TT#42767 Allow Range header in firmware downloads

ALE phones first download the first 256 bytes "header" of the firmware
to check if a new version is available. Support simple single Range
request in format "Range: bytes=X-Y" with X being start and Y being
end.

Also make sure to use $rs->count instead of $rs->first to only
execute the full query once and use a count query before instead,
otherwise we're fetching dozens of MB of data twice when fetching
the firmware.

Change-Id: I0c4e9f8b7d856d077eaa4ba8f2bc0aeaf42deebe

lib/NGCP/Panel/Controller/Device.pm

@@ -1890,11 +1890,10 @@ sub dev_field_firmware_download :Chained('dev_field_firmware_base') :PathPart('v
 
     $c->response->header ('Content-Disposition' => 'attachment; filename="' . $fw->filename . '"');
     $c->response->content_type('application/octet-stream');
-    $c->response->body(
-        NGCP::Panel::Utils::DeviceFirmware::get_firmware_data(
-            c => $c,
-            fw_id => $fw->id
-    ));
+    NGCP::Panel::Utils::DeviceFirmware::get_firmware_data_into_body(
+        c => $c,
+        fw_id => $fw->id
+    );
 }
 
 sub dev_field_firmware_version_base :Chained('dev_field_firmware_base') :PathPart('from') :CaptureArgs(1) {
@@ -1941,11 +1940,10 @@ sub dev_field_firmware_next :Chained('dev_field_firmware_version_base') :PathPar
 
     $c->response->header ('Content-Disposition' => 'attachment; filename="' . $fw->filename . '"');
     $c->response->content_type('application/octet-stream');
-    $c->response->body(
-        NGCP::Panel::Utils::DeviceFirmware::get_firmware_data(
-            c => $c,
-            fw_id => $fw->id
-    ));
+    NGCP::Panel::Utils::DeviceFirmware::get_firmware_data_into_body(
+        c => $c,
+        fw_id => $fw->id
+    );
 }
 
 sub dev_field_firmware_latest :Chained('dev_field_firmware_version_base') :PathPart('latest') :Args {
@@ -1978,11 +1976,10 @@ sub dev_field_firmware_latest :Chained('dev_field_firmware_version_base') :PathP
 
     $c->response->header ('Content-Disposition' => 'attachment; filename="' . $fw->filename . '"');
     $c->response->content_type('application/octet-stream');
-    $c->response->body(
-        NGCP::Panel::Utils::DeviceFirmware::get_firmware_data(
-            c => $c,
-            fw_id => $fw->id
-    ));
+    NGCP::Panel::Utils::DeviceFirmware::get_firmware_data_into_body(
+        c => $c,
+        fw_id => $fw->id
+    );
 }
 
 sub devices_preferences_list :Chained('devmod_base') :PathPart('preferences') :CaptureArgs(0) {

lib/NGCP/Panel/Utils/DeviceFirmware.pm

@@ -4,6 +4,9 @@ use warnings;
 use strict;
 
 use English;
+use POSIX;
+
+my $chunk_size = 10*1024*1024; # 10MB
 
 sub insert_firmware_data {
     my (%args)   = @_;
@@ -14,7 +17,6 @@ sub insert_firmware_data {
     my $data_fh  = $args{data_fh};
 
     # do not set it larger than 10M
-    my $chunk_size = 10*1024*1024; # 10MB
 
     $c->model('DB')->resultset('autoprov_firmwares')->find({id => $fw_id},{for => 'update'});
 
@@ -63,7 +65,7 @@ sub get_firmware_data {
     });
 
     my $data = '';
-    if ($rs->first) {
+    if ($rs->count) {
         foreach my $fw_data ($rs->all) {
             $data = $data . $fw_data->data;
         }
@@ -71,6 +73,78 @@ sub get_firmware_data {
 
     return $data;
 }
+
+sub get_firmware_data_into_body {
+    my (%args)   = @_;
+    my $c        = $args{c};
+    my $fw_id    = $args{fw_id};
+
+    my ($range_from, $range_to, $range_len);
+    if  ($c->request->headers->header('Range')) {
+        my $range = $c->request->headers->header('Range');
+        if ($range =~ /^bytes=(\d+)\-(\d+)$/) {
+            $range_from = int($1);
+            $range_to = int($2);
+            $range_len = $range_to - $range_from + 1;
+            if ($range_to < $range_from) {
+                $range_from = $range_to = undef;
+            }
+        }
+    }
+
+    # TODO: for now, if the requested range fits into the first chunk, request that range
+    # directly from db, otherwise we fetch all and extract the requested part
+    # later, due to the chunking in the db;
+    # this should be optimized to only request the range needed directly from db, but
+    # it must be ensured that we also handle cross-chunk ranges
+    my ($col, $limit);
+    if (defined $range_from && defined $range_to &&
+      $range_from < $chunk_size && ($range_from + $range_len) < $chunk_size) {
+        my $mysql_range_from = $range_from + 1;
+        $col = \"SUBSTRING(data, $mysql_range_from, $range_len)";
+        $limit = 1;
+    } else {
+        $col = 'data';
+        $limit = 0;
+    }
+
+    my $rs = $c->model('DB')->resultset('autoprov_firmwares_data')->search({
+        fw_id => $fw_id
+    },
+    {
+        select => [$col, \"OCTET_LENGTH(data)"],
+        as     => [qw/body data_length/],
+        order_by => { -asc => 'id' }
+    });
+
+    my $data = '';
+    my $full_len = 0;
+    my $use_chunk = 1;
+    if ($rs->count) {
+        foreach my $fw_data ($rs->all) {
+            if ($use_chunk) {
+                $data = $data . $fw_data->get_column('body');
+                if ($limit) {
+                    $use_chunk = 0;
+                }
+            }
+            $full_len += $fw_data->get_column('data_length');
+        }
+    }
+
+    if (defined $range_from && defined $range_to) {
+        unless ($limit) {
+            $data = substr($data, $range_from, $range_len);
+        }
+        $c->response->status(206);
+        $c->response->header("Content-Range" => "bytes $range_from-$range_to/$full_len");
+    }
+    $c->response->body($data);
+    return 0;
+}
+
+
+
 1;
 
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