Can't connect to ... nodename nor servname provided, or not known

Question

My question: why does my perl script--successful via home laptop--not work when run in the context of my hosting website? (Perhaps they have a firewall, for example. Perhaps my website needs to provide credentials. Perhaps this is in the realm of cross-site scripting. I DON'T KNOW and appeal for your help in my understanding what could be the cause and then the solution. Thanks!)

Note that all works fine IF I run the perl script from my laptop at home.

But if I upload the perl script to my web host, where I have a web page whose javascript successfully calls that perl script, there is an error back from the site whose URL is in the perl script (finance.yahoo in this example).

To bypass the javascript, I'm just typing the URL of my perl script, e.g. http://example.com/blah/script.pl

Here is the full error message from finance.yahoo when $url starts with http:

Can't connect to finance.yahoo.com:80 nodename nor servname provided, or not known at C:/Perl/lib/LWP/Protocol/http.pm line 47.

Here is the full error message from finance.yahoo when $url starts with https:

Can't connect to finance.yahoo.com:443 nodename nor servname provided, or not known at C:/Perl/lib/LWP/Protocol/http.pm line 47.

Code:

#!/usr/bin/perl
use strict; use warnings;
use LWP 6; # one site suggested loading this "for all important LWP classes"

use HTTP::Request;

### sample of interest: to scrape historical data and feed massaged facts to my private web page via js ajax
my $url = 'http://finance.yahoo.com/quote/sbux/profile?ltr=1';

my $browser = LWP::UserAgent->new;

# one site suggested having this empty cookie jar could help
$browser->cookie_jar({});

# another site suggested I should provide WAGuess
my @ns_headers = (
 'User-Agent' => 
        # 'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.130 Safari/537.36',
 'Mozilla/5.0 (Windows NT 10.0; WOW64; rv:46.0) Gecko/20100101 Firefox/46.0',
 'Accept' => 'text/html, */*',
 'Accept-Charset' => 'iso-8859-1,*,utf-8',
 'Accept-Language' => 'en-US',
);

my $response = $browser->get($url, @ns_headers);

# for now, I just want to confirm, in my web page itself, that 
# the target web page's contents was returned
my $content = $response->content;

# show such content in my web page
print "Content-type: text/html\n\n" . $content;

Answer 1

Well it is not obvious what is your final goal and it is possible that you over complicate the task.

You can retrieve above mentioned page with simpler perl code

#!/usr/bin/env perl
#
# vim: ai:ts=4:sw=4
#

use strict;
use warnings;
use feature 'say';

use HTTP::Tiny;

my $debug = 1;

my $url = 'https://finance.yahoo.com/quote/sbux/profile?ltr=1';

my $responce = HTTP::Tiny->new->get($url);

if ($responce->{success}) {
    my $html = $responce->{content};

    say $html if $debug;
}

In your post you indicated that javascript is somehow involved -- it is not clear how and what it's purpose in retrieving of the page.

Error message has a reference to at C:/Perl/lib/LWP/Protocol/http.pm line 47 which indicates that web hosting is taking place on Windows machine -- it would be nice to indicate it in your message.

Could you shed some light on purpose of following block in your code?

# WAGuess
$browser->env_proxy;
# WAGuess
$browser->cookie_jar({});

I do not see cookie_jar be utilized in your code anywhere.

Do you plan to use some authentication approach to extract some data under your personal account which is not accessible otherwise?

Please state in a few first sentences what you try to achieve on grand scale.

Answer 2

Perhaps it's about cookies or about using yahoo's "query" url instead.

Yahoo Finance URL not working