如何使用WWW :: Mechanize从网站下载图像文件？

Question

I try to download the image from the server. I try so far,

use warnings;
use strict; 
use WWW::Mechanize;

my $sequence = "MIPTLAAEPRKPARPPLPVRRESREEPVDAVIVGTGAGGAPLLARLAQAGLKVVALEAGNHWDPAADFATDEREQNKLFWFDERLSAGADPLAFGRNNSGIGVGGSTLHYTAYVPRPQPDDFRLYSDFGVGEDWPIGYGDLEPYFDELECFLGVSGPSPYPWGPARTPYPLAPMPLNAAAQLMARGCAALGLRTSPAANAVLSAPYFQSGVGWRSPCTNRGFCQAGCTTGGKAGMDVTFIPLALAHGAEVRSGAFVTRIETDRAGRVTGVVYVREGREERQRCRTLFLAAGAIETPRLLLLNGLANQSGEVGRNFMAHPGLQLWGQFSEATRPFKGVPGSLISEDTHRPKDADFAGGYLLQSIGVMPVTYATQTARGGGLWGEKLQSHMHGYNHTAGINILGECLPYAHNYLELSDEPDQRGLPKPRIHFSNGKNERRLRDHAEALMRRIWEAAGAQAVWTFERNAHTIGTCRMGADPKRAVVDPEGRAFDVPNLYIIDNSVFPSALSVNPALTIMALSLRTADRFIERTQRGEY";

my $mech = WWW::Mechanize -> new;
$mech->get('https://npsa-prabi.ibcp.fr/cgi-bin/npsa_automat.pl?page=/NPSA/npsa_sopma.html');
    $mech->submit_form(
        form_number => 1,
        fields => {
        'notice' => $sequence,
        },
    );


$mech->find_image( alt_regex => qr/.+sopma2.gif/ );
open (FH, ">soi.gif");
binmode (FH);
print FH $mech;

The image tag was like this:

<img align="TOP" src="/tmp/e3a3c2b34201.sopma2.gif">

I already have the link to the image parsed from the website, but I want to download this image. How can I do it?

Answer 1

The find_image method of WWW::Mechanize returns a WWW::Mechanize::Image object. That only contains the URI, filename and alt tag info about the image, not the content of the image itself. You need to download the image file first.

Luckily, you can use your $mech for that. The $image has a URI method that returns the full URL of that image file. Your $mech can get that image. It comes as a HTTP::Response.

my $image = $mech->find_image( url_regex => qr/sopma2\.gif$/ );
my $res = $mech->get($image->URI);

if ($res->is_success) {
  open (my $fh, '>', 'soi.gif') or die $!;
  binmode $fh;
  print $fh $res->decoded_content;
  # no need to close lexical filehandle
}

Et voila, there's your image file.

Answer 2

You can use $mech->get(...) to store URL content into local file.

if( my $image = $mech->find_image( alt_regex => qr/.+sopma2.gif/ )) {
  $mech->get( $img->url, ':content_file' => 'soi.gif');
}

How do i save an image with www::mechanize

man WWW::Mechanize

$mech->find_image()
Finds an image in the current page. It returns a WWW::Mechanize::Image object which describes the image. If it fails to find an image it returns undef.
...
$mech->get( $uri )
Given a URL/URI, fetches it. Returns an HTTP::Response object. $uri can be a well-formed URL string, a URI object, or a WWW::Mechanize::Link object. [...]
"get()" is a well-behaved overloaded version of the method in LWP::UserAgent. This lets you do things like
$mech->get( $uri, ':content_file' => $tempfile );

Answer 3

The problem is that you are searching for an image whose alt text contains the string sopma2.gif . That image doesn't have an alt text so your program doesn't find it

This program will fetch the gif file that you want. I'm using url_regex => qr/sopma2/i to find sopma2 in the URL instead. That succeeds and returns a WWW::Mechanize::Image object. Then all that is necessary is to fetch that objects absolute URL and use get with a :content_file parameter to save the data to a disk file

use strict;
use warnings;
use 5.010;

use WWW::Mechanize;

STDOUT->autoflush;

my $sequence = "MIPTLAAEPRKPARPPLPVRRESREEPVDAVIVGTGAGGAPLLARLAQAGLKVVALEAGNHWDPAADFATDEREQNKLFWFDERLSAGADPLAFGRNNSGIGVGGSTLHYTAYVPRPQPDDFRLYSDFGVGEDWPIGYGDLEPYFDELECFLGVSGPSPYPWGPARTPYPLAPMPLNAAAQLMARGCAALGLRTSPAANAVLSAPYFQSGVGWRSPCTNRGFCQAGCTTGGKAGMDVTFIPLALAHGAEVRSGAFVTRIETDRAGRVTGVVYVREGREERQRCRTLFLAAGAIETPRLLLLNGLANQSGEVGRNFMAHPGLQLWGQFSEATRPFKGVPGSLISEDTHRPKDADFAGGYLLQSIGVMPVTYATQTARGGGLWGEKLQSHMHGYNHTAGINILGECLPYAHNYLELSDEPDQRGLPKPRIHFSNGKNERRLRDHAEALMRRIWEAAGAQAVWTFERNAHTIGTCRMGADPKRAVVDPEGRAFDVPNLYIIDNSVFPSALSVNPALTIMALSLRTADRFIERTQRGEY";

my $mech = WWW::Mechanize->new;
$mech->get('https://npsa-prabi.ibcp.fr/cgi-bin/npsa_automat.pl?page=/NPSA/npsa_sopma.html');

say $mech->res->status_line;
say $mech->title;

$mech->submit_form(
    form_number => 1,
    fields => {
      notice => $sequence,
    },
);

say $mech->res->status_line;
say $mech->title;

my $image = $mech->find_image( url_regex => qr/sopma2/i );
my ($file) = $image->url =~ m|([^/]+\z)|;
$mech->get($image->url_abs, ':content_file' => $file);
say "$file saved";

output

200 OK
NPS@ : SOPMA secondary structure prediction
200 OK
NPS@ SOPMA secondary structure prediction results
373025433891.sopma2.gif saved

Answer 4

use LWP::Simple with WWW::Mechanize.

use WWW::Mechanize;
use LWP::Simple;
my $sequence = "MIPTLAA......";

my $mech = WWW::Mechanize -> new;
$mech->get('https://npsa-prabi.ibcp.fr/cgi-bin/npsa_automat.pl?page=/NPSA/npsa_sopma.html');
    $mech->submit_form(
        form_number => 1,
        fields => {
        'notice' => $sequence,
        },
    );

my $cont = $mech->content;  
($img) = $cont =~m/SRC=(.+sopma2\.gif)/g; 
$urL = "https://npsa-prabi.ibcp.fr/$img";
getstore($urL,"soi.gif");

$img stores the url of the image

Then save the image by using getstore method from the LWP::Simple

It is not good idea. See the @simbabque answer. But it give the result what you need.