Django community: RSS
This page, updated regularly, aggregates Community blog posts from the Django community.
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All Pre-Orders Have Been Shipped
We shipped all pre-ordered copies of Two Scoops of Django 1.8 on either Thursday, June 4 or Friday, June 5. When Will Mine Arrive? For details on when your book will arrive, check your tracking number, which you should have received via email. Packing the Orders On Wednesday, we received a huge delivery of books to our home. It was supposed to come on Friday, giving us the weekend to package our shipments. But it came two days early. We ended up staying up very late Wednesday and Thursday night to sign and package them. After signing each book, we shrinkwrapped and then packed it very carefully, to minimize the risk of damage in transit. On Saturday, June 7, we saw the first tweet about a book shipped directly from us! Look what the mailman just dropped off. Woohoo! Thanks guys! @pydanny @audreyr @twoscoopspress #python #django pic.twitter.com/9Octqj6x5X — Brett Thompson (@HKstrongside) June 6, 2015 -
All Pre-Orders Have Been Shipped
We shipped all pre-ordered copies of Two Scoops of Django 1.8 on either Thursday, June 4 or Friday, June 5. When Will Mine Arrive? For details on when your book will arrive, check your tracking number, which you should have received via email. Packing the Orders On Wednesday, we received a huge delivery of books to our home. It was supposed to come on Friday, giving us the weekend to package our shipments. But it came two days early. We ended up staying up very late Wednesday and Thursday night to sign and package them. After signing each book, we shrinkwrapped and then packed it very carefully, to minimize the risk of damage in transit. On Saturday, June 7, we saw the first tweet about a book shipped directly from us! Look what the mailman just dropped off. Woohoo! Thanks guys! @pydanny @audreyr @twoscoopspress #python #django pic.twitter.com/9Octqj6x5X — Brett Thompson (@HKstrongside) June 6, 2015 -
PyLadies RDU and Astro Code School Team Up for an Intro to Django Workshop
This past Saturday, Caktus developer Rebecca Conley taught a 4-hour introductory level workshop in Django hosted by PyLadies RDU. PyLadies RDU is the local chapter of an international mentorship group for women who love coding in Python. Their main focus is to empower women to become more active participants and leaders in the Python open-source community. The workshop was held in our Astro Code School space and sponsored by Windsor Circle, Astro Code School, and Caktus Group. Leslie Ray, the local organizer of PyLadies, is always looking for new opportunities “to create a supportive atmosphere for women to learn and teach Python.” With a strong interest in building projects in Django herself, Leslie thought an introductory workshop was the perfect offering for those looking to expand their knowledge in Python as well as a great platform from which Rebecca could solidify her own skills in the language. “Django is practical,” explains Rebecca, “and it’s the logical next step for those with experience in Python looking to expand their toolkit.” The event was extremely successful, with a total of thirty students in attendance. Rebecca was impressed with the students, who were “ enthusiastic and willing to work cooperatively,” which is always … -
Djangocon sprint: zest.releaser 5.0 runs on python 3
Good news! zest.releaser supports python 3.3+ now! Now... what is zest.releaser? zest.releaser takes care of the boring release tasks for you. So: make easy, quick and neat releases of your Python packages. The boring bit? Change the version number (1.2.dev0 -> 1.2 before releasing and 1.2 -> 1.3.dev0 after releasing). Add a new heading in your changelog. Preferrably record the release date in the changelog, too. svn/git/bzr/hg tag your project. Perhaps upload it to pypi. Zest.releaser takes care of this for you! Look at the docs on readthedocs.org for details. The short page on our assumptions about a releasable python project might be a good starting point. Now on to the python 3.3 support. It was on our wish list for quite some time and now Richard Mitchell added it, kindly sponsored by isotoma! We got a big pull request last week and I thought it would be a good idea to try and merge it at the djangocon sprint. Reason? There are people there who can help me with python 3. Pull request 101 was the important one. So if you want to get an idea of what needs to be done on a python package that was first … -
Formatting python log messages
