corduroy An asynchronous CouchDB client library
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client Python library Python couchdb CouchDB client

corduroy Description

corduroy is a Python module that provides a python-friendly wrapper around CouchDB’s HTTP-based API. Behind the scenes it hooks into the asynchronous i/o routines from your choice of Tornado or the Requests & Gevent modules.Using corduroy you can query the database without blocking your server’s event loop, making it ideal for CouchApp micro-middleware or scripted batch operations.UsageAs a real world(ish) example of working with Corduroy, consider this pair of Tornado event handlers which update a url-specifed document then query a view. The first uses explicit callbacks to resume execution after each response from the database is received:db = Database('players')class RankingsUpdater(tornado.web.RequestHandler): @tornado.web.asynchronous def post(self, player_id): self.new_score = int(self.request.body) db.get(player_id, callback=self.got_player) def got_player(doc, status): doc.score = self.new_score db.save(doc, callback=self.saved_player) def saved_player(conflicts, status): db.view('leaderboard/highscores', callback=self.got_highscores) def got_highscores(rows, status): self.write(json.dumps(rows)) self.finish()An alternative syntax is available (when using Tornado) through the use of the @relax decorator. Instead of defining callbacks for each database operation, the library can be called as part of a yield expression.Tornado’s generator module will intercept these yields and provide a callback automatically. The result is code that looks quite sequential but will still execute asyncronously:class RankingsUpdater(tornado.web.RequestHandler): @relax def post(self, player_id): # update this player's score doc = yield db.get(player_id) doc.score = int(self.request.body) yield db.save(doc) # return the new rankings highscores = yield db.view('leaderboard/highscores') self.write(json.dumps(highscores)) self.finish()For a gentle introduction to Corduroy (and CouchDB in general), take a look at the Guide. Documentation for all of Corduroy’s module-level classes can be found in the Reference section.InstallationAutomatic InstallationCorduroy can be found on PyPi and can be installed with your choice of pip or easy_install.Manual InstallationDownload corduroy-0.9.0.tar.gz:tar xvzf corduroy-0.9.0.tar.gzcd corduroy-0.9.0python setup.py installDependenciesIf you’re writing a Tornado app, Corduroy can use its pure-python HTTP client by installing with:pip install corduroy tornadoOr if you’d prefer the libcurl-based client (which supports pooling and other niceties), use:pip install corduroy tornado pycurlIf pycurl complains (I’m looking at you, OS X), try:env ARCHFLAGS="-arch x86_64" pip install pycurlGevent users can install with:pip install corduroy requests geventThe library can also be used with plain-old blocking i/o:pip install corduroy requestsProduct's homepage

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