DataLoader3.DataQuery Class Reference

Public Member Functions
def	__init__

def	query

Public Attributes
	url

Detailed Description

Supports simple user queries through the use of QueryEngine.
    (https://cdcvs.fnal.gov/redmine/projects/qengine/wiki)

Definition at line 135 of file DataLoader3.py.

Constructor & Destructor Documentation

def DataLoader3.DataQuery.__init__	(	self,
		url
	)

Class constructor.

    Args:
 url - Http URL to QueryEngine.

Definition at line 140 of file DataLoader3.py.

 
     def __init__(self, url):
         """ Class constructor.
 
             Args:
                  url - Http URL to QueryEngine.
         """
         self.url = url

DataLoader3.DataQuery.url

url

Definition: DataLoader3.py:146

DataLoader3.DataQuery.__init__

def __init__

Definition: DataLoader3.py:140

def DataLoader3.DataQuery.query	(	self,
		database,
		table,
		columns,
		where = `None`,
		order = `None`,
		limit = `None`,
		echoUrl = `False`
	)

Executes a simple query and returns the results in a list.  List data will
    be in the same order as listed in the columns attribute.

    Args:
 database - The name of the database to be queried.  (This database must
            be in QueryEngine's configuration file.)
 table - The name of the table to query on.
 columns - A comma separated string of the table columns to be returned.
 where - (optional) <column>:<op>:<value> - can be repeated; seperated by ampersand (&)
         op can be: lt, le, eq, ne, ge, gt
 order - (optional) A comma separated string of columns designating row order in the returned list.
         Start the string with a minus (-) for descending order.
 limit - (optional) - A integer designating the maximum number of rows to be returned.

Definition at line 148 of file DataLoader3.py.

 
     def query(self, database, table, columns, where=None, order=None, limit=None, echoUrl=False):
         """ Executes a simple query and returns the results in a list.  List data will
             be in the same order as listed in the columns attribute.
 
             Args:
                  database - The name of the database to be queried.  (This database must
                             be in QueryEngine's configuration file.)
                  table - The name of the table to query on.
                  columns - A comma separated string of the table columns to be returned.
                  where - (optional) <column>:<op>:<value> - can be repeated; seperated by ampersand (&)
                          op can be: lt, le, eq, ne, ge, gt
                  order - (optional) A comma separated string of columns designating row order in the returned list.
                          Start the string with a minus (-) for descending order.
                  limit - (optional) - A integer designating the maximum number of rows to be returned.
         """
 
         parameters = [
             ('dbname', database),
             ('t', table),
             ('c', columns),
             ('x', 'no'),
         ]
         if where is not None:
             parameters.append(('w', where))
         if order is not None:
             parameters.append(('o', order))
         if limit is not None:
             parameters.append(('l', limit))
         fullUrl = self.url + '?' + urllib.parse.urlencode(parameters, doseq=True)
         if echoUrl:
             print(("Url: %s" % fullUrl))
         req = urllib.request.Request(fullUrl)
         ssl_cert_file = os.environ.get("SSL_CERT_FILE")
         try:
             resp = urllib.request.urlopen(req) if ssl_cert_file else urllib.request.urlopen(req, context=ssl.SSLContext())
         except urllib.error.HTTPError as val:
             retValue = False
             code = "%s %s" % (val.code, val.msg)
             text = val.read().decode()
             print(f"\n*** ", code, text)
         except urllib.error.URLError:
             if fullUrl.lower().startswith("https") and ssl_cert_file:
                 print("\n*** Please verify CA certificate provided with SSL_CERT_FILE environment variable!\n")
             pass
         else:
             text = resp.read().decode()
             data = text.split('\n')
             return data[1:]
 
         return []

Public Member Functions

Public Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation