summaryrefslogtreecommitdiff
path: root/modules/caddyhttp/headers/caddyfile.go
blob: d893cab3dde3eca83d23d32341483eaebfc06482 (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
// 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 headers

import (
	"net/http"
	"strings"

	"github.com/caddyserver/caddy/v2/caddyconfig/httpcaddyfile"
	"github.com/caddyserver/caddy/v2/modules/caddyhttp"
)

func init() {
	httpcaddyfile.RegisterHandlerDirective("header", parseCaddyfile)
	httpcaddyfile.RegisterHandlerDirective("request_header", parseReqHdrCaddyfile)
}

// parseCaddyfile sets up the handler for response headers from
// Caddyfile tokens. Syntax:
//
//     header [<matcher>] [[+|-]<field> [<value|regexp>] [<replacement>]] {
//         [+]<field> [<value|regexp> [<replacement>]]
//         -<field>
//         [defer]
//     }
//
// Either a block can be opened or a single header field can be configured
// in the first line, but not both in the same directive. Header operations
// are deferred to write-time if any headers are being deleted or if the
// 'defer' subdirective is used.
func parseCaddyfile(h httpcaddyfile.Helper) (caddyhttp.MiddlewareHandler, error) {
	hdr := new(Handler)

	makeResponseOps := func() {
		if hdr.Response == nil {
			hdr.Response = &RespHeaderOps{
				HeaderOps: new(HeaderOps),
			}
		}
	}

	for h.Next() {
		// first see if headers are in the initial line
		var hasArgs bool
		if h.NextArg() {
			hasArgs = true
			field := h.Val()
			var value, replacement string
			if h.NextArg() {
				value = h.Val()
			}
			if h.NextArg() {
				replacement = h.Val()
			}
			makeResponseOps()
			CaddyfileHeaderOp(hdr.Response.HeaderOps, field, value, replacement)
			if len(hdr.Response.HeaderOps.Delete) > 0 {
				hdr.Response.Deferred = true
			}
		}

		// if not, they should be in a block
		for h.NextBlock(0) {
			field := h.Val()
			if field == "defer" {
				hdr.Response.Deferred = true
				continue
			}
			if hasArgs {
				return nil, h.Err("cannot specify headers in both arguments and block")
			}
			var value, replacement string
			if h.NextArg() {
				value = h.Val()
			}
			if h.NextArg() {
				replacement = h.Val()
			}
			makeResponseOps()
			CaddyfileHeaderOp(hdr.Response.HeaderOps, field, value, replacement)
			if len(hdr.Response.HeaderOps.Delete) > 0 {
				hdr.Response.Deferred = true
			}
		}
	}

	return hdr, nil
}

// parseReqHdrCaddyfile sets up the handler for request headers
// from Caddyfile tokens. Syntax:
//
//     request_header [<matcher>] [[+|-]<field> [<value|regexp>] [<replacement>]]
//
func parseReqHdrCaddyfile(h httpcaddyfile.Helper) (caddyhttp.MiddlewareHandler, error) {
	hdr := new(Handler)
	for h.Next() {
		if !h.NextArg() {
			return nil, h.ArgErr()
		}
		field := h.Val()

		// sometimes it is habitual for users to suffix a field name with a colon,
		// as if they were writing a curl command or something; see
		// https://caddy.community/t/v2-reverse-proxy-please-add-cors-example-to-the-docs/7349
		field = strings.TrimSuffix(field, ":")

		var value, replacement string
		if h.NextArg() {
			value = h.Val()
		}
		if h.NextArg() {
			replacement = h.Val()
			if h.NextArg() {
				return nil, h.ArgErr()
			}
		}

		if hdr.Request == nil {
			hdr.Request = new(HeaderOps)
		}
		CaddyfileHeaderOp(hdr.Request, field, value, replacement)

		if h.NextArg() {
			return nil, h.ArgErr()
		}
	}
	return hdr, nil
}

// CaddyfileHeaderOp applies a new header operation according to
// field, value, and replacement. The field can be prefixed with
// "+" or "-" to specify adding or removing; otherwise, the value
// will be set (overriding any previous value). If replacement is
// non-empty, value will be treated as a regular expression which
// will be used to search and then replacement will be used to
// complete the substring replacement; in that case, any + or -
// prefix to field will be ignored.
func CaddyfileHeaderOp(ops *HeaderOps, field, value, replacement string) {
	if strings.HasPrefix(field, "+") {
		if ops.Add == nil {
			ops.Add = make(http.Header)
		}
		ops.Add.Set(field[1:], value)
	} else if strings.HasPrefix(field, "-") {
		ops.Delete = append(ops.Delete, field[1:])
	} else {
		if replacement == "" {
			if ops.Set == nil {
				ops.Set = make(http.Header)
			}
			ops.Set.Set(field, value)
		} else {
			if ops.Replace == nil {
				ops.Replace = make(map[string][]Replacement)
			}
			field = strings.TrimLeft(field, "+-")
			ops.Replace[field] = append(
				ops.Replace[field],
				Replacement{
					SearchRegexp: value,
					Replace:      replacement,
				},
			)
		}
	}
}