标题: 使用curl/libcurl/pycurl时如何获取请求报文的Header

创建: 2015-05-13 15:49
更新:
链接: https://scz.617.cn/unix/201505131549.txt

很多人会碰上这种需求，查看HTTP响应的Header。有时也会碰上另一种类似的需求，
查看HTTP请求的Header。

如果是HTTP协议，直接Wireshark。

如果是HTTPS协议，中间人劫持、开发者工具等等。

我们这次简要介绍一下使用curl/libcurl/pycurl时如何获取请求报文的Header。在
一些快速测试过程中可能会用到。

对于curl，使用-v、--verbose参数即可:

$ curl -vs http://www.nsfocus.net -o /dev/null 2> >(sed "/^*/d")

--------------------------------------------------------------------------
> GET / HTTP/1.1
> User-Agent: curl/7.26.0
> Host: www.nsfocus.net
> Accept: */*
>
< HTTP/1.1 200 OK
< Date: Wed, 13 May 2015 02:19:53 GMT
< Server: Apache
< Expires: Wed, 13 May 2015 02:20:53 GMT
< Vary: Accept-Encoding
< Transfer-Encoding: chunked
< Content-Type: text/html
<
{ [data not shown]
--------------------------------------------------------------------------

冗余模式输出的内容太多了，请求报文以>号打头，响应报文以<号打头，还有以*号
打头的其他信息。上述命令删除了以*号打头的信息。

$ curl -vs http://www.nsfocus.net -o /dev/null 2> >(sed "/^[*{]/d") | cut -b3-

--------------------------------------------------------------------------
GET / HTTP/1.1
User-Agent: curl/7.26.0
Host: www.nsfocus.net
Accept: */*

HTTP/1.1 200 OK
Date: Wed, 13 May 2015 03:12:45 GMT
Server: Apache
Expires: Wed, 13 May 2015 03:13:45 GMT
Vary: Accept-Encoding
Transfer-Encoding: chunked
Content-Type: text/html
--------------------------------------------------------------------------

$ curl -vs http://www.nsfocus.net -o /dev/null 2> >(grep "^>") | cut -b1-2 --complement
$ curl -vs http://www.nsfocus.net -o /dev/null 2> >(grep "^>") | cut -b3-
$ curl -vs http://www.nsfocus.net -o /dev/null 2> >(grep "^>") | sed -e 's/^> \(.*\)/\1/g'
$ curl -vs http://www.nsfocus.net -o /dev/null 2> >(sed -e '/^[^>].*/d' -e 's/^> \(.*\)/\1/g')

--------------------------------------------------------------------------
GET / HTTP/1.1
User-Agent: curl/7.26.0
Host: www.nsfocus.net
Accept: */*
--------------------------------------------------------------------------

cut命令的"--complement"参数是取补集的意思。

下面提几个可能被误用于原始需求的curl参数:

-D, --dump-header <file>

    不能用来显示请求报文的Header，它的目标对象是响应报文

$ curl -sD - http://www.nsfocus.net -o /dev/null

--------------------------------------------------------------------------
HTTP/1.1 200 OK
Date: Wed, 13 May 2015 02:34:51 GMT
Server: Apache
Expires: Wed, 13 May 2015 02:35:51 GMT
Vary: Accept-Encoding
Transfer-Encoding: chunked
Content-Type: text/html
--------------------------------------------------------------------------

-I, --head

    发送HEAD请求并显示响应报文的Header。假设我们想看响应报文的Header，也不
    应该使用它，毕竟HEAD请求不同于GET、POST请求。

$ curl -sI http://www.nsfocus.net

--------------------------------------------------------------------------
HTTP/1.1 200 OK
Date: Wed, 13 May 2015 02:39:09 GMT
Server: Apache
Expires: Wed, 13 May 2015 02:40:09 GMT
Vary: Accept-Encoding
Content-Type: text/html
--------------------------------------------------------------------------

与之前-D对比，少了"Transfer-Encoding:"。

除了冗余模式，curl还有一个参数可以满足原始需求:

--trace <file>
--trace-ascii <file>

    针对请求、响应报文进行调试性转储。会覆盖之前的-v、--trace、--trace-ascii。

    二者区别在于前者进行16进制格式转储，后者进行文本格式转储。

$ curl -s --trace - http://www.example.com -o /dev/null

--------------------------------------------------------------------------
== Info: About to connect() to www.example.com port 80 (#0)
== Info:   Trying 93.184.216.34...
== Info: connected
== Info: Connected to www.example.com (93.184.216.34) port 80 (#0)
=> Send header, 79 bytes (0x4f)
0000: 47 45 54 20 2f 20 48 54 54 50 2f 31 2e 31 0d 0a GET / HTTP/1.1..
0010: 55 73 65 72 2d 41 67 65 6e 74 3a 20 63 75 72 6c User-Agent: curl
0020: 2f 37 2e 32 36 2e 30 0d 0a 48 6f 73 74 3a 20 77 /7.26.0..Host: w
0030: 77 77 2e 65 78 61 6d 70 6c 65 2e 63 6f 6d 0d 0a ww.example.com..
0040: 41 63 63 65 70 74 3a 20 2a 2f 2a 0d 0a 0d 0a    Accept: */*....
== Info: additional stuff not fine transfer.c:1037: 0 0
== Info: HTTP 1.1 or later with persistent connection, pipelining supported
<= Recv header, 17 bytes (0x11)
0000: 48 54 54 50 2f 31 2e 31 20 32 30 30 20 4f 4b 0d HTTP/1.1 200 OK.
0010: 0a                                              .
<= Recv header, 22 bytes (0x16)
0000: 41 63 63 65 70 74 2d 52 61 6e 67 65 73 3a 20 62 Accept-Ranges: b
0010: 79 74 65 73 0d 0a                               ytes..
<= Recv header, 31 bytes (0x1f)
0000: 43 61 63 68 65 2d 43 6f 6e 74 72 6f 6c 3a 20 6d Cache-Control: m
0010: 61 78 2d 61 67 65 3d 36 30 34 38 30 30 0d 0a    ax-age=604800..
<= Recv header, 25 bytes (0x19)
0000: 43 6f 6e 74 65 6e 74 2d 54 79 70 65 3a 20 74 65 Content-Type: te
0010: 78 74 2f 68 74 6d 6c 0d 0a                      xt/html..
<= Recv header, 37 bytes (0x25)
0000: 44 61 74 65 3a 20 57 65 64 2c 20 31 33 20 4d 61 Date: Wed, 13 Ma
0010: 79 20 32 30 31 35 20 30 33 3a 30 36 3a 33 33 20 y 2015 03:06:33
0020: 47 4d 54 0d 0a                                  GMT..
<= Recv header, 19 bytes (0x13)
0000: 45 74 61 67 3a 20 22 33 35 39 36 37 30 36 35 31 Etag: "359670651
0010: 22 0d 0a                                        "..
<= Recv header, 40 bytes (0x28)
0000: 45 78 70 69 72 65 73 3a 20 57 65 64 2c 20 32 30 Expires: Wed, 20
0010: 20 4d 61 79 20 32 30 31 35 20 30 33 3a 30 36 3a  May 2015 03:06:
0020: 33 33 20 47 4d 54 0d 0a                         33 GMT..
<= Recv header, 46 bytes (0x2e)
0000: 4c 61 73 74 2d 4d 6f 64 69 66 69 65 64 3a 20 46 Last-Modified: F
0010: 72 69 2c 20 30 39 20 41 75 67 20 32 30 31 33 20 ri, 09 Aug 2013
0020: 32 33 3a 35 34 3a 33 35 20 47 4d 54 0d 0a       23:54:35 GMT..
<= Recv header, 24 bytes (0x18)
0000: 53 65 72 76 65 72 3a 20 45 43 53 20 28 69 61 64 Server: ECS (iad
0010: 2f 31 38 32 41 29 0d 0a                         /182A)..
<= Recv header, 14 bytes (0xe)
0000: 58 2d 43 61 63 68 65 3a 20 48 49 54 0d 0a       X-Cache: HIT..
<= Recv header, 22 bytes (0x16)
0000: 78 2d 65 63 2d 63 75 73 74 6f 6d 2d 65 72 72 6f x-ec-custom-erro
0010: 72 3a 20 31 0d 0a                               r: 1..
<= Recv header, 22 bytes (0x16)
0000: 43 6f 6e 74 65 6e 74 2d 4c 65 6e 67 74 68 3a 20 Content-Length:
0010: 31 32 37 30 0d 0a                               1270..
<= Recv header, 2 bytes (0x2)
0000: 0d 0a                                           ..
<= Recv data, 1127 bytes (0x467)
0000: 3c 21 64 6f 63 74 79 70 65 20 68 74 6d 6c 3e 0a <!doctype html>.
0010: 3c 68 74 6d 6c 3e 0a 3c 68 65 61 64 3e 0a 20 20 <html>.<head>.
0020: 20 20 3c 74 69 74 6c 65 3e 45 78 61 6d 70 6c 65   <title>Example
0030: 20 44 6f 6d 61 69 6e 3c 2f 74 69 74 6c 65 3e 0a  Domain</title>.
0040: 0a 20 20 20 20 3c 6d 65 74 61 20 63 68 61 72 73 .    <meta chars
0050: 65 74 3d 22 75 74 66 2d 38 22 20 2f 3e 0a 20 20 et="utf-8" />.
--------------------------------------------------------------------------

