Django community: RSS
This page, updated regularly, aggregates Community blog posts from the Django community.
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Django Templating Language - Part IV
OK, for this exercise, assume I have a database table (in SQLite3) that contains student names and roll numbers. Let's look at this in steps.Import everything you need in views.py:import sqlite3from django.template import Template, ContextCreate a data structure that will hold your records:class Student (object): def __init__ (self, name, rno): self.name = name self.rno = rnoDefine your view and in it extract all records of student:def display (request): conn = sqlite3.connect ("/path/to/db/dbname.db") cur = conn.cursor () cur.execute ("select * from student") students = [] # Will store student records for row in cur: students.append (Student (row[0], row[1])) # Append to list 'students' an object of the class 'Student'Now it's time for the ol' Template/Context magic: t = Template ("/path/to/html/file/stud.html") c = Context ({'students':students}) html = t.render (c) return HttpReponse (html)But we're not done yet! We don't have the HTML file in which we define how the data is to be structured:<html> {% for student in students %} Roll … -
CSRF Token
I don't believe I didn't cover this before. Many of you (in fact all of you) must be getting a 'CSRF Token missing' error when you submit data using the POST method. First of all let me tell you what CSRF is.CSRF stands for Cross Site Request Forgery. When data is submitted using the GET method, it just gets encoded in the URL. But when it is submitted using the POST method it is sent directly to the servers. During this transfer if there is some bot snooping on that site, it can intercept the data and send it's own, infected data to the site.Anyway, coming back to Django, the solution to that error lies in Django's Templating Language. I myself am still trying to understand it. In the meantime, I found a temporary fix.NOTE: This is a temporary fix for development websites, and should not be deployed on production websites.Sorry for sneaking that on you like that. But it had to be done. You'll understand once I tell you how to (temporarily) fix it.Open settings.pyLook for a tuple named MIDDLEWARE_CLASSESYou'll see django.middleware.csrf.CsrfViewMiddleware inclulded in it.Comment that line out.Now do you see why this is so dangerous, even though it fixes the error? … -
Django Templating Language - Part III
We're finally here! We've already seen how to extract stuff from databases. Now let's put that to good use. Before we begin, let me explain two concepts here: Template and Context.Template is the front end, the looks of the page. This will mean the HTML (+CSS+jQuery+whatever else) code you write.Context means what you want to put in that page. In the earlier post, we had used the variable {{ name }}. Context will tell Python what value to pass to that variable.First things first. Let's import the necessary stuff.from django.template import Template, Contextfrom django.shortcuts import renderfrom django.http import HttpResponseNow what I do is pass HTML code as string to Template make it render it. While this is a neat method, I'm sure there are others out there that I don't know. So please comment so that I'll be able to learn other (maybe more efficient) ways to render templates.The way to do this would be to use file handling. So, in views.py:def showName (request): f1 = open ("/path/to/file/something.html") code = "" for i in f1.read (): code += iHope you understand what I did there. I opened a file called something.html, and returned everything in that file … -
Django Templating Language - Part II
Now let's look at some in-built tags. These will help you arrange data efficiently on your page. These are a lot like XML. However, the syntax is different and it is easier to manage.If you've noticed, it says Django Templating Language. Thus, as with every other language, this one also has control structures. Let's look at a few.(Note: We're still learning the language, and even at the end of this post the code will print raw data. I swear, we're really close to rendering data from Python. Just hang tight for one more post.)FOR:This simulates a for loop. It is useful when extracting data from a database and rendering on the page, especially when you don't know the number of rows that will be returned. This will simply iterate over the list and render everything.<html>{% for row in rows %} <b><i>{{ row }}</i></b><br>{% endfor %}</html>Let's look at this code step by step. First of all, let's map the for here with that in Python.In Python:for i in lstThus, i is row, the variable that we will use to iterate over the list of rows that the database returns. lst is rows, the list over which we need to iterate. You … -
Django 1.6
