SickGear/sickbeard/helpers.py

# Author: Nic Wolfe <nic@wolfeden.ca>
# URL: http://code.google.com/p/sickbeard/
#
# This file is part of Sick Beard.
#
# Sick Beard 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.
#
# Sick Beard 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 Sick Beard.  If not, see <http://www.gnu.org/licenses/>.

from __future__ import with_statement

import os
import re
import shutil
import socket
import stat
import time
import traceback
import urllib
import hashlib
import httplib
import urlparse
import uuid
import base64

from lib import requests
from httplib import BadStatusLine
from itertools import izip, cycle

try:
    import json
except ImportError:
    from lib import simplejson as json

try:
    import xml.etree.cElementTree as etree
except ImportError:
    import elementtree.ElementTree as etree

from xml.dom.minidom import Node
from datetime import datetime as dt

import sickbeard

from sickbeard.exceptions import MultipleShowObjectsException, ex
from sickbeard import logger, classes
from sickbeard.common import USER_AGENT, mediaExtensions, subtitleExtensions, XML_NSMAP, indexerStrings

from sickbeard import db
from sickbeard import encodingKludge as ek
from sickbeard import notifiers

from sickbeard.indexers import indexer_api, indexer_exceptions

from lib import subliminal
#from sickbeard.subtitles import EXTENSIONS

urllib._urlopener = classes.SickBeardURLopener()


def indentXML(elem, level=0):
    '''
    Does our pretty printing, makes Matt very happy
    '''
    i = "\n" + level * "  "
    if len(elem):
        if not elem.text or not elem.text.strip():
            elem.text = i + "  "
        if not elem.tail or not elem.tail.strip():
            elem.tail = i
        for elem in elem:
            indentXML(elem, level + 1)
        if not elem.tail or not elem.tail.strip():
            elem.tail = i
    else:
        # Strip out the newlines from text
        if elem.text:
            elem.text = elem.text.replace('\n', ' ')
        if level and (not elem.tail or not elem.tail.strip()):
            elem.tail = i

def replaceExtension(filename, newExt):
    '''
    >>> replaceExtension('foo.avi', 'mkv')
    'foo.mkv'
    >>> replaceExtension('.vimrc', 'arglebargle')
    '.vimrc'
    >>> replaceExtension('a.b.c', 'd')
    'a.b.d'
    >>> replaceExtension('', 'a')
    ''
    >>> replaceExtension('foo.bar', '')
    'foo.'
    '''
    sepFile = filename.rpartition(".")
    if sepFile[0] == "":
        return filename
    else:
        return sepFile[0] + "." + newExt

def isMediaFile(filename):
    # ignore samples
    if re.search('(^|[\W_])(sample\d*)[\W_]', filename, re.I):
        return False

    # ignore MAC OS's retarded "resource fork" files
    if filename.startswith('._'):
        return False

    sepFile = filename.rpartition(".")
    
    if re.search('extras?$', sepFile[0], re.I):
        return False
        
    if sepFile[2].lower() in mediaExtensions:
        return True
    else:
        return False

def isRarFile(filename):
    archive_regex = '(?P<file>^(?P<base>(?:(?!\.part\d+\.rar$).)*)\.(?:(?:part0*1\.)?rar)$)'
    
    if re.search(archive_regex, filename):
        return True
    
    return False

def isBeingWritten(filepath):
# Return True if file was modified within 60 seconds. it might still be being written to.
    ctime = max(ek.ek(os.path.getctime, filepath), ek.ek(os.path.getmtime, filepath))
    if ctime > time.time() - 60:
        return True
    
    return False

def sanitizeFileName(name):
    '''
    >>> sanitizeFileName('a/b/c')
    'a-b-c'
    >>> sanitizeFileName('abc')
    'abc'
    >>> sanitizeFileName('a"b')
    'ab'
    >>> sanitizeFileName('.a.b..')
    'a.b'
    '''
    
