perl的cgi高级编程介绍
一 CGI.pm中的方法(routines)调用
1. CGI.pm实现了两种使用方法,分别是面向对象的方式和传统的perlmodule方法的方式。
面向对象的方式:
#!/usr/local/bin/perl -w use CGI; # load CGI routines $q = CGI->new; # create new CGI object print $q->header, # create the HTTP header $q->start_html('hello world'), # start the HTML $q->h1('hello world'), # level 1 header $q->end_html; # end the HTML
传统的module方法的方式:
#!/usr/local/bin/perl use CGI qw/:standard/; # load standard CGI routines print header, # create the HTTP header start_html('hello world'), # start the HTML h1('hello world'), # level 1 header end_html; # end the HTML
2. CGI.pm中的方法。
CGI.pm中的方法,通常有很多的参数,所以一般我们使用命名参数的方式来调用,例如:
print $q->header(-type=>'image/gif',-expires=>'+3d');
命名参数的值可以为scalar或array reference类型,例如:
$q->param(-name=>'veggie',-value=>'tomato'); $q->param(-name=>'veggie',-value=>['tomato','tomahto','potato','potahto']);
3. CGI.pm中的html元素(html shortcuts)方法
所有的html的元素(例如h1,br等)在CGI.pm中都有对应的方法,这些方法根据需要动态的生成,且都包含2个参数,第一个参数为hash类型,对应html元素的属性,第二个参数的string类型,对应html元素的内容。例如html中的h1对应的方法为h1( ):
Code Generated HTML
---- --------------
h1() <h1>
h1('some','contents'); <h1>some contents</h1>
h1({-align=>left}); <h1 align="LEFT">
h1({-align=>left},'contents'); <h1 align="LEFT">contents</h1>
有时你想自己处理元素的开始和结尾,则可以使用start_tag_name和end_tag_name,例如
print start_h1,'Level 1 Header',end_h1;
有的时候start和end方法没有被自动生成,需要显示的指定,例如:
use CGI qw/:standard *table start_ul/;
用来自动生成start_table,end_table,start_ul和end_ul方法。
另一个实例:
print a({-href=>'fred.html',-target=>'_new'}, "Open a new frame"); <a href="fred.html",target="_new">Open a new frame</a>
二 CGI.pm中获取cgi的参数
@names = $query->param #get all params
@values = $query->param('foo'); #get param foo as list
$value = $query->param('foo'); #get param foo as scalar
param()获取参数的结果可以为scalar或array类型,例如当参数的结果来自多选的scrollinglist的时候就为array类型。如果参数的值在querystring中没有给定("name1=&name2="),param()将返回emptystring。如果参数在querystring中根本不存在,则param()则返回undef或emptylist。当参数为多个值时querystring中写法为var1=value1&var1=value2&var1=value3.
三 header and start_html
1. header指定html的header,例如
print header; # 返回默认的type:text/html print header('image/gif'); #设定type为:image/gif print header('text/html','204 No response'); $cookie1 = $q->cookie(-name=>'riddle_name', -value=>"The Sphynx's Question"); $cookie2 = $q->cookie(-name=>'answers', -value=>%answers); print header(-type=>'image/gif', -nph=>1, -status=>'402 Payment required', -expires=>'+3d', -cookie => [$cookie1,$cookie2] , -charset=>'utf-7', -attachment=>'foo.gif', -Cost=>'$2.00');
其中-type,-status,-expires,-cookie为可以设别的参数,其他的命名参数都被转化为html header属性。
-expires的值可以为:
+30s 30 seconds from now
+10m ten minutes from now
+1h one hour from now
-1d yesterday (i.e. "ASAP!")
