fileserver: Share template logic for both `templates` and `file_server browse` (#4093)

Co-authored-by: Matthew Holt <mholt@users.noreply.github.com>

5 files changed, 112 insertions, 46 deletions

diff --git a/modules/caddyhttp/fileserver/browse.go b/modules/caddyhttp/fileserver/browse.go
index 2712077..fc8bddb 100644
--- a/modules/caddyhttp/fileserver/browse.go
+++ b/modules/caddyhttp/fileserver/browse.go
@@ -17,14 +17,16 @@ package fileserver
 import (
 	"bytes"
 	"encoding/json"
-	"html/template"
+	"fmt"
 	"net/http"
 	"os"
 	"path"
 	"strings"
+	"text/template"
 
 	"github.com/caddyserver/caddy/v2"
 	"github.com/caddyserver/caddy/v2/modules/caddyhttp"
+	"github.com/caddyserver/caddy/v2/modules/caddyhttp/templates"
 	"go.uber.org/zap"
 )
 
@@ -82,7 +84,26 @@ func (fsrv *FileServer) serveBrowse(root, dirPath string, w http.ResponseWriter,
 		}
 		w.Header().Set("Content-Type", "application/json; charset=utf-8")
 	} else {
-		if buf, err = fsrv.browseWriteHTML(listing); err != nil {
+		var fs http.FileSystem
+		if fsrv.Root != "" {
+			fs = http.Dir(repl.ReplaceAll(fsrv.Root, "."))
+		}
+
+		var tplCtx = &templateContext{
+			TemplateContext: templates.TemplateContext{
+				Root:       fs,
+				Req:        r,
+				RespHeader: templates.WrappedHeader{Header: w.Header()},
+			},
+			browseTemplateContext: listing,
+		}
+
+		err = fsrv.makeBrowseTemplate(tplCtx)
+		if err != nil {
+			return fmt.Errorf("parsing browse template: %v", err)
+		}
+
+		if buf, err = fsrv.browseWriteHTML(tplCtx); err != nil {
 			return caddyhttp.Error(http.StatusInternalServerError, err)
 		}
 		w.Header().Set("Content-Type", "text/html; charset=utf-8")
@@ -93,10 +114,10 @@ func (fsrv *FileServer) serveBrowse(root, dirPath string, w http.ResponseWriter,
 	return nil
 }
 
-func (fsrv *FileServer) loadDirectoryContents(dir *os.File, root, urlPath string, repl *caddy.Replacer) (browseListing, error) {
+func (fsrv *FileServer) loadDirectoryContents(dir *os.File, root, urlPath string, repl *caddy.Replacer) (browseTemplateContext, error) {
 	files, err := dir.Readdir(-1)
 	if err != nil {
-		return browseListing{}, err
+		return browseTemplateContext{}, err
 	}
 
 	// user can presumably browse "up" to parent folder if path is longer than "/"
@@ -107,7 +128,7 @@ func (fsrv *FileServer) loadDirectoryContents(dir *os.File, root, urlPath string
 
 // browseApplyQueryParams applies query parameters to the listing.
 // It mutates the listing and may set cookies.
-func (fsrv *FileServer) browseApplyQueryParams(w http.ResponseWriter, r *http.Request, listing *browseListing) {
+func (fsrv *FileServer) browseApplyQueryParams(w http.ResponseWriter, r *http.Request, listing *browseTemplateContext) {
 	sortParam := r.URL.Query().Get("sort")
 	orderParam := r.URL.Query().Get("order")
 	limitParam := r.URL.Query().Get("limit")
@@ -139,17 +160,41 @@ func (fsrv *FileServer) browseApplyQueryParams(w http.ResponseWriter, r *http.Re
 	listing.applySortAndLimit(sortParam, orderParam, limitParam, offsetParam)
 }
 
