forked from caddyserver/caddy
-
Notifications
You must be signed in to change notification settings - Fork 0
/
rewrite.go
225 lines (191 loc) · 4.91 KB
/
rewrite.go
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
// Package rewrite is middleware for rewriting requests internally to
// a different path.
package rewrite
import (
"fmt"
"net/http"
"path"
"path/filepath"
"regexp"
"strings"
"github.com/mholt/caddy/middleware"
)
// Result is the result of a rewrite
type Result int
const (
// RewriteIgnored is returned when rewrite is not done on request.
RewriteIgnored Result = iota
// RewriteDone is returned when rewrite is done on request.
RewriteDone
// RewriteStatus is returned when rewrite is not needed and status code should be set
// for the request.
RewriteStatus
)
// Rewrite is middleware to rewrite request locations internally before being handled.
type Rewrite struct {
Next middleware.Handler
FileSys http.FileSystem
Rules []Rule
}
// ServeHTTP implements the middleware.Handler interface.
func (rw Rewrite) ServeHTTP(w http.ResponseWriter, r *http.Request) (int, error) {
outer:
for _, rule := range rw.Rules {
switch result := rule.Rewrite(rw.FileSys, r); result {
case RewriteDone:
break outer
case RewriteIgnored:
break
case RewriteStatus:
// only valid for complex rules.
if cRule, ok := rule.(*ComplexRule); ok && cRule.Status != 0 {
return cRule.Status, nil
}
}
}
return rw.Next.ServeHTTP(w, r)
}
// Rule describes an internal location rewrite rule.
type Rule interface {
// Rewrite rewrites the internal location of the current request.
Rewrite(http.FileSystem, *http.Request) Result
}
// SimpleRule is a simple rewrite rule.
type SimpleRule struct {
From, To string
}
// NewSimpleRule creates a new Simple Rule
func NewSimpleRule(from, to string) SimpleRule {
return SimpleRule{from, to}
}
// Rewrite rewrites the internal location of the current request.
func (s SimpleRule) Rewrite(fs http.FileSystem, r *http.Request) Result {
if s.From == r.URL.Path {
// take note of this rewrite for internal use by fastcgi
// all we need is the URI, not full URL
r.Header.Set(headerFieldName, r.URL.RequestURI())
// attempt rewrite
return To(fs, r, s.To, newReplacer(r))
}
return RewriteIgnored
}
// ComplexRule is a rewrite rule based on a regular expression
type ComplexRule struct {
// Path base. Request to this path and subpaths will be rewritten
Base string
// Path to rewrite to
To string
// If set, neither performs rewrite nor proceeds
// with request. Only returns code.
Status int
// Extensions to filter by
Exts []string
// Rewrite conditions
Ifs []If
*regexp.Regexp
}
// NewComplexRule creates a new RegexpRule. It returns an error if regexp
// pattern (pattern) or extensions (ext) are invalid.
func NewComplexRule(base, pattern, to string, status int, ext []string, ifs []If) (*ComplexRule, error) {
// validate regexp if present
var r *regexp.Regexp
if pattern != "" {
var err error
r, err = regexp.Compile(pattern)
if err != nil {
return nil, err
}
}
// validate extensions if present
for _, v := range ext {
if len(v) < 2 || (len(v) < 3 && v[0] == '!') {
// check if no extension is specified
if v != "/" && v != "!/" {
return nil, fmt.Errorf("invalid extension %v", v)
}
}
}
return &ComplexRule{
Base: base,
To: to,
Status: status,
Exts: ext,
Ifs: ifs,
Regexp: r,
}, nil
}
// Rewrite rewrites the internal location of the current request.
func (r *ComplexRule) Rewrite(fs http.FileSystem, req *http.Request) (re Result) {
rPath := req.URL.Path
replacer := newReplacer(req)
// validate base
if !middleware.Path(rPath).Matches(r.Base) {
return
}
// validate extensions
if !r.matchExt(rPath) {
return
}
// validate regexp if present
if r.Regexp != nil {
// include trailing slash in regexp if present
start := len(r.Base)
if strings.HasSuffix(r.Base, "/") {
start--
}
matches := r.FindStringSubmatch(rPath[start:])
switch len(matches) {
case 0:
// no match
return
default:
// set regexp match variables {1}, {2} ...
for i := 1; i < len(matches); i++ {
replacer.Set(fmt.Sprint(i), matches[i])
}
}
}
// validate rewrite conditions
for _, i := range r.Ifs {
if !i.True(req) {
return
}
}
// if status is present, stop rewrite and return it.
if r.Status != 0 {
return RewriteStatus
}
// attempt rewrite
return To(fs, req, r.To, replacer)
}
// matchExt matches rPath against registered file extensions.
// Returns true if a match is found and false otherwise.
func (r *ComplexRule) matchExt(rPath string) bool {
f := filepath.Base(rPath)
ext := path.Ext(f)
if ext == "" {
ext = "/"
}
mustUse := false
for _, v := range r.Exts {
use := true
if v[0] == '!' {
use = false
v = v[1:]
}
if use {
mustUse = true
}
if ext == v {
return use
}
}
if mustUse {
return false
}
return true
}
// When a rewrite is performed, this header is added to the request
// and is for internal use only, specifically the fastcgi middleware.
// It contains the original request URI before the rewrite.
const headerFieldName = "Caddy-Rewrite-Original-URI"