Is there visible workflow engine with django or python? in front-end webpage, user could handle workflow without coding via visible workflow interface.
if have these workflow, pls recommend to me its name.
thanks a lot!
did you mean workflow patterns, like http://workflowpatterns.com/
then in python we have spiff workflow engine: https://github.com/knipknap/SpiffWorkflow
specification is created based on the Business Process Model and Notation (BPMN)
I'm working on a website built with Django.
When I'm doing updates on the static files, the users have to hard refresh the website to get the latest version.
I'm using a CDN server to deliver my static files so using the built-in static storage from Django.
I don't know about the best practices but my idea is to generate a random string when I redeploy the website and have something like style.css?my_random_string.
I don't know how to handle such a global variable through the project (Using Gunicorn in production).
I have a RedisDB running, I can store the random string in it and clear it on redeployment.
I was thinking to have this variable globally available in templates with a context_processors.
What are your thoughts on this ?
Django's built-in contrib.staticfiles app already does this for you; see ManifestStaticFilesStorage and CachedStaticFilesStorage.
Here's my work around :
On deployment (from a bash script), I get the shasum of my css style.
I put this variable inside the environment.
I have a context processor for the template engine that will read from the environment.
Is there a decent way to "simulate" server side includes using Python on Google App Engine?
I would really like to split my static html files up into smaller pieces for two reasons:
They will be easier to manage from a development perspective
HTML that is redundant across multiple pages can be more easily re-used and updates to the HTML will show on all pages instead of having to copy and paste updates
Just use template library (Jinja2 is pre-installed on GAE).
"Getting started" doc provides examples.
What you want to use instead of SSI is template inheritance.
Or use a framework like django, which will help in inheritance of templates.
Say I need to have a templating system where a user can edit it online using an online editor.
So they can put if tags, looping tags etc., but ONLY for specific objects that I want to inject into the template.
Can this be made to be safe from security issues?
i.e. them somehow outputing sql connection string information or scripting things outside of the allowable tags and injected objects.
Yes, use a template engine that has sandboxing features, like jinja2
For some quick background, I'm an XHTML/CSS guy with some basic PHP knowledge. I'm trying to dip my feet into the Python pool, and so far understand how to start simple_server and access a simple Hello World return in the same .py file. This is the extent of what I understand though, heh.
How do I integrate the simple_server and your basic XHTML/CSS files? I want to start the server and automagically call, for instance, index.py (does it need to be .py?). Obviously within the index file I would have my markup and stylesheet and I would operate it like a normal site at that point.
My eventual goal is to get a basic message board going (post, edit, delete, user sessions). I realize I'll need access to a database, and I know my way around MySQL enough to not have to worry about those portions.
Thanks for the help.
EDIT: Allow me to clarify my goal, as I have been told Python does a LOT more than PHP. My goal is to begin building simple web applications into my pre-existing static XHTML pages. Obviously with PHP, you simply make sure its installed on your server and you start writing the code. I'd like to know how different Python is in that sense, and what I have to do to, say, write a basic message board in Python.
The other answers give good recommendations for what you probably want to do towards your "eventual goal", but, if you first want to persist with wsgiref.simple_server for an instructive while, you can do that too. WSGI is the crucial "glue" between web servers (not just the simple one in wsgiref of course -- real ones, too, such as Apache or Nginx [both with respective modules called mod_wsgi] as well as, for example, Google App Engine -- that one offers WSGI, too, as its fundamental API) and web applications (and frameworks that make it easier to write such applications).
Everybody's recommending various frameworks to you, but understanding WSGI can't hurt (since it will underlie whatever framework you eventually choose). And for the purpose of such understanding wsgiref.simple_server will serve you for a while longer, if you wish.
Essentially, what you want to do is write a WSGI app -- a function or class that takes two parameters (an "enviroment" dictionary, and a "start response" callable that it must call back with status and headers before returning the response's body). Your "WSGI app" can open your index.py or whatever else it wants to prep the status, headers and body it returns.
There's much more to WSGI (the middleware concept is particularly powerful), though of course you don't have to understand it very deeply -- only as deeply as you care to! See wsgi.org for tutorials &c. Gardner's two-part article, I think, is especially interesting.
Once (and if that's your choice) you understand WSGI, you can better decide whether you want it all hidden in a higher level framework such as Django (so you can focus on application-level issues instead) or use a very light and modular toolbox of WSGI utilities such as Werkzeug -- or anything in-between!-)
I would recommend Django.
"Obviously with PHP, you simply make sure its installed on your server and you start writing the code."
Not true with Python. Python is just a language, not an Apache plug-in like PHP.
Generally, you can use something like mod_wsgi to create a Python plug-in for Apache. What you find is that web page processing involves a lot of steps, none of which are part of the Python language.
You must use either extension libraries or a framework to process web requests in Python. [At this point, some PHP folks ask why Python is so popular. And the reason is because you have choices of which library or framework to use.]
PHP parses the request and allows you to embed code in the resulting page.
Python frameworks -- generally -- do not work this way. Most Python frameworks break the operation down into several steps.
Parsing the URL and locating an appropriate piece of code.
Running the code to get a result data objects.
Interpolating the resulting data objects into HTML templates.
"My goal is to begin building simple web applications into my pre-existing static XHTML pages."
Let's look at how you'd do this in Django.
Create a Django project.
Create a Django app.
Transform your XTHML pages into Django templates. Pull out the dynamic content and put in {{ somevariable }} markers. Depending on what the dynamic content is, this can be simple or rather complex.
Define URL to View function mappings in your urls.py file.
Define view functions in your views.py file. These view functions create the dynamic content that goes in the template, and which template to render.
At that point, you should be able to start the server, start a browser, pick a URL and see your template rendered.
"write a basic message board in Python."
Let's look at how you'd do this in Django.
Create a Django project.
Create a Django app.
Define your data model in models.py
Write unit tests in tests.py. Test your model's methods to be sure they all work properly.
Play with the built-in admin pages.
Create Django templates.
Define URL to View function mappings in your urls.py file.
Define view functions in your views.py file. These view functions create the dynamic content that goes in the template, and which template to render.
Take a look at CherryPy. It's a nice http framework.
It depends on what you want to achieve,
a) do you want to just write a web application without worrying too much abt what goes in the background, how request are being handled, or templates being rendered than go for a goo webframework, there are many choices simple http server is NOT one of them. e.g. use django, turbogears, webpy, cheerpy, pylons etc etc
see http://wiki.python.org/moin/WebFrameworks for full list
b) if you want to develope a simple web framework from start so that you understand internals and improve you knowledge of python, then I will suggest use simple http server
see
how can you create a URL scheme so that URLs are dispatched to correct python function,
see how can you render a html
template e.g. containing place
holder variables $title etc which
you can convert to string using
string.Template
b) would be difficult but interesting exercise to do, a) will get you started and you may be writing web apps in couple of days