diff --git a/README.md b/README.md index d136657b..d3d96619 100644 --- a/README.md +++ b/README.md @@ -41,7 +41,61 @@ Uninstalling Establishing a (secure) connection ---------------------------------- -One way of starting a session is to pass iRODS credentials as keyword +An `iRODSSession` instance is the interface object through which iRODS server +APIs can be invoked. + +One way to create the session object, assuming one has already successfully +set up a client environment via `iinit`, is by using a simple `make_session` +call: + +>>> from irods.helpers import make_session +>>> session = make_session() + +It is also possible to use the constructor form directly, passing +connection and authentication options within the call parameter list: + +>>> from irods.session import iRODSSession +>>> with iRODSSession(host='localhost', port=1247, user='bob', password='1234', zone='tempZone') as session: + +Once created, an instance can be managed with an application-appropriate choice +from a couple of possible patterns. Either the programmer can simply manage +the instance quite naturally, allowing reference counting to +let it pass out-of-scope and destruct its server connection(s) at the +proper time: + +```python +home_coll = session.collections.get(f'/tempZone/home/{session.username}') +# (... Further instances of calls to the server through 'session' may follow.) +``` + +This casual approach usually ends up being the most efficient, as connection +pooling will allow potentially disparate uses of a server connection to happen +consecutively without harm, and without the need for disposing of or +interrupting the connection. + +Alternatively, a context manager may be employed, forcing connections to be +temporarily cleared from the session object once a given block of code has +executed: + +```python +with make_session() as session: + my_user = session.users.get(session.username) + # Here, we can have further usage of 'session' in this code block, and at + # the end of it, session.cleanup() is implicitly called. +``` + +Either way, the instance remains available for further such use afterward, +until destructed. + +We should, of course, be careful how many still-connected `iRODSSession` +objects we retain references to in an application, as having more of them than +the system can support database connections for can result in spurious failure +of iRODS client connections. + +Finer points in connecting to the iRODS server +---------------------------------------------- + +iRODS credentials may also be passed as keyword arguments: ```python