bottle-sqlite/bottle_sqlite.py

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'''
Bottle-sqlite is a plugin that integrates SQLite3 with your Bottle
application. It automatically connects to a database at the beginning of a
request, passes the database handle to the route callback and closes the
connection afterwards.
To automatically detect routes that need a database connection, the plugin
searches for route callbacks that require a `db` keyword argument
(configurable) and skips routes that do not. This removes any overhead for
routes that don't need a database connection.
Usage Example::
import bottle
from bottle.ext import sqlite
app = bottle.Bottle()
plugin = sqlite.Plugin(dbfile='/tmp/test.db')
app.install(plugin)
@app.route('/show/:item')
def show(item, db):
row = db.execute('SELECT * from items where name=?', item).fetchone()
if row:
return template('showitem', page=row)
return HTTPError(404, "Page not found")
'''
__author__ = "Marcel Hellkamp"
__version__ = '0.1.2'
__license__ = 'MIT'
### CUT HERE (see setup.py)
import sqlite3
import inspect
from bottle import HTTPResponse, HTTPError
class SQLitePlugin(object):
''' This plugin passes an sqlite3 database handle to route callbacks
that accept a `db` keyword argument. If a callback does not expect
such a parameter, no connection is made. You can override the database
settings on a per-route basis. '''
name = 'sqlite'
def __init__(self, dbfile=':memory:', autocommit=True, dictrows=True,
keyword='db'):
self.dbfile = dbfile
self.autocommit = autocommit
self.dictrows = dictrows
self.keyword = keyword
def setup(self, app):
''' Make sure that other installed plugins don't affect the same
keyword argument.'''
for other in app.plugins:
if not isinstance(other, SQLitePlugin): continue
if other.keyword == self.keyword:
raise PluginError("Found another sqlite plugin with "\
"conflicting settings (non-unique keyword).")
def apply(self, callback, context):
# Override global configuration with route-specific values.
conf = context['config'].get('sqlite') or {}
dbfile = conf.get('dbfile', self.dbfile)
autocommit = conf.get('autocommit', self.autocommit)
dictrows = conf.get('dictrows', self.dictrows)
keyword = conf.get('keyword', self.keyword)
# Test if the original callback accepts a 'db' keyword.
# Ignore it if it does not need a database handle.
args = inspect.getargspec(context['callback'])[0]
if keyword not in args:
return callback
def wrapper(*args, **kwargs):
# Connect to the database
db = sqlite3.connect(dbfile)
# This enables column access by name: row['column_name']
if dictrows: db.row_factory = sqlite3.Row
# Add the connection handle as a keyword argument.
kwargs[keyword] = db
try:
rv = callback(*args, **kwargs)
if autocommit: db.commit()
except sqlite3.IntegrityError, e:
db.rollback()
raise HTTPError(500, "Database Error", e)
except HTTPError, e:
raise
except HTTPResponse, e:
if autocommit: db.commit()
raise
finally:
db.close()
return rv
# Replace the route callback with the wrapped one.
return wrapper
Plugin = SQLitePlugin