pydap.handlers.pcic

This module provides an Pydap handler which reads in-situ observations out of the BC Provincial Climate Data Set. It is implemented as a subclass of pydap.handlers.sql.Handler (the Pydap SQL handlers). Since the Pydap SQL handler is written to use an on-disk config file for each dataset, this handlers generates the config file dynamically in memory and then uses it to instantiate the base class.

The handler will configure a different dataset for each station based on the file path of the request. In general the file path is assumed to be

.../(raw|climo)/[network_name]/[native_id]/

Each dataset will contain a variety of global attributes such as the station and network names, latitude and longitide of the station and some contact information. Each dataset will contain one sequence named station_observations and some number of variables (including time) attached to that sequence. Each variable will be attributed with its name, long_name, CF standard_name, CF cell_method and the units.

class pydap.handlers.pcic.ClimoPcicSqlHandler(dsn, sesh=None)

Subclass of PcicSqlHandler which handles the climatological observations

get_full_query(stn_id, sesh)

Sends a special query to the database that actually retrieves generated SQL for constructing an observation table (time by variable) for a single station. Uses the query_one_station stored procedure.

Parameters:

• stn_id (int or str) – the database station_id of the desired station
• sesh – sqlalchemy session

get_vars(stn_id, sesh)

Makes a database query to retrieve all of the climatological variables for a particular station

class pydap.handlers.pcic.PcicSqlHandler(dsn, sesh=None)

A Pydap handler which reads in-situ observations from the BC Provincial Climate Data Set.

__call__(environ, start_response)

Parameters:environ – WSGI environment such that PATH_INFO is set to something that matches the pattern /[network_name]/[native_id].sql.[response] Return type:iterable WSGI response

__init__(dsn, sesh=None)

x.__init__(…) initializes x; see help(type(x)) for signature

__weakref__

list of weak references to the object (if defined)

create_ini(sesh, net_name, native_id)

Creates the actual text of a pydap SQL handler config file and returns it as a StringIO. self.filepath should be set before this is called. It will typically be something like .../[network_name]/[native_id].rsql. The database station_id is looked up from that.

Parameters:environ – WSGI environment which must contain a dsn string under the key pydap.handlers.pcic.dsn Return type:StringIO.StringIO

class pydap.handlers.pcic.RawPcicSqlHandler(dsn, sesh=None)

Subclass of PcicSqlHandler which handles the raw observations

get_full_query(stn_id, sesh)

Sends a special query to the database that actually retrieves generated SQL for constructing an observation table (time by variable) for a single station. The query needs to return at least one column (obs_time) with additional columns for each available variable, if any. Uses the query_one_station stored procedure.

Parameters:

• stn_id (int or str) – the database station_id of the desired station
• sesh – an sqlalchemy session

get_vars(stn_id, sesh)

Makes a database query to retrieve all of the raw variables for a particular station

pydap.handlers.pcic.session_scope(*args, **kwds)

Provide a transactional scope around a series of operations.