Leitrim and Cavan county borders were broken in Open Street Map for about 2 days just now, and it caused the townlands to break. I've updated the code to break when this happens (it means those counties aren't in the DB now), but the border has been fixed. Those counties should appear tomorrow.
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Oops. Turns out I had a bug in my "detect if this user is a bot" part, where my site would have an internal error if a bot when to it (and I'd get an error email from django obviously). I've fixed that now (hopefully).
And I wondered why there was like 1 or 2 pages coming up in the google search results for this site.... :P
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Django allows you to have management commands which allow you to have chucks of code which can be executed from the command line.
pip et al. are great ways to install software, and can be used to distribute your django app (e.g. Bare minimum setup.py for a django app)
If you have a management command, you will need to ensure that your packages line includes APPNAME.management and APPNAME.management.commands.
e.g. it should look something like this:
…
packages=['APPNAME', 'APPNAME.management', 'APPNAME.management.commands'],
…
Remember to include both the ….management and ….management.commands.
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Django comes with a handy template tag to turn any string into a nice 'slug', which you can use in URLs. If you ever need to use this in python, you can do this:
from django.template.defaultfilters import slugify
and then call the slugify function, e.g. slugify('My string here')
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You can migrate a django south app to a specific version with this command: python manage.py migrate $APPNAME $NUMBER, i.e. to migrate it to the one that starts with 0002_…, enter this command: python manage.py migrate $APPNAME 0002.
You can undo all the migrations by giving using zero, i.e. python manage.py migrate $APPNAME zero. I initially tried 0000, but that doesn't work. This will 'remove' all the migrations done for an app. (The migrations will still be there as files, but the models won't be there)
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When you have a ManyToMany field in Django and use the Django Admin, it by default uses a <select> widget. It's easy to change this to be a list of checkboxes (i.e. <input type=checkbox>).
Checkboxes, in the default Django Admin style/CSS are easier to read than a multiple select box.
If you have a Post object, with a tags ManyToMany field, then this code in your admin.py will turn the tags field into checkboxes.
class PostAdminForm(forms.ModelForm):
class Meta:
widgets = {
'tags': forms.CheckboxSelectMultiple
}
class PostAdmin(admin.ModelAdmin):
form = PostAdminForm
admin.site.register(Post, PostAdmin)
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Similar to my Bare minimum setup.py for a django app, here's how to do a setup.py for a python project that consists of a single module file.
Sometimes you only want to distribute a single python file as a module. It might just be a few simple functions, and rather than have a whole directory, it's much easier to have a single python file that can be imported and used.
Assuming your python file is called name_of_file.py, then make a file setup.py with this content in the same directory as name_of_file.py:
#! /usr/bin/env python
from setuptools import setup, find_packages
setup(name="name_of_package",
version="0.0.1",
author="Your Name",
author_email="you@example.org",
py_modules=['name_of_file'],
)
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If you have a png file with a transparent background, you can easily replace it with a white background using this command:
mogrify -flatten -background white FILENAME
(replace FILENAME with the name of the file).
It will work on the file itself, overwriting the old file.
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If you're using git to manage you files, and you have some changes to some files, and you want to throw away the changes (i.e. revert to the previous checked in version), then you can do it with this:
git checkout path/to/myfile.ext
(replace the path/to/my/file.ext with the path/filename of the file you want to 'revert')
This is the git equivalent of svn's svn revert path/to/myfile.ext
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I was doing some work on a git project, on the master branch, and made 2 commits. Then I thought I should really do this on a separate branch, instead of master. But I've already committed twice to master!
Luckily git is great.
Firstly, you want to move to your feature branch, so do git checkout -b name-of-new-branch, tis'll create a new branch with the 2 new commits.
Then switch to master with git checkout master, and look at the logs, with git log. You'll see your 2 new commits that you want to 'get rid of'. Look for the commit just before the 2 commits, and look at the commit: … line. Copy & paste the part after the :, it'll look something like: 09c171332d969c55bceb80db58c70a710be994e3.
