From harrisbw at notes.udayton.edu  Mon Aug  4 19:34:58 2008
From: harrisbw at notes.udayton.edu (Bryan Harris)
Date: Mon, 4 Aug 2008 13:34:58 -0400
Subject: [CentralOH] Python threads
Message-ID: <16d1d1250808041034t350c995fv3d66dcff3cac4130@mail.gmail.com>

Hi all,
Does anybody have any experience with threads in Python.  I wanted to
play with threads in python so I pulled down this code which looked
like a good starting place.  (First or second page of Google.)

It is obviously supposed to spawn 20 threads that then sleep for a
random time.  The proof would be that they report back out of order.
What really happens is that the threads report back in order with
random waits in between.  Obviously sleep isn't releasing the current
thread.

Is there some way to tell if you have threading support in the
interpreter you're running?  I read the "threading" module will import
dummy_threads if you don't have threading support.  How can you tell?

import threading
import time
import random

theVar = 1

class MyThread ( threading.Thread ):

   def run ( self ):

      global theVar
      time.sleep(random.random()*10)
      print 'This is thread ' + str ( theVar ) + ' speaking.'
      print 'Hello and good bye.'
      theVar = theVar + 1

for x in xrange ( 20 ):
    MyThread().start()

-- 
Bryan Harris
Research Engineer
Structures and Materials Evaluation Group
harrisbw at notes.udayton.edu
http://www.udri.udayton.edu/
(937) 229-5561

From steven_h at acm.org  Mon Aug  4 20:23:33 2008
From: steven_h at acm.org (Steven Huwig)
Date: Mon, 4 Aug 2008 14:23:33 -0400
Subject: [CentralOH] Python threads
In-Reply-To: <16d1d1250808041034t350c995fv3d66dcff3cac4130@mail.gmail.com>
References: <16d1d1250808041034t350c995fv3d66dcff3cac4130@mail.gmail.com>
Message-ID: <7505f2a60808041123l38e9aeetc4506f3ef9e46137@mail.gmail.com>

Your global counter is the problem. You should give the thread its own
number before you start the thread.

import threading
import time
import random

class MyThread ( threading.Thread ):
  def __init__(self, num):
      threading.Thread.__init__(self)
      self.num = num

  def run ( self ):
     time.sleep(random.random()*10)
     print 'This is thread ' + str ( self.num ) + ' speaking.'
     print 'Hello and good bye.'

for x in xrange ( 20 ):
   MyThread(x).start()

From nludban at osc.edu  Mon Aug  4 20:08:13 2008
From: nludban at osc.edu (Neil Ludban)
Date: Mon, 4 Aug 2008 14:08:13 -0400
Subject: [CentralOH] Python threads
In-Reply-To: <16d1d1250808041034t350c995fv3d66dcff3cac4130@mail.gmail.com>
References: <16d1d1250808041034t350c995fv3d66dcff3cac4130@mail.gmail.com>
Message-ID: <20080804140813.c4f02a83.nludban@osc.edu>

On Mon, 4 Aug 2008 13:34:58 -0400
"Bryan Harris" <harrisbw at notes.udayton.edu> wrote:
> It is obviously supposed to spawn 20 threads that then sleep for a
> random time.  The proof would be that they report back out of order.
> What really happens is that the threads report back in order with
> random waits in between.  Obviously sleep isn't releasing the current
> thread.

Threading is probably working fine, the example is obviously broken.
Improved, but not perfect:

>    def run ( self ):
> 
>       global theVar
	myVar = theVar
	theVar = theVar + 1
>       time.sleep(random.random()*10)
>       ###print 'This is thread ' + str ( theVar ) + ' speaking.'
        print 'This is thread ' + str ( myVar ) + ' speaking.'
>       print 'Hello and good bye.'
>       ###theVar = theVar + 1


From harrisbw at notes.udayton.edu  Mon Aug  4 20:51:41 2008
From: harrisbw at notes.udayton.edu (Bryan)
Date: Mon, 04 Aug 2008 14:51:41 -0400
Subject: [CentralOH] Python threads
In-Reply-To: <7505f2a60808041123l38e9aeetc4506f3ef9e46137@mail.gmail.com>
References: <16d1d1250808041034t350c995fv3d66dcff3cac4130@mail.gmail.com>
	<7505f2a60808041123l38e9aeetc4506f3ef9e46137@mail.gmail.com>
Message-ID: <1217875901.1433.18.camel@bryan-udri.udri.udayton.edu>

Yep Thanks!  It wasn't somehow blocking somewhere as I had
suspected.  :-p  It was doing what I told it to do....

