httpcaddyfile: Shorthands for parameterized placeholders (#3305)

* httpcaddyfile: Add shorthands for parameterized placeholders


httpcaddyfile: Now with regexp instead


httpcaddyfile: Allow dashes, gofmt


httpcaddyfile: Compile regexp only once


httpcaddyfile: Cleanup struct


httpcaddyfile: Optimize the replacers, pull out of the loop


httpcaddyfile: Add `{port}` shorthand

* httpcaddyfile: Switch `r.` to `re.`

caddytest/integration/caddyfile_adapt_test.go

@@ -539,3 +539,49 @@ func TestLogRollDays(t *testing.T) {
 	}
 }`)
 }
+
+func TestShorthandParameterizedPlaceholders(t *testing.T) {
+	caddytest.AssertAdapt(t, `
+	localhost:80
+	respond * "{header.content-type} {labels.0} {query.p} {path.0} {re.name.0}"
+	`, "caddyfile", `{
+	"apps": {
+		"http": {
+			"servers": {
+				"srv0": {
+					"listen": [
+						":80"
+					],
+					"routes": [
+						{
+							"match": [
+								{
+									"host": [
+										"localhost"
+									]
+								}
+							],
+							"handle": [
+								{
+									"handler": "subroute",
+									"routes": [
+										{
+											"handle": [
+												{
+													"body": "{http.request.header.content-type} {http.request.host.labels.0} {http.request.uri.query.p} {http.request.uri.path.0} {http.regexp.name.0}",
+													"handler": "static_response"
+												}
+											]
+										}
+									]
+								}
+							],
+							"terminal": true
+						}
+					]
+				}
+			}
+		}
+	}
+}`)
+}