0.24 Python bindings/Advanced

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This page is for advanced objects, not included in the normal import of the bindings, and for most purposes are not needed.

Connection Classes

DBConnection

This connection takes a single input, dbconn, which is a dictionary containing:

  • DBUserName
  • DBHostName
  • DBPassword
  • DBName
  • DBPort

This class provides automatic connection pooling. All database access is performed through the cursor interface, and in order to maintain thread safety, a single connection will only be shared among cursors of the same thread. If more threads attempt to access the database simultaneously than there are connections, a new single use connection will be opened for that specific cursor.

'release' and 'acquire' methods are available to manage the use of connections in the pool, and to automatically spawn new ones if needed. '__enter__' and '__exit__' exist for use as a context manager, and will return a new cursor to use. Each thread is given its own stack in the context manager, so multiple nested cursors are allowed.

The pool size is adjustable. The default pool size for new connection objects can be set with the 'setDefaultSize' classmethod, and an existing connection can be resized with the 'resizePool' method.

BEConnection

This connection takes the following inputs:

  • backend - must be an IP address
  • port
  • localname=None - if not set, will pull it from socket.gethostname()
  • opts=None - a BEConnOpts dictionary providing the capabilities of the connection
  • deadline=10 - a float specifying how long a query may wait for a response

FEConnection

XMLConnection

DBCache

BECache

BEEvent

Data Handling Classes

DictData

This class is based off the ordered dictionary implementation, and intends to provide access to lists of data as dictionary fields and class attributes. For use, this must be subclassed, and the following attributes provided:

  • _field_order - a list of strings containing field names in the order they will be input
  • _field_type - a list of integers indicating the type of data for each field
    1. integer
    2. float
    3. string
    4. unix timestamp (epoch time)
    5. date in ISO8601 format
    6. timestamp in RFC822 format

This class is initialized by providing a list of data, conforming to the provided _field_order and _field_type.

DBData

This class is based off DictData, and provides similar access for database entries. This class will set itself up completely automatically if allowed, but its defaults can be overridden by the following attributes:

  • _logmodule - used to identify the component printing the log
defaults to 'Python %s' % cls.__name__
  • _table - used to specify which database table this class should pull from
defaults to cls.__name__
  • _key - used to determine what fields to use to uniquely identify a database entry
defaults to table primary key
  • _where - used to generate SQL to search for unique entry
defaults to <_key[0]>=%s AND <_key[1]>=%s AND <_key[2]>=%s AND ...
  • _setwheredat - used to set _wheredat and provide the necessary arguments to the _where clause
defaults to self.<_key[0]>,self.<_key[1]>,self.<_key[2]>,...

This class can be initialized in three manners:

  1. Supply the necessary information for the _key
    Recorded((chanid,starttime))
  2. Supply the raw data from the database
    Recorded.fromRaw(cursor.fetchone())
  3. Pull all information from the database table
    Recorded.getAllEntries()

DBDataWrite

This class is based off DBData, and allows for creating, editing, and deleting entries. This class allows an extra attribute _defaults which can be used to populate default values when creating new entries. Any field marked as None will be stripped before being sent to the database, for creation or updates.

DBDataRef

DBDataCRef

Assorted Utility

SchemaUpdate

This class is intended to facilitate managing database schema for external plugins. This class must be subclassed, providing a _schema_name string, matching the setting field used to store the schema version. The create method is called if the variable is not set, and up<version> is called to update the schema. The final schema must issue a StopIteration to terminate the loop.

class MySchemaUpdate( SchemaUpdate ):
    _schema_name = 'MyDBSchemaVer'
    def create(self):
        with self.db.cursor(self.log) as cursor:
            cursor.execute("""CREATE TABLE ....""")
        return 1000
    def up1000(self):
        with self.db.cursor(self.log) as cursor:
            cursor.execute("""UPDATE ....""")
    def up1001(self):
        with self.db.cursor(self.log) as cursor:
            cursor.execute("""UPDATE ....""")
    def up1002(self): raise StopIteration

db = MythDB()
up = MySchemaUpdate(db)
up.run()

This class can also be passed to the DBCache._check_schema() call, or run automatically by setting the _schema_update variable in a DBData class.

databaseSearch

SplitInt

This class is to be included for use with dealing with data over Myth Protocol. It provides two staticmethods, splitInt and joinInt, which convert between a 64-bit long and two 32-bit ints.

CMPVideo

This class is to be included in DictData classes with title and subtitle fields. It allows comparison between classes with such fields for alphabetical sorting, first using title and then subtitle.

CMPRecord

This class is to be included in DictData classes dealing with recordings. It allows comparison between classes for alphabetical sorting , first using starttime and then chanid, falling through to CMPVideo if those fields do not exist.

deadlinesocket

MARKUPLIST

This class is to be included in classes dealing with markup information. It includes a _buildlist(start, end) method used to produce edit lists.

>>> rec = Recorded.getAllEntries().next()
## pull list of commercial breaks
>>> rec.markup._buildlist(static.MARKUP.MARK_COMM_START,static.MARKUP.MARK_COMM_END)
[(21113, 25761), (39842, 45553), (56389, 62395), (79798, 85832), (93379, 99973), (109325, 110523)]
## pull list of wanted content
>>> rec.markup._buildlist(static.MARKUP.MARK_COMM_END,static.MARKUP.MARK_COMM_START)
[(0, 21113), (25761, 39842), (45553, 56389), (62395, 79798), (85832, 93379), (99973, 109325), (110523, 9999999)]