Refactor parameter extraction into a ParameterListBuilder module

CONTEXT.md

@@ -0,0 +1,13 @@
+# Refitter
+
+Refitter generates C# REST API clients — Refit interfaces and their contracts —
+from OpenAPI specifications. It ships as a CLI tool, an MSBuild task, and a C#
+source generator, all driven by the same `.refitter` settings.
+
+## Language
+
+**Parameter list**:
+The ordered set of a generated Refit method's parameters, derived from an OpenAPI
+operation's path, query, header, body, and form inputs, plus any trailing
+request-options or cancellation-token argument.
+_Avoid_: arguments, args

src/Refitter.Core/Generation/InterfaceGenerator.cs

@@ -19,16 +19,15 @@ internal InterfaceGenerator(
         RefitGeneratorSettings settings,
         OpenApiDocument document,
         CustomCSharpClientGenerator generator,
-        XmlDocumentationGenerator docGenerator,
-        IParameterExtractor? parameterExtractor = null)
+        XmlDocumentationGenerator docGenerator)
         : this(
             settings,
             document,
             generator,
             docGenerator,
             new ReturnTypeGenerator(settings, generator),
             new MethodAttributeGenerator(settings, document),
-            new MethodSignatureGenerator(settings, parameterExtractor ?? new ParameterAggregator()))
+            new MethodSignatureGenerator(settings))
     {
     }
 

src/Refitter.Core/Generation/MethodSignatureGenerator.cs

@@ -3,27 +3,22 @@
 
 namespace Refitter.Core;
 
-internal class MethodSignatureGenerator(
-    RefitGeneratorSettings settings,
-    IParameterExtractor? parameterExtractor = null)
+internal class MethodSignatureGenerator(RefitGeneratorSettings settings)
     : IMethodSignatureGenerator
 {
-    private readonly IParameterExtractor parameterExtractor = parameterExtractor ?? new ParameterAggregator();
+    private readonly ParameterListBuilder parameterListBuilder = new(settings);
 
     public (string ParametersString, IReadOnlyList<string> Parameters, string? DynamicQuerystringParameters) Generate(
         CSharpOperationModel operationModel,
         OpenApiOperation operation,
         string dynamicQuerystringParameterType)
     {
-        var parameters = parameterExtractor.ExtractParameters(
-                operationModel,
-                operation,
-                settings,
-                dynamicQuerystringParameterType,
-                out var operationDynamicQuerystringParameters)
-            .ToList();
+        var parameterList = parameterListBuilder.Build(
+            operationModel,
+            operation,
+            dynamicQuerystringParameterType);
 
-        var parametersString = string.Join(", ", parameters);
-        return (parametersString, parameters, operationDynamicQuerystringParameters);
+        var parametersString = string.Join(", ", parameterList.Parameters);
+        return (parametersString, parameterList.Parameters, parameterList.DynamicQuerystringCode);
     }
 }

src/Refitter.Core/ParameterExtraction/BodyParameterExtractor.cs

@@ -3,9 +3,9 @@
 
 namespace Refitter.Core;
 
-internal class BodyParameterExtractor : IParameterTypeExtractor
+internal sealed class BodyParameterExtractor
 {
     public IEnumerable<string> Extract(
         CSharpOperationModel operationModel,
         OpenApiOperation operation,
         RefitGeneratorSettings settings)
@@ -14,17 +14,17 @@
             .Where(p => p.Kind == OpenApiParameterKind.Body && !p.IsBinaryBodyParameter)
             .Select(p =>
             {
-                var variableName = ParameterShared.GetVariableName(p);
-                return $"{ParameterShared.JoinAttributes(ParameterShared.GetBodyAttribute(p, settings), ParameterShared.GetAliasAsAttribute(p.Name, variableName))}{ParameterShared.GetParameterType(p, settings)} {variableName}";
+                var variableName = ParameterNaming.GetVariableName(p);
+                return $"{ParameterAttributeFormatter.JoinAttributes(ParameterAttributeFormatter.GetBodyAttribute(p, settings), ParameterAttributeFormatter.GetAliasAsAttribute(p.Name, variableName))}{ParameterTypeResolver.GetParameterType(p, settings)} {variableName}";
             })
             .ToList();
 
