finish implementing path parameters

SimpleHttpServer/HttpServer.cs

@@ -84,8 +84,11 @@ public sealed class HttpServer {
         RegisterConverter<decimal>();
     }
 
-    private readonly Dictionary<(string path, string rType), EndpointInvocationInfo> simpleEndpointMethodInfos = new();
+    private readonly MultiKeyDictionary<string, string, EndpointInvocationInfo> simpleEndpointMethodInfos = new(); // requestmethod, path
+    private readonly MultiKeyDictionary<string, string, EndpointInvocationInfo> pathEndpointMethodInfos = new(); // requestmethod, path
+    private readonly Dictionary<string, PathTree<EndpointInvocationInfo>> pathEndpointMethodInfosTrees = new(); // reqmethod : pathtree
     private static readonly Type[] expectedEndpointParameterTypes = new[] { typeof(RequestContext) };
+    internal static readonly int expectedEndpointParameterPrefixCount = expectedEndpointParameterTypes.Length;
 
     public void RegisterEndpointsFromType<T>(Func<T>? instanceFactory = null) where T : class { // T cannot be static, as generic args must be nonstatic
         if (stringToTypeParameterConverters.Count == 0)
@@ -119,6 +122,8 @@ public sealed class HttpServer {
 
             // check the rest of the method parameters
             var qparams = new List<QueryParameterInfo>();
+            var pparams = new List<PathParameterInfo>();
+            int mParamIndex = expectedEndpointParameterTypes.Length;
             for (int i = expectedEndpointParameterTypes.Length; i < methodParams.Length; i++) {
                 var par = methodParams[i];
                 var attr = par.GetCustomAttribute<ParameterAttribute>(false);
@@ -128,18 +133,25 @@ public sealed class HttpServer {
                     throw new ArgumentException($"A method argument cannot be tagged with both {nameof(ParameterAttribute)} and {nameof(PathParameterAttribute)}");
                 }
 
+                if (!stringToTypeParameterConverters.ContainsKey(par.ParameterType)) {
+                    throw new MissingParameterConverterException($"Parameter converter for type {par.ParameterType} for parameter at index {i} of method {GetFancyMethodName()} has not been registered (yet)!");
+                }
+
                 if (pathAttr != null) { // parameter is a path param
 
-                } else { // parameter is a normal one
+                    pparams.Add(new(
-                    qparams.Add(new(
+                        pathAttr?.Name ?? throw new ArgumentException($"C# variable name of path parameter at index {i} of method {GetFancyMethodName()} is null!"),
-                        attr?.Name ?? par.Name ?? throw new ArgumentException($"C# variable name of parameter at index {i} of method {GetFancyMethodName()} is null!"),
                         par.ParameterType,
+                        mParamIndex++
+                        )
+                    );
+                } else { // parameter is a normal query param
+                    qparams.Add(new(
+                        attr?.Name ?? par.Name ?? throw new ArgumentException($"C# variable name of query parameter at index {i} of method {GetFancyMethodName()} is null!"),
+                        par.ParameterType,
+                        mParamIndex++,
                         attr?.IsOptional ?? false)
                     );
-
-                    if (!stringToTypeParameterConverters.ContainsKey(par.ParameterType)) {
-                        throw new MissingParameterConverterException($"Parameter converter for type {par.ParameterType} has not been registered (yet)!");
-                    }
                 }
             }
 