Hi all! Today let's explore Django's newest version. This won't be in incredible detail, however. The post would be too long. We'll just see an overview. Even as we speak the developers are working on versions 1.7 and 1.8Let's start at the top. Django 1.3Django 1.6Project directory structureThe structure is the same as we explored earlier. Once you open the project directory, you can see the list of apps, __init__.py, manage.py, settings.py, and urls.py.The structure here is slightly different. Once you open the project directory, there is another folder with the same name as your project. The manage.py is here too. Inside the other directory are all the apps and settings etc. While this provides a certain level of independence and atomicity, I personally am disappointed with this. I liked the older one better, and the new one takes some getting used to.SettingsThe settings file contains all settings imaginable, with the ability to add your own.The default settings file shipped with 1.6 is spartan and contains only those settings that an app absolutely needs to run. Rest all need to be added, e.g. TEMPLATE_DIRS, STATIC_DIRS etc.WSGI (Web Server Gateway Interface)No additional wsgi fileShipped with a default wsgi file (wsgi.py) to … -
Webcast: Creating Enriching Web Applications with Django and Backbone.js
Our technical director, Mark Lavin, will be giving a tutorial on Django and Backbone.js during a free webcast for O’Reilly Media tomorrow, November 6th, 1pm EST. There will be demos and a discussion of common stumbling blocks when building rich client apps. Register today! Here’s a description of his talk: "Django and Backbone are two of the most popular frameworks for web backends and frontends respectively and this webcast will talk about how to use them together effectively. During the session we'll build a simple REST API with Django and connect it to a single page application built with Backbone. This will examine the separation of client and server responsibilities. We'll dive into the differences between client-side and server-side routing and other stumbling blocks that developers encounter when trying to build rich client applications. If you're familiar with Python/Django but unfamiliar with Javascript frameworks, you'll get some useful ideas and examples on how to start integrating the two. If you're a Backbone guru but not comfortable working on the server, you'll learn how the MVC concepts you know from Backbone can translate to building a Django application." Register at O’Reilly Media. -
Webcast: Creating Enriching Web Applications with Django and Backbone.js
Update: The live webcast is now available at O’Reilly Media Our technical director, Mark Lavin, will be giving a tutorial on Django and Backbone.js during a free webcast for O’Reilly Media tomorrow, November 6th, 1pm EST. There will be demos and a discussion of common stumbling blocks when building rich client apps. -
Win Free Copies of “Web Development with Django Cookbook”
Readers would be pleased to know that I have teamed up with Packt Publishing to organize a Giveaway of my book Web Development with Django Cookbook. Three lucky winners stand a chance to win an e-copy of the book. Keep reading to find out how you can be one of the lucky ones. Book OverviewImprove your skills by developing models, forms, views, and templatesCreate a rich user experience using Ajax and other JavaScript techniquesA practical guide to writing and using APIs to import or export data How to Enter?All you need to do is head on over to the book page and look through the product description of the book and drop a line via the comments below this post to let us know what interests you the most about this book. It’s that simple. PrizeWinners will get an e-copy of the Book. DeadlineThe contest will close on the 1st of December, 2014 at 00:00 GMT. Winners will be contacted by email, so be sure to use your real email address when you comment! -
uwsgi and uid
So recently, I moved home for this blog. It used to be on AWS EC2 and is now on Digital Ocean. I wanted to start from scratch so I started on a blank new Ubuntu 14.04 and later rsync'ed over all the data bit by bit (no pun intended). When I moved this site I copied the /etc/uwsgi/apps-enabled/peterbecom.ini file and started it with /etc/init.d/uwsgi start peterbecom. The settings were the same as before: # this is /etc/uwsgi/apps-enabled/peterbecom.ini [uwsgi] virtualenv = /var/lib/django/django-peterbecom/venv pythonpath = /var/lib/django/django-peterbecom user = django master = true processes = 3 env = DJANGO_SETTINGS_MODULE=peterbecom.settings module = django_wsgi2:application But I kept getting this error: Traceback (most recent call last): ... File "/var/lib/django/django-peterbecom/venv/local/lib/python2.7/site-packages/django/db/backends/postgresql_psycopg2/base.py", line 182, in _cursor self.connection = Database.connect(**conn_params) File "/var/lib/django/django-peterbecom/venv/local/lib/python2.7/site-packages/psycopg2/__init__.py", line 164, in connect conn = _connect(dsn, connection_factory=connection_factory, async=async) psycopg2.OperationalError: FATAL: Peer authentication failed for user "django" What the heck! I thought. I was able to connect perfectly fine with the same config on the old server and here on the new server I was able to do this: django@peterbecom:~/django-peterbecom$ source venv/bin/activate (venv)django@peterbecom:~/django-peterbecom$ ./manage.py shell Python 2.7.6 (default, Mar 22 2014, 22:59:56) [GCC 4.8.2] on linux2 Type "help", "copyright", "credits" or "license" for more information. (InteractiveConsole) >>> from … -
uwsgi and uid
