Python/Sqlite program, write as browser app or desktop app?_问答_开发者

I am in the planning stages of rewriting an Access db I wrote several years ago in a full fledged program. I have very slight experience coding, but not enough to call myself a programmer by far. I'll definitely be learning as I go, so I'd like to keep everything as simple as possible. I've decided on Python and SQLite for my program, but I need help on my next decision.

Here is my situation

1) It'll be run locally on each machine, all Windows computers

2) I would really like a nice looking GUI with colors, nice screens, menus, lists, etc,

3) I'm thinking about using a browser interface because (a) from what I've read, browser apps can look really great, and (b) I understand 开发者_JAVA技巧there are lots of free tools to assist in setting up the GUI/GUI code with drag and drop tools, so that helps my "keep it simple" goal.

4) I want the program to be totally portable so it runs completely from one single folder on a user's PC, with no installation(s) needed for it to run

(If I did it as a browser app, isn't there the possibility that a user's browser settings could affect or break the app. How likely is this?)

For my situation, should/could I make it a browser app? What would be the pros and cons for my situation?

Writing a desktop application as a locally-hosted web application isn't typically a good idea. Although it's possible to create great user interfaces with HTML, CSS, and Javascript, it's far easier to create interfaces with conventional GUI frameworks.

Using web technologies to create your desktop GUI would introduce a great deal of unnecessary complexity to your application.

Creating user interfaces with HTML and CSS is difficult and time-consuming. HTML is a document markup language and CSS is a document formatting language; neither is well-suited to creating GUIs.
Using web technologies makes your application depend on the user's web browser. Far too many people are still using old, crippled browsers such as IE 6 and 7 that don't follow modern standards. You'll spend hours if not days trying to track down interface bugs that only happen on certain browsers.
You'll need to serve your application with a web server, introducing another layer of complexity. Your application will have to communicate with your interface through restricted web technologies without any of the benefits of a true web application.

I recommend using a desktop GUI framework, instead. In particular, I think wxPython would be the best GUI framework for you to use; it's stable, widely used, well documented, and highly portable. In addition, you can use a GUI-based interface builder such as Boa Constructor or possibly wxGlade to design your application's user interface. In summary, creating an application with almost any desktop GUI framework would be easier than using web technologies.

I've done a desktop app running on windows and I think that it is a great way to develop app.

I would recommend to have a look at bottle. It is a lightweight web framework. It is less capabale than Django for example but it does well. It can be packed with py2exe if you want to deploy on machines without Python.

There is a lot of javascript libs on the web to help you. I like jquery and jquery-ui, raphaeljs ... but there are some others.

My app is running into a small browser based on the mshtml component of Pyjama-Desktop. This way, the user doesn't know that it is a web app. But you could let the app running into the favorite browser, webbrowser python module might be interesting for you.

If your app needs to access your filesystem, a browser-based app may be tricky. For security reasons, a browser doesn't have full access to your filesystem. However, you can mimick file open with ajaxupload and file save with an iframe.

If it only deals with a sqllite database, i think that it is a very good choice.

I hope it helps

Pyjamas-Desktop

You did not mention if you are on windows or linux or any other OS.
If you are writing a browser app the first thing you are going to need is a web server, if each user is running the app on his local machine => means each user has to have a webserver running locally.

Also there are a lot of Rapid Development GUI toolkits such as wxPython and Glade which make design of GUI apps simple and easier.

I would suggest that if you are building a network app -> Take the browser route.

If you are building standalone app then go with a native application.

Here is an almost exhaustive list of all the frameworks. you can choose whatever suits your needs. http://wiki.python.org/moin/GuiProgramming

I personally favor PyGtk, however it has a little learning curve associated with it if you havent done any GUI programming before.

I think it should work. What are you afraid of? Proxy settings, firewall?

I think running web server locally isn't hard for power user but it could be a problem for average user (even integrated with your app).

