httpcaddyfile: Add shortcut for expression matchers (#4976)

caddyconfig/caddyfile/lexer.go

@@ -191,3 +191,7 @@ func Tokenize(input []byte, filename string) ([]Token, error) {
 	}
 	return tokens, nil
 }
+
+func (t Token) Quoted() bool {
+	return t.wasQuoted > 0
+}

caddyconfig/httpcaddyfile/httptype.go

@@ -1201,6 +1201,7 @@ func (st *ServerType) compileEncodedMatcherSets(sblock serverBlock) ([]caddy.Mod
 
 func parseMatcherDefinitions(d *caddyfile.Dispenser, matchers map[string]caddy.ModuleMap) error {
 	for d.Next() {
+		// this is the "name" for "named matchers"
 		definitionName := d.Val()
 
 		if _, ok := matchers[definitionName]; ok {
@@ -1208,16 +1209,9 @@ func parseMatcherDefinitions(d *caddyfile.Dispenser, matchers map[string]caddy.M
 		}
 		matchers[definitionName] = make(caddy.ModuleMap)
 
-		// in case there are multiple instances of the same matcher, concatenate
-		// their tokens (we expect that UnmarshalCaddyfile should be able to
-		// handle more than one segment); otherwise, we'd overwrite other
-		// instances of the matcher in this set
-		tokensByMatcherName := make(map[string][]caddyfile.Token)
-		for nesting := d.Nesting(); d.NextArg() || d.NextBlock(nesting); {
-			matcherName := d.Val()
-			tokensByMatcherName[matcherName] = append(tokensByMatcherName[matcherName], d.NextSegment()...)
-		}
-		for matcherName, tokens := range tokensByMatcherName {
+		// given a matcher name and the tokens following it, parse
+		// the tokens as a matcher module and record it
+		makeMatcher := func(matcherName string, tokens []caddyfile.Token) error {
 			mod, err := caddy.GetModule("http.matchers." + matcherName)
 			if err != nil {
 				return fmt.Errorf("getting matcher module '%s': %v", matcherName, err)
@@ -1235,6 +1229,39 @@ func parseMatcherDefinitions(d *caddyfile.Dispenser, matchers map[string]caddy.M
 				return fmt.Errorf("matcher module '%s' is not a request matcher", matcherName)
 			}
 			matchers[definitionName][matcherName] = caddyconfig.JSON(rm, nil)
+			return nil
+		}
+
+		// if the next token is quoted, we can assume it's not a matcher name
+		// and that it's probably an 'expression' matcher
+		if d.NextArg() {
+			if d.Token().Quoted() {
+				err := makeMatcher("expression", []caddyfile.Token{d.Token()})
+				if err != nil {
+					return err
+				}
+				continue
+			}
+
+			// if it wasn't quoted, then we need to rewind after calling
+			// d.NextArg() so the below properly grabs the matcher name
+			d.Prev()
+		}
+
+		// in case there are multiple instances of the same matcher, concatenate
+		// their tokens (we expect that UnmarshalCaddyfile should be able to
+		// handle more than one segment); otherwise, we'd overwrite other
+		// instances of the matcher in this set
+		tokensByMatcherName := make(map[string][]caddyfile.Token)
+		for nesting := d.Nesting(); d.NextArg() || d.NextBlock(nesting); {
+			matcherName := d.Val()
+			tokensByMatcherName[matcherName] = append(tokensByMatcherName[matcherName], d.NextSegment()...)
+		}
+		for matcherName, tokens := range tokensByMatcherName {
+			err := makeMatcher(matcherName, tokens)
+			if err != nil {
+				return err
+			}
 		}
 	}
 	return nil

caddytest/integration/caddyfile_adapt/matcher_syntax.txt

@@ -19,27 +19,30 @@
 	@matcher6 vars_regexp "{http.request.uri}" `\.([a-f0-9]{6})\.(css|js)$`
 	respond @matcher6 "from vars_regexp matcher without name"
 
-	@matcher7 {
+	@matcher7 `path('/foo*') && method('GET')`
+	respond @matcher7 "inline expression matcher shortcut"
+
+	@matcher8 {
 		header Foo bar
 		header Foo foobar
 		header Bar foo
 	}
-	respond @matcher7 "header matcher merging values of the same field"
+	respond @matcher8 "header matcher merging values of the same field"
 
-	@matcher8 {
+	@matcher9 {
 		query foo=bar foo=baz bar=foo
 		query bar=baz
 	}
-	respond @matcher8 "query matcher merging pairs with the same keys"
+	respond @matcher9 "query matcher merging pairs with the same keys"
 
-	@matcher9 {
+	@matcher10 {
 		header !Foo
 		header Bar foo
 	}
-	respond @matcher9 "header matcher with null field matcher"
+	respond @matcher10 "header matcher with null field matcher"
 
-	@matcher10 remote_ip private_ranges
-	respond @matcher10 "remote_ip matcher with private ranges"
+	@matcher11 remote_ip private_ranges
+	respond @matcher11 "remote_ip matcher with private ranges"
 }
 ----------
 {
@@ -152,6 +155,19 @@
 								}
 							]
 						},
+						{
+							"match": [
+								{
+									"expression": "path('/foo*') \u0026\u0026 method('GET')"
+								}
+							],
+							"handle": [
+								{
+									"body": "inline expression matcher shortcut",
+									"handler": "static_response"
+								}
+							]
+						},
 						{
 							"match": [
 								{