Re^3: parsing XML fragments (xml log files) with... a regex

[ikegami]

For those interested, it can't handle

• Numerical entities (decimal and hex).*
• External entities (e.g. HTML's &eacute).*
• Character decoding.**
• UTF-16, UTF-32, UCS-2, UCS-4.**
• CDATA.
• Namespace prefixes. (They're included as part of the name.)***
• Comments.
• Identification of an element's namespace.***
• XML validation (i.e. it allows some malformed XML).
• (more? this wasn't a thorough analysis)

Up to you to decide if it fits your needs or not.

* — A post-processor could fix this if no entities were processed at all.

** — A pre-processor such as the following would fix this:

sub _predecode {
    my $enc;
    if    ( $_[0] =~ /^\xEF\xBB\xBF/ ) { $enc = 'UTF-8';    }
    elsif ( $_[0] =~ /^\xFF\xFE/     ) { $enc = 'UTF-16le'; }
    elsif ( $_[0] =~ /^\xFE\xFF/     ) { $enc = 'UTF-16be'; }
    elsif (substr($_[0], 0, 100) =~ /^[^>]* encoding="([^"]+)"/) { $en
+c = $1; }
    else                               { $enc = 'UTF-8';    }
    return decode($enc, $_[0], Encode::FB_CROAK | Encode::LEAVE_SRC);
}

*** — A post-processor could fix this, but one wasn't supplied.

Update: Added pre-processor I had previously coded.