Step-by-Step Guide to Building Python Web Apps with webpy on Windows

Python Installation

On Windows, download the appropriate Python version from the official site. Choose Python 2.7 when using webpy because webpy depends on it; newer 3.x versions may cause incompatibility. After installation, add the Python directory to the system PATH so you can run python from any command prompt.

Optionally install from source using --prefix=filepath to specify the install location.

Eclipse Install Python Plugin

Install the PyDev plugin in Eclipse via Help → Install New Software → Add, then select the PyDev package and follow the prompts. After restarting Eclipse, configure the Python interpreter under

Window → Preferences → PyDev → Interpreters → Python Interpreter

by adding the path to python.exe.

webpy Installation

Download webpy from its official site, extract it (preferably into the Python installation directory), and run python setup.py install. If you encounter an ImportError: model utils not exist, edit the generated __init__.py to include sys.path.append('your_webpy_path') so that the package can locate its modules.

MySQLdb Installation

MySQLdb provides Python‑MySQL connectivity. Install it using the Windows MSI installer from SourceForge, ensuring the system PATH points to the Python directory and that the Python and MySQLdb binaries match the same 32‑ or 64‑bit architecture. On Linux, install the libmysqlclient-dev package and adjust site.cfg if mysql_config is not found.

SQLAlchemy Installation

SQLAlchemy is an ORM that works with both Python 2 and 3. Download it from the official site, extract, and install with python setup.py install. After installation, configure the connection string, for example:

"mysql+mysqldb://" + Const.USERNAME + ":" + Const.PASSWD + "@" + Const.HOST + "/" + Const.DBNAME + "?charset=utf8&use_unicode=0&unix_socket=/tmp/mysql.sock"

Code Example

A minimal webpy application looks like this:

from web import application

urls = ("/", "index")

class index:
    def GET(self):
        return "Hello world"

if __name__ == "__main__":
    app = application(urls, globals())
    app.run()

Running the script starts a server on port 8080; visiting http://localhost:8080 displays "Hello world".

The tutorial also shows how to use webpy's form module, emphasizing that the form definition line $def with form must be the first line in the template.

Common Problems

Version mismatches between Python, webpy, and MySQLdb (e.g., using Python 3.x with webpy that requires 2.7).

Missing or incorrect sys.path entries causing import errors.

Incorrect socket paths for MySQL on Linux, leading to OperationalError.

Forgetting to call form.validate() before accessing submitted data.

Permission issues during installation on Linux; using sudo resolves them.