我有一个html如下:
<!DOCTYPE html
PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en-US" xml:lang="en-US">
<head>
<title></title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
</head>
<body bgcolor="white">
<h1>foo.c</h1>
<form method="post" action=""
enctype="application/x-www-form-urlencoded">
Compare this file to the similar file:
<select name="file2">
<option value="...">...</option>
</select>
<input type="hidden" name="file1" value="foo.c" /><br>
Show the results in this format:
</form>
<hr>
<p>
<pre>
some code
</pre>
我需要获取input name ='file'的值和HTML pre标签的内容.我不知道perl语言,通过谷歌搜索我写了这个小程序(我认为不是"优雅"):
#!/usr/bin/perl
package MyParser;
use base qw(HTML::Parser);
#Store the file name and contents obtaind from HTML Tags
my($filename, $file_contents);
#This value is set at start() calls
#and use in text() routine..
my($g_tagname, $g_attr);
#Process tag itself and its attributes
sub start {
my ($self, $tagname, $attr, $attrseq, $origtext) = @_;
$g_tagname = $tagname;
$g_attr = $attr;
}
#Process HTML tag body
sub text {
my ($self, $text) = @_;
#Gets the filename
if($g_tagname eq "input" and $g_attr->{'name'} eq "file1") {
$filename = $attr->{'value'};
}
#Gets the filecontents
if($g_tagname eq "pre") {
$file_contents = $text;
}
}
package main;
#read $filename file contents and returns
#note: it works only for text/plain files.
sub read_file {
my($filename) = @_;
open FILE, $filename or die $!;
my ($buf, $data, $n);
while((read FILE, $data, 256) != 0) {
$buf .= $data;
}
return ($buf);
}
my $curr_filename = $ARGV[0];
my $curr_file_contents = read_file($curr_filename);
my $parser = MyParser->new;
$parser->parse($curr_file_contents);
print "filename: ",$filename,"file contents: ",$file_contents;
然后我打电话./foo.pl html.html,但我从得到空值$filename和$file_contents变量.
如何解决这个问题？
像往常一样,有不止一种方法可以做到这一点.以下是如何使用DOM Parser of Mojolicious执行此任务:
#!/usr/bin/env perl
use strict;
use warnings;
use Mojo::DOM;
# slurp all lines at once into the DOM parser
my $dom = Mojo::DOM->new(do { local $/; <> });
print $dom->at('input[name=file1]')->attr('value');
print $dom->at('pre')->text;
输出:
foo.c
some code
使用xpath和HTML :: TreeBuilder :: XPath Perl模块(很少行):
#!/usr/bin/env perl
use strict; use warnings;
use HTML::TreeBuilder::XPath;
my $tree = HTML::TreeBuilder::XPath->new_from_content( <> );
print $tree->findvalue( '//input[@name="file1"]/@value' );
print $tree->findvalue( '//pre/text()' );
用法
./script.pl file.html
OUTPUT
foo.c
some code
笔记
HTML::TreeBuilder模块进行一些网络抓取.现在,我无法回到复杂性.HTML::TreeBuilder::XPath用有用的Xpath表达式做所有的魔术.new_from_file方法来打开文件或文件句柄而不是new_from_content,请参阅perldoc HTML::TreeBuilder(HTML::TreeBuilder::XPath继承方法HTML::TreeBuilder)<>这里允许以这种方式使用,因为HTML::TreeBuilder::new_from_content()特别允许以这种方式读取多行.大多数构造函数都不允许这种用法.您应该提供标量或使用其他方法.