endif -%}
         {
-            StatusCode = statusCode; 
-            Headers = headers; 
-            Stream = stream; 
-            _client = client; 
+            StatusCode = statusCode;
+            Headers = headers;
+            Stream = stream;
+            _client = client;
             _response = response;
         }
 
-        public void Dispose() 
+        public void Dispose()
         {
             Stream.Dispose();
             if (_response != null)
@@ -126,10 +129,10 @@ namespace {{ Namespace }}
         public int StatusCode { get; private set; }
 
         public System.Collections.Generic.IReadOnlyDictionary<string, System.Collections.Generic.IEnumerable<string>> Headers { get; private set; }
-        
-        public {{ responseClassName }}(int statusCode, System.Collections.Generic.IReadOnlyDictionary<string, System.Collections.Generic.IEnumerable<string>> headers) 
+
+        public {{ responseClassName }}(int statusCode, System.Collections.Generic.IReadOnlyDictionary<string, System.Collections.Generic.IEnumerable<string>> headers)
         {
-            StatusCode = statusCode; 
+            StatusCode = statusCode;
             Headers = headers;
         }
     }
@@ -138,8 +141,8 @@ namespace {{ Namespace }}
     public partial class {{ responseClassName }}<TResult> : {{ responseClassName }}
     {
         public TResult Result { get; private set; }
-        
-        public {{ responseClassName }}(int statusCode, System.Collections.Generic.IReadOnlyDictionary<string, System.Collections.Generic.IEnumerable<string>> headers, TResult result) 
+
+        public {{ responseClassName }}(int statusCode, System.Collections.Generic.IReadOnlyDictionary<string, System.Collections.Generic.IEnumerable<string>> headers, TResult result)
             : base(statusCode, headers)
         {
             Result = result;
@@ -171,7 +174,7 @@ namespace {{ Namespace }}
             : base(message + "\n\nStatus: " + statusCode + "\nResponse: \n" + ((response == null) ? "(null)" : response.Substring(0, response.Length >= 512 ? 512 : response.Length)), innerException)
         {
             StatusCode = statusCode;
-            Response = response; 
+            Response = response;
             Headers = headers;
         }
 

src/NSwag.CodeGeneration.TypeScript/Models/TypeScriptFileTemplateModel.cs

@@ -49,8 +49,14 @@ public TypeScriptFileTemplateModel(
             Types = dtoTypes.OrderByBaseDependency().Concatenate();
             ExtensionCodeBottom = GenerateExtensionCodeAfter();
             Framework = new TypeScriptFrameworkModel(settings);
+            SourceSha = _settings.ChecksumCacheEnabled ? _document.GetChecksum() : "";
         }
 
+        /// <summary>
+        /// Gets the checksum for the document that was used to produce the file.
+        /// </summary>
+        public string SourceSha { get; }
+
         /// <summary>Gets framework specific information.</summary>
         public TypeScriptFrameworkModel Framework { get; set; }
 
@@ -127,8 +133,8 @@ public IEnumerable<string> ResponseClassNames
         public bool RequiresFileParameterInterface =>
             !_settings.TypeScriptGeneratorSettings.ExcludedTypeNames.Contains("FileParameter") &&
             (_document.Operations.Any(o => o.Operation.ActualParameters.Any(p => p.ActualTypeSchema.IsBinary)) ||
-             _document.Operations.Any(o => o.Operation?.RequestBody?.Content?.Any(c => c.Value.Schema?.IsBinary == true || 
-                                                                                       c.Value.Schema?.ActualProperties.Any(p => p.Value.IsBinary || 
+             _document.Operations.Any(o => o.Operation?.RequestBody?.Content?.Any(c => c.Value.Schema?.IsBinary == true ||
+                                                                                       c.Value.Schema?.ActualProperties.Any(p => p.Value.IsBinary ||
                                                                                                                                  p.Value.Item?.IsBinary == true ||
                                                                                                                                  p.Value.Items.Any(i => i.IsBinary)
                                                                                                                                  ) == true) == true));

src/NSwag.CodeGeneration.TypeScript/Templates/File.liquid

@@ -3,6 +3,9 @@
 //----------------------
 // <auto-generated>
 //     Generated using the NSwag toolchain v{{ ToolchainVersion }} (http://NSwag.org)
+{% if SourceSha != "" -%}
+//     SourceSHA: {{ SourceSha }}
+{% endif -%}
 // </auto-generated>
 //----------------------
 // ReSharper disable InconsistentNaming

src/NSwag.CodeGeneration/ClientGeneratorBase.cs

@@ -7,6 +7,7 @@
 //-----------------------------------------------------------------------
 
