Django community: RSS
This page, updated regularly, aggregates Community blog posts from the Django community.
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Preserve file names with sorl for better SEO
We use sorl-thumbnail for scaling images by keeping the original one intact. Sorl proven to be a great tool for generating different sized images throughout the website. I presume that you know how to use sorl-thumbnail. Here we see how to preserve filename. Search Engines will give importance to image alt tag content but it definitely has some impact on relevant image file name too. Sorl will generate random names for the thumbnails it will create and as of now, there is no default setting to preserve filename in generating thumbnails. It is possible to have the same name for different sized images as sorl will create thumbnails in random folders, so, there will be no conflict in names. Here is the way to achieve that: We must override the thumbnail backend. So provide THUMBNAIL_BACKEND=’SEOThumbnailBackend’ Now we should create the class that returns our custom filenames. # thumbnailname.py from sorl.thumbnail.base import ThumbnailBackend, EXTENSIONS from sorl.thumbnail.conf import settings from sorl.thumbnail.helpers import tokey, serialize import os.path class SEOThumbnailBackend(ThumbnailBackend): def _get_thumbnail_filename(self, source, geometry_string, options): """ Computes the destination filename. """ key = tokey(source.key, geometry_string, serialize(options)) filename, _ext = os.path.splitext(os.path.basename(source.name)) path = '%s/%s' % (key, filename) return '%s%s.%s' % (settings.THUMBNAIL_PREFIX, path, EXTENSIONS[options['format']]) It’s important … -
Improving page speed score in Google Page Score test- PART1
About PageSpeed Insights: Google's Page Speed Insights measures the performance of a page for mobile devices and desktop devices. It fetches the url twice, once with a mobile user-agent, and once with a desktop-user agent. The PageSpeed Score ranges from 0 to 100 points. A higher score is better and a score of 85 or above indicates that the page is performing well. Please note that PageSpeed Insights is being continually improved and so the score will change as we add new rules or improve our analysis. PageSpeed Insights measures how the page can improve its performance on: time to above-the-fold load: Elapsed time from the moment a user requests a new page and to the moment the above-the-fold content is rendered by the browser. time to full page load: Elapsed time from the moment a user requests a new page to the moment the page is fully rendered by the browser. 1. time to above-the-fold-load: Above the fold content is some thing that appears on screen's worth, anything that you don't scroll. This is completely related to Designing part, so we'll not concentrate on this in this post. 2. time to full page load: Time to full page load depend upon … -
Useful commands for MySQL
Some useful MySQL commands that I need from time to time: MySQL List all users select User, Host from mysql.user; Remove a user show grants for 'USERNAME'@'localhost'; revoke all privileges, grant option from 'USERNAME'@'localhost'; drop user 'USERNAME'@'localhost'; List all databases show databases; Remove a database drop database DATABASENAME; Update password of user update mysql.user set password=PASSWORD("NEWPASSWORD") where User = 'USERNAME'; flush privileges; Create a database and user, assign user to database create database DATABASE defaukt character set utf8 collate utf8_general_ci; grant all on DATABASE.* to 'USERNAME'@'localhost' identified by 'PASSWORD'; flush privileges; -
Faster Django Sites with PyPy
This post was created as a collaboration between Lincoln Loop and Maciej Fijalkowski from baroquesoftware.com. In the space of web architecture, the prevalent belief states that "database based applications are I/O bound". While this might have been true in the past, two developments have highly encroached on that. First, memory has been getting bigger and bigger—minimizing the need to access the HD. Second, the database connection layers have been getting increasingly sophisticated—putting more and more pressure on the CPU. For CPU bound Python applications, using PyPy instead of the traditional CPython interpreter can provide massive improvements (5x or more is common). In this post we examine how PyPy can improve the Django ORM's execution times. We built a set of benchmarks using some "simple" queries with the Django ORM. These let us analyze PyPy's performance and warmup stats. Finally, we want to present some future developments to improve the current situation. Let's start with the benchmark description - it's a simple set of queries that were distilled from the BotBot IRC logging system. The original source can be found on GitHub. There is really nothing fancy, just a series of queries to a SQLite database. BotBot uses Postgres in production, … -
Encrypted Postgres Backups
Encrypted Postgres Backups -
Why you should use the Django admin: 9 tips