-func (fsrv *FileServer) browseWriteJSON(listing browseListing) (*bytes.Buffer, error) {
+// makeBrowseTemplate creates the template to be used for directory listings.
+func (fsrv *FileServer) makeBrowseTemplate(tplCtx *templateContext) error {
+	var tpl *template.Template
+	var err error
+
+	if fsrv.Browse.TemplateFile != "" {
+		tpl = tplCtx.NewTemplate(path.Base(fsrv.Browse.TemplateFile))
+		tpl, err = tpl.ParseFiles(fsrv.Browse.TemplateFile)
+		if err != nil {
+			return fmt.Errorf("parsing browse template file: %v", err)
+		}
+	} else {
+		tpl = tplCtx.NewTemplate("default_listing")
+		tpl, err = tpl.Parse(defaultBrowseTemplate)
+		if err != nil {
+			return fmt.Errorf("parsing default browse template: %v", err)
+		}
+	}
+
+	fsrv.Browse.template = tpl
+
+	return nil
+}
+
+func (fsrv *FileServer) browseWriteJSON(listing browseTemplateContext) (*bytes.Buffer, error) {
 	buf := bufPool.Get().(*bytes.Buffer)
+	defer bufPool.Put(buf)
 	err := json.NewEncoder(buf).Encode(listing.Items)
-	bufPool.Put(buf)
 	return buf, err
 }
 
-func (fsrv *FileServer) browseWriteHTML(listing browseListing) (*bytes.Buffer, error) {
+func (fsrv *FileServer) browseWriteHTML(tplCtx *templateContext) (*bytes.Buffer, error) {
 	buf := bufPool.Get().(*bytes.Buffer)
-	err := fsrv.Browse.template.Execute(buf, listing)
-	bufPool.Put(buf)
+	defer bufPool.Put(buf)
+	err := fsrv.Browse.template.Execute(buf, tplCtx)
 	return buf, err
 }
 
@@ -171,3 +216,11 @@ func isSymlinkTargetDir(f os.FileInfo, root, urlPath string) bool {
 	}
 	return targetInfo.IsDir()
 }
+
+// templateContext powers the context used when evaluating the browse template.
+// It combines browse-specific features with the standard templates handler
+// features.
+type templateContext struct {
+	templates.TemplateContext
+	browseTemplateContext
+}
diff --git a/modules/caddyhttp/fileserver/browse_test.go b/modules/caddyhttp/fileserver/browse_test.go
index 5d5874f..30862fa 100644
--- a/modules/caddyhttp/fileserver/browse_test.go
+++ b/modules/caddyhttp/fileserver/browse_test.go
@@ -1,16 +1,27 @@
+// Copyright 2015 Matthew Holt and The Caddy Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package fileserver
 
 import (
-	"html/template"
 	"testing"
-
-	"github.com/caddyserver/caddy/v2"
+	"text/template"
 )
 
 func BenchmarkBrowseWriteJSON(b *testing.B) {
 	fsrv := new(FileServer)
-	fsrv.Provision(caddy.Context{})
-	listing := browseListing{
+	listing := browseTemplateContext{
 		Name:     "test",
 		Path:     "test",
 		CanGoUp:  false,
@@ -30,12 +41,11 @@ func BenchmarkBrowseWriteJSON(b *testing.B) {
 
 func BenchmarkBrowseWriteHTML(b *testing.B) {
 	fsrv := new(FileServer)
-	fsrv.Provision(caddy.Context{})
 	fsrv.Browse = &Browse{
 		TemplateFile: "",
 		template:     template.New("test"),
 	}
-	listing := browseListing{
+	listing := browseTemplateContext{
 		Name:     "test",
 		Path:     "test",
 		CanGoUp:  false,
@@ -46,9 +56,13 @@ func BenchmarkBrowseWriteHTML(b *testing.B) {
 		Order:    "",
 		Limit:    42,
 	}
+	tplCtx := &templateContext{
+		browseTemplateContext: listing,
+	}
+	fsrv.makeBrowseTemplate(tplCtx)
 	b.ResetTimer()
 
 	for n := 0; n < b.N; n++ {
-		fsrv.browseWriteHTML(listing)
+		fsrv.browseWriteHTML(tplCtx)
 	}
 }
diff --git a/modules/caddyhttp/fileserver/browselisting.go b/modules/caddyhttp/fileserver/browsetplcontext.go
index 2b8c66c..489e8c0 100644
--- a/modules/caddyhttp/fileserver/browselisting.go
+++ b/modules/caddyhttp/fileserver/browsetplcontext.go
@@ -27,7 +27,7 @@ import (
 	"github.com/dustin/go-humanize"
 )
 
-func (fsrv *FileServer) directoryListing(files []os.FileInfo, canGoUp bool, root, urlPath string, repl *caddy.Replacer) browseListing {
+func (fsrv *FileServer) directoryListing(files []os.FileInfo, canGoUp bool, root, urlPath string, repl *caddy.Replacer) browseTemplateContext {
 	filesToHide := fsrv.transformHidePaths(repl)
 
 	var dirCount, fileCount int
@@ -62,7 +62,7 @@ func (fsrv *FileServer) directoryListing(files []os.FileInfo, canGoUp bool, root
 		})
 	}
 
