Planet Replay Forum Index Planet Replay
The Destination for ReplayTV Owners and TV Enthusiasts
Visit our partner site: ReplayFAQs.com
Back to top page
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

Funky error - "snapshot show data discrepancy"

 
Post new topic   Reply to topic    Planet Replay Forum Index -> IVSmagic
View previous topic :: View next topic  
Author Message
nded
Planet Master
Planet Master


Joined: 08 Jul 2005
Posts: 819
Location: Largo Florida

PostPosted: Sun Jan 28, 2007 12:49 pm    Post subject: Funky error - "snapshot show data discrepancy" Reply with quote

When my IVSmagic server tries to update the guide for one of my Replays, it returns an error message saying "snapshot show data discrepancy. an extra 12 bytes were found. attempting to correct! ".

What does this really mean?

Do I need to take any action in response to this error?
_________________
This signature under construction. Please check back soon for updates.
Back to top
View user's profile Send private message
jwc553911
Replay junkie
Replay junkie


Joined: 27 Jan 2004
Posts: 172
Location: Kokomo, Indiana

PostPosted: Mon Nov 05, 2007 7:07 pm    Post subject: Reply with quote

same problem, any answers yet?
_________________
00004-54831-47079 jwc553911
00004-54831-35256 jwc5539112
00004-54831-77286 jwc5539113
00004-42360-89180 jwc5539115 (VR)

Back to top
View user's profile Send private message Send e-mail
bybachler
Replay fan
Replay fan


Joined: 25 Jan 2006
Posts: 45
Location: USA, Canada, Switzerland

PostPosted: Sat Aug 09, 2008 10:52 am    Post subject: Reply with quote

Same error:

FATAL ERROR: Guide Snapshot failed !!!

Any ideas?

G
http://www.transformers-soundtrack.com
_________________
Guido Baechler
Also Skype me at: jeridoo.com
Back to top
View user's profile Send private message Send e-mail Visit poster's website Yahoo Messenger MSN Messenger
nded
Planet Master
Planet Master


Joined: 08 Jul 2005
Posts: 819
Location: Largo Florida

PostPosted: Sun Aug 10, 2008 4:30 am    Post subject: Reply with quote

No ideas. I've seen it come and go several times. It seems to heal itself with no rhyme or reason.
_________________
This signature under construction. Please check back soon for updates.
Back to top
View user's profile Send private message
jlv
Replay fan
Replay fan


Joined: 27 Jan 2008
Posts: 50
Location: MA

PostPosted: Tue Feb 24, 2009 8:47 am    Post subject: Reply with quote

I'm getting this error (with "an extra 6 bytes") when IVSm gets the guide from WiRNS. It also only downloads a portion of the guide (about half).
Back to top
View user's profile Send private message
jlv
Replay fan
Replay fan


Joined: 27 Jan 2008
Posts: 50
Location: MA

PostPosted: Tue Feb 24, 2009 4:09 pm    Post subject: I found what was causing this for me (+PATCH) Reply with quote

I found that was causing this in my case (IVSm getting the guide from WiRNS). It turns out to be a bug in WiRNS, or more probably, in the .NET library.

Basically, the HTTP request IVSmagic was sending for the guide was causing the HTTP response from WiRNS to not use the chunked transfer encoding. However, the byte stream in the response contained extraneous <CR><LF> where the next chunk would have started.

This is the request IVSmagic is making:
Code:
GET /http_replay_guide-get_snapshot?guide_file_name=0&serial_no=RTV4080K0000000000 HTTP/1.1^M
Pragma: no-cache^M
Accept: */*^M
Accept-Encoding: gzip^M
Host: 10.0.0.47:80^M
X-User-Agent: IVSMagic^M
X-Host-Addr: 10.0.0.16:8080^M
and it gets this back from WiRNS
Code:
HTTP/1.1 200 OK^M
Date: Thu, 01 Jan 1970 04:36:49 GMT^M
X-User-Agent: WiRNS^M
X-Host-Addr: 10.0.0.47^M
Server: Unknown/0.0 UPnP/1.0 Virata-EmWeb/R6_0_1^M
Content-Type: text/plain^M
Connection: close^M
Expires: Thu, 01 Jan 1970 04:36:49 GMT^M
Last-Modified: Thu, 01 Jan 1970 04:36:49 GMT^M
Cache-Control: no-cache^M
Pragma: no-cache^M
^M
00000000
guide_file_name=1235497696
RemoteFileName=1235497696
FileLength=113648
#####ATTACHED_FILE_START#####...
This all looks OK, and supposedly isn't using chuked encoding. However, the guide snapshot that gets returned is corrupted. If I turn on the export_path option in IVSmagic, I find that the size of the snapshot returned is 113654 - 6 bytes too long.