 using System.Collections.Generic;
+using System.IO;
 using System.Linq;
 using NJsonSchema;
 using NJsonSchema.CodeGeneration;
@@ -70,6 +71,12 @@ public string GenerateFile()
         /// <returns>The code</returns>
         public string GenerateFile(ClientGeneratorOutputType outputType)
         {
+            if (!OutputRequiresRefresh(BaseSettings.OutputFilePath))
+            {
+                // just give back the original file as it hasn't changed
+                return File.ReadAllText(BaseSettings.OutputFilePath);
+            }
+
             var clientTypes = GenerateAllClientTypes();
 
             var dtoTypes = BaseSettings.GenerateDtoTypes ?
@@ -92,6 +99,69 @@ public string GenerateFile(ClientGeneratorOutputType outputType)
                 .Replace("\n\n\n", "\n\n");
         }
 
+        private bool OutputRequiresRefresh(string outputFilePath)
+        {
+            if (!BaseSettings.ChecksumCacheEnabled || string.IsNullOrWhiteSpace(outputFilePath) || !File.Exists(outputFilePath))
+            {
+                // no point in checking
+                return true;
+            }
+
+            var sourceDocumentChecksum = _document.GetChecksum();
+            if (string.IsNullOrWhiteSpace(sourceDocumentChecksum))
+            {
+                return true;
+            }
+
+            // if we can match both source checksum and toolchain, we can presume file hasn't been changed
+            var checksumMatches = false;
+            var toolchainVersionMatches = false;
+            const string checksumMarker = "SourceSHA: ";
+            const string toolchainVersionMarker = "toolchain v";
+
+            try
+            {
+                using (var reader = new StreamReader(new FileStream(outputFilePath, FileMode.Open, FileAccess.Read, FileShare.Read)))
+                {
+                    // read multiple lines as we can have headers before version info
+                    var counter = 10;
+                    string line;
+                    while ((line = reader.ReadLine()) != null && counter > 0)
+                    {
+                        counter--;
+                        var checksumStartIndex = line.IndexOf(checksumMarker);
+                        if (checksumStartIndex > -1)
+                        {
+                            var startIndex = checksumStartIndex + checksumMarker.Length;
+                            var fileSourceSha = line.Substring(startIndex).Trim();
+                            checksumMatches = fileSourceSha == sourceDocumentChecksum;
+                        }
+
+                        var toolchainStartIndex = line.IndexOf(toolchainVersionMarker);
+                        if (toolchainStartIndex > -1)
+                        {
+                            var startIndex = toolchainStartIndex + toolchainVersionMarker.Length;
+                            var length = line.IndexOf(" ", startIndex) - startIndex;
+                            var fileToolchainVersion = line.Substring(startIndex, length).Trim();
+                            toolchainVersionMatches = fileToolchainVersion == OpenApiDocument.ToolchainVersion;
+                        }
+
+                        if (checksumMatches && toolchainVersionMatches)
+                        {
+                            // we are good to go with cached version, no need to refresh
+                            return false;
+                        }
+                    }
+                }
+            }
+            catch
+            {
+                // no-go
+            }
+
+            return true;
+        }
+
         /// <summary>Generates the file.</summary>
         /// <param name="clientTypes">The client types.</param>
         /// <param name="dtoTypes">The DTO types.</param>

src/NSwag.CodeGeneration/ClientGeneratorBaseSettings.cs

@@ -77,5 +77,11 @@ public string GenerateControllerName(string controllerName)
 
         /// <summary>Gets or sets the name of the response class (supports the '{controller}' placeholder).</summary>
         public string ResponseClass { get; set; }
+
+        /// <summary>Gets or sets the output file name, used to detect changes.</summary>
+        public string OutputFilePath { get; set; }
+
+        /// <summary>Gets or sets whether checksum based output caching can be used.
+        public bool ChecksumCacheEnabled { get; set; }
     }
 }

src/NSwag.Commands/Commands/CodeGeneration/CodeGeneratorCommandBase.cs

@@ -41,6 +41,13 @@ public string TemplateDirectory
         [Argument(Name = "EnumNameGeneratorType", IsRequired = false, Description = "The custom IEnumNameGenerator implementation type in the form 'assemblyName:fullTypeName' or 'fullTypeName').")]
         public string EnumNameGeneratorType { get; set; }
 
+        [Argument(Name = nameof(ChecksumCacheEnabled), IsRequired = false, Description = "Whether output generation can be skipped if source document checksum matches existing output (default: false).")]
+        public bool ChecksumCacheEnabled
+        {
+            get { return Settings.ChecksumCacheEnabled; }
+            set { Settings.ChecksumCacheEnabled = value; }
+        }
+
         // TODO: Use InitializeCustomTypes method
         public void InitializeCustomTypes(AssemblyLoader.AssemblyLoader assemblyLoader)
         {

src/NSwag.Commands/Commands/CodeGeneration/OpenApiToCSharpClientCommand.cs

@@ -254,9 +254,9 @@ public override async Task<object> RunAsync(CommandLineProcessor processor, ICon
             return result;
         }
 