@@ -153,19 +165,37 @@ public sealed class HttpServer {
 
             foreach (var location in attrib.Locations) {
                 var normLocation = NormalizeUrlPath(location);
-                int idx = normLocation.IndexOf('{');
-                if (idx >= 0) {
-                    // this path contains path parameters
-                    throw new NotImplementedException("Path parameters are not yet implemented!");
-                }
 
                 var reqMethod = Enum.GetName(attrib.RequestMethod) ?? throw new ArgumentException("Request method was undefined");
-                mainLogger.Information($"Registered endpoint: '{reqMethod} {normLocation}'");
+
-                simpleEndpointMethodInfos.Add((normLocation, reqMethod), new EndpointInvocationInfo(mi, qparams, requiredChecks, classInstance));
+                var pparamsCopy = new List<PathParameterInfo>(pparams);
+                var splittedLocation = location[1..].Split('/');
+                for (int i = 0; i < pparamsCopy.Count; i++) {
+                    var pp = pparamsCopy[i];
+                    var idx = Array.IndexOf(splittedLocation, pp.Name);
+                    Assert(idx != -1, "Path parameter name was incorrect?");
+                    pp.SegmentStartPos = idx;
+                    pparamsCopy[i] = pp;
+                }
+
+                var epInvocInfo = new EndpointInvocationInfo(mi, pparamsCopy, qparams, requiredChecks, classInstance);
+                if (pparams.Any()) {
+                    mainLogger.Information($"Registered path endpoint: '{reqMethod} {normLocation}'");
+                    Assert(normLocation[0] == '/');
+                    pathEndpointMethodInfos.Add(reqMethod, normLocation[1..], epInvocInfo);
+                } else {
+                    mainLogger.Information($"Registered simple endpoint: '{reqMethod} {normLocation}'");
+                    simpleEndpointMethodInfos.Add(reqMethod, normLocation, epInvocInfo);
                 }
             }
         }
 
+        // rebuild path trees
+        pathEndpointMethodInfosTrees.Clear();
+        foreach (var (reqMethod, d2) in pathEndpointMethodInfos.backingDict)
+            pathEndpointMethodInfosTrees.Add(reqMethod, new(d2));
+    }
+
     /// <summary>
     /// Serves all files located in <paramref name="filesystemDirectory"/> on a website path that is relative to <paramref name="requestPath"/>, 
     /// while restricting requests to inside the local filesystem directory. Static serving has a lower priority than registering an endpoint.
@@ -229,13 +259,23 @@ public sealed class HttpServer {
         }
         try {
 
-            if (simpleEndpointMethodInfos.TryGetValue((reqPath, requestMethod), out var endpointInvocationInfo)) {
+            /* Finding the endpoint that should process the request:
+             * 1. Try to see if there is a simple endpoint where request method and path match
+             * 2. Otherwise, try to see if a path-parameter-endpoint matches (duplicates throw an error on startup)
+             * 3. Otherwise, check if it is inside a static serve path
+             * 4. Otherwise, show 404 page */
+
+            EndpointInvocationInfo? pathEndpointInvocationInfo = null;
+            if (simpleEndpointMethodInfos.TryGetValue(requestMethod, reqPath, out var simpleEndpointInvocationInfo) ||
+                pathEndpointMethodInfosTrees.TryGetValue(requestMethod, out var pt) && pt.TryGetPath(reqPath, out pathEndpointInvocationInfo)) { // try to find simple or pathparam-endpoint
+                var endpointInvocationInfo = simpleEndpointInvocationInfo ?? pathEndpointInvocationInfo ?? throw new Exception("retrieved endpoint is somehow null");
                 var mi = endpointInvocationInfo.methodInfo;
                 var qparams = endpointInvocationInfo.queryParameters;
+                var pparams = endpointInvocationInfo.pathParameters;
                 var args = splitted.Length == 2 ? splitted[1] : null;
 
                 var parsedQParams = new Dictionary<string, string>();
-                var convertedQParamValues = new object[qparams.Count + 1];
+                var convertedMParamValues = new object[expectedEndpointParameterTypes.Length + pparams.Count + qparams.Count];
 
                 // run the checks to see if the client is allowed to make this request
                 if (!endpointInvocationInfo.CheckAll(rc.ListenerContext.Request)) { // if any check failed return Forbidden
@@ -263,32 +303,45 @@ public sealed class HttpServer {
 
