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caddy/modules/caddyhttp/fileserver/browse.go
kylosus 45132c5b24
caddyhttp: Add plaintext response to file_server browse (#6093)
* Added plaintext support to file_server browser

This commit is twofold: First it adds a new optional
field, `return_type`, to `browser` for setting the
default format of the returned index (html, json or plaintext).
This is used when the `Accept` header is set to `/*`.

Second, it adds a preliminary `text/plain`
support to the `file_server` browser that
returns a text representation of the file
system, when an `Accept: text/plain` header
is present, with the behavior discussed above.

* Added more details and better formatting to plaintext browser

* Replaced returnType conditions with a switch statement

* Simplify

---------

Co-authored-by: Matt Holt <mholt@users.noreply.github.com>
2024-04-01 18:12:40 +00:00

288 lines
9.3 KiB
Go

// 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 (
"bytes"
"context"
_ "embed"
"encoding/json"
"errors"
"fmt"
"io"
"io/fs"
"net/http"
"os"
"path"
"strings"
"sync"
"text/tabwriter"
"text/template"
"go.uber.org/zap"
"github.com/caddyserver/caddy/v2"
"github.com/caddyserver/caddy/v2/modules/caddyhttp"
"github.com/caddyserver/caddy/v2/modules/caddyhttp/templates"
)
// BrowseTemplate is the default template document to use for
// file listings. By default, its default value is an embedded
// document. You can override this value at program start, or
// if you are running Caddy via config, you can specify a
// custom template_file in the browse configuration.
//
//go:embed browse.html
var BrowseTemplate string
// Browse configures directory browsing.
type Browse struct {
// Filename of the template to use instead of the embedded browse template.
TemplateFile string `json:"template_file,omitempty"`
// Determines whether or not targets of symlinks should be revealed.
RevealSymlinks bool `json:"reveal_symlinks,omitempty"`
}
func (fsrv *FileServer) serveBrowse(fileSystem fs.FS, root, dirPath string, w http.ResponseWriter, r *http.Request, next caddyhttp.Handler) error {
fsrv.logger.Debug("browse enabled; listing directory contents",
zap.String("path", dirPath),
zap.String("root", root))
// Navigation on the client-side gets messed up if the
// URL doesn't end in a trailing slash because hrefs to
// "b/c" at path "/a" end up going to "/b/c" instead
// of "/a/b/c" - so we have to redirect in this case
// so that the path is "/a/" and the client constructs
// relative hrefs "b/c" to be "/a/b/c".
//
// Only redirect if the last element of the path (the filename) was not
// rewritten; if the admin wanted to rewrite to the canonical path, they
// would have, and we have to be very careful not to introduce unwanted
// redirects and especially redirect loops! (Redirecting using the
// original URI is necessary because that's the URI the browser knows,
// we don't want to redirect from internally-rewritten URIs.)
// See https://github.com/caddyserver/caddy/issues/4205.
// We also redirect if the path is empty, because this implies the path
// prefix was fully stripped away by a `handle_path` handler for example.
// See https://github.com/caddyserver/caddy/issues/4466.
origReq := r.Context().Value(caddyhttp.OriginalRequestCtxKey).(http.Request)
if r.URL.Path == "" || path.Base(origReq.URL.Path) == path.Base(r.URL.Path) {
if !strings.HasSuffix(origReq.URL.Path, "/") {
fsrv.logger.Debug("redirecting to trailing slash to preserve hrefs", zap.String("request_path", r.URL.Path))
return redirect(w, r, origReq.URL.Path+"/")
}
}
dir, err := fsrv.openFile(fileSystem, dirPath, w)
if err != nil {
return err
}
defer dir.Close()
repl := r.Context().Value(caddy.ReplacerCtxKey).(*caddy.Replacer)
// TODO: not entirely sure if path.Clean() is necessary here but seems like a safe plan (i.e. /%2e%2e%2f) - someone could verify this
listing, err := fsrv.loadDirectoryContents(r.Context(), fileSystem, dir.(fs.ReadDirFile), root, path.Clean(r.URL.EscapedPath()), repl)
switch {
case errors.Is(err, fs.ErrPermission):
return caddyhttp.Error(http.StatusForbidden, err)
case errors.Is(err, fs.ErrNotExist):
return fsrv.notFound(w, r, next)
case err != nil:
return caddyhttp.Error(http.StatusInternalServerError, err)
}
fsrv.browseApplyQueryParams(w, r, listing)
buf := bufPool.Get().(*bytes.Buffer)
buf.Reset()
defer bufPool.Put(buf)
acceptHeader := strings.ToLower(strings.Join(r.Header["Accept"], ","))
switch {
case strings.Contains(acceptHeader, "application/json"):
