Successfully migrate core OpenAPI parsing from NSwag to Microsoft.OpenApi

Copilot · christianhelle · Copilot · commit cdfb79e1dd69 · 2025-09-20T08:29:36.000Z
Co-authored-by: christianhelle &lt;710400+christianhelle@users.noreply.github.com&gt;
diff --git a/src/CurlGenerator.Core/CurlGenerator.Core.csproj b/src/CurlGenerator.Core/CurlGenerator.Core.csproj
@@ -12,9 +12,9 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.SourceLink.GitHub" Version="8.0.0" PrivateAssets="All" />
-    <PackageReference Include="NSwag.CodeGeneration.CSharp" Version="14.4.0" />
-    <PackageReference Include="NSwag.Core.Yaml" Version="14.4.0" />
+    <PackageReference Include="Microsoft.OpenApi.Readers" Version="1.6.25" />
     <PackageReference Include="Microsoft.Extensions.Azure" Version="1.12.0" />
+    <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/src/CurlGenerator.Core/OpenApiDocumentFactory.cs b/src/CurlGenerator.Core/OpenApiDocumentFactory.cs
@@ -1,5 +1,6 @@
 ﻿using System.Net;
-using NSwag;
+using Microsoft.OpenApi.Models;
+using Microsoft.OpenApi.Readers;
 
 namespace CurlGenerator.Core;
 
@@ -14,33 +15,20 @@ public static class OpenApiDocumentFactory
     /// <returns>A new instance of the <see cref="OpenApiDocument"/> class.</returns>
     public static async Task<OpenApiDocument> CreateAsync(string openApiPath)
     {
-        OpenApiDocument document;
         if (IsHttp(openApiPath))
         {
             var content = await GetHttpContent(openApiPath);
-
-            if (IsYaml(openApiPath))
-            {
-                document = await OpenApiYamlDocument.FromYamlAsync(content);
-            }
-            else
-            {
-                document = await OpenApiDocument.FromJsonAsync(content);
-            }
+            var reader = new OpenApiStringReader();
+            var readResult = reader.Read(content, out var diagnostic);
+            return readResult;
         }
         else 
         {
-            if (IsYaml(openApiPath))
-            {
-                document = await OpenApiYamlDocument.FromFileAsync(openApiPath);
-            }
-            else
-            {
-                document = await OpenApiDocument.FromFileAsync(openApiPath);
-            }
+            using var stream = File.OpenRead(openApiPath);
+            var reader = new OpenApiStreamReader();
+            var readResult = reader.Read(stream, out var diagnostic);
+            return readResult;
         }
-
-        return document;
     }
 
     /// <summary>
diff --git a/src/CurlGenerator.Core/OperationNameGenerator.cs b/src/CurlGenerator.Core/OperationNameGenerator.cs
@@ -1,22 +1,27 @@
 ﻿using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
-using NSwag;
-using NSwag.CodeGeneration.OperationNameGenerators;
+using Microsoft.OpenApi.Models;
 
 namespace CurlGenerator.Core;
 
-internal class OperationNameGenerator : IOperationNameGenerator
+internal interface IOperationNameGenerator
 {
-    private readonly IOperationNameGenerator defaultGenerator =
-        new MultipleClientsFromOperationIdOperationNameGenerator();
+    string GetOperationName(
+        OpenApiDocument document,
+        string path,
+        string httpMethod,
+        OpenApiOperation operation);
+}
 
+public class OperationNameGenerator : IOperationNameGenerator
+{
     [ExcludeFromCodeCoverage]
-    public bool SupportsMultipleClients => throw new NotImplementedException();
+    public bool SupportsMultipleClients => false;
 