If I make the same HTTP request without the X- headers, a slightly different response comes back:
Code:
HTTP/1.1 200 OK^M
Date: Thu, 01 Jan 1970 04:36:49 GMT^M
X-User-Agent: WiRNS^M
X-Host-Addr: 10.0.0.47^M
Server: Unknown/0.0 UPnP/1.0 Virata-EmWeb/R6_0_1^M
Transfer-Encoding: chunked^M
Connection: close^M
Content-Type: text/plain^M
Expires: Thu, 01 Jan 1970 04:36:49 GM^M
Last-Modified: Thu, 01 Jan 1970 04:36:49 GM^M
Cache-Control: no-cache^M
Pragma: no-cache^M
^M
00007ed3^M
00000000
guide_file_name=1235497689
RemoteFileName=1235497689
FileLength=113648
#####ATTACHED_FILE_START#####...
This is a chunked response with the first chunk being 0x7ed3 (32467) bytes. After that many bytes, the next chunk is in the data stream:
Code:
^M
00007e66^M
which basically says how long the next chunk is. There's a CR-LF before and after the number, and these 12 bytes marking the chunk are not part of the data stream.

Comparing the raw HTTP response bodies (without removing the chunking), the problem is hinted at (I used diff on the output of hd; the first response is the non-chunked (bad) one, the second is the chunked one):
Code:
< 00007ed0  01 00 00 0d 0a 00 00 00  00 40 00 45 7f 96 ee 00  |.........@.E....|
< 00007ee0  00 00 00 00 3b 00 00 00  00 00 00 12 07 21 7f 01  |....;........!..|
< 00007ef0  01 01 01 53 74 61 72 67  61 74 65 20 41 74 6c 61  |...Stargate Atla|
< 00007f00  6e 74 69 73 00 41 6c 6c  69 65 73 00 54 68 65 20  |ntis.Allies.The |
---
> 00007ed0  01 00 00 0d 0a 30 30 30  30 37 65 36 36 0d 0a 00  |.....00007e66...|
> 00007ee0  00 00 00 40 00 45 7f 96  ee 00 00 00 00 00 3b 00  |...@.E........;.|
> 00007ef0  00 00 00 00 00 12 07 21  7f 01 01 01 01 53 74 61  |.......!.....Sta|
> 00007f00  72 67 61 74 65 20 41 74  6c 61 6e 74 69 73 00 41  |rgate Atlantis.A|
> 00007f10  6c 6c 69 65 73 00 54 68  65 20 57 72 61 69 74 68  |llies.The Wraith|

The problem stands out when you look at the HTTP response data. I used wget to make the HTTP request and save the output to file, forcing the X-* headers for the first request:
Code:
< 00007ed0  01 00 00 0d 0a 00 00 00  00 40 00 45 7f 96 ee 00  |.........@.E....|
< 00007ee0  00 00 00 00 3b 00 00 00  00 00 00 12 07 21 7f 01  |....;........!..|
< 00007ef0  01 01 01 53 74 61 72 67  61 74 65 20 41 74 6c 61  |...Stargate Atla|
< 00007f00  6e 74 69 73 00 41 6c 6c  69 65 73 00 54 68 65 20  |ntis.Allies.The |
---
> 00007ed0  01 00 00 00 00 00 00 40  00 45 7f 96 ee 00 00 00  |.......@.E......|
> 00007ee0  00 00 3b 00 00 00 00 00  00 12 07 21 7f 01 01 01  |..;........!....|
> 00007ef0  01 53 74 61 72 67 61 74  65 20 41 74 6c 61 6e 74  |.Stargate Atlant|
> 00007f00  69 73 00 41 6c 6c 69 65  73 00 54 68 65 20 57 72  |is.Allies.The Wr|
Right there in the first line of the bad response, you can see an extra 0d 0a. There end up being 3 of these - one for each place there would have been a chunk (each being about 32000 bytes), had the result been chunked.


This bug only happens when getting a guide from WiRNS (not from DVarchive or a real ReplayTV), so it doesn't cover anyone else's report of this.

It makes no sense that these X-* headers should have this affect on the HTTP responses put out from .NET. Any fix for it would have to be ini WiRNS (or in an update to .NET).

However, a workaround for IVSmagic is trivial: just comment-out the two lines adding these extraneous headers.
Code:
$ cvs diff common.php
Index: common.php
===================================================================
RCS file: /var/cvs/IVSMagic/IVSm/include/common.php,v
retrieving revision 1.1
diff -r1.1 common.php
700,701c700,704
<   $header_array[]="X-User-Agent: IVSmagic";
<   $header_array[]="X-Host-Addr: " . $bind_address . ":" . $web_port;
---
>   // including these two lines cause WiRNS to output malformed
>   // chunked encodings, messing up guide parsing.
>   // see http://www.planetreplay.com/phpBB2/viewtopic.php?t=13893
>   //$header_array[]="X-User-Agent: IVSmagic";
>   //$header_array[]="X-Host-Addr: " . $bind_address . ":" . $web_port;

I've made the patched version of common.php available for download.
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    Planet Replay Forum Index -> IVSmagic All times are GMT - 8 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
Planet Replay topic RSS feed 


Powered by phpBB © 2001, 2005 phpBB Group