This writing is inspired by a comment on Reddit concerning my recent post: “The problem is that everyone I speak to seems to think the opposite - that the admin is super-limited, inflexible and hard to customize.” — andybak on Reddit I’m about to break this prejudice right now. The Django admin is a really brilliant piece of software, which can significantly speed up your development. Here are some tips about the Django admin, which I’ve found to be quite useful. -
Why you should use the Django admin: 9 tips
This writing is inspired by a comment on Reddit concerning my recent post: “The problem is that everyone I speak to seems to think the opposite - that the admin is super-limited, inflexible and hard to customize.” — andybak on Reddit I’m about to break this prejudice right now. The Django admin is a really brilliant piece of software, which can significantly speed up your development. Here are some tips about the Django admin, which I’ve found to be quite useful. -
Automatic Maintenance Page for Nginx+Django app
If you've used Django with Nginx, you are probably familiar with how to configure the Nginx process group to reverse proxy to a second Gunicorn or uWSGI Django process group. (The proxy_pass Nginx parameter passes traffic through Nginx to Django.)One benefit of this approach is that if your Django process crashes or if you are preforming an upgrade and take Django offline, Nginx can still be available to serve static content and offer some sort of "the system is down" message to users. With just a few lines of configuration, Nginx can be set to automatically display a splash page in the above scenarios.If the Django process running behind the reverse proxy becomes unavailable, a 502 error will be emitted by Nginx. By default, that 502 will be returned to the browser as an ugly error message. However, Nginx can be configured to catch that 502 error and respond with custom behavior. Specifically, if a 502 is raised by Nginx, Nginx can check for a custom html error page document and serve up that document if it exists. If that document does not exist, Nginx can just return the default ugly 502 error message. The Nginx configuration below executes this … -
Row Level Security in Postgres and Django
Postgres keeps introducing new things that pique my attention. One of the latest ones of these is [Row Level Permissions](http://www.postgresql.org/docs/devel/static/ddl-rowsecurity.html), which essentially hides rows that a given database user cannot view. There's a bit more to it than that, a good writeup is at [Postgres 9.5 feature highlight: Row-Level Security and Policies](http://michael.otacoo.com/postgresql-2/postgres-9-5-feature-highlight-row-level-security/). However, it's worth noting that the way Django connects to a database uses a single database user. Indeed, if your users table is in your database, then you'll need some way to connect to it to authenticate. I haven't come up with a nice way to use the Postgres users for authentication within Django just yet. I did have an idea about a workflow that may just work. * Single Postgres User is used for authentication (Login User). * Every Django user gets an associated Postgres User (Session User), that may not log in. * This Session User is automatically created using a Postgres trigger, whenever the Django users table is updated. * After authentication, a `SET SESSION ROLE` (or `SET SESSION AUTHORIZATION`) statement is used to change to the correct Session User for the remainder of the session. Then, we can implement the Postgres Row Level Security … -
reverse, lazy and resolve - Django url-resolvers
Working with urls is a core part of web development. The url-resolver utilities django provides makes working with them just that much easier. Look at using `reverse`, `reverse_lazy`, and `resolve` utility functions to write better idiomatic django.Watch Now... -
Headsupper.io
tl;dr Headsupper.io is a free GitHub webhook service that emails people when commits have the configurable keyword "headsup" in it. Introduction Headsupper.io is great for when you have a GitHub project with multiple people working on it and when you make a commit you want to notify other people by email. Basically, you set up a GitHub Webhook, on pushes, to push to https://headsupper.io and then it'll parse the incoming push and its commits and look for certain things in the commit message. By default, it'll look for the word "headsup". For example, a git commit message might look like this: fixes #123 - more juice in the Saab headsup! will require updating Or you can use the multi-line approach where the first line is short and sweat and after the break a bit more elaborate: bug 1234567 - tea kettle upgrade 2.1 Headsup: Next time you git pull from master, remember to run peep install on the requirements.txt file since this commit introduces a bunch of crazt dependency changes. Git commits that come through that don't have any match on this word will simply be ignored by Headsupper. How you use it Maybe paradoxically, you need to authenticate with … -
Headsupper.io
