Improved route order flexibility

README.md

@@ -2,9 +2,11 @@
 
 HTTP router based on radix trees.
 
-## Example
+## Usage
 
-We can save any type of data inside the router. Here is an example storing strings for each route:
+### Static
+
+We can save any type of data inside the router. Here is an example storing strings for static routes:
 
 ```go
 router := router.New[string]()
@@ -13,11 +15,34 @@ router.Add("GET", "/hello", "Hello")
 router.Add("GET", "/world", "World")
 ```
 
+### Parameters
+
+The router supports parameters:
+
+```go
+router.Add("GET", "/users/:id", "...")
+router.Add("GET", "/users/:id/comments", "...")
+```
+
+### Wildcards
+
+The router can also fall back to a catch-all route which is useful for file servers:
+
+```go
+router.Add("GET", "/images/*path", "...")
+```
+
 ## Benchmarks
 
-Requesting every single route in [github.txt](testdata/github.txt):
+Requesting every single route in [github.txt](testdata/github.txt) (≈200 requests) in each iteration:
 
 ```
 BenchmarkLookup-12                 33210             36134 ns/op           19488 B/op        337 allocs/op
 BenchmarkLookupNoAlloc-12         103437             11331 ns/op               0 B/op          0 allocs/op
-```
+```
+
+## Embedding
+
+If you'd like to embed this router into your own framework, please use `LookupNoAlloc` because it's much faster than `Lookup`.
+
+To build an http server you would of course store request handlers (functions), not strings.

Router.go

@@ -1,5 +1,7 @@
 package router
 
+import "os"
+
 // Router is a high-performance router.
 type Router[T comparable] struct {
 	get     Tree[T]
@@ -57,6 +59,12 @@ func (router *Router[T]) Bind(transform func(T) T) {
 	router.options.Bind(transform)
 }
 
+// Print shows a pretty print of all the routes.
+func (router *Router[T]) Print(method string) {
+	tree := router.selectTree(method)
+	tree.root.PrettyPrint(os.Stdout)
+}
+
 // selectTree returns the tree by the given HTTP method.
 func (router *Router[T]) selectTree(method string) *Tree[T] {
 	switch method {

Router_test.go

@@ -59,12 +59,26 @@ func TestWildcard(t *testing.T) {
 	router := router.New[string]()
 
 	router.Add("GET", "/", "Front page")
+	router.Add("GET", "/:slug", "Blog post")
+	router.Add("GET", "/users/:id", "Parameter")
 	router.Add("GET", "/images/*path", "Wildcard")
 
 	data, params := router.Lookup("GET", "/")
 	assert.Equal(t, len(params), 0)
 	assert.Equal(t, data, "Front page")
 
+	data, params = router.Lookup("GET", "/blog-post")
+	assert.Equal(t, len(params), 1)
+	assert.Equal(t, params[0].Key, "slug")
+	assert.Equal(t, params[0].Value, "blog-post")
+	assert.Equal(t, data, "Blog post")
+
+	data, params = router.Lookup("GET", "/users/42")
+	assert.Equal(t, len(params), 1)
+	assert.Equal(t, params[0].Key, "id")
+	assert.Equal(t, params[0].Value, "42")
+	assert.Equal(t, data, "Parameter")
+
 	data, params = router.Lookup("GET", "/images/favicon/256.png")
 	assert.Equal(t, len(params), 1)
 	assert.Equal(t, params[0].Key, "path")

treeNode.go

@@ -1,6 +1,8 @@
 package router
 
 import (
+	"fmt"
+	"io"
 	"strings"
 )
 
@@ -228,6 +230,7 @@ func (node *treeNode[T]) append(path string, data T) {
 
 // end is called when the node was fully parsed
 // and needs to decide the next control flow.
+// end is only called from `tree.Add`.
 func (node *treeNode[T]) end(path string, data T, i int, offset int) (*treeNode[T], int, controlFlow) {
 	char := path[i]
 
@@ -250,7 +253,7 @@ func (node *treeNode[T]) end(path string, data T, i int, offset int) (*treeNode[
 
 	// node: /user/|:id
 	// path: /user/|:id/profile
-	if node.parameter != nil {
+	if node.parameter != nil && path[i] == parameter {
 		node = node.parameter
 		offset = i
 		return node, offset, controlBegin
@@ -280,3 +283,47 @@ func (node *treeNode[T]) each(callback func(*treeNode[T])) {
 		node.wildcard.each(callback)
 	}
 }
+
+// PrettyPrint prints a human-readable form of the tree to the given writer.
+func (node *treeNode[T]) PrettyPrint(writer io.Writer) {
+	node.prettyPrint(writer, -1)
+}
+
+// prettyPrint
+func (node *treeNode[T]) prettyPrint(writer io.Writer, level int) {
+	prefix := ""
+
+	if level >= 0 {
+		prefix = strings.Repeat("  ", level) + "|_ "
+	}
+
+	switch node.kind {
+	case ':':
+		prefix += ":"
+	case '*':
+		prefix += "*"
+	}
+
+	fmt.Fprintf(writer, "%s%s [%v]\n", prefix, node.prefix, node.data)
+
+	for _, child := range node.children {
+		if child == nil {
+			continue
+		}
+
+		child.prettyPrint(writer, level+1)
+	}
+
+	if node.parameter != nil {
+		node.parameter.prettyPrint(writer, level+1)
+	}
+
+	if node.wildcard != nil {
+		node.wildcard.prettyPrint(writer, level+1)
+	}
+}
+
+// String returns the node prefix.
+func (node *treeNode[T]) String() string {
+	return node.prefix
+}