Refactor Caddyfile adapter and module registration

Use piles from which to draw config values.

Module values can return their name, so now we can do two-way mapping
from value to name and name to value; whereas before we could only map
name to value. This was problematic with the Caddyfile adapter since
it receives values and needs to know the name to put in the config.

3 files changed, 74 insertions, 44 deletions

diff --git a/modules/caddyhttp/fileserver/caddyfile.go b/modules/caddyhttp/fileserver/caddyfile.go
index 7d9ddd9..6fa94e7 100644
--- a/modules/caddyhttp/fileserver/caddyfile.go
+++ b/modules/caddyhttp/fileserver/caddyfile.go
@@ -15,59 +15,58 @@
 package fileserver
 
 import (
-	"github.com/caddyserver/caddy/v2/caddyconfig/caddyfile"
+	"encoding/json"
+
+	"github.com/caddyserver/caddy/modules/caddyhttp/rewrite"
 	"github.com/caddyserver/caddy/v2/caddyconfig/httpcaddyfile"
+	"github.com/caddyserver/caddy/v2/modules/caddyhttp"
 )
 
-// UnmarshalCaddyfile sets up the handler from Caddyfile tokens. Syntax:
-//
-//     file_server [<matcher>] [browse] {
-//         hide <files...>
-//         index <files...>
-//         browse [<template_file>]
-//         root <path>
-//     }
-//
-// If browse is given on the first line, it can't be used in the block also.
-// The default root is the one given by the root directive.
-func (fsrv *FileServer) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
-	for d.Next() {
-		args := d.RemainingArgs()
+func init() {
+	httpcaddyfile.RegisterHandlerDirective("file_server", parseCaddyfile)
+	httpcaddyfile.RegisterDirective("try_files", parseTryFiles)
+}
+
+func parseCaddyfile(h httpcaddyfile.Helper) (caddyhttp.MiddlewareHandler, error) {
+	var fsrv FileServer
+
+	for h.Next() {
+		args := h.RemainingArgs()
 		switch len(args) {
 		case 0:
 		case 1:
 			if args[0] != "browse" {
-				return d.ArgErr()
+				return nil, h.ArgErr()
 			}
 			fsrv.Browse = new(Browse)
 		default:
-			return d.ArgErr()
+			return nil, h.ArgErr()
 		}
 
-		for d.NextBlock() {
-			switch d.Val() {
+		for h.NextBlock() {
+			switch h.Val() {
 			case "hide":
-				fsrv.Hide = d.RemainingArgs()
+				fsrv.Hide = h.RemainingArgs()
 				if len(fsrv.Hide) == 0 {
-					return d.ArgErr()
+					return nil, h.ArgErr()
 				}
 			case "index":
-				fsrv.IndexNames = d.RemainingArgs()
+				fsrv.IndexNames = h.RemainingArgs()
 				if len(fsrv.Hide) == 0 {
-					return d.ArgErr()
+					return nil, h.ArgErr()
 				}
 			case "root":
-				if !d.Args(&fsrv.Root) {
-					return d.ArgErr()
+				if !h.Args(&fsrv.Root) {
+					return nil, h.ArgErr()
 				}
 			case "browse":
 				if fsrv.Browse != nil {
-					return d.Err("browsing is already configured")
+					return nil, h.Err("browsing is already configured")
 				}
 				fsrv.Browse = new(Browse)
-				d.Args(&fsrv.Browse.TemplateFile)
+				h.Args(&fsrv.Browse.TemplateFile)
 			default:
-				return d.Errf("unknown subdirective '%s'", d.Val())
+				return nil, h.Errf("unknown subdirective '%s'", h.Val())
 			}
 		}
 	}
@@ -77,11 +76,29 @@ func (fsrv *FileServer) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
 		fsrv.Root = "{http.var.root}"
 	}
 
-	return nil
+	return &fsrv, nil
 }
 
-// Bucket returns the HTTP Caddyfile handler bucket number.
-func (fsrv FileServer) Bucket() int { return 7 }
+func parseTryFiles(h httpcaddyfile.Helper) ([]httpcaddyfile.ConfigValue, error) {
+	if !h.Next() {
+		return nil, h.ArgErr()
+	}
+
+	try := h.RemainingArgs()
+	if len(try) == 0 {
+		return nil, h.ArgErr()
+	}
+
+	handler := rewrite.Rewrite{
+		URI: "{http.matchers.file.relative}{http.request.uri.query}",
+	}
 
