CherryPy-Psycopg2

CherryPy-Psycopg2 is a simple CherryPy Tool to manage a (thread-safe) pool of database connections and make them available to handlers.

Import cherrypy_psycopg2 to make the tool available in CherryPy's default toolbox.

The following configuration settings are understood:

• tools.psycopg2.minconn - passed to the psycopg2 pool constructor
• tools.psycopg2.maxconn - passed to the psycopg2 pool constructor
• tools.psycopg2.dsn - passed to the psycopg2 pool constructor
• tools.psycopg2.cursor_factory - passed to the psycopg2 connection's cursor() method

When the tool is enabled on a handler, it will collect a database connection from the pool, expose a cursor as cherrypy.request.psycopg2_cursor, execute the handler and then commit the transaction (if the handler was successful or raised one of the cherrypy_psycopg2.COMMITTABLE_HANDLER_EXCEPTIONS), or rollback the transaction if the handler raised any other exception.

For example:

class Root:
    @cherrypy.expose
    @cherrypy.tools.psycopg2()
    def index(self):
        cursor = cherrypy.request.psycopg2_cursor
        cursor.execute("SELECT now()")

        return cursor.fetchone()[0]