                         if (parsedQParams.TryGetValue(qparam.Name, out var qparamValue)) {
                             if (stringToTypeParameterConverters[qparam.Type].TryConvertFromString(qparamValue, out object objRes)) {
-                                convertedQParamValues[i] = objRes;
+                                convertedMParamValues[qparam.ArgPos] = objRes;
                             } else {
                                 await HandleDefaultErrorPageAsync(rc, HttpStatusCode.BadRequest);
                                 return;
                             }
                         } else {
                             if (qparam.IsOptional) {
-                                convertedQParamValues[i] = null!;
+                                convertedMParamValues[qparam.ArgPos] = null!;
                             } else {
                                 await HandleDefaultErrorPageAsync(rc, HttpStatusCode.BadRequest, $"Missing required query parameter {qparam.Name}");
                                 return;
                             }
                         }
                     }
-                } else {
+                } else { // check for missing query parameters
                     var requiredParams = qparams.Where(x => !x.IsOptional).Select(x => $"'{x.Name}'").ToList();
                     if (requiredParams.Any()) {
                         await HandleDefaultErrorPageAsync(rc, HttpStatusCode.BadRequest, $"Missing required query parameter(s): {string.Join(",", requiredParams)}");
                         return;
                     }
                 }
-                convertedQParamValues[0] = rc;
+                if (pparams.Count != 0) {
+                    var splittedReqPath = reqPath[1..].Split('/');
+                    for (int i = 0; i < pparams.Count; i++) {
+                        var pparam = pparams[i];
+                        if (pparam.IsCatchAll)
+                            convertedMParamValues[pparam.ArgPos] = string.Join('/', splittedReqPath[pparam.SegmentStartPos..]);
+                        else
+                            convertedMParamValues[pparam.ArgPos] = splittedReqPath[pparam.SegmentStartPos];
+                    }
+                }
+
+                convertedMParamValues[0] = rc;
                 rc.ParsedParameters = parsedQParams.AsReadOnly();
 
-                await (Task) (mi.Invoke(endpointInvocationInfo.typeInstanceReference, convertedQParamValues) ?? throw new NullReferenceException("Website func returned null unexpectedly"));
+                // todo read and convert pathparams
-            } else {
+
+                await (Task) (mi.Invoke(endpointInvocationInfo.typeInstanceReference, convertedMParamValues) ?? throw new NullReferenceException("Website func returned null unexpectedly"));
+            } else { // try to find suitable static serve path
                 if (requestMethod == "GET")
                     foreach (var (k, v) in staticServePaths) {
                         if (reqPath.StartsWith(k)) { // do a static serve

SimpleHttpServer/Types/EndpointInvocationInfo.cs

@@ -2,23 +2,46 @@
 using System.Reflection;
 
 namespace SimpleHttpServer.Types;
-internal readonly struct EndpointInvocationInfo {
+internal record EndpointInvocationInfo {
-    internal record struct QueryParameterInfo(string Name, Type Type, bool IsOptional);
+    //internal record struct QueryParameterInfo(string Name, Type Type, bool isPathParam, bool Path_isCatchAll, bool Query_IsOptional) {
+    //    public static QueryParameterInfo CreatePathParam(string name, Type type) => new(name, type, false, name == "$*", false);
+    //    public static QueryParameterInfo CreateQueryParam(string name, Type type, bool isOptional) => new(name, type, false, false, isOptional);
+    //}
+    internal record struct PathParameterInfo(string Name, Type Type, int ArgPos, int SegmentStartPos, bool IsCatchAll) {
+        public PathParameterInfo(string name, Type type, int argPos) : this(name, type, argPos, -1, name == "$*") { }
+    }
+
+    internal record struct QueryParameterInfo(string Name, Type Type, int ArgPos, bool IsOptional);
 
     internal readonly MethodInfo methodInfo;
     internal readonly List<QueryParameterInfo> queryParameters;
+    internal readonly List<PathParameterInfo> pathParameters;
     internal readonly InternalEndpointCheckAttribute[] requiredChecks;
     /// <summary>
     /// a reference to the object in which this method is defined (or null if the class is static)
     /// </summary>
     internal readonly object? typeInstanceReference;
 
