Rails - Jan 2006 - Beware of Mozilla + Rails

Hi all,

In re-doing the very first Hello World in the Agile Rails WEb Dev book, I 
continuously got blank pages, no matter what URL I put in, except when I put 
http://localhost:3000/

After eliminating everything else, I switched from Mozilla to Konqueror, and 
the symptom went away. I tried clearing cache on Mozilla, but that
didn''t
bring it back. I copied and pasted the URL from Konqueror to Mozilla to make 
sure I hadn''t made a mistake on the URL.

The exercise had worked perfectly on Mozilla yesterday, so it''s
intermittent.

Beware of Mozilla + Rails.

SteveT

Steve Litt
Author: 
   * Universal Troubleshooting Process courseware
   * Troubleshooting Techniques of the Successful Technologist
   * Rapid Learning: Secret Weapon of the Successful Technologist
Webmaster
   * Troubleshooters.Com
   * http://www.troubleshooters.com

Steve Litt wrote:
> Hi all,
> 
> In re-doing the very first Hello World in the Agile Rails WEb Dev book, 
> I
> continuously got blank pages, no matter what URL I put in, except when I 
> put
> http://localhost:3000/
I too had the same problem with Firefox. It was bizarre, but it went 
away when I closed all Firefox windows and started again.

-- 
Posted via http://www.ruby-forum.com/.

Remove your cookies.  And be sure to clear out the sessions in /tmp.

On 1/6/06, Steve Litt <slitt@troubleshooters.com>
wrote:
> Hi all,
>
> In re-doing the very first Hello World in the Agile Rails WEb Dev book, I
> continuously got blank pages, no matter what URL I put in, except when I
put
> http://localhost:3000/
>
> After eliminating everything else, I switched from Mozilla to Konqueror,
and
> the symptom went away. I tried clearing cache on Mozilla, but that
didn''t
> bring it back. I copied and pasted the URL from Konqueror to Mozilla to
make
> sure I hadn''t made a mistake on the URL.
>
> The exercise had worked perfectly on Mozilla yesterday, so it''s
intermittent.
>
> Beware of Mozilla + Rails.
>
> SteveT
>
> Steve Litt
> Author:
>    * Universal Troubleshooting Process courseware
>    * Troubleshooting Techniques of the Successful Technologist
>    * Rapid Learning: Secret Weapon of the Successful Technologist
> Webmaster
>    * Troubleshooters.Com
>    * http://www.troubleshooters.com
>
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>

Joe Van Dyk wrote:
> Remove your cookies.  And be sure to clear out the sessions in /tmp.
Yep, this fixed it properly for me. Thanks!

-- 
Posted via http://www.ruby-forum.com/.

On Friday 06 January 2006 10:11 pm, Edward OG wrote:
> Joe Van Dyk wrote:
> > Remove your cookies.  And be sure to clear out the sessions in /tmp.
>
> Yep, this fixed it properly for me. Thanks!
Yes, the minute I removed all cookies in Mozilla the problem vanished.

But this brings up a bigger problem. Mozilla + Firefox have a significant 
market share -- not one I''m willing to blow off.

If my visitors see a blank screen, with no explanation, nor even a way to 
email me, that''s very bad for business.

We need to figure out whether this "blank screen of death" is caused
by
aberant application programming, in which case we must identify the 
circumstances that cause it, or a defect in Rails, in which case that needs 
to be fixed.

Thanks

SteveT
 
Steve Litt
Author: 
   * Universal Troubleshooting Process courseware
   * Troubleshooting Techniques of the Successful Technologist
   * Rapid Learning: Secret Weapon of the Successful Technologist
Webmaster
   * Troubleshooters.Com
   * http://www.troubleshooters.com

(Legal Disclaimer) Follow these suggestions at your own risk.