tl;dr Headsupper.io is a free GitHub webhook service that emails people when commits have the configurable keyword "headsup" in it. Introduction Headsupper.io is great for when you have a GitHub project with multiple people working on it and when you make a commit you want to notify other people by email. Basically, you set up a GitHub Webhook, on pushes, to push to https://headsupper.io and then it'll parse the incoming push and its commits and look for certain things in the commit message. By default, it'll look for the word "headsup". For example, a git commit message might look like this: fixes #123 - more juice in the Saab headsup! will require updating Or you can use the multi-line approach where the first line is short and sweat and after the break a bit more elaborate: bug 1234567 - tea kettle upgrade 2.1 Headsup: Next time you git pull from master, remember to run peep install on the requirements.txt file since this commit introduces a bunch of crazt dependency changes. Git commits that come through that don't have any match on this word will simply be ignored by Headsupper. How you use it Maybe paradoxically, you need to authenticate with … -
Django forms and making datetime inputs localized
tl;dr To change from one timezone aware datetime to another, turn it into a naive datetime and then use pytz's localize() method to convert it back to the timezone you want it to be. Introduction Suppose you have a Django form where you allow people to enter a date, e.g. 2015-06-04 13:00. You have to save it timezone aware, because you have settings.USE_TZ on and it's just many times to store things in timezone aware dates. By default, if you have settings.USE_TZ and no timezone information is in the string that the django.form.fields.DateTimeField parses, it will use settings.TIME_ZONE and that timezone might be different from what it really should be. For example, in my case, I have an app where you can upload a CSV file full of information about events. These events belong to a venue which I have in the database. Every venue has a timezone, e.g. Europe/Berlin or US/Pacific. So if someone uploads a CSV file for the Berlin location 2015-06-04 13:00 means 13:00 o'clock in Berlin. I don't care where the server is hosted and what its settings.TIME_ZONE is. I need to make that input timezone aware specifically for Berlin/Europe. Examples Suppose you have settings.TIME_ZONE == … -
Django forms and making datetime inputs localized
tl;dr To change from one timezone aware datetime to another, turn it into a naive datetime and then use pytz's localize() method to convert it back to the timezone you want it to be. Introduction Suppose you have a Django form where you allow people to enter a date, e.g. 2015-06-04 13:00. You have to save it timezone aware, because you have settings.USE_TZ on and it's just many times to store things in timezone aware dates. By default, if you have settings.USE_TZ and no timezone information is in the string that the django.form.fields.DateTimeField parses, it will use settings.TIME_ZONE and that timezone might be different from what it really should be. For example, in my case, I have an app where you can upload a CSV file full of information about events. These events belong to a venue which I have in the database. Every venue has a timezone, e.g. Europe/Berlin or US/Pacific. So if someone uploads a CSV file for the Berlin location 2015-06-04 13:00 means 13:00 o'clock in Berlin. I don't care where the server is hosted and what its settings.TIME_ZONE is. I need to make that input timezone aware specifically for Berlin/Europe. Examples Suppose you have settings.TIME_ZONE == … -
Django Abstract Base Class - Model Inheritance
Model inheritance is a very useful and powerful feature of django, but used incorrectly it can cause a lot of confusion. Lets go ahead and take a look at some of those. Have you ever been looking through other peoples code and seen a model class Meta with abstract = True? That is the first type of inheritance we are going to look at, abstract base models. There is also multi-table inheritance, proxy models, and multiple inheritance available. Abstract Base Classes In this post we are going to focus on Abstract base classes. This is the easiest type of model inheritance to really understand because it works very much like normal inheritance. In OOP when you inherit from another object you get all of its members plus your own. You can modify those members or leave them the same. Abstract base classes are the same. Here are two example classes class Customer(models.Model): name = models.CharField(max_length=100) email = models.EmailField(max_length=100) address = models.CharField(max_length=100) purchase_history = models.ForeignKey('cart.Invoice') class Staff(models.Model): name = models.CharField(max_length=100) email = models.EmailField(max_length=100) address = models.CharField(max_length=100) bio = models.TextField() position = models.CharField(max_length=20) As you can see these two models are legitimate models with fields, but they do have common elements. In … -
Cyber Monday: 50% off Django book and videos
Are you looking for a good gift for a current or future Django developer? Check out Caktus technical director Mark Lavin’s work for O’Reilly: -
Comics v2.2.0 released with Django 1.5 support
