Eclipse, pydev notes, refresh errors and warnings

To refresh all errors project(s) widely do:
Project (from menu) -> Clean

Very useful when refactoring classes as all files will be parsed.

Python notes, halving list

Splitting list from the middle:

>>> a = [34,412,3,2,4,6,78,9,2]
>>> [a.pop(0) for alk in a]
[34, 412, 3, 2, 4]

... tricky ain't it.

Inkscape slicer

Download Inkscape slice effect a.k.a. 'slicer' 0.1.1 (bugfix)

Usage:

1.) Create layer e.g. named 'slices'.
2.) Create rectangles as your slices, set their Label* (select rect and Object -> Object properties) as the output filename (without extension).
3.) Run Effects -> Export -> Slicer, specify directory where you want your slices to be saved and Apply.

What program does:

1.) It takes all rectangles you give, puts opacity 0, stroke to none.
2.) And tries to save contents inside rectangles to new files.
3.) Returns the style to original value.

Installation:

Copy these two files (slicer.py, slicer.inx) to share/extensions directory inside inkscape, do not create directory for these files.

Extensions dir in common platforms:
Ubuntu 8.10 user scope: ~/.inkscape/extensions/
Ubuntu 8.10 global scope: /usr/share/inkscape/extensions/
Windows: c:\Program Files\Inkscape\share\extensions\

Thanks

Original idea from Matt Harrison:
WARNING, Matt's version didn't work with latest Ubuntu (8.10) and Inkscape 0.46, major API differences, that was the reason I rewrote whole script with features I needed. I have no intention to ripoff Matt's effort, so I fully thank Matt for his work, and if you somehow feel that I have broken the license in Matt's file you can contact me through comments in this blog.

* Label allows all characters, where as ID allows only few. I need ability to use spaces in filenames so ID is no go. One can switch it to back to ID by changing line in slicer.py:
basename = rect_label.lstrip("#")
to
basename = rect_id

Django and Eclipse

(When I have interest, I have planned to convert this to HTML, for now, let it be Plain text)
Anyone is welcome to edit, repost and/or distribute the following instructions, I just have a little wish: Provide link for this post.

Used: Eclipse Classic Ganymede (3.4.1), Django 1.0.2, PyDev

Install Pydev
=============
... TODO ...

Python interpreters (Eclipse preferences -> Pydev -> Interpreter - Python)
--------------------------------------------------------------------------
Press `New`
 Type (Ubuntu) `/usr/bin/python`
 Type (Windows) `C:\Python25\python.exe` *** Warning: not tested!
 Press `Ok`
  *IMPORTANT!*
  If you have installed Django to site-packages
   *UNCHECK* I repeat *UN*CHECK the Django from the Pythonpath list
   (Or remove from the list)
  (We are *NOT* going to use the site-packages django to this for development purposes)

Django project for Eclipse
==========================

File -> New -> Pydev project
 Project name: `Django`
 Grammar version: `2.5`
 Uncheck `Create default `src` folder and add it to the pythonpath?`
  Error about interpreter?: `Click here to configure an interpreter not listed` see above Install Pydev section


Pydev Package Explorer (the "file tree" on the left) -> Django (right click) -> Properties
 PyDev - PYTHONPATH
  Add source folder -> Choose `Django` (the project's "root" directory, for why, see (*1))

(Ubuntu) in terminal (go to your eclipse workspace directory):
 cd Django/
 svn co http://code.djangoproject.com/svn/django/tags/releases/1.0.2/ .

(Windows) Extract the django release to the Django/ dir:
 (after extraction you should have directories like `Django/django`, `Django/examples`, `Django/docs` ...)

Pydev Package Explorer (the "file tree" on the left) -> Django (right click) -> Refresh (now zip some coffee, this might take while)

All is set for Django project.

(*1) Why root? Because for instance `django` and `examples` directories in django distribution should be in pythonpath and they are in root, this is only reasonable way since we won't relocate them.


My django project:
==================

VERY IMPORTANT! DO THE DAMN `Django project for Eclipse` section FIRST! SINCE YOU WON'T GET THE AUTOCOMPLETE/*PLUGGABLE DJANGO VERSION BETWEEN APPLICATIONS* WITHOUT IT.