         var binaryBodyParameters = operationModel.Parameters
             .Where(p => p.Kind == OpenApiParameterKind.Body && p.IsBinaryBodyParameter)
             .Select(p =>
             {
-                var variableName = ParameterShared.GetVariableName(p);
-                var aliasAsAttribute = ParameterShared.GetAliasAsAttribute(p.Name, variableName);
+                var variableName = ParameterNaming.GetVariableName(p);
+                var aliasAsAttribute = ParameterAttributeFormatter.GetAliasAsAttribute(p.Name, variableName);
                 var generatedAliasAsAttribute = string.IsNullOrWhiteSpace(aliasAsAttribute)
                     ? string.Empty
                     : $"[{aliasAsAttribute}]";

src/Refitter.Core/ParameterExtraction/DynamicQuerystringParameterBuilder.cs

@@ -27,9 +27,9 @@ public static string Build(
 
         foreach (var operationParameter in queryParameters)
         {
-            var propertyType = ParameterShared.GetQueryParameterType(operationParameter, settings);
-            var variableName = ParameterShared.GetVariableName(operationParameter);
-            var attributes = $"{ParameterShared.JoinAttributes(ParameterShared.GetQueryAttribute(operationParameter, settings), ParameterShared.GetAliasAsAttribute(operationParameter.Name, variableName))}";
+            var propertyType = ParameterTypeResolver.GetQueryParameterType(operationParameter, settings);
+            var variableName = ParameterNaming.GetVariableName(operationParameter);
+            var attributes = $"{ParameterAttributeFormatter.JoinAttributes(ParameterAttributeFormatter.GetQueryAttribute(operationParameter, settings), ParameterAttributeFormatter.GetAliasAsAttribute(operationParameter.Name, variableName))}";
             var propertyName = variableName.CapitalizeFirstCharacter();
             if (operationParameter.IsRequired)
             {
@@ -48,7 +48,7 @@ public static string Build(
             if (settings.GenerateXmlDocCodeComments && !string.IsNullOrWhiteSpace(operationParameter.Description))
             {
                 var escapedDescription = XmlDocumentationGenerator.SanitizeResponseDescription(operationParameter.Description);
-                ParameterShared.AppendXmlDocComment(escapedDescription, propertiesCodeBuilder);
+                AppendXmlDocComment(escapedDescription, propertiesCodeBuilder);
             }
 
             propertiesCodeBuilder.Append(
@@ -59,7 +59,7 @@ public static string Build(
             var defaultValue = operationParameter.Schema.Default;
             if (defaultValue != null)
             {
-                var formattedDefaultValue = ParameterShared.FormatDefaultValue(defaultValue, propertyType);
+                var formattedDefaultValue = ParameterDefaultValueFormatter.FormatDefaultValue(defaultValue, propertyType);
                 propertiesCodeBuilder.Append($" = {formattedDefaultValue};");
             }
 
@@ -91,4 +91,32 @@ public static string Build(
 
         return codeBuilder.ToString();
     }
+
+    internal static void AppendXmlDocComment(string description, StringBuilder codeBuilder)
+    {
+        codeBuilder.Append(
+"""
+                /// <summary>
+""");
+
+        var lines = description.Split(
+            ["\r\n", "\r", "\n"],
+            StringSplitOptions.None);
+
+        foreach (var line in lines)
+        {
+            codeBuilder.AppendLine();
+            codeBuilder.Append(
+$$"""
+                /// {{line.Trim()}}
+""");
+        }
+
+        codeBuilder.AppendLine();
+        codeBuilder.Append(
+"""
+                /// </summary>
+""");
+        codeBuilder.AppendLine();
+    }
 }

src/Refitter.Core/ParameterExtraction/FormParameterExtractor.cs

@@ -4,9 +4,9 @@
 
 namespace Refitter.Core;
 