     [ExcludeFromCodeCoverage]
     public string GetClientName(OpenApiDocument document, string path, string httpMethod, OpenApiOperation operation)
     {
-        return defaultGenerator.GetClientName(document, path, httpMethod, operation);
+        return "ApiClient";
     }
 
     public string GetOperationName(
@@ -27,16 +32,24 @@ public string GetOperationName(
     {
         try
         {
-            return defaultGenerator
-                .GetOperationName(document, path, httpMethod, operation)
-                .CapitalizeFirstCharacter()
-                .ConvertKebabCaseToPascalCase()
-                .ConvertRouteToCamelCase()
-                .ConvertSpacesToPascalCase()
-                .Prefix(
-                    httpMethod
-                        .ToLowerInvariant()
-                        .CapitalizeFirstCharacter());
+            // Try to use operationId if available
+            if (!string.IsNullOrWhiteSpace(operation.OperationId))
+            {
+                return operation.OperationId
+                    .CapitalizeFirstCharacter()
+                    .ConvertKebabCaseToPascalCase()
+                    .ConvertRouteToCamelCase()
+                    .ConvertSpacesToPascalCase()
+                    .Prefix(
+                        httpMethod
+                            .ToLowerInvariant()
+                            .CapitalizeFirstCharacter());
+            }
+            
+            // Fallback to generating from path and method
+            return httpMethod.CapitalizeFirstCharacter() + 
+                   path.ConvertRouteToCamelCase()
+                       .ConvertSpacesToPascalCase();
         }
         catch (Exception e)
         {
@@ -53,14 +66,14 @@ public bool CheckForDuplicateOperationIds(
         List<string> operationNames = new();
         foreach (var kv in document.Paths)
         {
-            foreach (var operations in kv.Value)
+            foreach (var operations in kv.Value.Operations)
             {
                 var operation = operations.Value;
                 operationNames.Add(
                     GetOperationName(
                         document,
                         kv.Key,
-                        operations.Key,
+                        operations.Key.ToString(),
                         operation));
             }
         }
diff --git a/src/CurlGenerator.Core/ScriptFileGenerator.cs b/src/CurlGenerator.Core/ScriptFileGenerator.cs
@@ -6,8 +6,7 @@
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
-using NSwag;
-using NSwag.CodeGeneration.CSharp;
+using Microsoft.OpenApi.Models;
 
 public static class ScriptFileGenerator
 {
@@ -21,8 +20,7 @@ public static async Task<GeneratorResult> Generate(GeneratorSettings settings)
         var document = await OpenApiDocumentFactory.CreateAsync(settings.OpenApiPath);
         TryLog($"Document: {SerializeObject(document)}");
 
-        var generator = new CSharpClientGenerator(document, new CSharpClientGeneratorSettings());
-        generator.BaseSettings.OperationNameGenerator = new OperationNameGenerator();
+        var generator = new OperationNameGenerator();
 
         var baseUrl = settings.BaseUrl + document.Servers?.FirstOrDefault()?.Url;
         if (!Uri.IsWellFormedUriString(baseUrl, UriKind.Absolute) &&
@@ -41,23 +39,20 @@ public static async Task<GeneratorResult> Generate(GeneratorSettings settings)
     private static GeneratorResult GenerateCode(
         GeneratorSettings settings,
         OpenApiDocument document,
-        CSharpClientGenerator generator,
+        OperationNameGenerator generator,
         string baseUrl)
     {
         var files = new List<ScriptFile>();
         foreach (var kv in document.Paths)
         {
             TryLog($"Processing path: {kv.Key}");
-            foreach (var operations in kv.Value)
+            foreach (var operations in kv.Value.Operations)
             {
                 TryLog($"Processing operation: {operations.Key}");
 
                 var operation = operations.Value;
-                var verb = operations.Key.CapitalizeFirstCharacter();
-                var name = generator
-                    .BaseSettings
-                    .OperationNameGenerator
-                    .GetOperationName(document, kv.Key, verb, operation);
+                var verb = operations.Key.ToString().CapitalizeFirstCharacter();
+                var name = generator.GetOperationName(document, kv.Key, verb, operation);
 
                 var filename = !settings.GenerateBashScripts
                     ? $"{name.CapitalizeFirstCharacter()}.ps1"
@@ -99,7 +94,7 @@ private static string GenerateBashRequest(
 
