work towards path parameters

SimpleHttpServer/HttpServer.cs

@@ -107,27 +107,39 @@ public sealed class HttpServer {
             Assert(mi.IsPublic, $"Method tagged with HttpEndpointAttribute must be public! ({GetFancyMethodName()})");
 
             var methodParams = mi.GetParameters();
+            // check the mandatory prefix parameters
             Assert(methodParams.Length >= expectedEndpointParameterTypes.Length);
             for (int i = 0; i < expectedEndpointParameterTypes.Length; i++) {
                 Assert(methodParams[i].ParameterType.IsAssignableFrom(expectedEndpointParameterTypes[i]),
                     $"Parameter at index {i} of {GetFancyMethodName()} is of a type that cannot contain the expected type {expectedEndpointParameterTypes[i].FullName}.");
             }
 
+            // check return type
             Assert(mi.ReturnType == typeof(Task), $"Return type of {GetFancyMethodName()} is not {typeof(Task)}!");
 
-
+            // check the rest of the method parameters
             var qparams = new List<QueryParameterInfo>();
             for (int i = expectedEndpointParameterTypes.Length; i < methodParams.Length; i++) {
                 var par = methodParams[i];
                 var attr = par.GetCustomAttribute<ParameterAttribute>(false);
-                qparams.Add(new(
+                var pathAttr = par.GetCustomAttribute<PathParameterAttribute>(false);
-                    attr?.Name ?? par.Name ?? throw new ArgumentException($"C# variable name of parameter at index {i} of method {GetFancyMethodName()} is null!"),
-                    par.ParameterType,
-                    attr?.IsOptional ?? false)
-                );
 
-                if (!stringToTypeParameterConverters.ContainsKey(par.ParameterType)) {
+                if (attr != null && pathAttr != null) {
-                    throw new MissingParameterConverterException($"Parameter converter for type {par.ParameterType} has not been registered (yet)!");
+                    throw new ArgumentException($"A method argument cannot be tagged with both {nameof(ParameterAttribute)} and {nameof(PathParameterAttribute)}");
+                }
+
+                if (pathAttr != null) { // parameter is a path param
+
+                } else { // parameter is a normal one
+                    qparams.Add(new(
+                        attr?.Name ?? par.Name ?? throw new ArgumentException($"C# variable name of parameter at index {i} of method {GetFancyMethodName()} is null!"),
+                        par.ParameterType,
+                        attr?.IsOptional ?? false)
+                    );
+
+                    if (!stringToTypeParameterConverters.ContainsKey(par.ParameterType)) {
+                        throw new MissingParameterConverterException($"Parameter converter for type {par.ParameterType} has not been registered (yet)!");
+                    }
                 }
             }
 

SimpleHttpServer/Types/ParameterAttribute.cs

@@ -5,9 +5,6 @@
 /// </summary>
 [AttributeUsage(AttributeTargets.Parameter, Inherited = false, AllowMultiple = false)]
 public sealed class ParameterAttribute : Attribute {
-    // See the attribute guidelines at 
-    //  http://go.microsoft.com/fwlink/?LinkId=85236
-
     public string Name { get; }
     public bool IsOptional { get; }
     public ParameterAttribute(string name, bool isOptional = false) {

SimpleHttpServer/Types/PathParameterAttribute.cs

@@ -0,0 +1,24 @@
+namespace SimpleHttpServer.Types;
+
+/// <summary>
+/// Specifies the name of a http endpoint path parameter. Path parameter names must be in the format $1, $2, $3, ..., and the end of the path may be $*
+/// </summary>
+[AttributeUsage(AttributeTargets.Parameter, Inherited = false, AllowMultiple = false)]
+public sealed class PathParameterAttribute : Attribute {
+    public string Name { get; }
+    public PathParameterAttribute(string name) {
+        if (string.IsNullOrWhiteSpace(name)) {
+            throw new ArgumentException($"'{nameof(name)}' cannot be null or whitespace.", nameof(name));
+        }
+
+        if (!name.StartsWith('$')) {
+            throw new ArgumentException($"'{nameof(name)}' must start with $.", nameof(name));
+        }
+
+        if (name.Contains(' ')) {
+            throw new ArgumentException($"'{nameof(name)}' must not contain spaces.", nameof(name));
+        }
+
+        Name = name;
+    }
+}