Steve Litt wrote:
> On Friday 06 January 2006 10:11 pm, Edward OG wrote:
> 
>>Joe Van Dyk wrote:
>>
>>>Remove your cookies.  And be sure to clear out the sessions in /tmp.
>>
>>Yep, this fixed it properly for me. Thanks!
> 
> 
> Yes, the minute I removed all cookies in Mozilla the problem vanished.
> 
> But this brings up a bigger problem. Mozilla + Firefox have a significant 
> market share -- not one I''m willing to blow off.
> 
> If my visitors see a blank screen, with no explanation, nor even a way to 
> email me, that''s very bad for business.
> 
> We need to figure out whether this "blank screen of death" is
caused by
> aberant application programming, in which case we must identify the 
> circumstances that cause it, or a defect in Rails, in which case that needs
> to be fixed.
> 
> Thanks
> 
> SteveT
>  
> Steve Litt
> Author: 
>    * Universal Troubleshooting Process courseware
>    * Troubleshooting Techniques of the Successful Technologist
>    * Rapid Learning: Secret Weapon of the Successful Technologist
> Webmaster
>    * Troubleshooters.Com
>    * http://www.troubleshooters.com
> 
> (Legal Disclaimer) Follow these suggestions at your own risk.
Steve, there are some circumstances in which Rails fails without giving 
meaningful diagnostic information - either relating to misconfiguration, 
or, as you have discovered, because of having old session data which is 
incompatible with a new or changed application. The core team is aware 
of the need to improve this wherever possible.

For now, developers have to be aware of the need to clear out stale 
session data. Before long I would expect Rails to be a bit more robust, 
e.g. by logging the error and discarding the old session.

This was nothing to do with your choice of browser.

regards

   Justin

On Jan 7, 2006, at 8:39 AM, Justin Forder wrote:
> Steve Litt wrote:
>
>> On Friday 06 January 2006 10:11 pm, Edward OG wrote:
>>> Joe Van Dyk wrote:
>>>
>>>> Remove your cookies.  And be sure to clear out the sessions in
/
>>>> tmp.
>>>
>>> Yep, this fixed it properly for me. Thanks!
>> Yes, the minute I removed all cookies in Mozilla the problem  
>> vanished.
>> But this brings up a bigger problem. Mozilla + Firefox have a  
>> significant market share -- not one I''m willing to blow off.
>> If my visitors see a blank screen, with no explanation, nor even a  
>> way to email me, that''s very bad for business.
>> We need to figure out whether this "blank screen of death" is
>> caused by aberant application programming, in which case we must  
>> identify the circumstances that cause it, or a defect in Rails, in  
>> which case that needs to be fixed.
>> Thanks
>> SteveT
>>  Steve Litt
>> Author:    * Universal Troubleshooting Process courseware
>>    * Troubleshooting Techniques of the Successful Technologist
>>    * Rapid Learning: Secret Weapon of the Successful Technologist
>> Webmaster
>>    * Troubleshooters.Com
>>    * http://www.troubleshooters.com
>> (Legal Disclaimer) Follow these suggestions at your own risk.
>
> Steve, there are some circumstances in which Rails fails without  
> giving meaningful diagnostic information - either relating to  
> misconfiguration, or, as you have discovered, because of having old  
> session data which is incompatible with a new or changed  
> application. The core team is aware of the need to improve this  
> wherever possible.
>
> For now, developers have to be aware of the need to clear out stale  
> session data. Before long I would expect Rails to be a bit more  
> robust, e.g. by logging the error and discarding the old session.
>
> This was nothing to do with your choice of browser.
Agreed. This happens in Safari as well.
>
> regards
>
>   Justin
>
>
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
----
Bob Hutchison                  -- blogs at <http://www.recursive.ca/ 
hutch/>
Recursive Design Inc.          -- <http://www.recursive.ca/>
Raconteur                      -- <http://www.raconteur.info/>
xampl for Ruby                 -- <http://rubyforge.org/projects/xampl/>

On Saturday 07 January 2006 08:39 am, Justin Forder wrote:
> Steve, there are some circumstances in which Rails fails without giving
> meaningful diagnostic information - either relating to misconfiguration,
> or, as you have discovered, because of having old session data which is
> incompatible with a new or changed application. The core team is aware
> of the need to improve this wherever possible.
>
> For now, developers have to be aware of the need to clear out stale
> session data.
Thanks Justin!