This works as well without the init:


import threading
import time
import random

theVar = 1

class MyThread ( threading.Thread ):
      
   def run ( self ):
      global theVar
      myNumber = theVar
      theVar = theVar + 1
      time.sleep(random.random()*10)
      print 'This is thread ' + str ( myNumber ) + ' speaking.\nHello
and good bye.'      

for x in xrange ( 200 ):
    MyThread().start()



On Mon, 2008-08-04 at 14:23 -0400, Steven Huwig wrote:
> Your global counter is the problem. You should give the thread its own
> number before you start the thread.
> 
> import threading
> import time
> import random
> 
> class MyThread ( threading.Thread ):
>   def __init__(self, num):
>       threading.Thread.__init__(self)
>       self.num = num
> 
>   def run ( self ):
>      time.sleep(random.random()*10)
>      print 'This is thread ' + str ( self.num ) + ' speaking.'
>      print 'Hello and good bye.'
> 
> for x in xrange ( 20 ):
>    MyThread(x).start()
-- 
Bryan Harris
Research Engineer
Structures and Materials Evaluation Group
harrisbw at notes.udayton.edu
http://www.udri.udayton.edu/
(937) 229-5561


From harrisbw at notes.udayton.edu  Mon Aug  4 20:46:03 2008
From: harrisbw at notes.udayton.edu (Bryan)
Date: Mon, 04 Aug 2008 14:46:03 -0400
Subject: [CentralOH] Python threads
In-Reply-To: <7505f2a60808041123l38e9aeetc4506f3ef9e46137@mail.gmail.com>
References: <16d1d1250808041034t350c995fv3d66dcff3cac4130@mail.gmail.com>
	<7505f2a60808041123l38e9aeetc4506f3ef9e46137@mail.gmail.com>
Message-ID: <1217875563.1433.14.camel@bryan-udri.udri.udayton.edu>

Thanks!  I never would have figured that one out myself.  It makes sense
now.  

I think the threads _were_ actually running concurrently, they just
weren't being given a number based on their start order.

On Mon, 2008-08-04 at 14:23 -0400, Steven Huwig wrote:
> Your global counter is the problem. You should give the thread its own
> number before you start the thread.
> 
> import threading
> import time
> import random
> 
> class MyThread ( threading.Thread ):
>   def __init__(self, num):
>       threading.Thread.__init__(self)
>       self.num = num
> 
>   def run ( self ):
>      time.sleep(random.random()*10)
>      print 'This is thread ' + str ( self.num ) + ' speaking.'
>      print 'Hello and good bye.'
> 
> for x in xrange ( 20 ):
>    MyThread(x).start()
-- 
Bryan Harris
Research Engineer
Structures and Materials Evaluation Group
harrisbw at notes.udayton.edu
http://www.udri.udayton.edu/
(937) 229-5561


From catherine.devlin at gmail.com  Tue Aug  5 20:32:52 2008
From: catherine.devlin at gmail.com (Catherine Devlin)
Date: Tue, 5 Aug 2008 14:32:52 -0400
Subject: [CentralOH] Ohio LinuxFest
Message-ID: <6523e39a0808051132x66a51b10n4e6d52a93029511c@mail.gmail.com>

Hey everybody,

Remember, talk submissions for Ohio Linuxfest are due August 15.  Got
something to delight the FOSS crowd (and maybe expose them to some
Python, too)?  Submit it!

http://ohiolinux.org/

The Fest is Oct. 10-11 in Columbus.

I'm trying to think of a talk I could submit myself... I'd take suggestions!

Also, here's an idea I'm scheming on - not as a formal talk:

Would folks be interested in a table at Ohio LinuxFest to publicize
Python and PyOhio?

