158 lines
4.7 KiB
Python
158 lines
4.7 KiB
Python
# -*- coding: utf-8 -*-
|
|
# Relational
|
|
# Copyright (C) 2008 Salvo "LtWorf" Tomaselli
|
|
#
|
|
# Relation is free software: you can redistribute it and/or modify
|
|
# it under the terms of the GNU General Public License as published by
|
|
# the Free Software Foundation, either version 3 of the License, or
|
|
# (at your option) any later version.
|
|
#
|
|
# This program is distributed in the hope that it will be useful,
|
|
# but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
# GNU General Public License for more details.
|
|
#
|
|
# You should have received a copy of the GNU General Public License
|
|
# along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
#
|
|
# author Salvo "LtWorf" Tomaselli <tiposchi@tiscali.it>
|
|
#
|
|
# Stuff non-related to relational algebra, but used for maintenance.
|
|
|
|
import http.client
|
|
import urllib.parse
|
|
import os.path
|
|
|
|
from relational.relation import relation
|
|
from relational import parser
|
|
from relational.rtypes import is_valid_relation_name
|
|
|
|
|
|
def send_survey(data):
|
|
'''Sends the survey. Data must be a dictionary.
|
|
returns the http response'''
|
|
|
|
post = ''
|
|
for i in data.keys():
|
|
post += '%s: %s\n' % (i, data[i])
|
|
|
|
# sends the string
|
|
params = urllib.parse.urlencode({'survey': post})
|
|
headers = {"Content-type":
|
|
"application/x-www-form-urlencoded", "Accept": "text/plain"}
|
|
connection = http.client.HTTPConnection('feedback-ltworf.appspot.com')
|
|
connection.request("POST", "/feedback/relational", params, headers)
|
|
|
|
return connection.getresponse()
|
|
|
|
|
|
def check_latest_version():
|
|
'''Returns the latest version available.
|
|
Heavely dependent on server and server configurations
|
|
not granted to work forever.'''
|
|
connection = http.client.HTTPConnection('feedback-ltworf.appspot.com')
|
|
connection.request("GET", "/version/relational")
|
|
r = connection.getresponse()
|
|
|
|
# html
|
|
s = r.read()
|
|
if len(s) == 0:
|
|
return None
|
|
return s.decode().strip()
|
|
|
|
|
|
class user_interface (object):
|
|
|
|
'''It is used to provide services to the user interfaces, in order to
|
|
reduce the amount of duplicated code present in different user interfaces.
|
|
'''
|
|
|
|
def __init__(self):
|
|
self.relations = {}
|
|
|
|
def load(self, filename, name):
|
|
'''Loads a relation from file, and gives it a name to
|
|
be used in subsequent queries.'''
|
|
rel = relation(filename)
|
|
self.set_relation(name, rel)
|
|
|
|
def unload(self, name):
|
|
'''Unloads an existing relation.'''
|
|
del self.relations[name]
|
|
|
|
def store(self, filename, name):
|
|
'''Stores a relation to file.'''
|
|
pass
|
|
|
|
def get_relation(self, name):
|
|
'''Returns the relation corresponding to name.'''
|
|
return self.relations[name]
|
|
|
|
def set_relation(self, name, rel):
|
|
'''Sets the relation corresponding to name.'''
|
|
if not is_valid_relation_name(name):
|
|
raise Exception('Invalid name for destination relation')
|
|
self.relations[name] = rel
|
|
|
|
def suggest_name(self, filename):
|
|
'''
|
|
Returns a possible name for a relation, given
|
|
a filename.
|
|
|
|
If it is impossible to extract a possible name,
|
|
returns None
|
|
'''
|
|
name = os.path.basename(filename).lower()
|
|
if len(name) == 0:
|
|
return None
|
|
|
|
if (name.endswith(".csv")): # removes the extension
|
|
name = name[:-4]
|
|
|
|
if not is_valid_relation_name(name):
|
|
return None
|
|
return name
|
|
|
|
def execute(self, query, relname='last_'):
|
|
'''Executes a query, returns the result and if
|
|
relname is not None, adds the result to the
|
|
dictionary, with the name given in relname.'''
|
|
if not is_valid_relation_name(relname):
|
|
raise Exception('Invalid name for destination relation')
|
|
|
|
expr = parser.parse(query)
|
|
result = expr(self.relations)
|
|
self.relations[relname] = result
|
|
return result
|
|
|
|
def multi_execute(self, query):
|
|
'''Executes multiple queries, separated by \n
|
|
|
|
They can have a syntax of
|
|
[varname =] query
|
|
to assign the result to a new relation
|
|
'''
|
|
r = relation()
|
|
queries = query.split('\n')
|
|
for query in queries:
|
|
if query.strip() == '':
|
|
continue
|
|
parts = query.split('=', 1)
|
|
parts[0] = parts[0].strip()
|
|
if len(parts) > 1 and is_valid_relation_name(parts[0]):
|
|
relname, query = parts
|
|
else:
|
|
relname = 'last_'
|
|
|
|
try:
|
|
r = self.execute(query, relname)
|
|
except Exception as e:
|
|
raise Exception('Error in query: %s\n%s' % (
|
|
query,
|
|
str(e)
|
|
))
|
|
return r
|
|
|
|
|
|
|