$ curl -s --trace-ascii - http://www.example.com -o /dev/null

--------------------------------------------------------------------------
== Info: About to connect() to www.example.com port 80 (#0)
== Info:   Trying 93.184.216.34...
== Info: connected
== Info: Connected to www.example.com (93.184.216.34) port 80 (#0)
=> Send header, 79 bytes (0x4f)
0000: GET / HTTP/1.1
0010: User-Agent: curl/7.26.0
0029: Host: www.example.com
0040: Accept: */*
004d:
== Info: additional stuff not fine transfer.c:1037: 0 0
== Info: HTTP 1.1 or later with persistent connection, pipelining supported
<= Recv header, 17 bytes (0x11)
0000: HTTP/1.1 200 OK
<= Recv header, 22 bytes (0x16)
0000: Accept-Ranges: bytes
<= Recv header, 31 bytes (0x1f)
0000: Cache-Control: max-age=604800
<= Recv header, 25 bytes (0x19)
0000: Content-Type: text/html
<= Recv header, 37 bytes (0x25)
0000: Date: Wed, 13 May 2015 03:06:07 GMT
<= Recv header, 19 bytes (0x13)
0000: Etag: "359670651"
<= Recv header, 40 bytes (0x28)
0000: Expires: Wed, 20 May 2015 03:06:07 GMT
<= Recv header, 46 bytes (0x2e)
0000: Last-Modified: Fri, 09 Aug 2013 23:54:35 GMT
<= Recv header, 24 bytes (0x18)
0000: Server: ECS (iad/182A)
<= Recv header, 14 bytes (0xe)
0000: X-Cache: HIT
<= Recv header, 22 bytes (0x16)
0000: x-ec-custom-error: 1
<= Recv header, 22 bytes (0x16)
0000: Content-Length: 1270
<= Recv header, 2 bytes (0x2)
0000:
<= Recv data, 1270 bytes (0x4f6)
0000: <!doctype html>.<html>.<head>.    <title>Example Domain</title>.
0040: .    <meta charset="utf-8" />.    <meta http-equiv="Content-type
0080: " content="text/html; charset=utf-8" />.    <meta name="viewport
00c0: " content="width=device-width, initial-scale=1" />.    <style ty
0100: pe="text/css">.    body {.        background-color: #f0f0f2;.
0140:      margin: 0;.        padding: 0;.        font-family: "Open S
0180: ans", "Helvetica Neue", Helvetica, Arial, sans-serif;.        .
01c0:    }.    div {.        width: 600px;.        margin: 5em auto;.
0200:        padding: 50px;.        background-color: #fff;.        bo
0240: rder-radius: 1em;.    }.    a:link, a:visited {.        color: #
0280: 38488f;.        text-decoration: none;.    }.    @media (max-wid
02c0: th: 700px) {.        body {.            background-color: #fff;.
0300:         }.        div {.            width: auto;.            mar
0340: gin: 0 auto;.            border-radius: 0;.            padding:
0380: 1em;.        }.    }.    </style>    .</head>..<body>.<div>.
03c0: <h1>Example Domain</h1>.    <p>This domain is established to be
0400: used for illustrative examples in documents. You may use this.
0440:   domain in examples without prior coordination or asking for pe
0480: rmission.</p>.    <p><a href="http://www.iana.org/domains/exampl
04c0: e">More information...</a></p>.</div>.</body>.</html>.
--------------------------------------------------------------------------