Here's what I'm imagining:

- Table
- Friendly volunteer to chat about python or whatnot
- Laptop with big screen, running demos of nifty Python tricks (I can
supply this)
- PyOhio flyers
- Info sheets to hand out: What is Python, Getting Started with Python, ...
- Highly affordable swag:
   "Python" stickers (like the ones from PyCon)*
   Uh... PyOhio postcards?

Then, to capitalize on it all, we offer an intro Python workshop late
in the day.

Other ideas?

More importantly, volunteers to staff the booth?  We should have
multiple volunteers, so no one person has to give up too much
LinuxFest.  Of course, staffing the booth should be worthwhile in
itself.

-- 
- Catherine
http://catherinedevlin.blogspot.com/
*** PyOhio 2008 * Columbus * July 26, 2008 * pyohio.org ***

From mark at microenh.com  Wed Aug  6 04:51:33 2008
From: mark at microenh.com (Mark Erbaugh)
Date: Tue, 05 Aug 2008 22:51:33 -0400
Subject: [CentralOH] Python vs. Apache
Message-ID: <1217991094.23565.6.camel@P1900>

I want to do some server side programming in Python for my Apache
server.  From what I've seen there are a bunch of different ways to do
it.

CGI
mod_python
mod_wsgi / fastcgi or fcgi / wsgiref
wsgiref
???

Is there a 'preferred' method?  Is there a document that compares
various approaches?

I understand the limitations of pure CGI as Python has to be started for
every request.

At this point, I'm looking to do the programming in Python so I'm not
considering a Python-based web framework.

Mark



From jglands at att.net  Wed Aug  6 05:19:16 2008
From: jglands at att.net (Jesse Lands)
Date: Tue, 5 Aug 2008 20:19:16 -0700 (PDT)
Subject: [CentralOH] Python vs. Apache
In-Reply-To: <1217991094.23565.6.camel@P1900>
Message-ID: <293817.77933.qm@web80014.mail.sp1.yahoo.com>

My personal preference is mod_python.

Not sure about comparison or docs, but here is a post from the mod_python list.

http://www.modpython.org/pipermail/mod_python/2006-December/022841.html

Jesse



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From gacsinger at gmail.com  Wed Aug  6 13:54:45 2008
From: gacsinger at gmail.com (Greg Singer)
Date: Wed, 6 Aug 2008 07:54:45 -0400
Subject: [CentralOH] Python vs. Apache
In-Reply-To: <1217991094.23565.6.camel@P1900>
References: <1217991094.23565.6.camel@P1900>
Message-ID: <b032e3360808060454n7c55e5d3n72d61d7bca171b6d@mail.gmail.com>

If you're just experimenting or if server load isn't a big deal then
basic CGI is by far the easiest method to start with. Plus, it's easy
to migrate over to mod_python or one of the other methods in the
future if performance becomes an issue.

 - Greg

On Tue, Aug 5, 2008 at 10:51 PM, Mark Erbaugh <mark at microenh.com> wrote:
> I want to do some server side programming in Python for my Apache
> server.  From what I've seen there are a bunch of different ways to do
> it.
>
> CGI
> mod_python
> mod_wsgi / fastcgi or fcgi / wsgiref
> wsgiref
> ???
>
> Is there a 'preferred' method?  Is there a document that compares
> various approaches?

From wam at cisco.com  Wed Aug  6 17:49:03 2008
From: wam at cisco.com (William McVey)
Date: Wed, 06 Aug 2008 11:49:03 -0400
Subject: [CentralOH] Python vs. Apache
In-Reply-To: <1217991094.23565.6.camel@P1900>
References: <1217991094.23565.6.camel@P1900>
Message-ID: <1218037744.6311.35.camel@tardis>

On Tue, 2008-08-05 at 22:51 -0400, Mark Erbaugh wrote:
> I want to do some server side programming in Python for my Apache
> server.  From what I've seen there are a bunch of different ways to do
> it.
> 
> CGI
> mod_python
> mod_wsgi / fastcgi or fcgi / wsgiref
> wsgiref

Don't forget the option of building on top of BaseHTTPServer (or
SimpleHTTPServer) as well as the option of using the twisted web server.
All this can be seamlessly integrated into an Apache based website with
a mod-rewrite rule that reverse proxies requests to the python-based
service running on another port.

