httpcaddyfile: Rewrite root parsing to allow omitting matcher

caddyconfig/httpcaddyfile/builtins.go

@@ -40,7 +40,7 @@ import (
 func init() {
 	RegisterDirective("bind", parseBind)
 	RegisterDirective("tls", parseTLS)
-	RegisterHandlerDirective("root", parseRoot)
+	RegisterDirective("root", parseRoot)
 	RegisterHandlerDirective("vars", parseVars)
 	RegisterHandlerDirective("redir", parseRedir)
 	RegisterHandlerDirective("respond", parseRespond)
@@ -600,18 +600,45 @@ func parseTLS(h Helper) ([]ConfigValue, error) {
 // parseRoot parses the root directive. Syntax:
 //
 //	root [<matcher>] <path>
-func parseRoot(h Helper) (caddyhttp.MiddlewareHandler, error) {
-	var root string
-	for h.Next() {
+func parseRoot(h Helper) ([]ConfigValue, error) {
+	// consume directive name
+	if !h.NextArg() {
+		return nil, h.ArgErr()
+	}
+
+	// count the tokens to determine what to do
+	argsCount := h.CountRemainingArgs()
+	if argsCount == 0 {
+		return nil, h.Errf("too few arguments; must have at least a root path")
+	}
+	if argsCount > 2 {
+		return nil, h.Errf("too many arguments; should only be a matcher and a path")
+	}
+
+	// with only one arg, assume it's a root path with no matcher token
+	if argsCount == 1 {
 		if !h.NextArg() {
 			return nil, h.ArgErr()
 		}
-		root = h.Val()
-		if h.NextArg() {
-			return nil, h.ArgErr()
-		}
+		return h.NewRoute(nil, caddyhttp.VarsMiddleware{"root": h.Val()}), nil
+	}
+
+	// parse the matcher token into a matcher set
+	userMatcherSet, err := h.ExtractMatcherSet()
+	if err != nil {
+		return nil, err
+	}
+
+	// consume directive name, again, because extracting matcher does a reset
+	if !h.NextArg() {
+		return nil, h.ArgErr()
+	}
+	// advance to the root path
+	if !h.NextArg() {
+		return nil, h.ArgErr()
 	}
-	return caddyhttp.VarsMiddleware{"root": root}, nil
+	// make the route with the matcher
+	return h.NewRoute(userMatcherSet, caddyhttp.VarsMiddleware{"root": h.Val()}), nil
 }
 
 // parseVars parses the vars directive. See its UnmarshalCaddyfile method for syntax.

caddytest/integration/caddyfile_adapt/root_directive_permutations.txt

@@ -0,0 +1,108 @@
+:8080
+
+# With explicit wildcard matcher
+route {
+	root * /a
+}
+
+# With path matcher
+route {
+	root /path /b
+}
+
+# With named matcher
+route {
+	@named method GET
+	root @named /c
+}
+
+# With no matcher, assumed to be wildcard
+route {
+	root /d
+}
+----------
+{
+	"apps": {
+		"http": {
+			"servers": {
+				"srv0": {
+					"listen": [
+						":8080"
+					],
+					"routes": [
+						{
+							"handle": [
+								{
+									"handler": "subroute",
+									"routes": [
+										{
+											"handle": [
+												{
+													"handler": "vars",
+													"root": "/a"
+												}
+											]
+										}
+									]
+								},
+								{
+									"handler": "subroute",
+									"routes": [
+										{
+											"handle": [
+												{
+													"handler": "vars",
+													"root": "/b"
+												}
+											],
+											"match": [
+												{
+													"path": [
+														"/path"
+													]
+												}
+											]
+										}
+									]
+								},
+								{
+									"handler": "subroute",
+									"routes": [
+										{
+											"handle": [
+												{
+													"handler": "vars",
+													"root": "/c"
+												}
+											],
+											"match": [
+												{
+													"method": [
+														"GET"
+													]
+												}
+											]
+										}
+									]
+								},
+								{
+									"handler": "subroute",
+									"routes": [
+										{
+											"handle": [
+												{
+													"handler": "vars",
+													"root": "/d"
+												}
+											]
+										}
+									]
+								}
+							]
+						}
+					]
+				}
+			}
+		}
+	}
+}