[Bexley] Adapt postcode DB script to take URL for fetching CSV.

To allow for automatically pulling in updates via a cron for mysociety/societyworks#4463.

bin/bexley/make-bexley-ww-postcode-db

@@ -4,10 +4,6 @@
 
 make-bexley-ww-postcode-db
 
-=head1 USAGE
-
-make-bexley-ww-postcode-db
-
 =head1 DESCRIPTION
 
 Creates a SQLite database for postcode lookups for Bexley WasteWorks, pulled
@@ -32,8 +28,32 @@ use DBI;
 use FixMyStreet;
 use Text::CSV;
 use Cwd 'abs_path';
+use LWP::Simple;
+use IO::String;
+use Encode;
+use Getopt::Long::Descriptive;
+
+my ($opts, $usage) = describe_options(
+    '%c %o',
+    ['csv=s',   "a path to a LLPG CSV to use"],
+    ['fetch=s', "a url to fetch the LLPG CSV from"],
+    ['help|h',  "print usage message and exit" ],
+);
+print($usage->text), exit if $opts->help;
 
-my $csv_file = $ARGV[0] or die "Please provide a CSV file\n";
+my $csv = Text::CSV->new( { binary => 1, auto_diag => 1 } );
+my $fh;
+if (!($opts->csv) && ($opts->fetch)) {
+    say "Fetching the LLPG CSV via url."
+    my $csv_content = LWP::Simple::get($opts->fetch);
+    $csv_content = decode('UTF-8', $csv_content);
+    $fh = IO::String->new($csv_content);
+} elsif ($opts->csv && !($opts->fetch)) {
+    say "Using the CSV file provided."
+    open $fh, '<:encoding(utf8)', $opts->csv;
+} else {
+    die "A url or path to fetch the CSV from must be provided.";
+}
 
 # Delete any existing database file first
 my $db_file = BexleyAddresses::database_file;
@@ -119,9 +139,6 @@ my $query_postcodes = $db->prepare(
 SQL
 );
 
-my $csv = Text::CSV->new( { binary => 1, auto_diag => 1 } );
-open my $fh, '<:encoding(utf8)', $csv_file;
-
 my $id_street_descriptor = 15;
 my @columns_street_descriptor = (
     qw/