    # remove bad chars from the filename
    name = re.sub(r'[\\/\*]', '-', name)
    name = re.sub(r'[:"<>|?]', '', name)
    
    # remove leading/trailing periods and spaces
    name = name.strip(' .')
    
    return name


def getURL(url, post_data=None, headers=None, timeout=None):
    """
Returns a byte-string retrieved from the url provider.
"""


    req_headers = ['User-Agent', USER_AGENT, 'Accept-Encoding', 'gzip,deflate']
    if headers:
        for cur_header in headers:
            req_headers.append(cur_header)

    try:
        # Remove double-slashes from url
        parsed = list(urlparse.urlparse(url))
        parsed[2] = re.sub("/{2,}", "/", parsed[2]) # replace two or more / with one
        url = urlparse.urlunparse(parsed)

        it = iter(req_headers)
        resp = requests.get(url, data=post_data, headers=dict(zip(it, it)))
    except requests.HTTPError, e:
        logger.log(u"HTTP error " + str(e.errno) + " while loading URL " + url, logger.WARNING)
        return None

    except requests.ConnectionError, e:
        logger.log(u"Connection error " + str(e.message) + " while loading URL " + url, logger.WARNING)
        return None

    except Exception:
        logger.log(u"Unknown exception while loading URL " + url + ": " + traceback.format_exc(), logger.WARNING)
        return None

    return resp.content

def _remove_file_failed(file):
    try:
        os.remove(file)
    except:
        pass

def download_file(url, filename):
    try:
        req = requests.get(url, stream=True)
        #CHUNK = 16 * 1024
        with open(filename, 'wb') as fp:
            for chunk in req.iter_content(chunk_size=1024):
                if chunk:
                    fp.write(chunk)
                    fp.flush()
            fp.close()
        req.close()

    except requests.HTTPError, e:
        _remove_file_failed(filename)
        logger.log(u"HTTP error " + str(e.errno) + " while loading URL " + url, logger.WARNING)
        return False

    except requests.ConnectionError, e:
        logger.log(u"Connection error " + str(e.message) + " while loading URL " + url, logger.WARNING)
        return False

    except Exception:
        _remove_file_failed(filename)
        logger.log(u"Unknown exception while loading URL " + url + ": " + traceback.format_exc(), logger.WARNING)
        return False
    
    return True

def findCertainShow(showList, indexerid):
    results = filter(lambda x: x.indexerid == indexerid, showList)
    if len(results) == 0:
        return None
    elif len(results) > 1:
        raise MultipleShowObjectsException()
    else:
        return results[0]

def makeDir(path):
    if not ek.ek(os.path.isdir, path):
        try:
            ek.ek(os.makedirs, path)
            # do the library update for synoindex
            notifiers.synoindex_notifier.addFolder(path)
        except OSError:
            return False
    return True


def searchDBForShow(regShowName, useIndexer=False):

    showNames = [re.sub('[. -]', ' ', regShowName),regShowName]

    myDB = db.DBConnection()

    yearRegex = "([^()]+?)\s*(\()?(\d{4})(?(2)\))$"

    for showName in showNames:

        show = get_show_by_name(showName,sickbeard.showList, useIndexer==useIndexer)
        if show:
            sqlResults = myDB.select("SELECT * FROM tv_shows WHERE show_name LIKE ? OR show_name LIKE ?", [show.name, show.name])
        else:
            sqlResults = myDB.select("SELECT * FROM tv_shows WHERE show_name LIKE ? OR show_name LIKE ?", [showName, showName])

        if len(sqlResults) == 1:
            return (sqlResults[0]["indexer"], int(sqlResults[0]["indexer_id"]), sqlResults[0]["show_name"])

        else:

            # if we didn't get exactly one result then try again with the year stripped off if possible
            match = re.match(yearRegex, showName)
            if match and match.group(1):
                logger.log(u"Unable to match original name but trying to manually strip and specify show year", logger.DEBUG)
                sqlResults = myDB.select("SELECT * FROM tv_shows WHERE (show_name LIKE ? OR show_name LIKE ?) AND startyear = ?", [match.group(1) + '%', match.group(1) + '%', match.group(3)])

            if len(sqlResults) == 0:
                logger.log(u"Unable to match a record in the DB for " + showName, logger.DEBUG)
                continue
            elif len(sqlResults) > 1:
                logger.log(u"Multiple results for " + showName + " in the DB, unable to match show name", logger.DEBUG)
                continue
            else:
                return (sqlResults[0]["indexer"], int(sqlResults[0]["indexer_id"]), sqlResults[0]["show_name"])

    return None

def searchIndexersForShow(regShowName):

    showNames = [re.sub('[. -]', ' ', regShowName),regShowName]

    yearRegex = "([^()]+?)\s*(\()?(\d{4})(?(2)\))$"

