See the PyGrunn website for more info about this one-day Python conference in Groningen, The Netherlands.

You can use tornado for web sockets, streaming, etc. It is a non-blocking web server. You can handle thousands of connections. We is it at PayLogic for something secret.

Three concepts: callback, timeout, event. A callback is something that you want to retun to later. An event is something that happens in a socket. When an event happens, a handler is called. When nothing happens there is a timeout and at the latest then we run the callbacks again. This is all done during an IOLoop.

Handling a web request is coded as some callbacks.

You can keep state around in the code, sharable over all request, so you have less things that you need to build up at the start of a request and have to tear down at the end. This makes it fast.

Push notifications can be done this way.

Audience: Tornado is between Twisted and Django.

See the PyGrunn website for more info about this one-day Python conference in Groningen, The Netherlands.

This is a Python and friends conference, so this is a talk about the Go language.

Go was announced in November 2009, so very new. Ken Thompson and Rob Pike have worked on it, known for working C, Unix, Plan 9, etc.

It is somewhat conservative:

• using {braces}
• imperative
• static typing
• 'unhurried' innovativity

Go is pragmatic:

• it compiles fast
• has garbage collection
• it has a convenient type system
• concurrency primitives
• extensive standard library
• using UTF-8 everywhere

You declare interfaces and types.

You can achieve concurrency with channels and 'go' routines. [Looks simple enough to me, Maurits.] He shows how to handle errors; he likes the exception handling less than in Python. With an unscientific benchmerk for an HTTP daemon Go performed much better than Python in memory usage and requests per second.

Go knows several ways of importing modules, like this, using the 'go' tool:

import {
    "fmt"
    "os"
    "github.com/droundy/goopt"
    "path/filepath"
    "regexp"
    }

Those dependencies are handled during compile time.

Cross-compilation is supported, so compiling for Windows on Linux.

Some problems:

• there are leaks on 32-bit systems
• garbage collection is far from perfect
• due to the name it can be hard to search for on search engines; use 'go lang' as search query

More info: http://golang.org/

See the PyGrunn website for more info about this one-day Python conference in Groningen, The Netherlands.

Most Python web frameworks approach HTTP in the same way. For a project I started looking at it in a more basic way, wondering if the lower TCP level would be enough.

Usually you have a request object, you return a response object, and some other layers (like in WSGI) may change some things along the way. Why don't we abstract that more? What do we like about HTTP?

• It is plain text.
• You can use the REST concept.
• Content negotiation (returning html or json).
• Incredibly well supported: every browser supports it.
• It works where TCP does not. In some cases you cannot use TCP, but can use HTTP, like Windows mobile before version 7.
• It is somewhat simple to implement.
• You can upgrade to custom protocols when needed.

You can stream HTTP or buffer it up. In Python the headers will always be buffered up in WSGI. Same for headers, forms, files. When all has been gathered and is ready, the HTTP is streamed back to the client.

When your server has started reading the data of a request, it can no longer tell the client to stop sending. You could reject too large requests. But what is large? A form of 16 MB that needs to be loaded in memory may be too large. A big half gigabyte file that is directly stored on disk, hardly using any memory in the process, may be fine. So lots of Python web frameworks are vulnerable to attacks by sending it big requests.

See the PyGrunn website for more info about this one-day Python conference in Groningen, The Netherlands.

Inspired by the Haskell programming language he wrote a package for traversing. It does various things with mapping (applying a function to all items in a list) and reducing (combining a list into one return value). There are ways to reduce starting with the left-most value or the right-most value. So there is more flexibility than the standard Python list comprehension. It generalizes generators. Next to the normal yields of a generator you can have a return value at the end.

The theory and definitions went very quick. Then he showed code examples that needed too much formatting and too much explanation to write down here properly, sorry.

He needs to write some documentation and then will put it on PyPI (as traverse.tree or some other name).

See the PyGrunn website for more info about this one-day Python conference in Groningen, The Netherlands.

I will be blogging today about this conference. You may want to check blogs for this day by my brother Reinout too.

Berco Beute, CEO of PayLogic welcomes us, also on behalf of fellow organizers Goldmund Wyldebeast & Wunderliebe. They do a lot with open source, mostly Python. The PyGrunn conference is even more popular now than last year; we are sold out.