[LON-CAPA-dev] Extracting problems from page or sequence

Jeremy Bowers lon-capa-dev@mail.lon-capa.org
Fri, 21 Feb 2003 15:24:04 -0500

H. K. Ng wrote:
> Presumably you are referring to the ID that is embedded in the symbolic 
> name. I was able to get the page from which the problem comes from but 
> could not get the symbolic names for other problems from the same page.

I just committed a new lonnavmaps that includes a "getResourceByUrl" 
method on the lonnavmaps object, so you can ask the $navmap for the map 
directly if you know the URL. (It turns out to be useful in many 
contexts, not surprisingly.)

Of course if you want this before the next release that doesn't help 
much, but you can look at the code as an example if you want, as the 
"getResourceByUrl" code should work in the .6.2 release, if you want to 
implement it somewhere else or include it in your local copy.

Here's how it's coded (and documented) in the latest lonnavmaps, package 
Apache::lonnavmaps::navmap :


=item * B<getResourceByUrl>(url): Retrieves a resource object by URL of 
the resource. If passed a resource object, it will simply return it, so 
it is safe to use this method in code like "$res = 
$navmap->getResourceByUrl($res)", if you're not sure if $res is already 
an object, or just a URL. If the resource appears multiple times in the 
course, only the first instance will be returned. As a result, this is 
probably useful only for maps.


sub getResourceByUrl {
     my $self = shift;
     my $resUrl = shift;

     if (ref($resUrl)) { return $resUrl; }

     $resUrl = &Apache::lonnet::clutter($resUrl);
     my $resId = $self->{NAV_HASH}->{'ids_' . $resUrl};
     if ($resId =~ /,/) {
         $resId = (split (/,/, $resId))[0];
     if (!$resId) { return ''; }
     return $self->getById($resId);