So recently, I moved home for this blog. It used to be on AWS EC2 and is now on Digital Ocean. I wanted to start from scratch so I started on a blank new Ubuntu 14.04 and later rsync'ed over all the data bit by bit (no pun intended). When I moved this site I copied the /etc/uwsgi/apps-enabled/peterbecom.ini file and started it with /etc/init.d/uwsgi start peterbecom. The settings were the same as before: # this is /etc/uwsgi/apps-enabled/peterbecom.ini [uwsgi] virtualenv = /var/lib/django/django-peterbecom/venv pythonpath = /var/lib/django/django-peterbecom user = django master = true processes = 3 env = DJANGO_SETTINGS_MODULE=peterbecom.settings module = django_wsgi2:application But I kept getting this error: Traceback (most recent call last): ... File "/var/lib/django/django-peterbecom/venv/local/lib/python2.7/site-packages/django/db/backends/postgresql_psycopg2/base.py", line 182, in _cursor self.connection = Database.connect(**conn_params) File "/var/lib/django/django-peterbecom/venv/local/lib/python2.7/site-packages/psycopg2/__init__.py", line 164, in connect conn = _connect(dsn, connection_factory=connection_factory, async=async) psycopg2.OperationalError: FATAL: Peer authentication failed for user "django" What the heck! I thought. I was able to connect perfectly fine with the same config on the old server and here on the new server I was able to do this: django@peterbecom:~/django-peterbecom$ source venv/bin/activate (venv)django@peterbecom:~/django-peterbecom$ ./manage.py shell Python 2.7.6 (default, Mar 22 2014, 22:59:56) [GCC 4.8.2] on linux2 Type "help", "copyright", "credits" or "license" for more information. (InteractiveConsole) >>> from … -
Django 1.7 et écriture de tests, petites explorations
Je me suis enfin lancé dans l’écriture d’une app django gérant les badges (ou les succès si vous préférez). L’objectif étant de pouvoir réécrire de zéro histoires de rôlistes. L’idée était de tenter de faire une vraie app django, en mode réutilisable, histoire que peut-être des gens puissent trouver intéressant de l’utiliser. Je me suis retrouvé avec deux problèmes concernant mes tests : Souvent on gagne un badge quand on a créé suffisamment de chose (comme des checkin, des billets de blogs ou des contributions diverses). Sauf que je ne voulais pas créer dans mon app des models ne servant à rien, juste pour pouvoir en créer lors de mes tests. Je voulais pouvoir créer des badges se gagnant sur un critère du style ‘être venu un certain nombre de fois sur une URL.’ Donc mettre en place des décorateurs sur des vues. Mais là encore, je ne voulais pas avoir à créer des vues dans mon application rien que pour les tests. Au final, en lisant un peu de doc, j’ai réussi à faire ce que je voulais. Tester un décorateur sans créer des vues inutiles dans son app. Je savais déjà comment forger des requests avec la RequestFactory. … -
Shout-out to eventlog
If you do things with the Django ORM and want an audit trails of all changes you have two options: Insert some cleverness into a pre_save signal that writes down all changes some way. Use eventlog and manually log things in your views. (you have other options too but I'm trying to make a point here) eventlog is almost embarrassingly simple. It's basically just a model with three fields: User An action string A JSON dump field You use it like this: from eventlog.models import log def someview(request): if request.method == 'POST': form = SomeModelForm(request.POST) if form.is_valid(): new_thing = form.save() log(request.user, 'mymodel.create', { 'id': new_thing.id, 'name': new_thing.name, # You can put anything JSON # compatible in here }) return redirect('someotherview') else: form = SomeModelForm() return render(request, 'view.html', {'form': form}) That's all it does. You then have to do something with it. Suppose you have an admin page that only privileged users can see. You can make a simple table/dashboard with these like this: from eventlog.models import Log # Log the model, not log the function def all_events(request): all = Log.objects.all() return render(request, 'all_events.html', {'all': all}) And something like this to to all_events.html: <table> <tr> <th>Who</th><th>When</th><th>What</th><th>Details</th> </tr> {% for event in … -
Shout-out to eventlog
If you do things with the Django ORM and want an audit trails of all changes you have two options: Insert some cleverness into a pre_save signal that writes down all changes some way. Use eventlog and manually log things in your views. (you have other options too but I'm trying to make a point here) eventlog is almost embarrassingly simple. It's basically just a model with three fields: User An action string A JSON dump field You use it like this: from eventlog.models import log def someview(request): if request.method == 'POST': form = SomeModelForm(request.POST) if form.is_valid(): new_thing = form.save() log(request.user, 'mymodel.create', { 'id': new_thing.id, 'name': new_thing.name, # You can put anything JSON # compatible in here }) return redirect('someotherview') else: form = SomeModelForm() return render(request, 'view.html', {'form': form}) That's all it does. You then have to do something with it. Suppose you have an admin page that only privileged users can see. You can make a simple table/dashboard with these like this: from eventlog.models import Log # Log the model, not log the function def all_events(request): all = Log.objects.all() return render(request, 'all_events.html', {'all': all}) And something like this to to all_events.html: <table> <tr> <th>Who</th><th>When</th><th>What</th><th>Details</th> </tr> {% for event in … -
Passing parameters to Django admin action