-    public EndpointInvocationInfo(MethodInfo methodInfo, List<QueryParameterInfo> queryParameters, InternalEndpointCheckAttribute[] requiredChecks, object? typeInstanceReference) {
+    public EndpointInvocationInfo(MethodInfo methodInfo, List<PathParameterInfo> pathParameters, List<QueryParameterInfo> queryParameters, InternalEndpointCheckAttribute[] requiredChecks, 
+        object? typeInstanceReference) {
+
         this.methodInfo = methodInfo ?? throw new ArgumentNullException(nameof(methodInfo));
         this.queryParameters = queryParameters ?? throw new ArgumentNullException(nameof(queryParameters));
+        this.pathParameters = pathParameters ?? throw new ArgumentNullException(nameof(pathParameters));
         this.requiredChecks = requiredChecks;
         this.typeInstanceReference = typeInstanceReference;
+
+        if (pathParameters.Any()) {
+            Assert(pathParameters.Count(x => x.IsCatchAll) <= 1); // at most one catchall parameter
+            var argPoses = pathParameters.Select(x => x.ArgPos).Concat(queryParameters.Select(x => x.ArgPos)).ToArray();
+            var argCnt = pathParameters.Count + queryParameters.Count;
+            Assert(argPoses.Distinct().Count() == argCnt); // ArgPoses must be unique
+            Assert(argPoses.Min() == HttpServer.expectedEndpointParameterPrefixCount); // ArgPoses must start from just after the prefix
+            Assert(argPoses.Max() == HttpServer.expectedEndpointParameterPrefixCount + argCnt - 1); // ArgPoses must be contiguous
+
+            Assert(pathParameters.All(x => x.SegmentStartPos != -1));
+        }
     }
 
-    public readonly bool CheckAll(HttpListenerRequest req) => requiredChecks.All(x => x.Check(req));
+    public bool CheckAll(HttpListenerRequest req) => requiredChecks.All(x => x.Check(req));
 }

SimpleHttpServer/Types/MultiKeyDictionary.cs

@@ -0,0 +1,22 @@
+using System.Diagnostics.CodeAnalysis;
+
+namespace SimpleHttpServer.Types;
+internal class MultiKeyDictionary<K1, K2, V> where K1 : notnull where K2 : notnull {
+    internal readonly Dictionary<K1, Dictionary<K2, V>> backingDict = new();
+    public MultiKeyDictionary() { }
+
+    public void Add(K1 k1, K2 k2, V value) {
+        if (!backingDict.TryGetValue(k1, out var d2))
+            d2 = new();
+        d2.Add(k2, value);
+        backingDict[k1] = d2;
+    }
+
+    public bool TryGetValue(K1 k1, K2 k2, [MaybeNullWhen(false)] out V value) {
+        if (backingDict.TryGetValue(k1, out var d2) && d2.TryGetValue(k2, out value))
+            return true;
+
+        value = default;
+        return false;
+    }
+}

SimpleHttpServer/Types/PathParameterAttribute.cs

@@ -19,6 +19,10 @@ public sealed class PathParameterAttribute : Attribute {
             throw new ArgumentException($"'{nameof(name)}' must not contain spaces.", nameof(name));
         }
 
+        if (!uint.TryParse(name[1..], out _) && name != "$*") {
+            throw new ArgumentException($"'{nameof(name)}' must only consist of spaces or be exactly '$*'.", nameof(name));
+        }
+
         Name = name;
     }
 }