         // Add query parameters directly to the URL if there are any
         var queryParams = operation.Parameters
-            .Where(p => p.Kind == OpenApiParameterKind.Query)
+            .Where(p => p.In == ParameterLocation.Query)
             .Select(p => $"{p.Name}=${{{p.Name.ConvertKebabCaseToSnakeCase()}}}")
             .ToList();
 
@@ -108,9 +103,8 @@ private static string GenerateBashRequest(
 
         code.AppendLine($"  -H \"Accept: application/json\" \\");
 
-        // Determine content type based on consumes or request body
-        var contentType = operation.Consumes?.FirstOrDefault()
-                          ?? operation.RequestBody?.Content?.Keys.FirstOrDefault()
+        // Determine content type based on request body
+        var contentType = operation.RequestBody?.Content?.Keys.FirstOrDefault()
                           ?? "application/json";
 
         TryLog($"Content type for operation {operation.OperationId}: {contentType}");
@@ -138,8 +132,8 @@ private static string GenerateBashRequest(
             }
             else
             {
-                var requestBodySchema = operation.RequestBody.Content[contentType].Schema.ActualSchema;
-                var requestBodyJson = requestBodySchema?.ToSampleJson()?.ToString() ?? string.Empty;
+                var requestBodySchema = operation.RequestBody.Content[contentType].Schema;
+                var requestBodyJson = GenerateSampleJsonFromSchema(requestBodySchema);
                 code.AppendLine($"  -d '{requestBodyJson}'");
             }
         }
@@ -162,10 +156,10 @@ private static void AppendBashParameters(
     {
         var parameters = operation.Parameters
             .Where(p =>
-                p.Kind == OpenApiParameterKind.Path ||
-                p.Kind == OpenApiParameterKind.Query ||
-                p.Kind == OpenApiParameterKind.Header ||
-                p.Kind == OpenApiParameterKind.Cookie)
+                p.In == ParameterLocation.Path ||
+                p.In == ParameterLocation.Query ||
+                p.In == ParameterLocation.Header ||
+                p.In == ParameterLocation.Cookie)
             .ToArray();
 
         if (parameters.Length == 0)
@@ -181,7 +175,7 @@ private static void AppendBashParameters(
             var name = parameter.Name.ConvertKebabCaseToSnakeCase();
             code.AppendLine(
                 parameter.Description is null
-                    ? $"# {parameter.Kind.ToString().ToLowerInvariant()} parameter: {name}"
+                    ? $"# {parameter.In.ToString().ToLowerInvariant()} parameter: {name}"
                     : $"# {parameter.Description}");
 
             code.AppendLine($"{name}=\"\""); // Initialize the parameter
@@ -246,6 +240,90 @@ private static string SerializeObject(object obj)
         return Newtonsoft.Json.JsonConvert.SerializeObject(obj, Newtonsoft.Json.Formatting.Indented);
     }
 
