Programmer blog

An example project and a basic guide showing how to run Django/Celery on Heroku. Basic requirements First of all, let's actually set up a typical Django project for this. We would need virtualenvwrapper   for that. One could use any other particular method. I prefer this one. $ cd dev $ mkvirtualenv dch ( dch ) $ pip install django ( dch ) $ django-admin startproject djheroku ( dch ) $ cd djheroku # Make sure is working: ( dch ) $ ./manage.py runserver From now I will consider working on a terminal with this (dch) environment on. Heroku hosting setup We would need our project set up for heroku python server. The docs live HERE , as for moment of this guide writing. One would need to follow and setup a basic heroku project. I will not stop here rewriting official guide as it is good enough. Installing celery Assuming we have a basic django dyno at heroku here we will continue. Now let's install Celery and add it to our requirements list (as we had just sta...

I have a task to migrate a website. Old one is plain HTML and new one is Django CMS. I have a script that parses an HTML page from old website in to CMS page and places it into proper place. Task is to migrate all the page content (that is a CMS TextPlugin) into an interlinked pages setup. Like we have text <p>blah blah </p><a href="/page/url">Text</a><p> some other text</p> And I need to change it into CMS LinkPlugin that is nested inside of the TextPlugin. It have become a common standard in the Django CMS world now. Note we need to have a LinkPlugin because of the requirement to interlink pages. E.g. <a href="/page/url"> is a link to CMS Page object. The solution is divided into two major parts. First we need to have the link plugin added to a placeholder of the text plugin. It must also be nested by the TextPlugin, like Django CMS admin web UI would do.  So our plugin would look somehow like this in the CMS Pag...

Sometimes you need to get out of standard behaviour of your Django admin. It means expanding its functionality with custom things. In our case we have a model that we want to add a custom html element. Button that must load something via AJAX from another place to be exact. We have a typical Django polls application for simplicity. Here is its structure: First of all we need to create a structure. So here comes our model: # models.py from django.db import models class Poll (models.Model): question = models.CharField(max_length= 200 ) pub_date = models.DateTimeField( 'date published' ) We have to have our django application admin configuration to display that model: # admin.py from django.contrib import admin from polls.models import Poll admin.site.register(Poll) It will look in Django admin like so: You can see polls available here in admin. You can do all the typical things with Polls model. Add/Delete/Edit... Using standard D...

One of main features and troubles for Django projects is the Django version you are using. Example for this would be the occasion of starting project for Django 1.4.x version. Trying to run it under Django 1.7.x would lead to various troubles, counting template changes, misconfiguration errors and so on. Solution is to use virtual environment. The tool for this is called Virtualenv . It is a wrapper for a python interpreter. It enables you to have multiple versions of python packages that run independently. The Virtualenv creates you a standalone environment. Basically it copies and keeps a system Python of yours in a specified directory. All the python packages will be installed there. (In case you have not forgot to activate it first, of course) Lets get started then. We need Virtualenv itself for the first. There are many ways to install it depending on your system . Most obvious to use pip. Your installation command will look something like that: pip install virtualenv Thi...

Developing a website for Django CMS I have done a plugin. This plugin however have had a problem. It had an m2m field. While selecting images there (It was a gallery plugin). It was not saving it to production. This way main problem with this field was that plugin have displayed m2m choices on a draft page and while storing it to live it fails. Django CMS Pages is built like so it has multiple versions of pages. Each Page model that is changed is stored under new revision. And so plugin is copied and relinked to that page too. So plugin revisions multiply to. For e.g. in case you have a Draft page with two plugins that have model primary key number (pk in future) 12 and 14 accordingly. Say you hit publish changes. Not only PK of Page model rises and data are copypasted into new empty Page model instance. Those plugins are copied to. So mentioned plugins PK would change to 15 and 16 accordingly, assuming 14 is the latest plugin pk. New copied plugins will be linked to new page. Tha...

I have had a task to implement Radio Select field with "Other" choice field in a Django Model Form. Here is my implementation in case someone would benefit from it. The idea is to have it all stored to Django's CharField type of data and have a preselected set of fields. We have a model: # models.py class Entry (models.Model): SET_OF_CHOICES = ( ( 'choice1' , 'choice1' ), ( 'choice2' , 'choice2' ), ( 'choice3' , 'choice3' ), ( 'Other' , 'Other Please Specify' ), ) choice = models.CharField(_( "Selected your choice" ), max_length= 250 ) That makes it ready for the set of fields for for our form. We are overriding Model form default field for this type of data (CharField) by intentionally specifying field with the same name. # forms.py from django.forms import ModelForm, ChoiceField, RadioSelect from models import Entry ...

I have had a problem with compiling Pillow recently. the error was with Pillow/Pil compilation. pillow install error clang: error: unknown argument: '-mno-fused-madd' [-Wunused-command-line-argument-hard-error- in -future] Apple updated command line tools. So the cc command was updated too. $ gcc --version Configured with : --prefix= /Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1 Apple LLVM version 5.1 (clang- 503.0 . 38 ) (based on LLVM 3.4 svn) Target: x86_64-apple-darwin13. 1.0 Thread model: posix The bug is in GCC. It is quite serious because those flags support will be dropped in future. Fortunately there is a worakround for now: export ARCHFLAGS= "-Wno-error=unused-command-line-argument-hard-error-in-future" It works for Pillow 2.4.0 and I can compile it with Apple LLVM 5.1 (That is current now), as of Xcode 5.1. Hope my findings will help someone.

It often gets that you need it because you invent something that is meant to be displayed for admin. E.g. some nasty form field or something. Here is my recipe to add some additional Django static to your admin. Rather than writing a widget , that is more proper way here... I was using a widget already (from another package). So I could not use it properly, at least without a ton of overrides and complexity it leads to. SO I've decided to add the JS functionality to override a lack of backend. First of all we should add the javascript/css like so: # admin.py class MyModelAdmin (admin.ModelAdmin): # admin additions class Media : css = { "all" : ( "css/my_style.css" ,) } js = ( "js/my_script.js" ,) This add should list your files, loaded in the admin . So you can access them and see in the Django admin frontend itself. Like so: Now that your script and style are loaded you could jus...

Here I will describe an example form using jQuery Form  plugin. It will provide a good frontend, while Django serving a simple backend. I made this AJAX form using unobtrusive javascript. With human language it means the form will function with JavaScript disabled. And so jQuery.form plugin will work as an AJAX speedup addition and not as a major requirement. Features: * Works both with JavaScript  and without. * Uses standard Django ideology/hooks. * Uses the most known jQuery plugin for forms AJAX handling. Theory: Main idea that Django supports both normal and AJAX request in a standard view. And has a handy request.is_ajax() request method. It returns True/False depending on if request search has HTTP_X_REQUESTED_WITH header for the string 'XMLHttpRequest' . jQuery.form plugin sure does have that. Backend Django. We will create an app called 'contact' for our task and place it in the example django project. Urls from the project will redirect to ...