couch.py

""" CouchDB Wrapper Class
This is based on an example wrapper class found in
http://wiki.apache.org/couchdb/Getting_started_with_Python.

TODO:
    * Support Keep-Alive
"""


import httplib
import json


class Couch:
    """Basic wrapper class for operations on a couchDB"""

    def __init__(self, host, port=5984, options=None):
        self.host = host
        self.port = port

    def connect(self):
        return httplib.HTTPConnection(self.host, self.port) # No close()

    # Database operations

    def createDb(self, dbName):
        """Creates a new database on the server"""
        res = self.put('/{0}/'.format(dbName), "")
        success = 200 <= res.status < 300
        return (success, json.loads(res.read()))

    def deleteDb(self, dbName):
        """Deletes the database on the server"""
        res = self.delete('/{0}/'.format(dbName))
        success = 200 <= res.status < 300
        return (success, json.loads(res.read()))

    def listDb(self):
        """List the databases on the server"""
        res = self.get('/_all_dbs')
        return json.loads(res.read())

    def infoDb(self, dbName):
        """Returns info about the couchDB"""
        res = self.get('/{0}/'.format(dbName))
        success = 200 <= res.status < 300
        return (success, json.loads(res.read()))

    def listDocs(self, dbName):
        """List all documents in a given database"""
        res = self.get('/{0}/_all_docs'.format(dbName))
        success = 200 <= res.status < 300
        return (success, json.loads(res.read())['rows'])

    # Document operations

    def readDoc(self, dbName, docId):
        """Open a document in a given database"""
        res = self.get('/{0}/{1}'.format(dbName, docId))
        if res.status >= 300:
            return None
        else:
            return res.read()

    def writeDoc(self, body, dbName, docId=None, rev=None):
        """Create/update a document in a given database"""
        if docId:
            uri = '/{0}/{1}'.format(dbName, docId)
            if rev:  uri += '?={0}'.format(rev)
            res = self.put(uri, body)
        else:
            res = self.post('/{0}/'.format(dbName), body)

        success = 200 <= res.status < 300
        return (success, json.loads(res.read()))

    def deleteDoc(self, dbName, docId, rev):
        """Delete a document of a given revision in a given database"""
        res = self.delete('/{0}/{1}?rev={2}'.format(dbName, docId, rev))

        success = 200 <= res.status < 300
        return (success, json.loads(res.read()))

    # Basic http methods

    def get(self, uri):
        c = self.connect()
        headers = {"Accept": "application/json"}
        c.request("GET", uri, None, headers)
        return c.getresponse()

    def post(self, uri, body):
        c = self.connect()
        headers = {"Content-type": "application/json"}
        c.request('POST', uri, body, headers)
        return c.getresponse()

    def put(self, uri, body):
        c = self.connect()
        if len(body) > 0:
            headers = {"Content-type": "application/json"}
            c.request("PUT", uri, body, headers)
        else:
            c.request("PUT", uri, body)
        return c.getresponse()

    def delete(self, uri):
        c = self.connect()
        c.request("DELETE", uri)
        return c.getresponse()