SimpleHttpServer/Types/PathTree.cs

@@ -0,0 +1,107 @@
+using System.Data;
+using System.Diagnostics.CodeAnalysis;
+
+namespace SimpleHttpServer.Types;
+
+internal class PathTree<T> where T : class {
+    private readonly Node? rootNode = null;
+
+    public PathTree() : this(new()) { }
+    public PathTree(Dictionary<string, T> dict) {
+        if (dict == null || dict.Count == 0)
+            return;
+
+        rootNode = new();
+        var currNode = rootNode;
+        var unpackedPaths = dict.Keys.Select(p => p.Split('/').ToArray()).ToArray();
+        var unpackedLeafData = dict.Values.ToArray();
+        for (int i = 0; i < unpackedPaths.Length; i++) {
+            var path = unpackedPaths[i];
+            var catchallidx = Array.IndexOf(path, "$*");
+            if (catchallidx != -1 && catchallidx != path.Length - 1) {
+                throw new Exception($"Found illegal catchall-wildcard in path: '{string.Join('/', path)}'");
+            }
+
+            var leafdata = unpackedLeafData[i];
+            rootNode.AddSuccessor(path, leafdata);
+        }
+    }
+
+    internal bool TryGetPath(string reqPath, [MaybeNullWhen(false)] out T? endpoint) {
+        if (rootNode == null) {
+            endpoint = null;
+            return false;
+        }
+
+        // try to find path-match
+        Node currNode = rootNode;
+        Assert(reqPath[0] == '/');
+        var splittedPath = reqPath[1..].Split("/");
+        Node? lastCatchallNode = null;
+        for (int i = 0; i < splittedPath.Length; i++) {
+
+            // keep track of the current best catchallNode
+            if (currNode.catchAllNext != null) {
+                lastCatchallNode = currNode.catchAllNext;
+            }
+
+            var seg = splittedPath[i];
+            if (currNode.next?.TryGetValue(seg, out var next) == true) { // look for an explicit path to follow greedily
+                currNode = next;
+            } else if (currNode.pathWildcardNext != null) { // otherwise look for a single-wildcard to follow
+                currNode = currNode.pathWildcardNext;
+            } else { // otherwise we are done, there is no valid path --> fall back to the most specific catchall
+                endpoint = lastCatchallNode?.leafData;
+                return lastCatchallNode != null;
+            }
+        }
+
+        // return found path
+        endpoint = currNode.leafData;
+        return true;
+    }
+
+    private class Node {
+        public T? leafData = null;
+        public Dictionary<string, Node>? next = null;
+        public Node? pathWildcardNext = null; // path wildcard
+        public Node? catchAllNext = null; // trailing-catchall wildcard
+
+        public void AddSuccessor(string[] segments, T? newLeafData) {
+            if (segments.Length == 0) { // actually add the data to this node
+                Assert(leafData == null);
+                leafData = newLeafData;
+                return;
+            }
+
+            var seg = segments[0];
+            bool newIsWildcard = seg.Length > 1 && seg[0] == '$';
+            if (newIsWildcard) {
+                bool newIsCatchallWildcard = newIsWildcard && seg.Length == 2 && seg[1] == '*';
+                if (newIsCatchallWildcard) { // this is a catchall wildcard
+                    Assert(catchAllNext == null);
+                    catchAllNext = new();
+                    catchAllNext.AddSuccessor(segments[1..], newLeafData);
+                    return;
+                } else { // must be single wildcard otherwise
+                    Assert(pathWildcardNext == null);
+                    pathWildcardNext = new();
+                    pathWildcardNext.AddSuccessor(segments[1..], newLeafData);
+                    return;
+                }
+            }
+
+            // otherwise we want to add a new constant path successor
+            if (next == null) {
+                next = new();
+            }
+
+            if (next.TryGetValue(seg, out var existingNode)) {
+                existingNode.AddSuccessor(segments[1..], newLeafData);
+            } else {
+                var newNode = next[seg] = new();
+                newNode.AddSuccessor(segments[1..], newLeafData);
+            }
+        }
+    }
+}