How would I clear out stale session data? I want to make sure my visitors 
never see the white screen of death. Also, clearing old session data sounds 
like a good security move.

Thanks

SteveT

Steve Litt
Author: 
   * Universal Troubleshooting Process courseware
   * Troubleshooting Techniques of the Successful Technologist
   * Rapid Learning: Secret Weapon of the Successful Technologist
Webmaster
   * Troubleshooters.Com
   * http://www.troubleshooters.com

On 1/7/06, Steve Litt <slitt@troubleshooters.com>
wrote:
> On Saturday 07 January 2006 08:39 am, Justin Forder wrote:
>
> > Steve, there are some circumstances in which Rails fails without
giving
> > meaningful diagnostic information - either relating to
misconfiguration,
> > or, as you have discovered, because of having old session data which
is
> > incompatible with a new or changed application. The core team is aware
> > of the need to improve this wherever possible.
> >
> > For now, developers have to be aware of the need to clear out stale
> > session data.
>
> Thanks Justin!
>
> How would I clear out stale session data? I want to make sure my visitors
> never see the white screen of death. Also, clearing old session data sounds
> like a good security move.
Remove the ruby session files in /tmp.

This is only a problem (I believe) when you''re doing active
development on the site.  Everytime that you change classes that are
in the session (i.e. the User class), you should remove the old
sessions before deploying the site.

Joe

On 07/01/06, Steve Litt <slitt@troubleshooters.com> wrote:
> How would I clear out stale session data? I want to make sure my visitors
> never see the white screen of death. Also, clearing old session data sounds
> like a good security move.
it depends where you keep them. If it''s in the filesystem (by default)
just write
a cron job to delete session files older than N days.

--
Rasputin :: Jack of All Trades - Master of Nuns
http://number9.hellooperator.net/

Steve Litt wrote:
> On Saturday 07 January 2006 08:39 am, Justin Forder wrote:
> 
> 
>>Steve, there are some circumstances in which Rails fails without giving
>>meaningful diagnostic information - either relating to misconfiguration,
>>or, as you have discovered, because of having old session data which is
>>incompatible with a new or changed application. The core team is aware
>>of the need to improve this wherever possible.
>>
>>For now, developers have to be aware of the need to clear out stale
>>session data.
> 
> 
> Thanks Justin!
> 
> How would I clear out stale session data? I want to make sure my visitors 
> never see the white screen of death. Also, clearing old session data sounds
> like a good security move.
As Joe van Dyk pointed out, things will only break if you change the 
application, making it incompatible with existing session data. But you 
shouldn''t allow session data to accumulate indefinitely - see the bit 
about "Clearing out Sessions" in Agile Web Development with Rails (in 
section 22.4).

regards

   Justin

On Sunday 08 January 2006 03:31 am, Justin Forder wrote:
> As Joe van Dyk pointed out, things will only break if you change the
> application, making it incompatible with existing session data. But you
> shouldn''t allow session data to accumulate indefinitely - see the
bit
> about "Clearing out Sessions" in Agile Web Development with Rails
(in
> section 22.4).
>
> regards
>
>    Justin
Thanks Justin!

You were absolutely right, as was the book.

Everyone: If you''re following this thread or reading "Agile Web
Development
With Rails", be aware that session data MIGHT NOT be kept in the /tmp 
directory.

I''ve built my applications at /home/slitt/tcrails/appname, and my
session data
is contained in /home/slitt/tmp, so be aware. I guess my app is running as 
user slitt or something like that.

For my own personal understanding, I''d like to be able to manipulate
the
session file with a text editor, but so far, every time I''ve tried
it''s
produced the "dreaded blank screen", necessitating deletion of the
file. Does
anyone know the binary structure of these files? I clearly see my f1 and f2 
keys in there, but cannot find a way to manipulate their values.

Anyone have an idea for a good binary editor to use on these things? Once 
again, I''m doing this for the sake of understanding -- I''m not
a mad
scientist about to include self-modifying code in his Rails app :-)

Thanks

SteveT