This post will show how to pass parameters to custom Django admin actions. This post assumes that you have an idea of Django actions. Django provides a default admin action which is 'Delete selected rows'. Changelist page for all the models registered with admin has this action available. This action allows to select multiple rows and delete them in a single POST request. Problem statement We want to allow following Django action from admin. There is a model called Instrument. It has a field price Allow selecting multiple rows for this model and update the value of price for selected rows. Price should not be hardcoded. Admin should be able to enter the price. We should be able to achieve something like: Solution Setup the project first. Setup project Start a Django project inside virtual environment /tmp $ mkvirtualenv custom-actions (custom-actions)/tmp $ django-admin.py startproject actions (custom-actions)/tmp/actions $ python manage.py startapp instruments Writing the model in instruments/models.py class Instrument(models.Model): name = models.CharField(max_length=100) price = models.IntegerField() def __unicode__(self): return self.name Add instruments to INSTALLED_APPS Run syncdb (custom-actions)/tmp/actions $ python manage.py syncdb Register this model with admin in instruments/admin.py from django.contrib import admin from .models import Instrument admin.site.register(Instrument) You should be able to … -
Travis and coveralls for private repo
Before we begin, i recommend you to read this first Continous integration with travis and coveralls.io for Django apps. Here is how .travis.yml example file looks like: language: python python: - 2.7 install: - pip install -r requirements.txt - pip install coveralls script: coverage run manage.py test after_success: coveralls Setting up coveralls for private repositories requires you to add just one more file .coveralls.yml. 1) Create a .coveralls.yml and make sure it resides in your project's root directory. 2) Add the following to this file: service_name: travis-pro repo_token: **** service_name is to specify where Coveralls should look to find additional information about your builds. You can get the repo_token from your repository's page on Coveralls, if you have the admin privileges. This is to tell which project on Coveralls your project maps to. Make sure your repo_token remains secret and do not add this to your public repository. 3) Add the file, commit it and make a git push. 4) If everything is OK you should see some thing like the below in your travis build: Submitting coverage to coveralls.io... Coverage submitted! Job #22.1 https://coveralls.io/jobs/54864565 Thats it now get a coverage badge from coveralls and add this badge in your … -
Ubuntu PPA madness
I'm going flipping insane. In ye olde days, when I was programming with the python CMS Plone, my dependencies were limited to python and PIL. Perhaps lxml. LXML was a pain to install sometimes, but there were ways around it. Working on OSX was no problem. Server setup? Ubuntu. The only thing you really had to watch in those days was your python version. Does this old site still depends on python 2.4 or is it fine to use 2.6? Plone had its own Zope database, so you didn't even need database bindings. Now I'm working on Django sites. No problem with Django, btw! But... the sites we build with it are pretty elaborate geographical websites with lots of dependencies. Mapnik, matplotlib, numpy, scipy, gdal, spatialite, postgis. And that's not the full list. So developing on OSX is no fun anymore, using a virtual machine (virtualbox or vmware) is a necessity. So: Ubuntu. But... ubuntu 12.04, which we still use on most of the servers, has too-old versions of several of those packages. We need a newer gdal, for instance. And a newer spatialite. The common solution is to use a PPA for that, like ubuntugis-stable. Now for some random … -
Using Arrow for Better Datetime
Learn how to be better at dealing with dates and times in python in a few short minutes. Working with dates and times in python is a lot easier than other languages, but can be convoluted and confusing. Arrow provides a convenient api for working with and manipulating dates and times. See what it takes to get started.Watch Now... -
Contributing Back to the Community - Django Cookbook
In the early beginning of year 2014, the IT book publishing company "Packt Publishing" contacted me with an interesting offer: to share my Django experience in a form of a book. I thought it might be a good challenge for me and also value for the Django community, as I had been working with Django for 7 years or so, and during that time there was quite a lot of knowledge gathered and used practically. So for the next 9 months on late evenings and weekends I was adapting some of the most useful code snippets and describing them in the book. The great staff from the Packt Publishing helped me to structure the content, make everything clear and understandable, and get the grammar correct. Finally, the book was released and it's called "Web Development with Django Cookbook". This book is written for intermediate or advanced Django web developers. When writing the book, my own purpose was not to fully cover every possible web development task, but rather to have enough useful bits of knowledge for those who seek information about web development with Django. The book was written in the format of recipes. There are over 70 recipes giving … -
Useful Shell Aliases For Python (and Django) Developers!