I see three conflicting styles of log formatting in most of the code I come across. Basically: import logging logging = logging.getLogger(__name__) logger.info("%s went %s wrong", 42, 'very') logger.info("{} went {} wrong".format(42, 'very')) logger.info("%s went %s wrong" % (42, 'very')) I looked at the official PEP 282 and at the official docs. With the help of someone's stackoverflow question I think I understand it now. Use the first version of the three examples. So: The actual log message with the old, well-known %s (and %d, %f, etc) string formatting indicators. As many extra arguments as you have %s-thingies in your string. Don't use the second and third example, as both of them format the string before it gets passed to the logger. So even if the log message doesn't need to be actually logged somewhere, the full string gets created. The first example only gets passed a string and some extra arguments and only turns it into a real full string for in your logfile if it actually gets logged. So if you only display WARN level and higher, your DEBUG messages don't need to be calculated. There is no easy way to use the first example with {} instead … -
Zweite Hamburger Python Unconference
Vom 04. bis 06. September 2015 findet die 2. Python Unconference Hamburg im Institut für organische Chemie der Universität Hamburg statt. Erwartet werden weit über 200 Python-User bzw. Developer aus Hamburg und dem Rest der Welt. Von "Greenhorns" bis zu "proven Experts" aus den Bereichen Mathematik, Data Science, System-Administration und DevOps bis hin zu Web-Development und Python-Core-Entwicklung werden alle nur erdenklichen Facetten der Python-Welt vertreten sein. Wie im letzten Jahr findet die Unconference am Samstag und Sonntag im Barcamp-Stil statt, mit Vorträgen und Diskussionen aus allen Bereichen der Python Welt. Neu ist der Freitag: am Freitag gibt es Raum für Sprints, Tutorials und Workshops. Aktuell gibt es noch Early Bird Tickets für 42,- Euro. Mehr Informationen gibt es unter www.pyunconf.de. -
How do you run distributed standups?
I run a distributed team, across nine hours of time zone offset, so staying in sync takes some work. We’ve been fooling around with different methods and cadances for our sync-ups, so as a way of gathering ideas, I did a quick “twitter poll” yesterday: https://twitter.com/jacobian/status/606118584515993600 The results were super interesting! Do distributed teams do daily standups? Yes, overwhelmingly: 42 people said their teams do daily standups. 8 did standups, but less frequently (ranging from every other day, to weekly). -
Djangocon: React.js workshop - Maik Hoepfel
He compares react.js to angular. Angular basically want to take over your whole page. Multiple apps on one page, mixed with some jquery, isn't really possible. You also have to learn a lot of terminology. It is a full stack framework. And angular 2.0 won't have a migration path from angular 1.x... React.js only does one thing and does it well: the view. It doesn't do data fetching, url routing and so. React.js is quite pythonic. You can start adding little bits at a time to your code. You cannot really do anything wrong with it. A core idea is that the html is in one corner. That's the output. And the state is in the other corner. They're strictly seperated, which makes it easier to reason about. It is build by facebook. They take page load time seriously. You can even run react.js partially on the server side ("react native", inside node.js), taking down rendering time, especially on mobile. Facebook is pretty deeply invested in it, so the chances of it disappearing are low. (As opposed to angular: google is barely using it itself). When you start using react.js on a page, you'll have to start thinking about components. … -
Loop Letters | Tracy Osborn
The following is the second installment of our Loop Letters series, an interview with Tracy Osborn. Tracy is the author of Hello Web App, a book to help designers and non-programmers get up and running with Python and Django. Tracy comes from a designer background herself and offers a unique and refreshing take on programming in her writing. We asked Tracy all about getting involved with Django, recent talks she's given, any advice she has, and what she enjoys doing away from a screen. Let's get started! Your startup, Wedding Lovely, has turned into your full time job. What inspired you to get this going? What’s your favorite part about what you do each day? I have an Art degree and I've always loved wedding invitations — they're such beautiful pieces of art. When I first decided to do a startup, I wanted to build a website to help people do the typography for their own invitations. Unfortunately, that turned into a harder problem to solve than I thought; outputting a PDF with perfect typography is no easy task! Instead, I decided to teach myself programming and start with an easier idea: building a simple directory of freelance and small … -
Djangocon: The net is dark and full of terrors - James Bennett
