Source code for foundations.common

#!/usr/bin/env python
# -*- coding: utf-8 -*-

"""
**common.py**

**Platform:**
	Windows, Linux, Mac Os X.

**Description:**
	This module defines **Foundations** package common utilities objects that don't fall in any specific category.

**Others:**
	:func:`isBinaryFile` from Jorge Orpinel:
	http://stackoverflow.com/questions/898669/how-can-i-detect-if-a-file-is-binary-non-text-in-python
	:func:`dependencyResolver` from Louis RIVIERE: http://code.activestate.com/recipes/576570-dependency-resolver/

"""

#**********************************************************************************************************************
#***	Future imports.
#**********************************************************************************************************************
from __future__ import unicode_literals

#**********************************************************************************************************************
#***	External imports.
#**********************************************************************************************************************
import itertools
import os
import socket
import urllib2

#**********************************************************************************************************************
#***	Internal imports.
#**********************************************************************************************************************
import foundations.verbose

#**********************************************************************************************************************
#***	Module attributes.
#**********************************************************************************************************************
__author__ = "Thomas Mansencal"
__copyright__ = "Copyright (C) 2008 - 2013 - Thomas Mansencal"
__license__ = "GPL V3.0 - http://www.gnu.org/licenses/"
__maintainer__ = "Thomas Mansencal"
__email__ = "thomas.mansencal@gmail.com"
__status__ = "Production"

__all__ = ["LOGGER",
		"CONNECTION_IP",
		"DEFAULT_HOST_IP",
		"wait",
		"uniqify",
		"unpackDefault",
		"orderedUniqify",
		"pathExists",
		"filterPath",
		"getFirstItem",
		"getLastItem",
		"isBinaryFile",
		"repeat",
		"dependencyResolver",
		"isInternetAvailable",
		"getHostAddress"]

LOGGER = foundations.verbose.installLogger()

CONNECTION_IP = "www.google.com"
DEFAULT_HOST_IP = "127.0.0.1"

#**********************************************************************************************************************
#***	Module classes and definitions.
#**********************************************************************************************************************
[docs]def uniqify(sequence): """ This definition uniqifies the given sequence even if unhashable. :param sequence: Sequence. ( Object ) :return: Uniqified sequence. ( List ) :note: The sequence order is not maintained by this definition. """ return [key for key, group in itertools.groupby(sorted(sequence))]
[docs]def orderedUniqify(sequence): """ This definition uniqifies the given hashable sequence while preserving its order. :param sequence: Sequence. ( Object ) :return: Uniqified sequence. ( List ) """ items = set() return [key for key in sequence if key not in items and not items.add(key)]
[docs]def unpackDefault(iterable, length=3, default=None): """ This definition unpacks given iterable maintaining given length and filling missing entries with given default. :param iterable: iterable. ( Object ) :param length: Iterable length. ( Integer ) :param default: Filling default object. ( Object ) :return: Unpacked iterable. ( Object ) """ return itertools.islice(itertools.chain(iter(iterable), itertools.repeat(default)), length)
[docs]def pathExists(path): """ This definition returns if given path exists. :param path: Path. ( String ) :return: Path existence. ( Boolean ) """ if not path: return False else: return os.path.exists(path)
[docs]def filterPath(path): """ This definition filters given path. :param path: Path. ( String ) :return: Filtered path. ( String ) """ return path if pathExists(path) else ""
[docs]def getFirstItem(iterable, default=None): """ This definition returns the first item of given iterable. :param iterable: Iterable. ( Object ) :param default: Default value. ( Object ) :return: First iterable item. ( Object ) """ if not iterable: return default for item in iterable: return item
[docs]def getLastItem(iterable, default=None): """ This definition returns the last item of given iterable. :param iterable: Iterable. ( Object ) :param default: Default value. ( Object ) :return: Last iterable item. ( Object ) """ if not iterable: return default return iterable[-1]
[docs]def isBinaryFile(file): """ This definition returns if given file is a binary file. :param file: File path. ( String ) :return: Is file binary. ( Boolean ) """ fileHandle = open(file, "rb") try: chunkSize = 1024 while True: chunk = fileHandle.read(chunkSize) if chr(0) in chunk: return True if len(chunk) < chunkSize: break finally: fileHandle.close() return False
[docs]def repeat(object, iterations=1): """ This definition repeats given object iterations times. :param object: Object to repeat. ( Object ) :param iterations: Repetitions number. ( Integer ) :return: Object return values. ( List ) """ return [object() for i in range(iterations)]
[docs]def dependencyResolver(dependencies): """ This definition resolves given dependencies. :param dependencies: Dependencies to resolve. ( Dictionary ) :return: Resolved dependencies. ( List ) """ items = dict((key, set(dependencies[key])) for key in dependencies) resolvedDependencies = [] while items: batch = set(item for value in items.values() for item in value) - set(items.keys()) batch.update(key for key, value in items.items() if not value) resolvedDependencies.append(batch) items = dict(((key, value - batch) for key, value in items.items() if value)) return resolvedDependencies
[docs]def isInternetAvailable(ip=CONNECTION_IP, timeout=1.5): """ This definition returns if an internet connection is available. :param ip: Alternative address ip to check against. ( String ) :param timeout: Timeout in seconds. ( Integer ) :return: Is internet available. ( Boolean ) """ try: urllib2.urlopen("http://{0}".format(ip), timeout=timeout) return True except (urllib2.URLError, socket.error) as error: return False
[docs]def getHostAddress(host=None, defaultAddress=DEFAULT_HOST_IP): """ This definition returns the given host address. :param host: Host to retrieve the address. ( String ) :param defaultAddress: Default address if the host is unreachable. ( String ) :return: Host address. ( String ) """ try: return unicode(socket.gethostbyname(host or socket.gethostname())) except Exception as error: return defaultAddress