File -> New -> Pydev project
 Project name: `Django Poll`
 Grammar version: `2.5`
 *Check* I repeat *Check* (It should be checked by default) the `Create default `src` folder and add it to the pythonpath?`
  Error about interpreter?: This can't be, you set it up on `Django project for Eclipse`
 Click `Next`
  (In reference page)
  Check `Django` (the Django project you created earlier, remember that?)
  Press `Finish`

Django-admin.py from within Eclipse:
------------------------------------

Run -> External tools -> External tools configurations
 Left side tree: Right click `Program` -> New
  Name: `Django-admin (for project src directory)`
  Location (Ubuntu): `/bin/bash`
  Location (Windows): `c:\Windows\system32\cmd.exe`   *** Warning: Not tested
  Working directory: `${project_loc}/src`

 Environment tab:
  New (from right)
   Name: `PATH`
   Value (Ubuntu): `${env_var:PATH}:${workspace_loc:Django/django/bin}`
   Value (Windows): `${env_var:PATH};${workspace_loc:Django/django/bin}`   *** Warning: Not tested
   Click `Ok`
  New (from right)
   Name: `PYTHONPATH`
   Value (Ubuntu): `${project_loc}/src:${workspace_loc:Django/}`
   Value (Windows): `${project_loc}/src;${workspace_loc:Django/}`   *** Warning: Not tested
   Click `Ok`

  Press `Apply` and `Close` (Don't try to Run, it will (most likely) give error)

Run -> External tools -> Organize favorites
 Click `Add`
  Choose `Django-admin (for project src directory)`
  Click `Ok`
 Click `Ok`

Now in order to run this tool one must do *TWO* things:

1.) Pydev Package Explorer (the "file tree" on the left) -> Click on the `Django Poll` project (even if it is selected, just click it (to get focus on it))

2.) Run -> External tools -> `Django-admin (for project src directory)`
 *** If you get error about `Variable references empty selection: ${project_loc}`, you didn't do 1.) well enough, you *MUST* click it first and nothing else afterwards, the *project folder* in *Pydev Package Explorer* must have *focus* (being selected is not enough)!

 Console window (if not visible do Window -> Show view -> Console), type: 
  `django-admin.py`

 If all went well you should get something like: `Type django-admin.py help for usage.`
 
 Following is from official django tutorial http://docs.djangoproject.com/en/dev/intro/tutorial01/#intro-tutorial01

 Console window, type: 
  `django-admin.py startproject mysite`

PyDev Package Explorer (the tree on the left) -> `Django Poll` (right click) -> Refresh
(If all worked well you should now have directory `src/mysite` in your project)

Manage.py from within Eclipse
-----------------------------

PyDev package explorer (tree in the left) -> `Django Poll` (your project name) -> src -> manage.py (right click) -> Properties
 (You should be in dialog called `Properties for manage.py`)
 Click `New...`
  Choose `Python Run`
   (For reason unknown Eclipse doesn't prepopulate the following fields)
   Name: `Django Poll -- Custom manage.py`  (Yes you read it right, I prefixed it with project name for extra verbosity)

   Main tab (default tab):
    Project click `Browse`, choose your project `Django Poll`
    Main module click `Browse`, choose `src -> mysite -> manage.py`, click `Ok` (it should now read ${workspace_loc:Django Poll/src/mysite/manage.py} )

   Arguments tab:
    Press `Variables` (from Program arguments)
     Choose `string_prompt`
     (It should have added this `${string_prompt}`)
     Click `Ok`
   Click `Ok`
 Click `Ok`


Running test:

Locate Run button from toolbar (Green play button, with arrow downwards next to it), press the arrow -> Choose `Organize Favorites`
 Press `Add...`
  Check the `Django Poll: Custom manage.py`

Run button (press the arrow) -> `Django Poll -- Custom manage.py`
 (If all went well, you should be given prompt)
 Type: `help`
  (If all worked well, you should get long list of commands, beginning:

  `Type 'manage.py help <subcommand>' for help on a specific subcommand.`
  ...)