(One of the summaries of a talk at the 2015 Djangocon EU conference). James Bennett worked already with Django for 9 years. And especially: he's been involved with Django's security releases for 8 years now. So this talk is about a history of django and security and how django tries to protect you. And where django screwed up and what you can learn from it. Bottom line: security is hard. There are always things that can be improved, always things that could be more secure. Some history He showed the first ever django security bug. And the last one (number 49). The last one had a proper full release, the first one told you to overwrite one specific file. The first issue played down the problem a bit, the last one didn't. See the full list of all security issues. In 2007, there was still an informal security process. In 2008, django 1.0, django started autoescaping in the templates. Quite controversial with a long discussion, but it was decided it was so important that it was enabled by default. In 2010, django 1.2, modern csrf protection got added. Security by default. Better to be safe out of the box. Next … -
Djangocon: How to write a view - David Winterbottom
(One of the summaries of a talk at the 2015 Djangocon EU conference). David Winterbottom says that on the one hand, views are simple: a request comes in and a response goes out. On the other hand, you have lots of freedom in views, which might lead to problems. A central principle in software architecture is separation of concerns. For instance by encapsulation: providing a clean interface and hiding information from other parts of the system. A well-known design pattern is MVC, model-view-controller. Originally used for desktop application, but also used in most web frameworks. Note that every web framework interpretes it differently. Model: business logic. Domain logic. The data, the rules. View: what the user sees. Controller: steers the whole process. The user interacts with the controller. Django talks about MTV: model, template, view. He'd say that what's the view in MVC is mostly the templates and static files. The Controller in django is then views, middleware, urls.py. What David often notices in django projects is that the views.py is too big. There's data validation in there. Some of the model layer creeps into the view. And so on. You're not encapsulating everything like you could be. Django is … -
Djangocon: Hypothesis, randomised testing for Django - Rae Knowler
(One of the summaries of a talk at the 2015 Djangocon EU conference). Rae Knowler talks about hypothesis. It is a property based testing library inspired by Haskell's Quickcheck. So: it took out a a bunch of good ideas and you don't need to know a lot of scary Haskell :-) The core idea is that it uses randomized data. You tell it to test your login page, for instance, with a name, an age and an email address. It then creates 1000 random names/ages/emails and feeds them to your form. It simplifies examples of failures. What that means: if it finds an error, it tries iterating on it, finding out in the end that perhaps your form doesn't handle a name with a $ in it. It remembers interesting inputs. It works with pytest, unittests, everything. It is just a library. There's django integration: https://pypi.python.org/pypi/hypothesis-django/ . Custom field types are allowed. It can generate child models. And since last sunday it supports fixtures. Rae showed a demo. With random numbers, hypothesis reliably found a DivideByZero bug. Nice! Hypothesis makes discovering this kind of bugs easy. It makes it simple to write tests without having to rigorously figure out the … -
Djangocon: An ageing coder tackles his ageing code - Owen Campbell
(One of the summaries of a talk at the 2015 Djangocon EU conference). Owen Campbell himself is the ageing coder he talks about. He picked the title because he qualified for early bird tickets because of his age :-) His experience started at age 11 with a 1kB synclair ZX81 that you could only program in z80 assembly language. Storage? Cassette tapes. In university he did assembly programming on the 8086 and 86000. And for an extra course he did Fortran, a "high level language" which meant submitting code to the mainframe and getting a print back that you missed a comma. Please re-submit. He showed an impressive list of programming languages he used in all those years. For his own company he needed an accounting system. He re-used an older Lotus project and re-did it in microsoft access. Later he moved it to MSSQL server and a dotnet frontend. All in all it ran well for 15 years. But he got enough of the server license costs and the microsoft development environment. That accounting system is the "old code" from the title. He wanted to convert it to a web app. He started out with Ruby & Rails. He … -
Djangocon: lookups, transforms and expressions - Anssi Kääriäinen
