Appsterdam Guru Session: Google App Engine for beginners

One of the things I was not expecting when I moved to Amsterdam was its active and vibrant tech community. Appsterdam, a non-profit organization focused around aggregating people with a passion for technology, is probably one of the central forces in this movement.

In my year in Amsterdam I had been to a few meetups organized by people from Appsterdam and always came back home having learned something new. This is why when my colleague Matt (who himself is quite an active Appsterdam member) talked me into presenting a guru session on Google App Engine, I saw that as an opportunity to return the favor.

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User authentication with webapp2 on Google App Engine

Google App Engine for Python ships with the capability to manage user accounts without the need of any additional library. This functionality is, however, insufficiently documented. This post will be structured as a step-by-step tutorial addressing user registration, login, password reset and a few other details.

The webapp2 framework on Google App Engine for Python 2.7 is definitely a step forward from the original webapp.
Despite the increase in flexibility and functionality, however, there are a few items that are still more laborious than in other frameworks. The most notable aspect is user account management.

Unsurprisingly, since it is meant to run on Google’s App Engine, using Google Accounts with webapp2 takes one line of code. OpenID authentication, while still defined experimental, is almost trivial to implement as well. There are some open source projects like SimpleAuth that attempt to offer a standard and unified API to handle signing in with Google, OAuth and OpenID accounts.

While it generally makes sense to offer support for authentication through popular services – it decreases friction for new users to try a service – in some cases users may prefer having a special login to access your application.

As experience teaches us, managing passwords securely is not a trivial task, and users legitimately expect application developers to take all the necessary measures to protect their passwords.

Since this is a use case that has to be considered countless time, there is significant value in using library functions to handle user accounts.

Here is how to do that using the functionalities embedded in the webapp2_extras package that is distributed with all standard installations of App Engine for Python 2.7.

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Do languages shape IDEs or IDEs shape languages?

Duke, the Java Mascot, in the waving pose. Duk...I spend most of my days at work on powerful IDEs like Eclipse or Netbeans, tools so advanced in functionalities that their feature lists span over several pages. Their power, however, has its own drawbacks: their memory consumption is measured in the gigabytes, and running them on underpowered computers is the most frustrating of experiences. Issues that any Java developer on Earth will have to face, sooner or later.

Having grown frustrated by Eclipse being too slow on my 4 years old work laptop (I will not comment on this), I decided to drop the IDE for a while, switching to an extremely powerful editor that offered me the one thing that matters the most to me: blazing fast navigation between different source files.

Of course I knew I would miss some of Eclipse’s advanced features but I wanted to give it a try, especially since Andraz’s post left me with a bit of curiosity: how much the tools we use affect our abilities? And why IDEs are so used by desktop developers while they are not so popular with web frontend developers who generally use scripting languages?

A commonly accepted explanation is that it is easier to write IDEs for static languages, when lots of information is known at compile time. It is easier to extract information from the code and use it to build powerful and useful features.

However, after a few weeks of experimentation, I ended up with a slightly different point of view on the whole matter: the popularity of IDEs for Java encouraged coding conventions would not be so widely accepted if the majority of coders used a plain text editor to edit their source files. Those conventions grew so popular that that today Java appears to be designed to be used with an IDE. Let me give a few examples.

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Tip: serve local files over HTTP with one console command

This weekend I was playing with Facebook’s JavaScript SDK and I needed a quick way to serve over HTTP the files I was working on, so that I could access them in a browser window at http://localhost.

I didn’t want to go through the hassle of setting up Apache on my Mac, though, and I was looking for some quick alternative to installing a local web server. After some Googling, I found a wonderful one liner that did the job, provided that you have Python installed.

Open a Terminal window and go to the directory containing the files you want to serve and run:

python -m SimpleHTTPServer

or, if you are using Python 3,

python -m http.server

you will then be able to access your files on http://localhost:8000/. (You can specify a different port number by passing the number as last argument, just remember that you need root permissions to open sockets on ports lower than 1024.)