-	return browseListing{
+	return browseTemplateContext{
 		Name:     path.Base(urlPath),
 		Path:     urlPath,
 		CanGoUp:  canGoUp,
@@ -72,7 +72,8 @@ func (fsrv *FileServer) directoryListing(files []os.FileInfo, canGoUp bool, root
 	}
 }
 
-type browseListing struct {
+// browseTemplateContext provides the template context for directory listings.
+type browseTemplateContext struct {
 	// The name of the directory (the last element of the path).
 	Name string `json:"name"`
 
@@ -106,7 +107,7 @@ type browseListing struct {
 
 // Breadcrumbs returns l.Path where every element maps
 // the link to the text to display.
-func (l browseListing) Breadcrumbs() []crumb {
+func (l browseTemplateContext) Breadcrumbs() []crumb {
 	if len(l.Path) == 0 {
 		return []crumb{}
 	}
@@ -130,7 +131,7 @@ func (l browseListing) Breadcrumbs() []crumb {
 	return result
 }
 
-func (l *browseListing) applySortAndLimit(sortParam, orderParam, limitParam string, offsetParam string) {
+func (l *browseTemplateContext) applySortAndLimit(sortParam, orderParam, limitParam string, offsetParam string) {
 	l.Sort = sortParam
 	l.Order = orderParam
 
@@ -207,10 +208,12 @@ func (fi fileInfo) HumanModTime(format string) string {
 	return fi.ModTime.Format(format)
 }
 
-type byName browseListing
-type byNameDirFirst browseListing
-type bySize browseListing
-type byTime browseListing
+type (
+	byName         browseTemplateContext
+	byNameDirFirst browseTemplateContext
+	bySize         browseTemplateContext
+	byTime         browseTemplateContext
+)
 
 func (l byName) Len() int      { return len(l.Items) }
 func (l byName) Swap(i, j int) { l.Items[i], l.Items[j] = l.Items[j], l.Items[i] }
diff --git a/modules/caddyhttp/fileserver/browselisting_test.go b/modules/caddyhttp/fileserver/browsetplcontext_test.go
index 6d58b7e..01e6c8f 100644
--- a/modules/caddyhttp/fileserver/browselisting_test.go
+++ b/modules/caddyhttp/fileserver/browsetplcontext_test.go
@@ -1,3 +1,17 @@
+// Copyright 2015 Matthew Holt and The Caddy Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package fileserver
 
 import (
@@ -25,7 +39,7 @@ func TestBreadcrumbs(t *testing.T) {
 	}
 
 	for _, d := range testdata {
-		l := browseListing{Path: d.path}
+		l := browseTemplateContext{Path: d.path}
 		actual := l.Breadcrumbs()
 		if len(actual) != len(d.expected) {
 			t.Errorf("wrong size output, got %d elements but expected %d", len(actual), len(d.expected))
diff --git a/modules/caddyhttp/fileserver/staticfiles.go b/modules/caddyhttp/fileserver/staticfiles.go
index dd44817..f2320aa 100644
--- a/modules/caddyhttp/fileserver/staticfiles.go
+++ b/modules/caddyhttp/fileserver/staticfiles.go
@@ -17,7 +17,6 @@ package fileserver
 import (
 	"bytes"
 	"fmt"
-	"html/template"
 	weakrand "math/rand"
 	"mime"
 	"net/http"
@@ -118,23 +117,6 @@ func (fsrv *FileServer) Provision(ctx caddy.Context) error {
 		fsrv.IndexNames = defaultIndexNames
 	}
 
-	if fsrv.Browse != nil {
-		var tpl *template.Template
-		var err error
-		if fsrv.Browse.TemplateFile != "" {
-			tpl, err = template.ParseFiles(fsrv.Browse.TemplateFile)
-			if err != nil {
-				return fmt.Errorf("parsing browse template file: %v", err)
-			}
-		} else {
-			tpl, err = template.New("default_listing").Parse(defaultBrowseTemplate)
-			if err != nil {
-				return fmt.Errorf("parsing default browse template: %v", err)
-			}
-		}
-		fsrv.Browse.template = tpl
-	}
-
 	// for hide paths that are static (i.e. no placeholders), we can transform them into
 	// absolute paths before the server starts for very slight performance improvement
 	for i, h := range fsrv.Hide {