if err := json.NewEncoder(buf).Encode(listing.Items); err != nil {
return caddyhttp.Error(http.StatusInternalServerError, err)
}
w.Header().Set("Content-Type", "application/json; charset=utf-8")
case strings.Contains(acceptHeader, "text/plain"):
writer := tabwriter.NewWriter(buf, 0, 8, 1, '\t', tabwriter.AlignRight)
// Header on top
if _, err := fmt.Fprintln(writer, "Name\tSize\tModified"); err != nil {
return caddyhttp.Error(http.StatusInternalServerError, err)
}
// Lines to separate the header
if _, err := fmt.Fprintln(writer, "----\t----\t--------"); err != nil {
return caddyhttp.Error(http.StatusInternalServerError, err)
}
// Actual files
for _, item := range listing.Items {
if _, err := fmt.Fprintf(writer, "%s\t%s\t%s\n",
item.Name, item.HumanSize(), item.HumanModTime("January 2, 2006 at 15:04:05"),
); err != nil {
return caddyhttp.Error(http.StatusInternalServerError, err)
}
}
if err := writer.Flush(); err != nil {
return caddyhttp.Error(http.StatusInternalServerError, err)
}
w.Header().Set("Content-Type", "text/plain; charset=utf-8")
default:
var fs http.FileSystem
if fsrv.Root != "" {
fs = http.Dir(repl.ReplaceAll(fsrv.Root, "."))
}
tplCtx := &templateContext{
TemplateContext: templates.TemplateContext{
Root: fs,
Req: r,
RespHeader: templates.WrappedHeader{Header: w.Header()},
},
browseTemplateContext: listing,
}
tpl, err := fsrv.makeBrowseTemplate(tplCtx)
if err != nil {
return fmt.Errorf("parsing browse template: %v", err)
}
if err := tpl.Execute(buf, tplCtx); err != nil {
return caddyhttp.Error(http.StatusInternalServerError, err)
}
w.Header().Set("Content-Type", "text/html; charset=utf-8")
}
_, _ = buf.WriteTo(w)
return nil
}
func (fsrv *FileServer) loadDirectoryContents(ctx context.Context, fileSystem fs.FS, dir fs.ReadDirFile, root, urlPath string, repl *caddy.Replacer) (*browseTemplateContext, error) {
files, err := dir.ReadDir(10000) // TODO: this limit should probably be configurable
if err != nil && err != io.EOF {
return nil, err
}
// user can presumably browse "up" to parent folder if path is longer than "/"
canGoUp := len(urlPath) > 1
return fsrv.directoryListing(ctx, fileSystem, files, canGoUp, root, urlPath, repl), nil
}
// 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 *browseTemplateContext) {
layoutParam := r.URL.Query().Get("layout")
sortParam := r.URL.Query().Get("sort")
orderParam := r.URL.Query().Get("order")
limitParam := r.URL.Query().Get("limit")
offsetParam := r.URL.Query().Get("offset")
switch layoutParam {
case "list", "grid", "":
listing.Layout = layoutParam
default:
listing.Layout = "list"
}
// figure out what to sort by
switch sortParam {
case "":
sortParam = sortByNameDirFirst
if sortCookie, sortErr := r.Cookie("sort"); sortErr == nil {
sortParam = sortCookie.Value
}
case sortByName, sortByNameDirFirst, sortBySize, sortByTime:
http.SetCookie(w, &http.Cookie{Name: "sort", Value: sortParam, Secure: r.TLS != nil})
}
// then figure out the order
switch orderParam {
case "":
orderParam = "asc"
if orderCookie, orderErr := r.Cookie("order"); orderErr == nil {
orderParam = orderCookie.Value
}
case "asc", "desc":
http.SetCookie(w, &http.Cookie{Name: "order", Value: orderParam, Secure: r.TLS != nil})
}
// finally, apply the sorting and limiting
listing.applySortAndLimit(sortParam, orderParam, limitParam, offsetParam)
}
// makeBrowseTemplate creates the template to be used for directory listings.
func (fsrv *FileServer) makeBrowseTemplate(tplCtx *templateContext) (*template.Template, 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 nil, fmt.Errorf("parsing browse template file: %v", err)
}
} else {
tpl = tplCtx.NewTemplate("default_listing")
tpl, err = tpl.Parse(BrowseTemplate)
if err != nil {
return nil, fmt.Errorf("parsing default browse template: %v", err)
}
}
return tpl, nil
}
// isSymlinkTargetDir returns true if f's symbolic link target
// is a directory.
func (fsrv *FileServer) isSymlinkTargetDir(fileSystem fs.FS, f fs.FileInfo, root, urlPath string) bool {
if !isSymlink(f) {
return false
}
target := caddyhttp.SanitizedPathJoin(root, path.Join(urlPath, f.Name()))
targetInfo, err := fs.Stat(fileSystem, target)
if err != nil {
return false
}
return targetInfo.IsDir()
}
// isSymlink return true if f is a symbolic link.
func isSymlink(f fs.FileInfo) bool {
return f.Mode()&os.ModeSymlink != 0
}
// 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
}
// bufPool is used to increase the efficiency of file listings.
var bufPool = sync.Pool{
New: func() any {
return new(bytes.Buffer)
},
}