$ curl -s --trace-ascii - http://www.example.com -o /dev/null | grep -vP "^[<>=]" | cut -b7-

--------------------------------------------------------------------------
GET / HTTP/1.1
User-Agent: curl/7.26.0
Host: www.example.com
Accept: */*

HTTP/1.1 200 OK
Accept-Ranges: bytes
Cache-Control: max-age=604800
Content-Type: text/html
Date: Wed, 13 May 2015 03:10:45 GMT
Etag: "359670651"
Expires: Wed, 20 May 2015 03:10:45 GMT
Last-Modified: Fri, 09 Aug 2013 23:54:35 GMT
Server: ECS (iad/182A)
X-Cache: HIT
x-ec-custom-error: 1
Content-Length: 1270

<!doctype html>.<html>.<head>.    <title>Example Domain</title>.
.    <meta charset="utf-8" />.    <meta http-equiv="Content-type
" content="text/html; charset=utf-8" />.    <meta name="viewport
" content="width=device-width, initial-scale=1" />.    <style ty
pe="text/css">.    body {.        background-color: #f0f0f2;.
     margin: 0;.        padding: 0;.        font-family: "Open S
ans", "Helvetica Neue", Helvetica, Arial, sans-serif;.        .
   }.    div {.        width: 600px;.        margin: 5em auto;.
       padding: 50px;.        background-color: #fff;.        bo
rder-radius: 1em;.    }.    a:link, a:visited {.        color: #
38488f;.        text-decoration: none;.    }.    @media (max-wid
th: 700px) {.        body {.            background-color: #fff;.
        }.        div {.            width: auto;.            mar
gin: 0 auto;.            border-radius: 0;.            padding:
1em;.        }.    }.    </style>    .</head>..<body>.<div>.
<h1>Example Domain</h1>.    <p>This domain is established to be
used for illustrative examples in documents. You may use this.
  domain in examples without prior coordination or asking for pe
rmission.</p>.    <p><a href="http://www.iana.org/domains/exampl
e">More information...</a></p>.</div>.</body>.</html>.
--------------------------------------------------------------------------

$ curl -s --trace-ascii - http://www.example.com -o /dev/null | grep -vP "^[<>=]" | cut -b7- | head -n 17

--------------------------------------------------------------------------
GET / HTTP/1.1
User-Agent: curl/7.26.0
Host: www.example.com
Accept: */*

HTTP/1.1 200 OK
Accept-Ranges: bytes
Cache-Control: max-age=604800
Content-Type: text/html
Date: Wed, 13 May 2015 03:15:41 GMT
Etag: "359670651"
Expires: Wed, 20 May 2015 03:15:41 GMT
Last-Modified: Fri, 09 Aug 2013 23:54:35 GMT
Server: ECS (iad/182A)
X-Cache: HIT
x-ec-custom-error: 1
Content-Length: 1270
--------------------------------------------------------------------------

显然，就原始需求而言，--trace-ascii不如-v好用，前者无法有效分离请求报文的
Header。

前面已经很好地演示了使用curl时如何查看请求报文的Header，在shell script编程
中可以利用这些技术。现在我们演示在pycurl编程中查看请求报文的Header。

