Can I use any external libraries that are developed for python on Pyramid?
I mean is it the 'normal python' to which I can import external libraries as I do with the standard python downloaded from python.org
What is the situation for Django and Flask and Bottle?
My intention is to create backend for a mobile app. I want to do it specifically in Python because I need to learn python.
The app is a native android app. Therefore the there is no need to use response with nice html code.
I just want Django/Flask/Pyramid to direct http request to relevant python functions. Everything else including user auth, database is handled by my code I write. Is there a better more simpler way to map http request/responses with the relevant functions without using these 3 platforms?
In case I use one of these can I still use my own libraries?
Yes, all of those frameworks are simply running Python code to handle requests. Within limits you can use external libraries just fine.
The limits usually are dictated by the WSGI server and the nature of HTTP requests; if your library changes the event model (like gevents) or relies heavily on changing the interpreter state (global state, localization) or takes a long,long time to produce results, then you may need to do more work to integrate.
Related
I'm trying to build a desktop application using Python. To make it able to be used on as many platforms as possible, I think web UI may be a good choice. This boils down to the problem of making a local HTTP server first. I did some survey and found that people are mainly talking about BaseHTTPServer and SimpleHTTPServer. For prototyping, subclassing them may suffice.
Besides pure prototyping, I also want to leave some room for extension to real service. That is, once mature, I'd like to move the codes to a real dedicated HTTP server, so that end users only need a browser to use it.
I say "extensible" in the following sense:
The code modification is as minimum as possible in the migration process.
I will focus on algorithm in the prototyping stage. I also want to leave some room for future front end designer.
It looks WSGI + Django is a widely mentioned combination. After some search, what I found is using WSGI in apache or nginx. Is it possible to use self-contained modules? i.e. wsgiref + Django, so that I can start everything just from one entry script. I don't want to bother potential first adopters by asking them install apache and configure it. It will be very good if you have sample codes or pointers for further reading.
I'm new to Python and web programming in Python. Thanks for your help. I just try to make sure I'm on the right track. My underlying algorithms is implemented in Python 2.7. So the UI solution had better also be in Python 2.7.
I think what you may want is Bottle. It is a web framework that only needs the standard library to be installed. It also has compatibility with many other production servers, as well as shipping with it's own development server. And if that isn't good enough, it is all in a single file, and has support with many different templating languages, as well as it's own built in templating language.
Check it out here: http://bottlepy.org/docs/dev/
As mentioned bottle is a good choice, I personally like Flask, which if I recall correctly is what bottle is based off of. Anyways there are three things that really make Flask a joy to use.
Blueprints - essentially an application architecture
Flask-Sijax - allows for comet technology
Celery - an asynchronous task queue/job queue based on distributed message passing
there are a lot of other plugins, including one for an admin interface that I haven't tried out yet but it looks promising, and it works with Python 2.7
In essence I want to run existing python scripts through a web browser, display the text and plots(if any) and also keeping the ability to run them through the command line.
I am wondering is there any toolkit that can help me with the development.Also it would be nice if the toolkit does or allows JavaScript based interactive plots.
Thanks!
-Abhi
WSGI is designed for just this purpose - it provides an interface for a web server to initiate python scripts.
You probably don't want to work with WSGI in the raw. Flask is a straightforward, simple framework you might use for this.
The details of how to actually build a WSGI web server are well beyond the scope of a stackoverflow answer - you can find plenty of tutorial docs on Flask's website.
I am used to PHP having applications. For example,
c:\xampp\htdocs\app1
c:\xampp\htdocs\app2
can be accessed as
localhost://app1/page.php
localhost://app2/page.php
Things to be noticed:
a directory placed inside the www-root directory maps directly with the URL
when a file/directory is added/removed/changed, the worker processes seamlessly reflect that change (new files are hot-deployed).
I am on the lookout for a mature python web framework. Its for a web API which will be deployed for multiple clients, and each copy will diverge on customization. And our workflow has frequent interaction/revision cycles between us and our clients. Hence the "drag and drop" deployment is a must.
Which python framework enables this? I prefer a lightweight solution (which doesnt impose MVC, ORMs etc)
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fastcgi, cherrypy, and python
No mature python framework that I'm aware of allows you to map urls to python modules, and frankly, for good reason. You can do this with CGI, but it's definitely not the recommended way to deploy python apps. Setting that requirement aside, flask and bottle are both lightweight micro web-frameworks with similar approaches, both allow you to reload automatically when changes are detected (this is only wise during development).
There is no web framework in Python that I know of that lets you do that out of the box, but if you need it it's not to hard to add with a bit of convention over configuration.
Simply pick your web framework of choice in Python and then write a wrapper to the main application that walks a directory or set of directory and auto-registers routes from the modules inside of them. Have your modules do the same thing in their __init__.py files to the other files located with them. Then just set up your WSGI code to autoreload when the WSGI script is updated and your deployment during development simply becomes a two step process - add file then touch dev_app.wsgi. You could even add a real deployment option to this wrapper that walks a set up dev environment like this and generates hard-coded URL-to-function mappings for deployment.
However, all of this work isn't really necessary. Python is not PHP and the way you develop in one doesn't necessarily translate to the other well. If the client wants variable routes, use dynamic routes and give them (or you) an admin interface to control the mapping of content to URL. Use flat files, SQLite, a NoSQL datastore, or the ether to store these mappings and the content. Use a template engine like Jinja2, Mako, Cheetah or Genshi to maintain your general layout. Wrap this all up with an object oriented structure to make extending it easy (or use a functional paradigm if that comes more naturally to you). Or, drop the whole dynamic in production portion and generate flat HTML files a la Jekyll.
