cgi.3

视频监控网络部分的协议ddns,的模块的实现代码,请大家大胆指正.

.\" Automatically generated by Pod::Man 2.16 (Pod::Simple 3.05)
.\"
.\" Standard preamble:
.\" ========================================================================
.de Sh \" Subsection heading
.br
.if t .Sp
.ne 5
.PP
\fB\\$1\fR
.PP
..
.de Sp \" Vertical space (when we can't use .PP)
.if t .sp .5v
.if n .sp
..
.de Vb \" Begin verbatim text
.ft CW
.nf
.ne \\$1
..
.de Ve \" End verbatim text
.ft R
.fi
..
.\" Set up some character translations and predefined strings.  \*(-- will
.\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
.\" double quote, and \*(R" will give a right double quote.  \*(C+ will
.\" give a nicer C++.  Capital omega is used to do unbreakable dashes and
.\" therefore won't be available.  \*(C` and \*(C' expand to `' in nroff,
.\" nothing in troff, for use with C<>.
.tr \(*W-
.ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p'
.ie n \{\
.    ds -- \(*W-
.    ds PI pi
.    if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch
.    if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\"  diablo 12 pitch
.    ds L" ""
.    ds R" ""
.    ds C` ""
.    ds C' ""
'br\}
.el\{\
.    ds -- \|\(em\|
.    ds PI \(*p
.    ds L" ``
.    ds R" ''
'br\}
.\"
.\" Escape single quotes in literal strings from groff's Unicode transform.
.ie \n(.g .ds Aq \(aq
.el       .ds Aq '
.\"
.\" If the F register is turned on, we'll generate index entries on stderr for
.\" titles (.TH), headers (.SH), subsections (.Sh), items (.Ip), and index
.\" entries marked with X<> in POD.  Of course, you'll have to process the
.\" output yourself in some meaningful fashion.
.ie \nF \{\
.    de IX
.    tm Index:\\$1\t\\n%\t"\\$2"
..
.    nr % 0
.    rr F
.\}
.el \{\
.    de IX
..
.\}
.\"
.\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
.\" Fear.  Run.  Save yourself.  No user-serviceable parts.
.    \" fudge factors for nroff and troff
.if n \{\
.    ds #H 0
.    ds #V .8m
.    ds #F .3m
.    ds #[ \f1
.    ds #] \fP
.\}
.if t \{\
.    ds #H ((1u-(\\\\n(.fu%2u))*.13m)
.    ds #V .6m
.    ds #F 0
.    ds #[ \&
.    ds #] \&
.\}
.    \" simple accents for nroff and troff
.if n \{\
.    ds ' \&
.    ds ` \&
.    ds ^ \&
.    ds , \&
.    ds ~ ~
.    ds /
.\}
.if t \{\
.    ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u"
.    ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u'
.    ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u'
.    ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u'
.    ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u'
.    ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u'
.\}
.    \" troff and (daisy-wheel) nroff accents
.ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V'
.ds 8 \h'\*(#H'\(*b\h'-\*(#H'
.ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#]
.ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H'
.ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u'
.ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#]
.ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#]
.ds ae a\h'-(\w'a'u*4/10)'e
.ds Ae A\h'-(\w'A'u*4/10)'E
.    \" corrections for vroff
.if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u'
.if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u'
.    \" for low resolution devices (crt and lpr)
.if \n(.H>23 .if \n(.V>19 \
\{\
.    ds : e
.    ds 8 ss
.    ds o a
.    ds d- d\h'-1'\(ga
.    ds D- D\h'-1'\(hy
.    ds th \o'bp'
.    ds Th \o'LP'
.    ds ae ae
.    ds Ae AE
.\}
.rm #[ #] #H #V #F C
.\" ========================================================================
.\"
.IX Title "CGI 3"
.TH CGI 3 "2007-12-18" "perl v5.10.0" "Perl Programmers Reference Guide"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH "NAME"
CGI \- Simple Common Gateway Interface Class
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 2
\&  # CGI script that creates a fill\-out form
\&  # and echoes back its values.
