The OpenERP Client Library is a Python library to communicate with an OpenERP Server using its web services in an user-friendly way. It was created for those that doesn't want to code XML-RPC calls on the bare metal. It handles XML-RPC as well as JSON-RPC protocol and provides a bunch of syntaxic sugar to make things a lot easier.

First install the library:

sudo easy_install openerp-client-lib

Now copy-paste the following script describing a simple interaction with an OpenERP server:

import openerplib

connection = openerplib.get_connection(hostname="localhost", database="my_db", \
    login="my_user", password="xxx")
user_model = connection.get_model("res.users")
ids = user_model.search([("login", "=", "admin")])
user_info = user_model.read(ids[0], ["name"])
print user_info["name"]
# will print "Administrator"

In the previous script, the get_connection() method creates a Connection object that represents a communication channel with authentification to an OpenERP server. By default, get_connection() uses XML-RPC, but you can specify it to use JSON-RPC. You can also change the port. Example with a JSON-RPC communication on port 6080:

connection = openerplib.get_connection(hostname="localhost", protocol="jsonrpc", port=6080, ...)

The get_model() method on the Connection object creates a Model object. That object represents a remote model on the OpenERP server (for OpenERP addon programmers, those are also called osv). Model objects are dynamic proxies, which means you can remotely call methods in a natural way. In the previous script we demonstrate the usage of the search() and read() methods. That scenario is equivalent to the following interaction when you are coding an OpenERP addon and this code is executed on the server:

user_osv = self.pool.get('res.users')
ids = user_osv.search(cr, uid, [("login", "=", "admin")])
user_info = user_osv.read(cr, uid, ids[0], ["name"])

Also note that coding using Model objects offer some syntaxic sugar compared to vanilla addon coding:

• You don't have to forward the "cr" and "uid" to all methods.

• The read() method automatically sort rows according the order of the ids you gave it to.

• The Model objects also provides the search_read() method that combines a search and a read, example:

  user_info = user_model.search_read([('login', '=', 'admin')], ["name"])[0]
  

Here are also some considerations about coding using the OpenERP Client Library:

• Since you are using remote procedure calls, every call is executed inside its own transaction. So it can be dangerous, for example, to code multiple interdependant row creations. You should consider coding a method inside an OpenERP addon for such cases. That way it will be executed on the OpenERP server and so it will be transactional.
• The browse() method can not be used. That method returns a dynamic proxy that lazy loads the rows' data from the database. That behavior is not implemented in the OpenERP Client Library.

• XML-RPC: OpenERP version 6.1 and superior
• JSON-RPC: OpenERP version 8.0 (upcoming) and superior