--------------------------------------------------------------------------
#!/usr/bin/env python
# -*- encoding: utf-8 -*-

import sys, pycurl
from cStringIO import StringIO

info            = []
send_header     = []
recv_header     = []
recv_body       = []
ssl_recv_body   = []

def debug_callback ( debug_type, debug_data ) :

    if pycurl.INFOTYPE_TEXT == debug_type :
        info.append( debug_data )
    elif pycurl.INFOTYPE_HEADER_OUT == debug_type :
        send_header.append( debug_data )
    elif pycurl.INFOTYPE_HEADER_IN == debug_type :
        recv_header.append( debug_data )
    #
    # 对于HTTPS，这里存放的是解密后的数据
    #
    # 如果响应报文Header中含有
    #
    # Content-Encoding: gzip
    # Content-Length: 8379
    #
    # 这里存放的是压缩数据，并未自动解压还原。Content-Length对应压缩数据的
    # 长度。但c.body.getvalue()返回的是解压后的数据。
    #
    elif pycurl.INFOTYPE_DATA_IN == debug_type :
        recv_body.append( debug_data )
    #
    # 对于HTTPS，这里存放的是解密前的数据
    #
    elif pycurl.INFOTYPE_SSL_DATA_IN == debug_type :
        ssl_recv_body.append( debug_data )

#
# end of debug_callback
#

httpheader      =   \
[
r'User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; InfoPath.2; .NET4.0C; .NET4.0E)',
r'Accept: image/jpeg, application/x-ms-application, image/gif, application/xaml+xml, image/pjpeg, application/x-ms-xbap, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*',
r'Connection: close'
]
c               = pycurl.Curl()
c.setopt( pycurl.URL, 'https://www.cia.gov' )
c.setopt( pycurl.HTTPHEADER, httpheader )
c.setopt( pycurl.FOLLOWLOCATION, True )
#c.setopt( pycurl.MAXREDIRS, 5 )
#c.setopt( pycurl.REDIR_PROTOCOLS, 3 )
#c.setopt( pycurl.PROTOCOLS, 3 )
c.setopt( pycurl.SSL_VERIFYPEER, False )
c.setopt( pycurl.SSL_VERIFYHOST, False )
c.setopt( pycurl.ENCODING, "" )
c.setopt( pycurl.SSL_CIPHER_LIST, "DEFAULT" )
c.setopt( pycurl.DEBUGFUNCTION, debug_callback )
#
# 查看pycurl源码中的module.c、easy.c，pycurl没有真正支持CURLOPT_STDERR
#
# c.setopt( pycurl.STDERR, ... )
#
# pycurl.NOPROGRESS缺省就是True
#
# c.setopt( pycurl.NOPROGRESS, True )
#
# the DEBUGFUNCTION has no effect until we enable VERBOSE
#
c.setopt( pycurl.VERBOSE, True )
#
# 不要用CURLOPT_NOBODY，它将导致HEAD请求
#
# c.setopt( pycurl.NOBODY, True )
#
# 靠下面两行代码捕捉响应报文的Body，避免其向stdout输出
#
c.body          = StringIO()
c.setopt( pycurl.WRITEFUNCTION, c.body.write )
c.perform()

print "".join( send_header )
print "".join( info )
print "".join( recv_header )
print c.body.getvalue()
--------------------------------------------------------------------------
GET / HTTP/1.1
Host: www.cia.gov
Accept-Encoding: deflate, gzip
User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; InfoPath.2; .NET4.0C; .NET4.0E)
Accept: image/jpeg, application/x-ms-application, image/gif, application/xaml+xml, image/pjpeg, application/x-ms-xbap, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*
Connection: close

GET /index.html HTTP/1.1
Host: www.cia.gov
Accept-Encoding: deflate, gzip
User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; InfoPath.2; .NET4.0C; .NET4.0E)
Accept: image/jpeg, application/x-ms-application, image/gif, application/xaml+xml, image/pjpeg, application/x-ms-xbap, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*
Connection: close