Lets create app:

Run button press the arrow -> `Django Poll -- Custom manage.py`
 Type: `startapp polls`

Now refresh your project directory from Pydev Package explorer (the tree in the left)
(If all worked well you should now have directory `src/mysite/polls` in your project)


Running the development server
------------------------------
Run button (press the arrow) -> `Django Poll -- Custom manage.py`
 Type: `runserver --noreload`

(You can use it without `--noreload`, but the console window is rather useless in that case, since Eclipse can't handle the refresh behaviour of `manage.py`.)


Other Eclipse preferences (optional), though highly recommended
===============================================================

More run configurations
-----------------------
Since you most likely need manage.py's commands `runserver`, `syncdb`, `reset` the most, create own run configurations for those, using similar steps as in "Manage.py from within Eclipse" section.


Tasks of project
----------------

Window -> Show view -> Tasks

Tasks (little `downward triangle` before minimize of tasks window) -> Configure contents
 Right side of the window: check `On any element in same project`
 Left side of the window: check `TODOs`

SFTP umask

Do this pico /opt/sftp-server.sh

#!/bin/bash
# This is a wrapper around the sftp-server subsystem to set umask. Point
# the subsystem in /etc/ssh/sshd_config to this file. (Ubuntu/Debian
# file locations assumed)

umask 0002
exec /usr/lib/openssh/sftp-server

Remember to chmod ugo+x /opt/sftp-server.sh

Then pico /etc/ssh/sshd_config

Replace/edit this part:

# Subsystem sftp /usr/lib/openssh/sftp-server # replaced with below
Subsystem sftp /opt/sftp-server.sh

Finally remember: /etc/init.d/ssh restart

Django 1.0 custom admin two fields shown as one

I needed a way to have two model fields to be shown/edited on one form field. And I came up with the following.

(CurrencyField (expense) shows and edits fields `value` and `currency` in the actual model)

from django.contrib import admin
from budget.models import Expense
from django import forms
from django.forms.util import ValidationError

class CurrencyField(forms.CharField):
   def clean(self, value):
       amount = 0
       currency = ''
       try:
           amount = float(value.split(" ")[0].strip())
       except (ValueError, TypeError), te:
           raise ValidationError('Amount is incorrect!')
      
       try:
           currency = value.split(" ")[1].strip().upper()
           if len(currency) != 3:
               raise TypeError('cur')
       except (ValueError, TypeError), te:
           raise ValidationError('Currency is incorrect! Should be three letter universal sign (e.g. EUR)')
      
       return (amount, currency)

class ExpenseForm(forms.ModelForm):
   expense = CurrencyField()
   def __init__(self, *args, **kwargs):
       super(ExpenseForm, self).__init__(*args, **kwargs)
       self.initial['expense'] = "%s %s" % (self.instance.value or '',
                                            self.instance.currency or '')
  
   def save(self, commit=True):
       self.instance.value, self.instance.currency = self.cleaned_data['expense']
       return super(ExpenseForm, self).save(commit)
  
   class Meta:
       model = Expense

# Note added:
# Expense is like this:
# class Expense(models.Model):
#     ...
#     value = models.FloatField(...)    # This contains the amount of currency, like 120.32
#     currency = models.CharField(...)  # Currency is e.g. 'USD', 'EUR' identifier of currency
#     ...

class ExpenseAdmin(admin.ModelAdmin):
   list_display = ('date', 'time', 'local_currency', 'in_euro', 'description', 'tags')
   ordering = ('date','time')
   form = ExpenseForm
   fields = ('expense', 'date', 'time', 'description', 'tags')
  
admin.site.register(Expense, ExpenseAdmin)

Django 1.0 admin custom inlines

...

class ChangeSetForm(forms.ModelForm):
  dosomething = forms.BooleanField(label="Do something")
  class Meta:
      model = ChangeSet
      exclude = ('modified',) # Note: This doesn't work!
      fields = ('old_title',) # Note: This doesn't work!
    
ChangeSetInlineFormSet = inlineformset_factory(
  Article, ChangeSet,
  form = ChangeSetForm
)

class InlineChangeSet(admin.TabularInline):
  model = ChangeSet
  form = ChangeSetForm
  extra = 0
  raw_id_fields = ('editor',)
  fields = ('old_title', ) # This works.

...

Completely custom inline (without delete checkbox etc)

coming...