> Is there a 'preferred' method?  

Yes, there are many preferred methods. The problem is that set of
preferred methods vary depending on the developer you ask and even in
some cases the project that developer is working on.

> Is there a document that compares
> various approaches?

It's not really comparing, but it's worth reviewing:
http://wiki.python.org/moin/WebProgramming and
http://wiki.python.org/moin/WebFrameworks

> I understand the limitations of pure CGI as Python has to be started for
> every request.

Not quite always the case. If your CGI scripts are written in python,
you can use mod_python.cgihandler to execute those scripts without
forking additional copies of python (with some caveats related to thread
management). I'm certainly not advocating this approach, but it is
important to know where the true limits are.

> At this point, I'm looking to do the programming in Python so I'm not
> considering a Python-based web framework.

Programming an application using a full stack web framework such as
Django or TurboGears *is* programming in python, so implying that you
are not considering these frameworks because you want to program in
python doesn't make sense to me. If anything, web apps coded using these
frameworks generally have a higher percentage of python code than other
approaches since you generally don't have to have embedded SQL or HTML
in your application. 

More importantly though is that a "framework" is just a set of generally
useful functionality that has been provided to you so that you don't
have to implement that functionality in your own code. Packages like
mod_wsgi, wsgiref, mod_python and even cgi.py are all web development
frameworks. They may not be full-stack frameworks that provide all the
functionality of something like Django or Turbogears, but they're
providing the application writer an easier to use or more powerful
interface for building their app than if that framework didn't exist.
It's also important to realize that even with the full stack frameworks,
most of the provided functionality is optional. For example, if you
don't need middleware, you don't need to enable it. If you don't want
object to relational database mapping, you don't have to use it.

  -- William


From pythondevdang at lazytwinacres.net  Sat Aug  9 15:11:04 2008
From: pythondevdang at lazytwinacres.net (Daniel 'Dang' Griffith)
Date: Sat, 09 Aug 2008 09:11:04 -0400
Subject: [CentralOH] Mathematics and Database Design
In-Reply-To: <mailman.7.1218016801.18463.centraloh@python.org>
References: <mailman.7.1218016801.18463.centraloh@python.org>
Message-ID: <6.2.3.4.2.20080809090721.02294698@mail.lazytwinacres.net>

There was a guy at PyOhio, "Nugent", who I spoke with briefly about a
book on the mathematics of [relational] database design.  I'm wondering
if he's on this list, and if so, would he please let me know the book title,
ISBN, author, etc.

Or, if anyone else out there has heard of such a book. I'm looking for
some rigorous backing to explain/justify some of my data model design
decisions. Or refute them, of course, if I've been doing it wrong (ahem).

Thanks,
     --dang


From wam at cisco.com  Mon Aug 11 16:39:44 2008
From: wam at cisco.com (William McVey)
Date: Mon, 11 Aug 2008 10:39:44 -0400
Subject: [CentralOH] Mathematics and Database Design
In-Reply-To: <6.2.3.4.2.20080809090721.02294698@mail.lazytwinacres.net>
References: <mailman.7.1218016801.18463.centraloh@python.org>
	<6.2.3.4.2.20080809090721.02294698@mail.lazytwinacres.net>
Message-ID: <1218465584.6277.3.camel@tardis>

On Sat, 2008-08-09 at 09:11 -0400, Daniel 'Dang' Griffith wrote:
> There was a guy at PyOhio, "Nugent", who I spoke with briefly about a
> book on the mathematics of [relational] database design.  I'm wondering
> if he's on this list, and if so, would he please let me know the book title,
> ISBN, author, etc.
> 
> Or, if anyone else out there has heard of such a book. I'm looking for
> some rigorous backing to explain/justify some of my data model design
> decisions. Or refute them, of course, if I've been doing it wrong (ahem).

