-
-
Notifications
You must be signed in to change notification settings - Fork 114
/
regexp.go
171 lines (155 loc) · 5.05 KB
/
regexp.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
// The code in this file is taken and adapated from gorilla/mux package.
// Copyright (c) 2012-2018 The Gorilla Authors. All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
package mux
import (
"bytes"
"fmt"
"regexp"
"strconv"
"strings"
)
func newRouteRegexp(path string) (*routeRegexp, error) {
// Check if it is well-formed.
idxs, errBraces := braceIndices(path)
if errBraces != nil {
return nil, errBraces
}
// Backup the original.
template := path
// Now let's parse it.
defaultPattern := "[^/]+"
varsN := make([]string, len(idxs)/2)
varsR := make([]*regexp.Regexp, len(idxs)/2)
pattern := bytes.NewBufferString("")
pattern.WriteByte('^')
reverse := bytes.NewBufferString("")
var end int
var err error
for i := 0; i < len(idxs); i += 2 {
// Set all values we are interested in.
raw := path[end:idxs[i]]
end = idxs[i+1]
parts := strings.SplitN(path[idxs[i]+1:end-1], ":", 2)
name := parts[0]
patt := defaultPattern
if len(parts) == 2 {
patt = parts[1]
}
// Name or pattern can't be empty.
if name == "" || patt == "" {
return nil, fmt.Errorf("mux: missing name or pattern in %q",
path[idxs[i]:end])
}
// Build the regexp pattern.
fmt.Fprintf(pattern, "%s(?P<%s>%s)", regexp.QuoteMeta(raw), varGroupName(i/2), patt)
// Build the reverse template.
fmt.Fprintf(reverse, "%s%%s", raw)
// Append variable name and compiled pattern.
varsN[i/2] = name
varsR[i/2], err = regexp.Compile(fmt.Sprintf("^%s$", patt))
if err != nil {
return nil, err
}
}
// Add the remaining.
raw := path[end:]
pattern.WriteString(regexp.QuoteMeta(raw))
pattern.WriteByte('$')
// Compile full regexp.
reg, errCompile := regexp.Compile(pattern.String())
if errCompile != nil {
return nil, errCompile
}
// Check for capturing groups which used to work in older versions
if reg.NumSubexp() != len(idxs)/2 {
panic(fmt.Sprintf("route %s contains capture groups in its regexp. ", template) +
"Only non-capturing groups are accepted: e.g. (?:pattern) instead of (pattern)")
}
// Done!
return &routeRegexp{
template: template,
regexp: reg,
reverse: reverse.String(),
varsN: varsN,
varsR: varsR,
}, nil
}
// routeRegexp stores a regexp to match a host or path and information to
// collect and validate route variables.
type routeRegexp struct {
// The unmodified template.
template string
// Expanded regexp.
regexp *regexp.Regexp
// Reverse template.
reverse string
// Variable names.
varsN []string
// Variable regexps (validators).
varsR []*regexp.Regexp
}
// varGroupName builds a capturing group name for the indexed variable.
func varGroupName(idx int) string {
return "v" + strconv.Itoa(idx)
}
// braceIndices returns the first level curly brace indices from a string.
// It returns an error in case of unbalanced braces.
func braceIndices(s string) ([]int, error) {
var level, idx int
var idxs []int
for i := 0; i < len(s); i++ {
switch s[i] {
case '{':
if level++; level == 1 {
idx = i
}
case '}':
if level--; level == 0 {
idxs = append(idxs, idx, i+1)
} else if level < 0 {
return nil, fmt.Errorf("mux: unbalanced braces in %q", s)
}
}
}
if level != 0 {
return nil, fmt.Errorf("mux: unbalanced braces in %q", s)
}
return idxs, nil
}
func (route *routeRegexp) extractRouteParams(path string, routeParams *RouteParams) {
matches := route.regexp.FindStringSubmatchIndex(path)
if len(matches) > 0 {
extractVars(path, matches, route.varsN, routeParams.Vars)
}
}
func extractVars(input string, matches []int, names []string, output map[string]string) {
for i, name := range names {
output[name] = input[matches[2*i+2]:matches[2*i+3]]
}
}