\&
\&  use CGI qw/:standard/;
\&  print header,
\&        start_html(\*(AqA Simple Example\*(Aq),
\&        h1(\*(AqA Simple Example\*(Aq),
\&        start_form,
\&        "What\*(Aqs your name? ",textfield(\*(Aqname\*(Aq),p,
\&        "What\*(Aqs the combination?", p,
\&        checkbox_group(\-name=>\*(Aqwords\*(Aq,
\&                       \-values=>[\*(Aqeenie\*(Aq,\*(Aqmeenie\*(Aq,\*(Aqminie\*(Aq,\*(Aqmoe\*(Aq],
\&                       \-defaults=>[\*(Aqeenie\*(Aq,\*(Aqminie\*(Aq]), p,
\&        "What\*(Aqs your favorite color? ",
\&        popup_menu(\-name=>\*(Aqcolor\*(Aq,
\&                   \-values=>[\*(Aqred\*(Aq,\*(Aqgreen\*(Aq,\*(Aqblue\*(Aq,\*(Aqchartreuse\*(Aq]),p,
\&        submit,
\&        end_form,
\&        hr;
\&
\&   if (param()) {
\&       my $name      = param(\*(Aqname\*(Aq);
\&       my $keywords  = join \*(Aq, \*(Aq,param(\*(Aqwords\*(Aq);
\&       my $color     = param(\*(Aqcolor\*(Aq);
\&       print "Your name is",em(escapeHTML($name)),p,
\&             "The keywords are: ",em(escapeHTML($keywords)),p,
\&             "Your favorite color is ",em(escapeHTML($color)),
\&             hr;
\&   }
.Ve
.SH "ABSTRACT"
.IX Header "ABSTRACT"
This perl library uses perl5 objects to make it easy to create Web
fill-out forms and parse their contents.  This package defines \s-1CGI\s0
objects, entities that contain the values of the current query string
and other state variables.  Using a \s-1CGI\s0 object's methods, you can
examine keywords and parameters passed to your script, and create
forms whose initial values are taken from the current query (thereby
preserving state information).  The module provides shortcut functions
that produce boilerplate \s-1HTML\s0, reducing typing and coding errors. It
also provides functionality for some of the more advanced features of
\&\s-1CGI\s0 scripting, including support for file uploads, cookies, cascading
style sheets, server push, and frames.
.PP
\&\s-1CGI\s0.pm also provides a simple function-oriented programming style for
those who don't need its object-oriented features.
.PP
The current version of \s-1CGI\s0.pm is available at
.PP
.Vb 2
\&  http://www.genome.wi.mit.edu/ftp/pub/software/WWW/cgi_docs.html
\&  ftp://ftp\-genome.wi.mit.edu/pub/software/WWW/
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
.Sh "\s-1PROGRAMMING\s0 \s-1STYLE\s0"
.IX Subsection "PROGRAMMING STYLE"
There are two styles of programming with \s-1CGI\s0.pm, an object-oriented
style and a function-oriented style.  In the object-oriented style you
create one or more \s-1CGI\s0 objects and then use object methods to create
the various elements of the page.  Each \s-1CGI\s0 object starts out with the
list of named parameters that were passed to your \s-1CGI\s0 script by the
server.  You can modify the objects, save them to a file or database
and recreate them.  Because each object corresponds to the \*(L"state\*(R" of
the \s-1CGI\s0 script, and because each object's parameter list is
independent of the others, this allows you to save the state of the
script and restore it later.
.PP
For example, using the object oriented style, here is how you create
a simple \*(L"Hello World\*(R" \s-1HTML\s0 page:
.PP
.Vb 7
\&   #!/usr/local/bin/perl \-w
\&   use CGI;                             # load CGI routines
\&   $q = new CGI;                        # create new CGI object
\&   print $q\->header,                    # create the HTTP header
\&         $q\->start_html(\*(Aqhello world\*(Aq), # start the HTML
\&         $q\->h1(\*(Aqhello world\*(Aq),         # level 1 header
\&         $q\->end_html;                  # end the HTML
.Ve
.PP
In the function-oriented style, there is one default \s-1CGI\s0 object that
you rarely deal with directly.  Instead you just call functions to
retrieve \s-1CGI\s0 parameters, create \s-1HTML\s0 tags, manage cookies, and so
on.  This provides you with a cleaner programming interface, but
limits you to using one \s-1CGI\s0 object at a time.  The following example
prints the same page, but uses the function-oriented interface.
The main differences are that we now need to import a set of functions
into our name space (usually the \*(L"standard\*(R" functions), and we don't
need to create the \s-1CGI\s0 object.
.PP
.Vb 6
\&   #!/usr/local/bin/perl
\&   use CGI qw/:standard/;           # load standard CGI routines
\&   print header,                    # create the HTTP header
\&         start_html(\*(Aqhello world\*(Aq), # start the HTML
\&         h1(\*(Aqhello world\*(Aq),         # level 1 header
\&         end_html;                  # end the HTML
.Ve
.PP
The examples in this document mainly use the object-oriented style.