I'm not exactly sure which book "Nugent" might have been referring to,
but here are some possible contenders:

Applied Mathematics for Database Professionals
http://www.apress.com/book/view/1590597451

Database in Depth:  Relational Theory for Practitioners
http://oreilly.com/catalog/9780596100124/index.html

  -- William


From mark at microenh.com  Mon Aug 11 19:02:33 2008
From: mark at microenh.com (Mark Erbaugh)
Date: Mon, 11 Aug 2008 13:02:33 -0400
Subject: [CentralOH] XML
Message-ID: <1218474153.22141.3.camel@P1900>

I'm parsing some XML generated by JavaScript in a web browser.

When the browser is Internet Explorer (I've only tested v 6), a boolean
is returned as "-1" (true) or "0" (false). When the browser is not IE
(I've tested Mozilla, Firefox and Opera), booleans are returned as
"true" or "false".  Is there a standard way to convert these values to
Python bool's or do I just need to do string comparisons?  Do other
browser's return different values?

Thanks,
Mark


From mark at microenh.com  Mon Aug 11 20:00:38 2008
From: mark at microenh.com (Mark Erbaugh)
Date: Mon, 11 Aug 2008 14:00:38 -0400
Subject: [CentralOH] Web Server Response
Message-ID: <1218477638.25024.6.camel@P1900>

I'm working on a Python web server that allow users to update a database
using a browser.  It's possible that the user could submit a database
update that is disallowed by the database server, i.e. deleting a row
that is a referenced by a foreign key or inserting a duplicate key.

Is there an HTTP status code that can be used for the response?  I could
use 400 (bad request), but is there a better choice?

Thanks,
Mark


From samus at codeargyle.com  Mon Aug 11 19:42:10 2008
From: samus at codeargyle.com (Sam Corder)
Date: Mon, 11 Aug 2008 13:42:10 -0400 (EDT)
Subject: [CentralOH] Web Server Response
In-Reply-To: <1218477638.25024.6.camel@P1900>
Message-ID: <4931682.2401218476530109.JavaMail.root@spring.codeargyle.com>

It really depends.  Most of the time people don't bother with the response code and just output a 200 OK and a message to the browser client saying that you can't do that.  If you're working on this for more of a machine to machine communication style I'd definitely go with one of the 400 level codes.
----- Original Message -----
From: Mark Erbaugh <mark at microenh.com>
To: centraloh at python.org
Sent: Monday, August 11, 2008 2:00:38 PM GMT-0500 Auto-Detected
Subject: [CentralOH] Web Server Response

I'm working on a Python web server that allow users to update a database
using a browser.  It's possible that the user could submit a database
update that is disallowed by the database server, i.e. deleting a row
that is a referenced by a foreign key or inserting a duplicate key.

Is there an HTTP status code that can be used for the response?  I could
use 400 (bad request), but is there a better choice?

Thanks,
Mark

_______________________________________________
CentralOH mailing list
CentralOH at python.org
http://mail.python.org/mailman/listinfo/centraloh


From wam at cisco.com  Mon Aug 11 23:08:57 2008
From: wam at cisco.com (William McVey)
Date: Mon, 11 Aug 2008 17:08:57 -0400
Subject: [CentralOH] Web Server Response
In-Reply-To: <1218477638.25024.6.camel@P1900>
References: <1218477638.25024.6.camel@P1900>
Message-ID: <1218488938.6277.15.camel@tardis>

On Mon, 2008-08-11 at 14:00 -0400, Mark Erbaugh wrote:
> I'm working on a Python web server that allow users to update a database
> using a browser.  It's possible that the user could submit a database
> update that is disallowed by the database server, i.e. deleting a row
> that is a referenced by a foreign key or inserting a duplicate key.
> 
> Is there an HTTP status code that can be used for the response?  I could
> use 400 (bad request), but is there a better choice?

Note that error code 400 is used to convey that the server was unable to
parse or otherwise understand the request. It's not a generic "failure"
because the request was "bad". Some error codes that seem like they
might be appropriate include:

      * 401 Unauthorized
      * 403 Forbidden
      * 405 Method Not Allowed

That last one should probably only be used if your service is truly a
RESTful interface, in that each resource (e.g. a row in the table) has
it's own URI. Presumably this would be in response to a POST or DELETE
method type, and your reply would indicate that only 'GET' is
acceptable.

These error codes are all defined in section 10 of RFC 2616 defining
HTTP/1.1 (viewable at
http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10 ).

  -- William