-// Interface guard
-var _ httpcaddyfile.HandlerDirective = (*FileServer)(nil)
+	matcherSet := map[string]json.RawMessage{
+		"file": h.JSON(MatchFile{
+			Root:     "{http.var.root}",
+			TryFiles: try,
+		}, nil),
+	}
+
+	return h.NewRoute(matcherSet, handler), nil
+}
diff --git a/modules/caddyhttp/fileserver/matcher.go b/modules/caddyhttp/fileserver/matcher.go
index eca0e8f..b091250 100644
--- a/modules/caddyhttp/fileserver/matcher.go
+++ b/modules/caddyhttp/fileserver/matcher.go
@@ -20,16 +20,13 @@ import (
 	"os"
 	"time"
 
-	"github.com/caddyserver/caddy/v2/caddyconfig/caddyfile"
 	"github.com/caddyserver/caddy/v2"
+	"github.com/caddyserver/caddy/v2/caddyconfig/caddyfile"
 	"github.com/caddyserver/caddy/v2/modules/caddyhttp"
 )
 
 func init() {
-	caddy.RegisterModule(caddy.Module{
-		Name: "http.matchers.file",
-		New:  func() interface{} { return new(MatchFile) },
-	})
+	caddy.RegisterModule(MatchFile{})
 }
 
 // MatchFile is an HTTP request matcher that can match
@@ -52,12 +49,20 @@ type MatchFile struct {
 	TryPolicy string `json:"try_policy,omitempty"`
 }
 
+// CaddyModule returns the Caddy module information.
+func (MatchFile) CaddyModule() caddy.ModuleInfo {
+	return caddy.ModuleInfo{
+		Name: "http.matchers.file",
+		New:  func() caddy.Module { return new(MatchFile) },
+	}
+}
+
 // UnmarshalCaddyfile sets up the matcher from Caddyfile tokens. Syntax:
 //
 //     file {
 //         root <path>
 //         try_files <files...>
-//         try_policy <first_exist|smallest_size|largest_size|most_recent_modified>
+//         try_policy first_exist|smallest_size|largest_size|most_recent_modified
 //     }
 //
 func (m *MatchFile) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
@@ -82,6 +87,9 @@ func (m *MatchFile) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
 			}
 		}
 	}
+	if m.Root == "" {
+		m.Root = "{http.var.root}"
+	}
 	return nil
 }
 
@@ -121,7 +129,7 @@ func (m MatchFile) Match(r *http.Request) bool {
 func (m MatchFile) selectFile(r *http.Request) (rel, abs string, matched bool) {
 	repl := r.Context().Value(caddy.ReplacerCtxKey).(caddy.Replacer)
 
-	root := repl.ReplaceAll(m.Root, "")
+	root := repl.ReplaceAll(m.Root, ".")
 
 	// if list of files to try was omitted entirely,
 	// assume URL path
diff --git a/modules/caddyhttp/fileserver/staticfiles.go b/modules/caddyhttp/fileserver/staticfiles.go
index 1b542cf..cdac453 100644
--- a/modules/caddyhttp/fileserver/staticfiles.go
+++ b/modules/caddyhttp/fileserver/staticfiles.go
@@ -36,10 +36,7 @@ import (
 func init() {
 	weakrand.Seed(time.Now().UnixNano())
 
-	caddy.RegisterModule(caddy.Module{
-		Name: "http.handlers.file_server",
-		New:  func() interface{} { return new(FileServer) },
-	})
+	caddy.RegisterModule(FileServer{})
 }
 
 // FileServer implements a static file server responder for Caddy.
@@ -50,6 +47,14 @@ type FileServer struct {
 	Browse     *Browse  `json:"browse,omitempty"`
 }
 
+// CaddyModule returns the Caddy module information.
+func (FileServer) CaddyModule() caddy.ModuleInfo {
+	return caddy.ModuleInfo{
+		Name: "http.handlers.file_server",
+		New:  func() caddy.Module { return new(FileServer) },
+	}
+}
+
 // Provision sets up the static files responder.
 func (fsrv *FileServer) Provision(ctx caddy.Context) error {
 	if fsrv.IndexNames == nil {