See \s-1HOW\s0 \s-1TO\s0 \s-1IMPORT\s0 \s-1FUNCTIONS\s0 for important information on
function-oriented programming in \s-1CGI\s0.pm
.Sh "\s-1CALLING\s0 \s-1CGI\s0.PM \s-1ROUTINES\s0"
.IX Subsection "CALLING CGI.PM ROUTINES"
Most \s-1CGI\s0.pm routines accept several arguments, sometimes as many as 20
optional ones!  To simplify this interface, all routines use a named
argument calling style that looks like this:
.PP
.Vb 1
\&   print $q\->header(\-type=>\*(Aqimage/gif\*(Aq,\-expires=>\*(Aq+3d\*(Aq);
.Ve
.PP
Each argument name is preceded by a dash.  Neither case nor order
matters in the argument list.  \-type, \-Type, and \-TYPE are all
acceptable.  In fact, only the first argument needs to begin with a
dash.  If a dash is present in the first argument, \s-1CGI\s0.pm assumes
dashes for the subsequent ones.
.PP
Several routines are commonly called with just one argument.  In the
case of these routines you can provide the single argument without an
argument name.  \fIheader()\fR happens to be one of these routines.  In this
case, the single argument is the document type.
.PP
.Vb 1
\&   print $q\->header(\*(Aqtext/html\*(Aq);
.Ve
.PP
Other such routines are documented below.
.PP
Sometimes named arguments expect a scalar, sometimes a reference to an
array, and sometimes a reference to a hash.  Often, you can pass any
type of argument and the routine will do whatever is most appropriate.
For example, the \fIparam()\fR routine is used to set a \s-1CGI\s0 parameter to a
single or a multi-valued value.  The two cases are shown below:
.PP
.Vb 2
\&   $q\->param(\-name=>\*(Aqveggie\*(Aq,\-value=>\*(Aqtomato\*(Aq);
\&   $q\->param(\-name=>\*(Aqveggie\*(Aq,\-value=>[\*(Aqtomato\*(Aq,\*(Aqtomahto\*(Aq,\*(Aqpotato\*(Aq,\*(Aqpotahto\*(Aq]);
.Ve
.PP
A large number of routines in \s-1CGI\s0.pm actually aren't specifically
defined in the module, but are generated automatically as needed.
These are the \*(L"\s-1HTML\s0 shortcuts,\*(R" routines that generate \s-1HTML\s0 tags for
use in dynamically-generated pages.  \s-1HTML\s0 tags have both attributes
(the attribute=\*(L"value\*(R" pairs within the tag itself) and contents (the
part between the opening and closing pairs.)  To distinguish between
attributes and contents, \s-1CGI\s0.pm uses the convention of passing \s-1HTML\s0
attributes as a hash reference as the first argument, and the
contents, if any, as any subsequent arguments.  It works out like
this:
.PP
.Vb 6
\&   Code                           Generated HTML
\&   \-\-\-\-                           \-\-\-\-\-\-\-\-\-\-\-\-\-\-
\&   h1()                           <h1>
\&   h1(\*(Aqsome\*(Aq,\*(Aqcontents\*(Aq);         <h1>some contents</h1>
\&   h1({\-align=>left});            <h1 align="LEFT">
\&   h1({\-align=>left},\*(Aqcontents\*(Aq); <h1 align="LEFT">contents</h1>
.Ve
.PP
\&\s-1HTML\s0 tags are described in more detail later.
.PP
Many newcomers to \s-1CGI\s0.pm are puzzled by the difference between the
calling conventions for the \s-1HTML\s0 shortcuts, which require curly braces
around the \s-1HTML\s0 tag attributes, and the calling conventions for other
routines, which manage to generate attributes without the curly
brackets.  Don't be confused.  As a convenience the curly braces are
optional in all but the \s-1HTML\s0 shortcuts.  If you like, you can use
curly braces when calling any routine that takes named arguments.  For
example:
.PP
.Vb 1
\&   print $q\->header( {\-type=>\*(Aqimage/gif\*(Aq,\-expires=>\*(Aq+3d\*(Aq} );
.Ve
.PP
If you use the \fB\-w\fR switch, you will be warned that some \s-1CGI\s0.pm argument
names conflict with built-in Perl functions.  The most frequent of
these is the \-values argument, used to create multi-valued menus,
radio button clusters and the like.  To get around this warning, you
have several choices:
.IP "1." 4