URL resolve (operations on path etc.)

bliako has asked for the wisdom of the Perl Monks concerning the following question:

Esteemed Monks,

I am trying to translate the following Node.js fragment to Perl (it takes a URL and sort of chdir to it, clever enough to remove endpoint if a file and query):

const url = require('url');
const x = 'http:/a.com/a/b/c/d/e.json?x=1&y=2';
const y = '../../../';
console.log(url.resolve(x, y));
[download]

result is : http:/a.com/a/

Now, if x='http:/a.com/a/b/c/d/e.json/?x=1&y=2'; (i.e. the path points to a "directory" rather than to a "file") the result is http:/a.com/a/b/ (as expected IMO)

I tried to do this with URI but failed:

use URI;
my $x = 'http:/a.com/a/b/c/d/e.json?x=1&y=2';
my $y = '../../../';
my $u = URI->new($x);
my $p = $u->path().'/'.$y;
$u->path($p);
print $u;
<c>
<p>With this result: <c>http:/a.com/a/b/c/d/e.json/../../../?x=1&y=2
[download]

The Node.js version seems to be able to understand that the last segment before the query is a "file" and removes it. Then it does the merging of the two paths including successful relative operations (../). What is the safest way to achieve that behaviour in Perl? The last resort would be to shell-out to Node.js ...

bw, bliako

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Re: URL resolve (operations on path etc.) by haukex (Archbishop) on Jul 31, 2022 at 07:52 UTC
`use warnings; use strict; use URI; my $x = 'http://a.com/a/b/c/d/e.json?x=1&y=2'; my $y = '../../../'; my $u = URI->new($y); print $u->abs($x), "\n"; __END__ http://a.com/a/` [download]	[reply] [d/l]
Re^2: URL resolve (operations on path etc.) by bliako (Monsignor) on Jul 31, 2022 at 08:03 UTC
Thanks haukex++ (I swear last night `abs` was not working!!!!!!) EDIT!: ouchhhh I was doing the reverse!!!!!: `# this is wrong, note new($x)!! abs($y) it should be the reverse my $u = URI->new($x); # this is wrong print $u->abs($y), "\n"; # this is wrong` [download] Edit2: that's definetely an X-Y problem hehe	[reply] [d/l] [select]
Re^2: URL resolve (operations on path etc.) by ikegami (Patriarch) on Aug 01, 2022 at 22:50 UTC
All you need is `URI->new_abs($y, $x)` [download]	[reply] [d/l]
Re^2: URL resolve (operations on path etc.) by harangzsolt33 (Chaplain) on Jul 31, 2022 at 11:31 UTC
Could this be resolved with a regex maybe? Like for example: `#!/usr/bin/perl use strict; use warnings; my $PATH = 'http://a.com/a/b/c/d/e.json?something' . '/' . '/../../../ +'; $PATH =~ tr\|/\|\|s; my $PREV = 0; my $LEN; for (;;) { $PATH =~ s/\/[^\/]+\/\.\.//; $LEN = length($PATH); last if ($PREV == $LEN); $PREV = $LEN; } print $PATH;` [download] I put the regex in a for(;;) loop, because adding global flag didn't do what I want: `$PATH =~ s/\/[^\/]+\/\.\.//g;`	[reply] [d/l] [select]
Re: URL resolve (operations on path etc.) by Your Mother (Archbishop) on Jul 31, 2022 at 17:27 UTC
haukex already solved it but this is the way I generally handle these. It lends itself to bulk changes; URI. `~>perl -MURI -E '$x = "http://a.com/a/b/c/d/e.json?x=1&y=2"; $y = "../ +../../"; say URI->new_abs($y,$x);' http://a.com/a/` [download]	[reply] [d/l]


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