Version 2.2.0 of my comics aggregator is now released. It features a general upgrade of dependencies, including the move from Django 1.4 to Django 1.5, and a lot of updates to comic crawlers. The Django upgrade was completed months ago and it’s been running my Comics instance since, so it’s about time to get it released before Django 1.6 arrives in a month or two. Regarding the crawler updates, it’s a bit sad to see that many of the crawlers have been broken for months without me or anybody else noticing, but it’s hard to catch some content lacking in the middle of a firehose of similar content. I guess I’ll have to make it a monthly task to look through the crawler status page of my Comics instance and do patch releases with updated crawlers. Check out the project docs for more information about Comics and this release in particular. -
Comics v2.3.0 released with better mobile support
Version 2.3.0 of my comics aggregator is now released. As always, dependencies have been updated, including the routine Django upgrade from Django 1.5 to 1.6, just in time for the upcoming 1.7 release. The largest change this time around is the move from Bootstrap 2 to 3, which includes a refreshed, flatter design and lots of tweaking to make Comics both look good and work nicely on mobile devices, something it didn’t use to do. The dependency overview at requires.io has been a great motivation for doing some maintenance work on Comics. The only dependency left outdated is django-registration, as 1.0 moves to class-based views, which requires some larger changes to my customizations. Thus, the upgrade of django-registration has been deferred together with the related upgrade of my vendorized copy of django-invitation. Most, if not all, of the other dependencies seems to support Python 3 now, though some lack the right Trove classifiers in their PyPI registration, so they are not correctly labeled by requires.io. I found an open pull request for cssmin and a recent commit for django-compressor adding the missing Trove classifiers. I’ve also done my part to improve the Python 3 metadata by sending a pull request … -
Sorting querysets with NULLs in Django
One thing which I’ve found surprisingly hard to do in Django over the years is sort a list of items on a database column when that column might have NULLs in it. The problem is that the default Postgres behaviour is to give NULL a higher sort value than everything else, so when sorting in descending order, all the NULLs appear at the top. This is particularly strange if, say, you want a list of items sorted by most recently updated, and the ones at the top are the ones that have never had an update. If we were writing the SQL directly, we could just add NULLS LAST to the ORDER BY clause, but that would be a really rubbish reason to drop down to raw SQL mode in Django. Fortunately, Django 1.8 has introduced a new feature: Func() expressions. These expressions let you run SQL-level functions like LOWER(), SUM() etc. and annotate your queryset with a new column containing the result. I didn’t want to run a database function, but what I discovered was that it is really easy to subclass and make your own Func() expression, giving you access to a template for generating SQL! The base … -
Moya Template Language
Moya's template language is a spiritual successor to Django, and Jinja templates. It borrows a number of constructs from both, and adds a few of its own. There is a slight difference in the syntax in that variables are substituted with ${variable} rather than {{ variable }}, but tags still use the familiar {% tag %} syntax. Template languages are generally quite extensible, so there is probably nothing that Moya template can do that Django / Jinja can't (via a plugin or extension), but there are a few things which are I think are more elegant in Moya's templates language (and built-in). I'm going to talk about a few of them in this post. The Attrib Tag How often have you written code like this? <div id="{{ article_id }}" class="{% if type %}{{ type }}{% endif %}{% if active %} active{% endif %}{% if highlight %} highlight{% endif %}"> {{ content }} </div> This code renders a div with an id attribute and a few optional classes. It is easy to follow, but verbose. It's also a little error prone to write; we have to be careful about the whitespace between the classes, or we could end up generating the … -
Fixing SSL certificate chains
This blog post applies when the following two cases are true: Your browser does not complain about your https site. Everything seems fine. Some other tool does complain about not finding your certificate or not finding intermediate certificates. What is the problem? So: your browser doesn't complain. Let's see a screenshot: Examples of the errors you can see Some examples of complaining tools. First curl: $ curl https://api.letsgxxxxxxx curl: (60) SSL certificate problem: Invalid certificate chain More details here: http://curl.haxx.se/docs/sslcerts.html curl performs SSL certificate verification by default, using a "bundle" of Certificate Authority (CA) public keys (CA certs). If the default bundle file isn't adequate, you can specify an alternate file using the --cacert option. If this HTTPS server uses a certificate signed by a CA represented in the bundle, the certificate verification probably failed due to a problem with the certificate (it might be expired, or the name might not match the domain name in the URL). If you'd like to turn off curl's verification of the certificate, use the -k (or --insecure) option. curl has the right error message: Invalid certificate chain. Let us look at wget: $ wget https://api.letsgxxxxxx --2015-11-23 10:54:28-- https://api.letsgxxxxx Resolving api.letsgxxxxxx... 87.233.157.170 Connecting to … -
