Not a HASH reference

[fdavidg2019]

Hello, I have been away from Perl for about 10 years and I am trying to get back up to speed. The following script returns a "Not a HASH reference" error as shown in this printout from running the script (the script follow the ouput:

C:\Strawberry\perl\bin>C:\Strawberry\perl\bin\perl.exe "C:\Users\Bonni
+e\My Documents\alexa2.pl" http://www.gamegrene.com/

URI: http://data.alexa.com/data?cli=10&dat=snba&ver=7.0&url=http%3A%2F
+%2Fwww.gam
egrene.com%2F

Page: <?xml version="1.0" encoding="UTF-8"?>

<!-- Need more Alexa data?  Find our APIs here: https://aws.amazon.com
+/alexa/ --
>
<ALEXA VER="0.9" URL="gamegrene.com/" HOME="0" AID="=" IDN="gamegrene.
+com/">
<RLS PREFIX="http://" more="0">
<RL HREF="www.gamereport.com/" TITLE="The Game Report Online"/>
<RL HREF="www.chimeramag.com/" TITLE="Chimera The Codependent Gaming M
+agazine"/>

<RL HREF="www.videounderbelly.com/wiki/Main_Page" TITLE="Main Page - V
+ideo Under
belly"/>
<RL HREF="www.ncbuy.com/" TITLE="Ncbuy"/>
<RL HREF="www.gnomestew.com/" TITLE="Gnome Stew, the Game Mastering Bl
+og"/>
<RL HREF="www.findwhitepapers.com/" TITLE="Find White Papers and Techn
+ology Rese
arch"/>
<RL HREF="www.disobey.com/" TITLE="Disobey: Content for the Discontent
+ed"/>
<RL HREF="www.3dgamers.com/" TITLE="3D Gamers"/>
<RL HREF="andreys.info/" TITLE="andrey&apos;s daily light and shadow |
+ photo blo
g | photography by"/>
<RL HREF="www.womengamers.com/" TITLE="Women Gamers"/>
</RLS>
<SD TITLE="A" FLAGS="" HOST="gamegrene.com">
<TITLE TEXT="Gamegrene"/>
<OWNER NAME="Disobey"/>
</SD>
<SD><POPULARITY URL="gamegrene.com/" TEXT="6678166" SOURCE="panel"/><R
+EACH RANK=
"5826716"/><RANK DELTA="-550802"/></SD></ALEXA>

XML: HASH(0x410f378)

XML: HASH(0x410f378)
Not a HASH reference at C:\Users\Bonnie\My Documents\alexa2.pl line 65
+ (#1)
    (F) Perl was trying to evaluate a reference to a hash value, but f
+ound a
    reference to something else instead.  You can use the ref() functi
+on to
    find out what kind of ref it really was.  See perlref.

Uncaught exception from user code:
        Not a HASH reference at C:\Users\Bonnie\My Documents\alexa2.pl
+ line 65.
        main::handle_xml("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\x
+{d}\x{a}\x
{d}\x{a}<!-- Need more Alex"...) called at C:\Users\Bonnie\My Document
+s\alexa2.p
l line 83

C:\Strawberry\perl\bin>

#!/usr/bin/perl -w
use diagnostics;
use strict;
no strict qw(refs);
use URI;
use LWP::Simple; 
use Net::Amazon;
use XML::Simple;
use constant AMAZON_TOKEN => 'amzn.mws.ccb04f71-d980-5fa6-0aed-b874a4b
+a9d58';
use constant DEBUG => 0;

# get our arguments. the first argument is the
# URL to fetch, and the second is the output.
my $url = shift || die "$0 <url> [<output>]\n";
my $output = shift || '/www/htdocs/cloud.html';

# we'll need to fetch the Alexa XML at some point, and
# we'll do it a few different times, so we create a 
# subroutine for it. Using the URI module, we can
# correctly encode a URL with a query. In fact, you'll
# notice the majority of this function is involved with
# this, and at the end we use LWP::Simple to actually
# download and return the XML.
#####################################################
sub fetch_xml {
    my $url = shift;
    $url = "http://$url" unless $url =~ m[^http://];
    warn "Fetching Alexa data for $url\n" if DEBUG;

    my @args = (
        cli => 10,     dat => 'snba',
        ver => '7.0',  url => $url
    );
    
    my $base = 'http://data.alexa.com/data';
    my $uri = URI->new( $base );
    $uri->query_form( @args );
    $uri = $uri->as_string;
    print "\nURI: $uri\n";