+    private static string GenerateSampleJsonFromSchema(OpenApiSchema? schema)
+    {
+        if (schema == null)
+            return "{}";
+
+        try
+        {
+            var sampleObject = GenerateSampleObjectFromSchema(schema);
+            return Newtonsoft.Json.JsonConvert.SerializeObject(sampleObject, Newtonsoft.Json.Formatting.Indented);
+        }
+        catch
+        {
+            return "{}";
+        }
+    }
+
+    private static object GenerateSampleObjectFromSchema(OpenApiSchema schema)
+    {
+        if (schema.Example != null)
+        {
+            return ConvertOpenApiAnyToObject(schema.Example);
+        }
+
+        switch (schema.Type)
+        {
+            case "object":
+                var obj = new Dictionary<string, object>();
+                if (schema.Properties != null)
+                {
+                    foreach (var prop in schema.Properties)
+                    {
+                        obj[prop.Key] = GenerateSampleObjectFromSchema(prop.Value);
+                    }
+                }
+                return obj;
+
+            case "array":
+                if (schema.Items != null)
+                {
+                    return new[] { GenerateSampleObjectFromSchema(schema.Items) };
+                }
+                return new object[0];
+
+            case "string":
+                return schema.Format switch
+                {
+                    "date" => DateTime.Today.ToString("yyyy-MM-dd"),
+                    "date-time" => DateTime.Now.ToString("yyyy-MM-ddTHH:mm:ssZ"),
+                    "email" => "user@example.com",
+                    "uri" => "https://example.com",
+                    _ => "string"
+                };
+
+            case "integer":
+                return 0;
+
+            case "number":
+                return 0.0;
+
+            case "boolean":
+                return false;
+
+            default:
+                return "value";
+        }
+    }
+
+    private static object ConvertOpenApiAnyToObject(Microsoft.OpenApi.Any.IOpenApiAny openApiAny)
+    {
+        return openApiAny switch
+        {
+            Microsoft.OpenApi.Any.OpenApiString str => str.Value,
+            Microsoft.OpenApi.Any.OpenApiInteger integer => integer.Value,
+            Microsoft.OpenApi.Any.OpenApiLong longVal => longVal.Value,
+            Microsoft.OpenApi.Any.OpenApiFloat floatVal => floatVal.Value,
+            Microsoft.OpenApi.Any.OpenApiDouble doubleVal => doubleVal.Value,
+            Microsoft.OpenApi.Any.OpenApiBoolean boolVal => boolVal.Value,
+            Microsoft.OpenApi.Any.OpenApiDateTime dateTime => dateTime.Value,
+            Microsoft.OpenApi.Any.OpenApiObject obj => obj.ToDictionary(kv => kv.Key, kv => ConvertOpenApiAnyToObject(kv.Value)),
+            Microsoft.OpenApi.Any.OpenApiArray array => array.Select(ConvertOpenApiAnyToObject).ToArray(),
+            _ => openApiAny.ToString() ?? "value"
+        };
+    }
+
 
     private static string GenerateRequest(
         GeneratorSettings settings,
@@ -295,8 +373,8 @@ private static string GenerateRequest(
             return code.ToString();
 
         var requestBody = operation.RequestBody;
-        var requestBodySchema = requestBody.Content[contentType].Schema.ActualSchema;
-        var requestBodyJson = requestBodySchema?.ToSampleJson()?.ToString() ?? string.Empty;
+        var requestBodySchema = requestBody.Content[contentType].Schema;
+        var requestBodyJson = GenerateSampleJsonFromSchema(requestBodySchema);
 
         code.AppendLine($"  -d '{requestBodyJson}'");
         return code.ToString();
@@ -310,7 +388,7 @@ private static Dictionary<string, string> AppendParameters(
     {
         var parameters = operation
             .Parameters
-            .Where(c => c.Kind is OpenApiParameterKind.Path or OpenApiParameterKind.Query)
+            .Where(c => c.In is ParameterLocation.Path or ParameterLocation.Query)
             .ToArray();
 
         if (parameters.Length == 0)
diff --git a/src/CurlGenerator.Tests/CurlGenerator.Tests.csproj b/src/CurlGenerator.Tests/CurlGenerator.Tests.csproj
@@ -13,6 +13,7 @@
     <PackageReference Include="Atc.Test" Version="1.1.18" />
     <PackageReference Include="FluentAssertions" Version="7.2.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.14.1" />
+    <PackageReference Include="Microsoft.OpenApi.Readers" Version="1.6.25" />
     <PackageReference Include="xunit" Version="2.9.3" />
     <PackageReference Include="xunit.runner.visualstudio" Version="3.1.4">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
diff --git a/src/CurlGenerator.Tests/OperationNameGeneratorTests.cs b/src/CurlGenerator.Tests/OperationNameGeneratorTests.cs
