How do I create an absolute URL from two components, in Perl? - perl

Question

Suppose I have:
my $a = "http://site.com";
my $part = "index.html";
my $full = join($a,$part);
print $full;
>> http://site.com/index.html
What do I have to use as join, in order to get my snippet to work?
EDIT: I'm looking for something more general. What if a ends with a slash, and part starts with one? I'm sure in some module, someone has this covered.

Answer 1

I believe what you're looking for is URI::Split, e.g.:
use URI::Split qw(uri_join);
$uri = uri_join('http', 'site.com', 'index.html')

Answer 2

use URI;
URI->new("index.html")->abs("http://site.com")
will produce
"http://site.com/index.html"
URI->abs will take care of merging the paths properly following your uri specification,
so
URI->new("/bah")->abs("http://site.com/bar")
will produce
"http://site.com/bah"
and
URI->new("index.html")->abs("http://site.com/barf")
will produce
"http://site.com/barf/index.html"
and
URI->new("../uplevel/foo")->abs("http://site.com/foo/bar/barf")
will produce
"http://site.com/foo/uplevel/foo"
alternatively, there's a shortcut sub in URI namespace that I just noticed:
URI->new_abs($url, $base_url)
so
URI->new_abs("index.html", "http://site.com")
will produce
"http://site.com/index.html"
and so on.

Answer 3

No need for ‘join‘, just use string interpolation.
my $a = "http://site.com";
my $part = "index.html";
my $full = "$a/$part";
print $full;
>> http://site.com/index.html
Update:
Not everything requires a module. CPAN is wonderful, but restraint is needed.
The simple approach above works very well if you have clean inputs. If you need to handle unevenly formatted strings, you will need to normalize them somehow. Using a library in the URI namespace that meets your needs is probably the best course of action if you need to handle user input. If the variance is minor File::Spec or a little manual clean-up may be good enough for your needs.
my $a = 'http://site.com';
my #paths = qw( /foo/bar foo //foo/bar );
# bad paths don't work:
print join "\n", "Bad URIs:", map "$a/$_", #paths;
my #cleaned = map s:^/+::, #paths;
print join "\n", "Cleaned URIs:", map "$a/$_", #paths;
When you have to handle bad stuff like $path = /./foo/.././foo/../foo/bar; is when you want definitely want to use a library. Of course, this could be sorted out using File::Spec's cannonical path function.
If you are worried about bad/bizarre stuff in the URI rather than just path issues (usernames, passwords, bizarre protocol specifiers) or URL encoding of strings, then using a URI library is really important, and is indisputably not overkill.

Answer 4

You might want to take a look at this, an implementation of a function similar to Python's urljoin, but in Perl:
http://sveinbjorn.org/urljoin_function_implemented_using_Perl

Answer 5

As I am used to Java java.net.URL methods, I was looking for a similar way to concatenate URI without any assumption about scheme, host or port (in my case, it is for possibly complex Subversion URL):
http://site.com/page/index.html
+ images/background.jpg
=> http://site.com/page/images/background.jpg
Here is the way to do it in Perl:
use URI;
my $base = URI->new("http://site.com/page/index.html");
my $result = URI->new_abs("images/background.jpg", $base);