(One of the summaries of a talk at the 2015 Djangocon EU conference). (Anssi Kääriäinen gave a great talk last year at "django under the hood" about the django ORM. Look at that one, too.) Lookups, transforms and expressions are new features in the ORM (part in 1.7, part in 1.8). They are ways to inject custom SQL in a well-structured way. Custom lookups are things like __glob that you can write yourself in addition to the build-in ones like __gte. Custom transforms? __lower, as an example. How you could do this previously was by using .extra(), you could tweak the sql this way. The new approach is more reusable. It can also be chained (somefield__lower__glob)! Another drawback of .extra() is that it quite a hacky part of the django code. The new functionality Lookups. Those are basically "a condition in the query's WHERE clause". Examples in django are lt, gt, gte, contains and so. To create a custom lookup, you subclass models.Lookup. You set the lookup_name and you implement the .as_sql() method. Afterwards you register it for the various Field types for which it is valid. An example (very quickly and incompletely copied over from the presentation): @models.CharField.register_lookup class … -
Djangocon: Better web applications through user testing - Ludvig Wadenstein
(One of the summaries of a talk at the 2015 Djangocon EU conference). Ludvig Wadenstein is a developer, but he also does a lot of UX (user experience) work and user testing. What is user testing? You make someone use your application and see what comes out of it. Then you fix things. Why user testing? You see if your user "gets" your UI. And you get a fresh look. And perhaps you discover small changes that can make a big difference. Test while you build it and test it when it is finished. Keep in mind that the earlier you test, the cheaper it is to change something. A rule of thumb is to test it once a month. Who should be your test participant? Don't focus too much on finding the perfect participant, almost everybody is OK as long as they don't have much experience with building the system. Aim for a mix of beginners and experts. There are many ways to test. Their method takes about 50 minutes. They have two rooms, one is the test chamber, the other is the observation room. In the test chamber you have the participant and a facilitator. The facilitator should … -
Djangocon: Project templates - alternatives and tools - Emmanuelle Delescolle
(One of the summaries of a talk at the 2015 Djangocon EU conference). Emmanuelle Delescolle says the django community is quite welcoming and friendly. The increased effort that is being poured into diversity is great. She showed a sample django project filesystem structure. It looked like a bit of a mess. Not too standard. Then she showed the structure that has her preference, including the settings that belong to it. Well, once you're happy with such a structure, how can you use it all the time? Django now allows you to pass a template parameter to "startproject". Then your template gets used instead of the standard django one: $ django-admin startproject --template your-preferred_template/ You could make one for your reusable apps you want to release as open source. Automatically include a license file, for instance. See the django docs . How does such a template look? Basically the same as a regular django project, only certain parameters get replaced. A folder project_name gets renamed in your project's name, for instance. Same for python files: you can use {{ project_name }}-like strings in there and they'll get replaced. But it is not enough. Only python files can be templated. Not other … -
Djangocon: CMS Panel - Iacopo Spalletti and Tom Dyson
(One of the summaries of a talk at the 2015 Djangocon EU conference). The panel consisted of Iacopo Spalletti of Django CMS and Tom Dyson of Wagtail. For many people, a CMS is the way they get acquainted with django, so it is pretty important. Often they come from Wordpress originally. What is the main philosophy of your CMS? Django CMS tries to be just another django app. After a while, django cms grew to support multiple roles. The content manager, the front-end designer, the main editors and the other editors. The main editors set up the content structure of the site and the other editors fill it. Wagtail doesn't try to give editors as much power as django CMS (and Drupal and so) do. Often the super-powers aren't even used. It is more aimed at django programmers. It has its own UI (instead of the standard django admin). Performance is a key priority. In practice, how does the philosophy work out for you? Django CMS is build upon the flexibility of the django admin. They use it everywhere and it gives them a lot of power. The only pain point is the URLconf. They love django. They wouldn't be … -
Djangocon: What it’s really like building RESTful APIs with Django - Paul Hallett