Rebuilt URL to: https://www.cia.gov/
  Trying 23.47.179.36...
Connected to www.cia.gov (23.47.179.36) port 443 (#0)
TLSv1.2, TLS Unknown, Unknown (22):
TLSv1.2, TLS handshake, Client hello (1):
SSLv2, Unknown (22):
TLSv1.2, TLS handshake, Server hello (2):
SSLv2, Unknown (22):
TLSv1.2, TLS handshake, CERT (11):
SSLv2, Unknown (22):
TLSv1.2, TLS handshake, Server key exchange (12):
SSLv2, Unknown (22):
TLSv1.2, TLS handshake, Server finished (14):
SSLv2, Unknown (22):
TLSv1.2, TLS handshake, Client key exchange (16):
SSLv2, Unknown (20):
TLSv1.2, TLS change cipher, Client hello (1):
SSLv2, Unknown (22):
TLSv1.2, TLS handshake, Finished (20):
SSLv2, Unknown (20):
TLSv1.2, TLS change cipher, Client hello (1):
SSLv2, Unknown (22):
TLSv1.2, TLS handshake, Finished (20):
SSL connection using TLSv1.2 / ECDHE-RSA-AES256-GCM-SHA384
Server certificate:
     subject: jurisdictionC=US; C=US; ST=Virginia; L=McLean; businessCategory=Government Entity; serialNumber=Government Entity; O=Central Intelligence Agency; CN=www.cia.gov
     start date: 2015-04-01 00:00:00 GMT
     expire date: 2016-04-11 23:59:59 GMT
     issuer: C=US; O=Symantec Corporation; OU=Symantec Trust Network; CN=Symantec Class 3 EV SSL CA - G3
     SSL certificate verify result: unable to get local issuer certificate (20), continuing anyway.
SSLv2, Unknown (23):
SSLv2, Unknown (23):
Closing connection 0
SSLv2, Unknown (21):
TLSv1.2, TLS alert, Client hello (1):
Issue another request to this URL: 'https://www.cia.gov/index.html'
Hostname www.cia.gov was found in DNS cache
  Trying 23.47.179.36...
Connected to www.cia.gov (23.47.179.36) port 443 (#1)
SSL re-using session ID
SSLv2, Unknown (22):
TLSv1.2, TLS handshake, Client hello (1):
SSLv2, Unknown (22):
TLSv1.2, TLS handshake, Server hello (2):
SSLv2, Unknown (20):
TLSv1.2, TLS change cipher, Client hello (1):
SSLv2, Unknown (22):
TLSv1.2, TLS handshake, Finished (20):
SSLv2, Unknown (20):
TLSv1.2, TLS change cipher, Client hello (1):
SSLv2, Unknown (22):
TLSv1.2, TLS handshake, Finished (20):
SSL connection using TLSv1.2 / ECDHE-RSA-AES256-GCM-SHA384
Server certificate:
     subject: jurisdictionC=US; C=US; ST=Virginia; L=McLean; businessCategory=Government Entity; serialNumber=Government Entity; O=Central Intelligence Agency; CN=www.cia.gov
     start date: 2015-04-01 00:00:00 GMT
     expire date: 2016-04-11 23:59:59 GMT
     issuer: C=US; O=Symantec Corporation; OU=Symantec Trust Network; CN=Symantec Class 3 EV SSL CA - G3
     SSL certificate verify result: unable to get local issuer certificate (20), continuing anyway.
SSLv2, Unknown (23):
SSLv2, Unknown (23):
Closing connection 1
SSLv2, Unknown (21):
TLSv1.2, TLS alert, Client hello (1):

HTTP/1.1 301 Moved Permanently
Content-Length: 0
Location: https://www.cia.gov/index.html
Date: Wed, 13 May 2015 06:55:35 GMT
Connection: close

HTTP/1.1 200 OK
ETag: "d0add78de1a39a4786dd944690fb2543:1431444402"
Last-Modified: Tue, 12 May 2015 15:14:21 GMT
Accept-Ranges: bytes
Content-Type: text/html
Vary: Accept-Encoding
Content-Encoding: gzip
Date: Wed, 13 May 2015 06:55:36 GMT
Content-Length: 8379
Connection: close

<!DOCTYPE html>
...
--------------------------------------------------------------------------

真正的要点是:

c.setopt( pycurl.DEBUGFUNCTION, debug_callback )

在回调函数debug_callback()中可以任意处理请求、响应报文的Header、Body。

curl/libcurl/pycurl会自动处理HTTPS所涉及的加解密环节，在临时测试HTTPS时，
前述技术极大地方便了测试者，使得我们专注于明文部分。