CherryPy is a mature web framework that redeploys automatically when changes are detected. The file structure - URL isn't there, but it is a lightweight framework that doesn't impose ORM, MVC, or even a templating engine.
If you are used to PHP, you might want to take a look at the Apache modules mod_python or mod_wsgi (and WSGI in general if you do web development -- which is the Pythonic way).
With those two modules, the Python interpreter gets started every time a request comes in (similar to PHP). Needless to say, this slows things down but you'll always get the result based on your newest code. Depending on your expected traffic numbers, this might or might not be okay for you.
BUT: If you decide to write your own framework, you most probably do not want to write a system that supports "hot-deploying". Even though the reload() command is built-in, it takes more than just that and will get you into a world full of pain.
what is the advantage of using a python virtualbox API instead of using XPCOM?
The advantage is that pyvb is lot easier to work with.
On the contrary the documentation for the python API of XPCOM doesn't exist, and the API is not pythonic at all. You can't do introspection to find methods/attributes of an object, etc. So you have to check the C++ source to find how it works or some python scripts already written (like vboxshell.py and VBoxWebSrv.py).
On the other hand pyvb is really just python wrapper that call VirtuaBoxManager on the command line. I don't know if it's a real disadvantage or not?
I would generally recommend against either one. If you need to use virtualization programmatically, take a look at libvirt, which gives you cross platform and cross hypervisor support; which lets you do kvm/xen/vz/vmware later on.
That said, the SOAP api is using two extra abstraction layers (the client and server side of the HTTP transaction), which is pretty clearly then just calling the XPCOM interface.
If you need local host only support, use XPCOM. The extra indirection of libvirt/SOAP doesn't help you.
If you need to access virtualbox on a various hosts across multiple client machines, use SOAP or libvirt
If you want cross platform support, or to run your code on Linux, use libvirt.
From sun's site on VirtualBox python APIs:
SOAP allows to control remote VMs over
HTTP, while XPCOM is much more
high-performing and exposes certain
functionality not available with SOAP.
They use very different technologies
(SOAP is procedural, while XPCOM is
OOP), but as it is ultimately API to
the same functionality of the
VirtualBox, we kept in bindings
original semantics, so other that
connection establishment, code could
be written in such a way that people
may not care what communication
channel with VirtualBox instance is
used.
From that article, I'm having trouble seeing the difference between "python virtualbox API" and "XPCOM". Could you provide a link to the API you're thinking of?
Given that I know no web frameworks in Python and would like to keep it Very Simple at the moment (as I am Very Stupid), for what is a prototype of sketchy longevity, are there any streamlined, simple, "batteries-included" modules for this? (It is also too early in my Python career to evaluate frameworks, select one, and learn it.) I see a module named "Cookie," which could serve as a foundation, but nothing session-specific.
I'm familiar with the basic session concepts, having used them in classic ASP and gotten into the nuts-and-bolts of them in Perl, but I am not seeing a lot for Python. Beaker looks interesting, but then the documentation seems to require middleware with WSGI and I'm back to the frameworks problem.
I've found an old recipe on ActiveState for sessions, which could obviously use some buffing up. The information being held is not anything anyone would mind having been grabbed, so while I am normally quite security conscious, I would be willing to be a little bit more lax with this prototype.
Or is this a "roll-your-own" problem?
I will be using Python 2.6 on IIS 7.0.
I think the web2py (web framework) is easy enough for you. I think it is the simplest approach of making a website or webservice. It will be also easier, than to understand Cookie or the other modules of python related to web-things.
You can start a session, by just typing:
session.your_session_name = "blabla" # or whatever you want to store
To make a cookie, just look here.
In web2py you don't have to configure anything. Just download it and start web2py.py. (you must have python 2.6 < installed.) You can also find some examples and a web-slide.
The Python Cookie module does nothing more than to hold some values in a dictonary-like object, but I think you have to store it yourself on your harddisk.
CherryPy is worth looking into. Yes it is a framework, and yes it requires WSGI, but it is extremely lightweight compared to other more robust alternatives.
There is another question that was answered on SO that gives a brief example on how to manage sessions with CherryPy. As you can see it makes it very easy to get up and running quickly.
Lastly, here is a little document about setting up IIS for use with CherryPy.
WSGI is not a framework, nor does it require that you choose one -- it's THE standard way to run any Python web app framework on any Python-supporting web server, including a CGI one. If you have a WSGI application named app, and want to run it on CGI, see the docs and use wsgiref.handlers.CGIHandler().run(app), as the docs say.
So, you can perfectly well use Beaker via WSGI (on top of CGI) -- e.g., take the example in Beaker's docs and just add (the needed imports and) the run call above (using the wsgi_app object that example constructs, plus of course a session.save and as well needed as, again, the Beaker docs explain right afterwards).
Rich or heavy frameworks have their place but so do lightweight, flexible components like Beaker -- and WSGI middleware is a great way to leverage such components without requiring any "framework-y" arrangements, just good old WSGI (on top of CGI or anything else).
BTW, the best way to run WSGI on IIS might be isapi-wsgi (I can only say "might" because I have no IIS installation on which to test it;-). But as long as you code to WSGI (with any framework or with none at all), that will only be an optimization -- your application won't change (net of what handler's run or equivalent method you need to call;-) whether it's running on CGI, IIS via ISAPI, Google App Engine, or any other server-and-interface-thereto combination