summaryrefslogtreecommitdiff
path: root/modules/caddyhttp/fileserver/browse.go
blob: 90263560cecd1d7c6dd75538cf2c38cd7c43c72b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
// 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"
	_ "embed"
	"encoding/json"
	"fmt"
	"io/fs"
	"net/http"
	"os"
	"path"
	"strings"
	"sync"
	"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"
)

//go:embed browse.html
var defaultBrowseTemplate string

// Browse configures directory browsing.
type Browse struct {
	// Use this template file instead of the default browse template.
	TemplateFile string `json:"template_file,omitempty"`
}

func (fsrv *FileServer) serveBrowse(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(dirPath, w)
	if err != nil {
		return err
	}
	defer dir.Close()

	repl := r.Context().Value(caddy.ReplacerCtxKey).(*caddy.Replacer)

	// calling path.Clean here prevents weird breadcrumbs when URL paths are sketchy like /%2e%2e%2f
	listing, err := fsrv.loadDirectoryContents(dir.(fs.ReadDirFile), root, path.Clean(r.URL.Path), repl)
	switch {
	case os.IsPermission(err):
		return caddyhttp.Error(http.StatusForbidden, err)
	case os.IsNotExist(err):
		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"], ","))

	// write response as either JSON or HTML
	if 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")
	} else {
		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,
		}

		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(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 {
		return browseTemplateContext{}, err
	}

	// user can presumably browse "up" to parent folder if path is longer than "/"
	canGoUp := len(urlPath) > 1

	return fsrv.directoryListing(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) {
	sortParam := r.URL.Query().Get("sort")
	orderParam := r.URL.Query().Get("order")
	limitParam := r.URL.Query().Get("limit")
	offsetParam := r.URL.Query().Get("offset")

	// first 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(defaultBrowseTemplate)
		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(f fs.FileInfo, root, urlPath string) bool {
	if !isSymlink(f) {
		return false
	}
	target := caddyhttp.SanitizedPathJoin(root, path.Join(urlPath, f.Name()))
	targetInfo, err := fsrv.fileSystem.Stat(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)
	},
}