Probably You should run your app as service because forcing user to start server before entering web page, could be frustrating.

I would prefer other solutions. I would probably use Java (Swing) or C++ with QT. But I like Your approach, especially that it allows easy prototyping. If You prefer web style development you could try http://www.appcelerator.com/products/titanium-desktop-application-development/ it creates desktop apps using html+java script +webkit. But I didn't tried it my self (but I would like to).

Also Adobe Air could be probably good option for You.

I would suggest a browser application. This eliminates the need for installation on client computers (and as such, as OS agnostic), and is accessible from anywhere in the world if the DNS is set up correctly for the server.

Using a web interface allows you to make use of some of the more powerful User Interface tools, such as:

The ability to use CSS for spectacular design
The availability of JavaScript Utilities (jQuery, ExtJS, etc.)
Easily modified compared to Desktop applications
Higher accessibility
Consistent UI (e.g. Users already know how "back" works, etc)
Centralized updates (Just update the server, not each client)

Your choice of application type will be related both to the technology constraints and the type of user experience you plan to deliver.

Rich Client Application: Usually developed as a stand-alone application. Can support disconnected or occasionally connected scenarios. Uses the processing and storage resources of the local machine.
Web Application: Can support multiple platforms and browsers. Supports only connected scenarios. Uses the processing and storage resources of the server.

I personally favor PyQt in your case for a portable application.

The homepage for PyQt is http://www.riverbankcomputing.com/software/pyqt/

PyQt supports the Windows, Linux, UNIX and MacOS/X platforms.

PyQt4 is a set of Python bindings for Qt 4 that are dual-licensed under the GPL (version 2 and 3, with additional license exceptions) and a commercial license. There is also PySide by Nokia - new alternative bindings (as of November 2009) with LGPL license that struggle to be API compatible (at least until Qt 4.6) with PyQt4.

Tools and docs

PyQt Reference Documentation.
PyQt4 book: http://www.qtrac.eu/pyqtbook.html
The pyuic4 utility is a command line interface to the uic module. Conver xml ui from Qt to python.

Qt Designer is a powerful cross-platform GUI layout and forms builder. It allows you to rapidly design and build widgets and dialogs using on-screen forms using the same widgets that will be used in your application. PyQt4 exposes much of the functionality of Qt 4 (From Nokia) to Python, including:

A comprehensive set of widgets
Flexible layout managers
Standard GUI features for applications (menus, toolbars, dock windows)
Easy communication between application components (signals and slots)
A unified painting system with transparency, anti-aliasing, OpenGL integration and SVG support
Internationalization (i18n) support and integration with the Qt Linguist translation tool
Etc.

You question is a little broad. I'll try to cover as much as I can.

First, what I understood and my assumptions.

In your situation, the sqlite database is just a data store. Only one process (unless your application is multiprocess) will be accessing it so you won't need to worry about locking issues. The application doesn't need to communicate with other instances etc. over the network. It's a single desktop app. The platform is Windows.

Here are some thoughts that come to mind.

If you develop an application in Python (either web based or desktop), you will have to package it as a single executable and distribute it to your users. They might have to install the Python runtime as well as any extra modules that you might be using.
Guis are in my experience easier to develop using a standalone widget system than in a browser with Javascript. There are things like Pyjamas that make this better but it's still hard.
While it's not impossible to have local web applications running on each computer, your real benefits come if you centralise it. One place to update software. No need to "distribute" etc. This of course entails that you use a more powerful database system and you can actually manage multiple users. It will also require that you worry about browser specific quirks.

I'd go with a simple desktop app that uses a prepackaged toolkit (perhaps Tkinter which ships with Python). It's not the best of approaches but it will avoid problems for you. I'd also consider using a language that's more "first class" on windows like C# so that the runtimes and other things are already there. You requirement for a fancy GUI is secondary and I'd recommend that you get the functionality working fine before you focus on the bells and whistles.

Good luck.