(One of the summaries of a talk at the 2015 Djangocon EU conference). Paul Hallett considers himself an "API fanatic". He works for lyst, a website for buying clothes. They had an existing API, json-rpc, and wanted to have a better API that fitted better with http. RPC (remote procedure call) means you only have one endpoint (=url) and everything is a POST request, even if you only request information. "RPC for http is bad" is what he said. He wanted to do it with django rest framework. Django is a batteries-included webframework, django rest framework is a batteries-included API framework. If you need to re-build some existing API as a rest API, think of it as a chance to rebuild. If it is an existing API, the program probably changed a bit from how it looked originally. Shouldn't you clean it up a bit? Change a couple of models? The alternatively is to shoe-horn non-fitting models into an otherwise nice API... REST focuses on Resources. In django terms, you often think "a model". This isn't necessarily true, it might be either more or less. A model might actually have two separate sets of attributes that you'd rather treat as … -
Djangocon: Demystifying mixins with Django - Ana Balica
(One of the summaries of a talk at the 2015 Djangocon EU conference). Ana Balica talks about mixins. Mixins are ways to add extra behaviour into classes. Mixins aren't anything special in python. They are just classes. Mixins are nice for providing modularity. They should have one specific goal and they should not themselves be extended or instantiated. You could use them for instance to work around copy-pasting code around between classes. Just make a class with the otherwise copy-pasted code. How do you use it? Python's multi-inheritance. A class can have multiple parents: class Foo(SomeMixin, BaseFoo): pass In django, mixins are especially useful for class based views. As an example, let's build a mixin that checks if our users are logged in: class LoginRequiredMixin(object): def dispatch(self, request, *args, **kwargs): if not request.user.is_authenticated(): raise PermissionDenied return super(LoginRequiredMixin, self).dispatch( request, *args, **kwargs) class AboutView(LoginRequiredMixin, TemplateView): template_name = 'about.html' dispatch() is handy to keep in mind. Likewise .get_context_data(). (Note by Reinout: doing something with get_context_data is probably not needed). How do you discover what's in django's class based views? You could look at the source code of django. But looking at http://ccbv.co.uk/ is handier. There are a lot of mixins already written … -
Djangocon: Coding with knives (pt II) - Adrienne Lowe
(One of the summaries of a talk at the 2015 Djangocon EU conference). Adrienne Lowe wants to share some lessons she learned while learning to code. And how to use knowledge learned in one area in another one. Another area? Cooking! She cooked a lot. Working in restaurants, private cook, training, everything. She started a blog called coding with knives. Three lessons she has for new coders: If one tutorial doesn't work for you, choose another one. Don't let it reflect on your own opinion of yourself. If you're a cook and a cookbook doesn't work for you, you simply pick another! So simply look around for a different tutorial. Reach out. Don't be afraid to ask basic questions. The person answering also learns something: being a better teacher. So you both learn! In the cooking community, you exchange recipes. You help each other with tips. The same here in the django community. It is so friendly! And most of it is open source. Great! Let your goal guide you. You'll inevitable run into problems as a beginner. Don't let that discourage you. Make sure you have a specific goal you're working to and celebrate when you reach it. Simply … -
Djangocon: Conformity and you - a question of style - Greg Chapple
(One of the summaries of a talk at the 2015 Djangocon EU conference). Greg Chapple works half his time on Django projects, half on Rust projects. Some things you'll probably never hear: "Can't wait to fix some pep8 violations today". Style conventions probably aren't the sort of thing you take into account when picking a language or a framework. Every line of code follows some sort of style convention. Intentional or not. The style of our code can identify us. Same as with this talk: Greg speaks with a slight Dublin accent, by default. Something to ask yourself: if you look at a piece of code inside your company, could you identify the person that wrote it? Let's get back to Greg's accent and the way he speaks. How did he come by this? Where he grew up, of course. The people he's around regularly. You can change it, though. He spend two weeks in the USA and when he came back he got funny looks for some of the US pronouncement that krept into his vocabulary. The same with your code style! You're influenced by the code you're surrounded by. If you want to make changes, it takes quite … -
