Re: Better way of finding HTML tags positions in HTML string

[talexb]

Looking at the source code for HTML::TagReader, it looks like the module only operates on files. That tells me that if you want to use this module, you'll need to create a (temporary) file, write your string into it, and go from there. The File::Temp module is a good choice for that.

[phoenix007]

Is there any other way to get tags and there position similar to HTML::TagReader. Or any other module which operate on string

[holli]

I just patched the TagReader.xs file like so:
Read more... (19 kB)
Basically I added this function. I didnt test it thoroughly. It seems to work though.

HTML::TagReader
tr_new_from_io(class, pio)
    SV *class
    InputStream pio
CODE:
    if (pio == NULL){
        croak("ERROR: Help");
    }
    /* malloc and zero the struct */
        Newz(0, RETVAL, 1, struct trstuct );    
    
    /* malloc */
        New(0, RETVAL->filename, 1, char );
    strncpy(RETVAL->filename,newSVpv("",0),0);
    /* put a zero at the end of the string, perl might not do it */
    *(RETVAL->filename + 1 )=(char)0;
    
    /* malloc initial buffer */
        New(0, RETVAL->buffer, BUFFLEN+1, char );
    RETVAL->currbuflen=BUFFLEN;
        
    RETVAL->fd=pio; 
    RETVAL->charpos=0;
    RETVAL->tagcharpos=0;
    RETVAL->fileline=1;
    RETVAL->tagline=0;
OUTPUT:
    RETVAL

And then you can use it as

my $str = "<blockquote>\n<i>Perlmonks</i>\n</blockquote>\n";
open my $io, "<", \$str;
my $p = HTML::TagReader->new_from_io($io);
my @tag;
while(@tag = $p->gettag(1)){
    print "line: $tag[1]: col: $tag[2]: $tag[0]\n";
}

Which gives you

line: 1: col: 2: <blockquote>
line: 2: col: 1: <i>
line: 2: col: 13: </i>
line: 3: col: 1: </blockquote>

Note, the module is buggy (or maybe to the spec i dont know), but if the html does not end with a newline the last tag gets "forgotten".

my $str = "<blockquote>\n<i>Perlmonks</i>\n</blockquote>"; #no newline
+ at the end
open my $io, "<", \$str;
my $p = HTML::TagReader->new_from_io($io);
my @tag;
while(@tag = $p->gettag(1)){
    print "line: $tag[1]: col: $tag[2]: $tag[0]\n";
}

Which gives you

line: 1: col: 2: <blockquote>
line: 2: col: 1: <i>
line: 2: col: 13: </i>

[talexb]

Maybe HTML::Bare? Have a look around CPAN, there are plenty of options. That's just the first one that looked like it might do the job.

[haukex]

What's wrong with File::Temp? It's a core module, and it cleans up after itself pretty reliably:

use File::Temp qw/tempfile/;

my ($tfh,$tfn) = tempfile(UNLINK=>1);
print $tfh $contents;
close $tfh;

# File named $tfn will exist till end of program

And if you want to control the filename, you can do something like tempfile( TMPDIR=>1, TEMPLATE=>'.something_XXXXXXXXXX', SUFFIX => '.html', UNLINK=>1 ), or if you wanted to create the file in the same directory and based on the same name as some other file (File::Basename is also a core module):

use File::Basename qw/fileparse/;
use File::Temp qw/tempfile/;

my ($fn,$dir,$ext) = fileparse($filename, qr/\.[^.]+$/);
my ($tfh,$tfn) = tempfile(DIR=>$dir, TEMPLATE=>'.'.$fn.'_XXXXXXXXXX',
    SUFFIX => $ext, UNLINK=>1 );
...

I also like to use something like Corion's Text::CleanFragment on the above $fn, but that's not necessarily required.

Update: Since I'm already dumping some File::Temp snippets, here's two more that use a temporary directory instead, allowing you to keep the original file name. File::Spec is also a core module. tempdir supports the same TEMPLATE, DIR, and TMPDIR arguments as above. Note that if you use only TEMPLATE with a relative name, the resulting filename will also be relative to the current working directory, which is IMO not good, so I'd strongly recommend using an additional TMPDIR=>1 or DIR argument.

use File::Temp qw/tempdir/;
use File::Basename qw/fileparse/;
use File::Spec::Functions qw/catfile/;

my $tmpdir = tempdir(CLEANUP=>1);
my $tfn = catfile($tmpdir, scalar fileparse($filename));
...

# - OR -

my ($fn,$dir) = fileparse($filename);
my $tmpdir = tempdir(DIR=>$dir, TEMPLATE=>'.XXXXXXXXXX', CLEANUP=>1 );
my $tfn = catfile($tmpdir, $fn);
...