This is the id of a commit, (and tree of files), and it can act like a branch. You can checkout that 'branch' with git checkout 09c171332d969c55bceb80db58c70a710be994e3, which will give you a few lines message about how it's a "detached HEAD". Once it's checked out, give this a name, with git checkout -b master2. We are calling this new branch, master2. It's got everything in master, but without the 2 commits which want to have on the feature branch. Then just delete the old master branch (git branch -d master), and rename master2 to master (git branch -m master2 master).
master will now have everything but without the last 2 commits, and name-of-new-branch will have master and the 2 commits, so you can continue work there.
Obviously things get a bit more complicated if you've pushed master somewhere or if you have a lot of local changes. Best to not do it in that case.
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I had a weird bug.
This site is a Django web application and I use Apache and mod_wsgi to serve it up in a standard django deployment setup. I wanted to use scipy, so I pip install'ed it, and then… nothing!
My Django application appeared to just freeze. When I open a webpage, it just hangs. There is no noticable high load or CPU or memory usage on my server. There is no apache access log or error log messages. Other static apache websites I have hosted on the same machine, with the same apache instance, work fine. It's just the Django… hanging.
This is a weird problem, and is caused by scipy being a python library that's written in C, and there's some complication with the python GIL and mos_wsgi, which means it'll hang.
Luckily, there's a simple fix. You have to add this line to your Apache configuration file.
WSGIApplicationGroup %{GLOBAL}
And then it all works fine.
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Inspired by a sparks, a bash sparkline programme, I've created something exactly the same, but in python
It's on PyPI, so just install it with
pip install ascii_sparks
The code is also on github, feel free to contribute.
>>> import ascii_sparks
>>> print ascii_sparks.sparks([0, 0, 1, 2, 1, 10])
????
Yes I know it's technically not ASCII, since it uses Unicode characters. However I'm using 'ascii' to refer to the style of textual drawing.
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distutils & pip is a great way to install python (incl. Django) packages. Django has lots of installable apps. This is the barebones setup.py that you need for your django app:
Let's pretend you have an app called appname. (i.e. you started it with django-admin.py startapp appname). In the same directory as your appname folder, create a file setup.py and put this in:
#! /usr/bin/env python
from distutils.core import setup
setup(name="django-appname",
version="0.0.1",
author="Rory McCann",
author_email="rory@technomancy.org",
packages=['appname'],
)
Then you'll be able to install your django app with pip install /path/to/where/you/created/the/app
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I use django flatpages for most of the current content on celtic knot creator, and it's great. But I want to include some django template tags in the flatpages, but they don't show up.
The solution is to use django-qwert ( source code ) and then evalulate the template.
pip install django-qwert
Then add 'qwert' to your INSTALLED_APPS setting
You have to have a template for your flatpages to use, follow the instructions, except, replace your instance of `{{ flatpage.content }} with:
{% load evaluate_tag %}
{% evaluate flatpage.content %}
That's all! Then you can use template expressions (e.g. {% … %}) from within your flatpages.
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Installing Django with pip is quite easy, but I wanted to install Django from SVN to get the latest and greatest (and because they fixed a bug. This is how you do it:
pip install svn+http://code.djangoproject.com/svn/django/trunk/
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If you want to resize a window on the Ubuntu command line you can use the cool tool wmctrl, and it works with the new Unity Desktop from Ubuntu. You can install wmctrl with sudo aptitude install wmctrl or click on this link
List all the windows currently open with this command: wmctrl -l, you'll get some output like this:
0x02600004 -1 lugus Desktop
0x01800002 -1 lugus unity-2d-panel
0x01600026 -1 lugus unity-2d-launcher
0x04a00006 0 lugus Terminal
0x0361a16b 0 lugus New Tab - Chromium
You can see my hostname (lugus) and the titles of the windows.
To resize a window: wmctrl -r Chromium -e 0,-1,-1,480,800, that will resize any window that has `Chromium`` in the title to be 480 by 800 pixels.
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I use a HTC Desire as my primary smart phone, and want to make sure this website & Django admin works well on my phone, so I need to test it.
So for the record, the HTC Desire is 480 pixels wide, and 800 pixels tall, i.e. 480×800
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As should be obvious, Celtic Knot Creator is back. I intent to blog a lot about the progress of this project/business.
About a year ago I made an online celtic knot page, that's not live now, but I'll put it back later. At the moment I'm setting some clip art, which you can find on the home page.
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Here's the first post to test
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