Djangocon: Lightning talks
(One of the summaries of a talk at the 2015 Djangocon EU conference). Pycon Namibia - Daniele Procida In february 2015, the python conference in Africa actually took place! In Namibia! Daniele Procida talked about the plans at many conference (like at djangocon.eu 2014). It was really good. They formed valuable relationships and learned a lot. Several of the attendees are here at the conference. They're going to organize another conference later this year. So if you want to escape a dreadful European winter... I'm new to django but why should I use it? - Ben Sharif Why should you use it? You're new, so why Django? He's in that situation. He's a medical student. He's not a doctor yet. It also means he isn't a professional programmer. He wants to quickly prototype ideas for medical web apps. He wants something that lets him develop things fast: Django fits the bill. He started learning python in may 2014. He tried the django tutorial, but that didn't really work. He got pointed at web2py. Easy to get started. Almost no configuration. Through the web development. His demo is at http://medboard.co.uk/ So... what is he missing? The django community is absolutely massive. … -
Djangocon: lightning talks day 2
(One of the summaries of a talk at the 2015 Djangocon EU conference). (These talks only take 5 minutes, so I'm bound to miss things, especially names. If something needs correcting, just post a comment below or mail me at reinout@vanrees.org ). Django under the hood 2015 This year django under the hood happens again. It'll be bigger, so there'll be more tickets so that it probably won't sell out in about 4 minutes again. http://www.djangounderthehood.com/ It is in november. 1.5 day of talks and a day of sprinting. Detailed talks, for instance about all the details of an http request or about django's security measures or about files in django. Djangocon Europe 2016 Djangocon Europe 2016 will be held in.... Europe! We don't know yet where it will be, though. They are still looking at the proposals. If you're not ready, but might want to do it in 2017: the plan is to let one or more people from 2017 help organize 2016 to help with knowledge transfer. Django and robotic telescopes - Edward Gomez He works at http://lcogt.net/ and normally speaks to astronomers or school kids. They have a network of 12 robotic telescopes all over the world. … -
Djangocon: Into the rabbit hole - Ola Sendecka
(One of the summaries of a talk at the 2015 Djangocon EU conference). Ola Sendecka organized the Warsaw djangocon in 2013 and started the djangogirls organization. She told us a story in which she paraphrased "Alice in Wonderland" as "Alice in Djangoland" :-) Complete with code examples. Fun. Alice's sister asked her to have tea with her. "Fine, I'll be there in 10 minutes". And she starts adding a small feature. But ran into a small problem. Oh, I'll fix that with a small change to the object manager. "Are you coming for tea now?". Yeah, almost done. I just need to fix this small bug in the new code. So she had to make a small modification to override something in the form layer. Oh. Traceback. "The tea is getting cold". I'll just override something in a the form field. And some extra customization there. In the end, the code was horrible. And Alice's sister was angry. What happened? Good question! The problem: Alice was in a rabbit hole. She got so caught up in what she was doing that she just kept doing that for hours on end without really getting anywhere. You fall into a rabbit hole … -
Djangocon: Give your pony wings - Benjamin Wohlwend
(One of the summaries of a talk at the 2015 Djangocon EU conference). Benjamin Wohlwend confesses that he's a lazy programmer. He also likes his code to be lazy: he doesn't want his code to do too much. Why? Code that doesn't do much is code that is fast. If you have performance problems, how do you find them? He uses django-debug-toolbar and django-devserver a lot. django-debug-toolbar is great, especially because it lists the number of queries (which is a common performance problem). django-devserver also prints out the number of queries and the time it took. For every request. Handy. It is a runserver replacement. To reduce the number of queries, django provides select_related() and prefetch_related() Select_related is for immediately grabbing related objects in one big query. prefetch_related does something similar, but it is better suited for many-to-many fields and reverse foreign keys. There are many more tricks. You can use django's annotate function to let the database count numbers of related objects instead of grabbing them all. Much quicker. Also .defer() helps, this lets you tell django not to grab certain columns as they're not needed. Caching can make your code way faster. But cache invalidation is hard. It …