-internal class FormParameterExtractor : IParameterTypeExtractor
+internal sealed class FormParameterExtractor
 {
     public IEnumerable<string> Extract(
         CSharpOperationModel operationModel,
         OpenApiOperation operation,
         RefitGeneratorSettings settings)
@@ -16,10 +16,10 @@
 
         foreach (var p in operationModel.Parameters.Where(p => p.Kind == OpenApiParameterKind.FormData && !p.IsBinaryBodyParameter))
         {
-            var variableName = ParameterShared.ConvertToVariableName(p.VariableName);
+            var variableName = ParameterNaming.ConvertToVariableName(p.VariableName);
             if (seenFormParameterNames.Add(variableName))
             {
-                formParameters.Add($"{ParameterShared.JoinAttributes(ParameterShared.GetAliasAsAttribute(p.Name, variableName))}{ParameterShared.GetParameterType(p, settings)} {variableName}");
+                formParameters.Add($"{ParameterAttributeFormatter.JoinAttributes(ParameterAttributeFormatter.GetAliasAsAttribute(p.Name, variableName))}{ParameterTypeResolver.GetParameterType(p, settings)} {variableName}");
             }
         }
 
@@ -40,13 +40,13 @@
 
                     if (!isBinary)
                     {
-                        var propertyType = ParameterShared.GetCSharpType(propertySchema, settings);
-                        var variableName = ParameterShared.ConvertToVariableName(property.Key);
+                        var propertyType = ParameterTypeResolver.GetCSharpType(propertySchema, settings);
+                        var variableName = ParameterNaming.ConvertToVariableName(property.Key);
 
                         if (seenFormParameterNames.Add(variableName))
                         {
-                            var aliasAttribute = ParameterShared.GetAliasAsAttribute(property.Key, variableName);
-                            var parameter = $"{ParameterShared.JoinAttributes(aliasAttribute)}{propertyType} {variableName}";
+                            var aliasAttribute = ParameterAttributeFormatter.GetAliasAsAttribute(property.Key, variableName);
+                            var parameter = $"{ParameterAttributeFormatter.JoinAttributes(aliasAttribute)}{propertyType} {variableName}";
                             formParameters.Add(parameter);
                         }
                     }

src/Refitter.Core/ParameterExtraction/HeaderParameterExtractor.cs

@@ -3,9 +3,9 @@
 
 namespace Refitter.Core;
 
-internal class HeaderParameterExtractor : IParameterTypeExtractor
+internal sealed class HeaderParameterExtractor
 {
     public IEnumerable<string> Extract(
         CSharpOperationModel operationModel,
         OpenApiOperation operation,
         RefitGeneratorSettings settings)
@@ -26,8 +26,8 @@
                 .Where(p => !anyIgnoredHeaders || !ignoredHeaders.Contains(p.Name, StringComparer.OrdinalIgnoreCase))
                 .Select(p =>
                 {
-                    var variableName = ParameterShared.GetVariableName(p);
-                    return $"{ParameterShared.JoinAttributes($"Header(\"{p.Name}\")")}{ParameterShared.GetParameterType(p, settings)} {variableName}";
+                    var variableName = ParameterNaming.GetVariableName(p);
+                    return $"{ParameterAttributeFormatter.JoinAttributes($"Header(\"{p.Name}\")")}{ParameterTypeResolver.GetParameterType(p, settings)} {variableName}";
                 })
                 .ToList();
         }
@@ -47,7 +47,7 @@
                     && securityScheme.In == OpenApiSecurityApiKeyLocation.Header
                     && !operationModel.Parameters.Any(p => p.Kind == OpenApiParameterKind.Header && p.IsHeader && p.Name == securityScheme.Name))
                 {
-                    headerParameters.Add($"[Header(\"{securityScheme.Name}\")] string {ParameterShared.ReplaceUnsafeCharacters(securityScheme.Name)}");
+                    headerParameters.Add($"[Header(\"{securityScheme.Name}\")] string {ParameterNaming.ReplaceUnsafeCharacters(securityScheme.Name)}");
                 }
                 else if (securityScheme is { Type: OpenApiSecuritySchemeType.Http }
                     && string.Equals(securityScheme.Scheme, "bearer", StringComparison.OrdinalIgnoreCase))

src/Refitter.Core/ParameterExtraction/OptionalParameterReorderer.cs

@@ -23,7 +23,7 @@ public static List<string> Reorder(
             if (NullablePattern.IsMatch(parameters[index]))
             {
                 var parameterString = parameters[index];
-                var defaultValue = ParameterShared.GetDefaultValueForParameter(parameterString, parameterModels);
+                var defaultValue = ParameterDefaultValueFormatter.GetDefaultValueForParameter(parameterString, parameterModels);
                 parameters[index] = parameterString + " = " + defaultValue;
             }
         }