使用perl解析abnf语法

Question

感谢您在链接Parse::ABNF perl usage上提出的问题。我仍然面临着解决我的问题的困难。请求检查我下面的问题，并提供指向解决方案的指针。

现在，我已经在一个文件中创建了ABNF格式的sip语法(命名为sip.abnf)。我在如下所示的文件(recd_message.txt)中有带标头的sip消息：

From: <sip:07455900064@212.136.178.216:5060;user=phone>;tag=1526438727-1338998848384-
To: "govoice-lab2-aokanlawon"<sip:441127653485@isf.fire.ipgcom.com>
Contact: <sip:07455900064@10.12.33.29:5070;transport=udp>
Allow: ACK,BYE,CANCEL,INFO,INVITE,OPTIONS,PRACK,REFER,NOTIFY
Accept: multipart/mixed,application/media_control+xml,application/sdp

我创建了一个Perl程序，使用ABNF语法来验证上面的头消息，将其命名为testSipHeader.pl，内容如下：

use strict; use warnings;
use File::Slurp;
use Parse::ABNF ;
use Data::Dumper;

my $grammar_file = shift;
my $messages = shift;
my @header_name;
my $header_status;

my $grammar = scalar read_file( $grammar_file );
$grammar =~ s/\x0d\x0a/\n/g;
$grammar =~ s/^\s+(?=[\w-]+\s*=)//mg;

$grammar = Parse::ABNF->new->parse(  scalar read_file( $grammar_file ) );
if (defined $grammar) {
    print "Grammar is now defined...\n";
    my $header;
    open ( $header , "<", $messages) or die "Could not open $messages file";
    while(<$header>) {
        print "Processing the message $_\n";
        @header_name = split(': ', $_);
        if ($header_name[0] eq "From") {
            $header_status = $grammar->From($_) ;
        } elsif ($header_name[0] eq "To") {
            $header_status = $grammar->To($_) ;
        } elsif ($header_name[0] eq "Contact") {
            $header_status = $grammar->Contact($_) ;
        } elsif ($header_name[0] eq "Allow") {
            $header_status = $grammar->Allow($_) ;
        } elsif ($header_name[0] eq "Accept") {
            $header_status = $grammar->Accept($_) ;
        } else {
            print "Error: Unsupported header $header_name[0] received\n";
        }
    }
} else {
        print "Error: grammar is not defined\n";
}

下面是Perl调用和输出/错误

$> perl -I. testSipHeader.pl sip.abnf recd_messages.txt
Grammar is now defined...
Processing the message From: <sip:07455900064@212.136.178.216:5060;user=phone>;tag=1526438727-

Can't call method "From" on unblessed reference at testSipHeader.pl line 21, <$header> line 1.

注意:目前我有一个生成SIP头的C程序，我正在尝试通过这个perl函数来验证头的内容。我正在尝试使用与链接Parse::RecDescent grammar not working as expected中给出的用法类似的用法

我必须在您的脚本中做一点修改，以包含Parse::ABNF和处理输入文件，然后接收到的输出出现在路径https://drive.google.com/file/d/0B8KDQDXsCKR_ZERzV3IyY1M2NW8/edit?usp=sharing中

Answer 1

我重写了一下你的脚本，输出是什么？

use Data::Dumper;
my $grammar_rules;
{
    local $/=undef;
    open(my $fh,'<',$grammar_file) or die $grammar_file,$!;
    $grammar_rules = <$fh>;
    $grammar_rules =~ s/\x0d\x0a/\n/g;
    $grammar_rules =~ s/^\s+(?=[\w-]+\s*=)//mg;
}
print Dumper('rules',$grammar_rules);
my $grammar = Parse::ABNF->new->parse(  $grammar_rules );
print Dumper('grammar',$grammar);
die "Error: grammar is not defined" if ! defined $grammer;
print "Grammar is now defined...\n";

open ( my $header_fh , "<", $messages) or die "Could not open $messages file, $!";
while(my $line = <$header_fh>) {
    chomp($line);
    print "Processing the message $line\n";
    @header_name = split(': ', $line);
    if ($header_name[0] eq "From") {
        $header_status = $grammar->From($line) ;
    } elsif ($header_name[0] eq "To") {
        $header_status = $grammar->To($line) ;
    } elsif ($header_name[0] eq "Contact") {
        $header_status = $grammar->Contact($line) ;
    } elsif ($header_name[0] eq "Allow") {
        $header_status = $grammar->Allow($line) ;
    } elsif ($header_name[0] eq "Accept") {
        $header_status = $grammar->Accept($line) ;
    } else {
        print "Error: Unsupported header $header_name[0] received\n";
    }
}