How To Create Installable, Reusable Django Packages
name : Django Package Ecosystem: cookiecutter-djangopackage align : center alt : Django Package Ecosystem: cookiecutter-djangopackage target : https://www.pydanny.com/how-to-create-installable-django-packages.html What I mean by an \"installable Django package\": a reusable component that can be shared across Django projects, allowing us to combine our own efforts with others. Some examples include: django-test-plus django-crispy-forms dj-stripe dj-spam Ever want to quickly create a similarly installable Django package to submit to PyPI and Django Packages? One that goes beyond the basics described in the Django tutorial? Specifically, a package that includes: Test runner so you don't need a example/test project (Although those can be useful). The important configuration in place: Travis, editorconfig, gitignore, etc. The important documentation in place: Readme, License, Read the Docs-ready Sphinx docs, etc. Static files ready to go. A base DTL/Jinja2 template ready to go. All those other fiddly bits not included in django-admin.py startapp that are hard to remember. Well, here's how I do it. Introducing cookiecutter-djangopackage cookiecutter-djangopackage is a Cookiecutter template for creating reusable Django packages. Using it is easy: First, get Cookiecutter. Trust me, it's awesome: $ pip install cookiecutter Now run it against this repo: $ cookiecutter https://github.com/pydanny/cookiecutter-djangopackage.git You'll be prompted to enter some values. Enter them. Then … -
How To Create Installable, Reusable Django Packages
What I mean by an "installable Django package": a reusable component that can be shared across Django projects, allowing us to combine our own efforts with others. Some examples include: django-test-plus django-crispy-forms dj-stripe dj-spam Ever want to quickly create a similarly installable Django package to submit to PyPI and Django Packages? One that goes beyond the basics described in the Django tutorial? Specifically, a package that includes: Test runner so you don't need a example/test project (Although those can be useful). The important configuration in place: Travis, editorconfig, gitignore, etc. The important documentation in place: Readme, License, Read the Docs-ready Sphinx docs, etc. Static files ready to go. A base DTL/Jinja2 template ready to go. All those other fiddly bits not included in django-admin.py startapp that are hard to remember. Well, here's how I do it. Introducing cookiecutter-djangopackage cookiecutter-djangopackage is a Cookiecutter template for creating reusable Django packages. Using it is easy: First, get Cookiecutter. Trust me, it's awesome: $ pip install cookiecutter Now run it against this repo: $ cookiecutter https://github.com/pydanny/cookiecutter-djangopackage.git You'll be prompted to enter some values. Enter them. Then an installable Django package will be built for you. Warning: app_name must be a valid Python module name … -
How To Create Installable Django Packages
What I mean by an "installable Django package": a reusable component that can be shared across Django projects, allowing us to combine our own efforts with others. Some examples include: django-test-plus django-crispy-forms dj-stripe dj-spam Ever want to quickly create a similarly installable Django package to submit to PyPI and Django Packages? One that goes beyond the basics described in the Django tutorial? Specifically, a package that includes: Test runner so you don't need a example/test project (Although those can be useful). The important configuration in place: Travis, editorconfig, gitignore, etc. The important documentation in place: Readme, License, Read the Docs-ready Sphinx docs, etc. Static files ready to go. A base DTL/Jinja2 template ready to go. All those other fiddly bits not included in django-admin.py startapp that are hard to remember. Well, here's how I do it. Introducing cookiecutter-djangopackage First, get Cookiecutter. Trust me, it's awesome: $ pip install cookiecutter Now run it against this repo: $ cookiecutter https://github.com/pydanny/cookiecutter-djangopackage.git You'll be prompted to enter some values. Enter them. Then an installable Django package will be built for you. Warning: app_name must be a valid Python module name or you will have issues on imports. Enter the new package (in my case, … -
Installing Wagtail
Wagtail has become a very popular CMS in the last year. Start with this video to see how to get it up and running for your project, and get content on the homepage.Watch Now...