-        public async Task<Dictionary<string, string>> RunAsync()
+        public Task<Dictionary<string, string>> RunAsync()
         {
-            return await Task.Run(async () =>
+            return Task.Run(async () =>
             {
                 var document = await GetInputSwaggerDocument().ConfigureAwait(false);
                 var clientGenerator = new CSharpClientGenerator(document, Settings);
@@ -270,6 +270,8 @@ public async Task<Dictionary<string, string>> RunAsync()
                 }
                 else
                 {
+                    // when generating single file allow caching
+                    Settings.OutputFilePath = OutputFilePath;
                     return new Dictionary<string, string>
                     {
                         { OutputFilePath ?? "Full", clientGenerator.GenerateFile(ClientGeneratorOutputType.Full) }

src/NSwag.Commands/Commands/CodeGeneration/OpenApiToTypeScriptClientCommand.cs

@@ -270,7 +270,7 @@ public TypeScriptEnumStyle EnumStyle
             get { return Settings.TypeScriptGeneratorSettings.EnumStyle; }
             set { Settings.TypeScriptGeneratorSettings.EnumStyle = value; }
         }
-        
+
         [Argument(Name = "UseLeafType", IsRequired = false, Description = "Generate leaf types for an object with discriminator (default: false).")]
         public bool UseLeafType
         {
@@ -394,16 +394,17 @@ public override async Task<object> RunAsync(CommandLineProcessor processor, ICon
             return code;
         }
 
-        public async Task<string> RunAsync()
+        public Task<string> RunAsync()
         {
-            return await Task.Run(async () =>
+            return Task.Run(async () =>
             {
                 var additionalCode = ExtensionCode ?? string.Empty;
                 if (DynamicApis.FileExists(additionalCode))
                 {
                     additionalCode = DynamicApis.FileReadAllText(additionalCode);
                 }
 
+                Settings.OutputFilePath = OutputFilePath;
                 Settings.TypeScriptGeneratorSettings.ExtensionCode = additionalCode;
 
                 var document = await GetInputSwaggerDocument().ConfigureAwait(false);

src/NSwag.Commands/Commands/OutputCommandBase.cs

@@ -25,7 +25,7 @@ public abstract class OutputCommandBase : IOutputCommand
 
         public abstract Task<object> RunAsync(CommandLineProcessor processor, IConsoleHost host);
 
-        protected async Task<OpenApiDocument> ReadSwaggerDocumentAsync(string input)
+        protected Task<OpenApiDocument> ReadSwaggerDocumentAsync(string input)
         {
             if (!IsJson(input) && !IsYaml(input))
             {
@@ -34,35 +34,35 @@ protected async Task<OpenApiDocument> ReadSwaggerDocumentAsync(string input)
                     if (input.EndsWith(".yaml", StringComparison.OrdinalIgnoreCase) ||
                         input.EndsWith(".yml", StringComparison.OrdinalIgnoreCase))
                     {
-                        return await OpenApiYamlDocument.FromUrlAsync(input).ConfigureAwait(false);
+                        return OpenApiYamlDocument.FromUrlAsync(input);
                     }
                     else
                     {
-                        return await OpenApiDocument.FromUrlAsync(input).ConfigureAwait(false);
+                        return OpenApiDocument.FromUrlAsync(input);
                     }
                 }
                 else
                 {
                     if (input.EndsWith(".yaml", StringComparison.OrdinalIgnoreCase) ||
                         input.EndsWith(".yml", StringComparison.OrdinalIgnoreCase))
                     {
-                        return await OpenApiYamlDocument.FromFileAsync(input).ConfigureAwait(false);
+                        return OpenApiYamlDocument.FromFileAsync(input);
                     }
                     else
                     {
-                        return await OpenApiDocument.FromFileAsync(input).ConfigureAwait(false);
+                        return OpenApiDocument.FromFileAsync(input);
                     }
                 }
             }
             else
             {
                 if (IsYaml(input))
                 {
-                    return await OpenApiYamlDocument.FromYamlAsync(input).ConfigureAwait(false);
+                    return OpenApiYamlDocument.FromYamlAsync(input);
                 }
                 else
                 {
-                    return await OpenApiDocument.FromJsonAsync(input).ConfigureAwait(false);
+                    return OpenApiDocument.FromJsonAsync(input);
                 }
             }
         }