now immediately
+3M in three months
+10y in ten years time
Thursday, 25-Apr-1999 00:40:33 GMT at the indicated time & date
2. start_html 创建页面的顶层元素<html><header</header><body>
例如:
print start_html(-title=>'Secrets of the Pyramids', -author=>'fred@jbxue.org', -base=>'true', -target=>'_blank', -meta=>{'keywords'=>'pharaoh secret mummy', 'copyright'=>'copyright 1996 King Tut'}, -style=>{'src'=>'/styles/style1.css'}, -BGCOLOR=>'blue');
或者:
print start_html(-head=>[ Link({-rel=>'shortcut icon',href=>'favicon.ico'}), meta({-http_equiv => 'Content-Type',-content=> 'text/html'}) ] );
在header中加入javascript的例子:
$query = CGI->new; print header; $JSCRIPT=<<END; // Ask a silly question function riddle_me_this() { var r = prompt("What walks on four legs in the morning, " + "two legs in the afternoon, " + "and three legs in the evening?"); response(r); } // Get a silly answer function response(answer) { if (answer == "man") alert("Right you are!"); else alert("Wrong! Guess again."); } END print start_html(-title=>'The Riddle of the Sphinx', -script=>$JSCRIPT); print $q->start_html(-title=>'The Riddle of the Sphinx', -script=>{-type=>'JAVASCRIPT', -src=>'/javascript/sphinx.js'} ); print $q->start_html(-title=>'The Riddle of the Sphinx', -script=>[ { -type => 'text/javascript', -src => '/javascript/utilities10.js' }, { -type => 'text/javascript', -src => '/javascript/utilities11.js' }, { -type => 'text/jscript', -src => '/javascript/utilities12.js' }, { -type => 'text/ecmascript', -src => '/javascript/utilities219.js' } ] );
在header中使用css的例子:
use CGI qw/:standard :html3/; #here's a stylesheet incorporated directly into the page $newStyle=<<END; <!-- P.Tip { margin-right: 50pt; margin-left: 50pt; color: red; } P.Alert { font-size: 30pt; font-family: sans-serif; color: red; } --> END print header(); print start_html( -title=>'CGI with Style', -style=>{-src=>'//www.laike.net/style/st1.css', -code=>$newStyle} ); print h1('CGI with Style'), p({-class=>'Tip'}, "Better read the cascading style sheet spec before playing with this!"), span({-style=>'color: magenta'}, "Look Mom, no hands!", p(), "Whooo wee!" ); print end_html;
四 url
$full_url = url(); # http://your.host.com/path/to/script.cgi $full_url = url(-full=>1); # http://your.host.com/path/to/script.cgi $relative_url = url(-relative=>1); #script.cgi $absolute_url = url(-absolute=>1); #path/to/script.cgi $url_with_path = url(-path_info=>1); $url_with_path_and_query = url(-path_info=>1,-query=>1); $netloc = url(-base => 1); #http://your.host.com
五 CGI.pm中的html元素方法的特殊用法
如果元素的第二个参数为list类型,则会被分解,例如:
print ul( li({-type=>'disc'},['Sneezy','Doc','Sleepy','Happy']) );
相当于:
<ul>
<li type="disc">Sneezy</li>
<li type="disc">Doc</li>
<li type="disc">Sleepy</li>
<li type="disc">Happy</li>
</ul>
例如table可以写为:
print table({-border=>undef}, caption('When Should You Eat Your Vegetables?'), Tr({-align=>'CENTER',-valign=>'TOP'}, [ th(['Vegetable', 'Breakfast','Lunch','Dinner']), td(['Tomatoes' , 'no', 'yes', 'yes']), td(['Broccoli' , 'no', 'no', 'yes']), td(['Onions' , 'yes','yes', 'yes']) ] ) );
六 CGI.pm中非标准的html元素方法
print comment('here is my comment'); #generates an HTML comment (<!-- comment -->)
因为与perl方法冲突,所以大写的:
Select
Tr
Link
Delete
Accept
Sub
其他特殊的html元素方法:start_html(), end_html(), start_form(), end_form(), start_multipart_form() and all the fill-out form tags。
七 CGI.pm中的form相关
1 start_form 和start_multipart_form
print start_form(-method=>$method, -action=>$action, -enctype=>$encoding); <... various form stuff ...> print end_form; -or- print start_form($method,$action,$encoding); <... various form stuff ...> print end_form;
如果没有指定method,action,enctype,默认地为:
method: POST
action: this script
enctype: application/x-www-form-urlencoded for non-XHTML
multipart/form-data for XHTML, see multipart/form-data below.
当使用start_form的时候,enctype为application/x-www-form-urlencoded,如果需要新式的xhtml,则需要使用start_multipart_form,此时enctype为multipart/form-data。
更多内容请参考:cgi man page http://search.cpan.org/~markstos/CGI.pm-3.60/lib/CGI.pm