    return get( $uri );
}

# raw XML is no good for us, though, as we want to extract
# particular items of interest. we use XML::Simple to turn
# the XML into Perl data structures, because it's easier
# than fiddling with event handling (as with XML::Parser
# or XML::SAX), and we know there's only a small amount of
# data. we want the list of related sites and the list of
# related products. we extract and return both.
#####################################################
sub handle_xml {
    my $page = shift;
    print "\nPage: $page\n";
    my $xml = XMLin( $page );
    print "\nXML: $xml\n";
    my @related = map {
        {
            asin => $_->{ASIN},
            title => $_->{TITLE},
            href => $xml->{RLS}{PREFIX}.$_->{HREF}
        }
    } @{ $xml->{RLS}{RL} };
    print "\nXML: $xml\n";
    print $xml->{SD}{AMZN}{PRODUCT};
    my $refxml = (ref($xml->{SD}{AMZN}{PRODUCT}));
    print $refxml;

    my @products;
        if (ref($xml->{SD}{AMZN}{PRODUCT})  eq "ARRAY") {
        @products = map { $_->{ASIN} } @{ $xml->{SD}{AMZN}{PRODUCT} };
    } else { @products = $xml->{SD}{AMZN}{PRODUCT}{ASIN}; }

    return ( \@related, \@products );
}

# Functions done; now for the program:
warn "Start URL is $url\n" if DEBUG;
my @products; # running accumulation of product ASINs

{
    my $page = fetch_xml( $url );
    my ($related, $new_products) = handle_xml( $page );
    @products = @$new_products; # running list

    for (@$related) {
        my $xml = fetch_xml( $_->{href} );
        my ($related, $new_products) = handle_xml( $page );
        push @products, @$new_products;
    }
}

# We now have a list of products in @products, so
# we'd best do something with them. Let's look
# them up on Amazon and see what their titles are.
my $amazon = Net::Amazon->new( token => AMAZON_TOKEN );
my %products = map { $_ => undef } @products;

for my $asin ( sort keys %products ) {
    warn "Searching for $asin...\n" if DEBUG;
    my $response = $amazon->search( asin => $asin );
    my @products = $response->properties;
    die "ASIN is not unique!?" unless @products == 1;
    my $product = $products[0];
    $products{$asin} = {
        name => $product->ProductName,
        price => $product->OurPrice,
        asin => $asin,
    };
}

# Right. We now have name, price, and
# ASIN. Let's output an HTML report:
{
    umask 022;
    warn "Writing to $output\n" if DEBUG;
    open my $fh, '>', $output or die $!;
    print $fh "<html><head><title>Cloud around $url</title></head><bod
+y>";
    if (keys %products) {
        print $fh "<table>";
        for my $asin (sort keys %products) {
            my $data = $products{$asin};
            printf $fh "<tr><td>".
                       "<a href=\"http://amazon.com/exec/obidos/ASIN/%
+s\">".
                       "%s</a></td> <td>%s</td></tr>",
                       @{$data}{qw( asin name price )};
        }
        print $fh "</table>";
    }
    else { print $fh "No related products found.\n"; }
    print $fh "</body></html>\n";
}

The script is from the book "Spidering Hacks" and I wonder if I am running into problems as a result of changes in the Perl language from version 5.10 (when the book was written??) until today. I am using 5.30 Thank you for any and all insight on solving this. Frank

[poj]

Your XML has 2 SD elements

<SD TITLE="A" FLAGS="" HOST="gamegrene.com">
  <TITLE TEXT="Gamegrene"/>
  <OWNER NAME="Disobey"/>
</SD>
<SD>
  <POPULARITY URL="gamegrene.com/" TEXT="6678166" SOURCE="panel"/>
  <REACH RANK="5826716"/>
  <RANK DELTA="-550802"/>
</SD>

XMLin builds the structure as

{
  SD   => [
          {
            FLAGS => "",
            HOST  => "gamegrene.com",
            OWNER => { NAME => "Disobey" },
            TITLE => ["A", { TEXT => "Gamegrene" }],
          },
          {
            POPULARITY => { SOURCE => "panel", TEXT => 6678166, URL =>
+ "gamegrene.com/" },
            RANK => { DELTA => -550802 },
            REACH => { RANK => 5826716 },
          },
        ],
}

therefore $xml->{SD} is an arrayref not a hashref

poj

[fdavidg2019]

So when I check for an array in line 69 like this:

if (ref($xml->{SD}{AMZN}{PRODUCT})  eq "ARRAY")

it should return TRUE, but I keep getting a "NOT HASH reference" error at this line! Frank

[tobyink]

$xml->{SD} is an arrayref, so $xml->{SD}{AMZN} is not a thing.

I strongly advise switching to a saner XML module. XML::LibXML is my favourite.

[Jenda]

Please see Simpler than XML::Simple.

[Anonymous Monk]

i bet 5 internet points it's XML::Simples fault