We use almost all same commands everyday. There are a handful of aliases for git & docker written by a few. But it seems no one has mentioned any aliases for python. I just made a handful of aliases so that I can type little bit less in terminal. Here are a few of them.alias py='python'alias ipy='ipython'alias py3='python3'alias ipy3='ipython3'alias wo='workon'alias pf='pip freeze | sort'alias pi='pip install'alias pun='pip uninstall'alias dj="python manage.py"alias drs="python manage.py runserver"alias dsh="python manage.py shell"alias dsm="python manage.py schemamigration"alias dmm="python manage.py makemigration"alias dm="python manage.py migrate"alias ddd="python manage.py dumpdata"alias dld="python manage.py loaddata"alias dt="python manage.py test"# Show all alias related pythonpya() { alias | grep 'python\|workon\|pip' | \ sed "s/^\([^=]*\)=\(.*\)/\1 => \2/"| sed "s/['|\']//g";}These are a few repeatedly used commands. It takes time even to get used to aliases. So I added pya function at the end. In case if you don't remember aliases or if you want to checkout what aliases related to python are present in your dot file, you can use it.Just add the above aliases to your .bashrc or .zshrc or whatever shell you are using and source it. That's it. Hpy alsng! -
Ultimate Front End Development Setup
Ultimate Front End Development Setup -
5 million votes and counting at Rockhall.com
5 million votes and counting at Rockhall.com -
django-html-validator
A couple of weeks ago we had accidentally broken our production server (for a particular report) because of broken HTML. It was an unclosed tag which rendered everything after that tag to just plain white. Our comprehensive test suite failed to notice it because it didn't look at details like that. And when it was tested manually we simply missed the conditional situation when it was caused. Neither good excuses. So it got me thinking how can we incorporate HTML (html5 in particular) validation into our test suite. So I wrote a little gist and used it a bit on a couple of projects and was quite pleased with the results. But I thought this might be something worthwhile to keep around for future projects or for other people who can't just copy-n-paste a gist. With that in mind I put together a little package with a README and a setup.py and now you can use it too. There are however some caveats. Especially if you intend to run it as part of your test suite. Caveat number 1 You can't flood htmlvalidator.nu. Well, you can I guess. It would be really evil of you and kittens will die. If … -
django-html-validator
A couple of weeks ago we had accidentally broken our production server (for a particular report) because of broken HTML. It was an unclosed tag which rendered everything after that tag to just plain white. Our comprehensive test suite failed to notice it because it didn't look at details like that. And when it was tested manually we simply missed the conditional situation when it was caused. Neither good excuses. So it got me thinking how can we incorporate HTML (html5 in particular) validation into our test suite. So I wrote a little gist and used it a bit on a couple of projects and was quite pleased with the results. But I thought this might be something worthwhile to keep around for future projects or for other people who can't just copy-n-paste a gist. With that in mind I put together a little package with a README and a setup.py and now you can use it too. There are however some caveats. Especially if you intend to run it as part of your test suite. Caveat number 1 You can't flood htmlvalidator.nu. Well, you can I guess. It would be really evil of you and kittens will die. If … -
Call for contributors – Stream-Framework 1.1
Reblog, from: Call for contributors – Stream-Framework 1.1 Share and Enjoy: -
Call for contributors - Stream-Framework 1.1
Today we’ve released Stream Framework 1.1. Development has been a bit slow pending the rename from Feedly to Stream-Framework. Fortunately the community is growing faster than ever. Many users of GetStream.io are looking at Stream Framework and vice versa. We would like to take this moment to encourage contributions. We’re actively accepting pull requests and appreciate all the help. Especially the python 3 support on the roadmap is something which you can easily get started with. So if you’ve been searching for a project to contribute to, now is a good time :) Roadmap Python 3 support (pending CQLEngine) Documentation improvements (see issues) Database backend to facilitate small projects Relevancy based feeds (far future) API similar to getstream.io to allow other languages to Stream Framework (far future) Let us know which features you guys are looking forward to! What’s new Since the last blogpost we’ve made the following changes: Ability to customize the Activity object used in feeds and aggregated activity used in aggregated feeds. Hooks to collect metrics Updated CQLengine and Python-Driver Ability to filter Redis & Cassandra feeds using the .filter syntax() Ability to order Redis using the .order syntax (Thanks Anislav) Redis improvements to counts (Again, many …