    for name in showNames:
        for indexer in indexerStrings:
            logger.log(u"Trying to find the " + name + " on " + indexer, logger.DEBUG)

            try:
                lINDEXER_API_PARMS = {'indexer': indexer}

                lINDEXER_API_PARMS['search_all_languages'] = True
                lINDEXER_API_PARMS['custom_ui'] = classes.ShowListUI

                t = indexer_api.indexerApi(**lINDEXER_API_PARMS)
                showObj = t[name]
                return indexer
            except (indexer_exceptions.indexer_exception, IOError):
                # if none found, search on all languages
                try:
                    # There's gotta be a better way of doing this but we don't wanna
                    # change the language value elsewhere

                    lINDEXER_API_PARMS = {'indexer': indexer}

                    lINDEXER_API_PARMS['search_all_languages'] = True
                    lINDEXER_API_PARMS['custom_ui'] = classes.ShowListUI

                    t = indexer_api.indexerApi(**lINDEXER_API_PARMS)
                    showObj = t[name]
                    return indexer
                except (indexer_exceptions.indexer_exception, IOError):
                    pass

                continue
            except (IOError):
                continue

    return None

def sizeof_fmt(num):
    '''
    >>> sizeof_fmt(2)
    '2.0 bytes'
    >>> sizeof_fmt(1024)
    '1.0 KB'
    >>> sizeof_fmt(2048)
    '2.0 KB'
    >>> sizeof_fmt(2**20)
    '1.0 MB'
    >>> sizeof_fmt(1234567)
    '1.2 MB'
    '''
    for x in ['bytes', 'KB', 'MB', 'GB', 'TB']:
        if num < 1024.0:
            return "%3.1f %s" % (num, x)
        num /= 1024.0

def listMediaFiles(path):

    if not dir or not ek.ek(os.path.isdir, path):
        return []

    files = []
    for curFile in ek.ek(os.listdir, path):
        fullCurFile = ek.ek(os.path.join, path, curFile)

        # if it's a folder do it recursively
        if ek.ek(os.path.isdir, fullCurFile) and not curFile.startswith('.') and not curFile == 'Extras':
            files += listMediaFiles(fullCurFile)

        elif isMediaFile(curFile):
            files.append(fullCurFile)

    return files

def copyFile(srcFile, destFile):
    ek.ek(shutil.copyfile, srcFile, destFile)
    try:
        ek.ek(shutil.copymode, srcFile, destFile)
    except OSError:
        pass

def moveFile(srcFile, destFile):
    try:
        ek.ek(os.rename, srcFile, destFile)
        fixSetGroupID(destFile)
    except OSError:
        copyFile(srcFile, destFile)
        ek.ek(os.unlink, srcFile)

def link(src, dst):
    if os.name == 'nt':
        import ctypes
        if ctypes.windll.kernel32.CreateHardLinkW(unicode(dst), unicode(src), 0) == 0: raise ctypes.WinError()
    else:
        os.link(src, dst)

def hardlinkFile(srcFile, destFile):
    try:
        ek.ek(link, srcFile, destFile)
        fixSetGroupID(destFile)
    except:
        logger.log(u"Failed to create hardlink of " + srcFile + " at " + destFile + ". Copying instead", logger.ERROR)
        copyFile(srcFile, destFile)

def symlink(src, dst):
    if os.name == 'nt':
        import ctypes
        if ctypes.windll.kernel32.CreateSymbolicLinkW(unicode(dst), unicode(src), 1 if os.path.isdir(src) else 0) in [0, 1280]: raise ctypes.WinError()
    else:
        os.symlink(src, dst)

def moveAndSymlinkFile(srcFile, destFile):
    try:
        ek.ek(os.rename, srcFile, destFile)
        fixSetGroupID(destFile)
        ek.ek(symlink, destFile, srcFile)
    except:
        logger.log(u"Failed to create symlink of " + srcFile + " at " + destFile + ". Copying instead", logger.ERROR)
        copyFile(srcFile, destFile)

def make_dirs(path):
    """
    Creates any folders that are missing and assigns them the permissions of their
    parents
    """

    logger.log(u"Checking if the path " + path + " already exists", logger.DEBUG)

    if not ek.ek(os.path.isdir, path):
        # Windows, create all missing folders
        if os.name == 'nt' or os.name == 'ce':
            try:
                logger.log(u"Folder " + path + " didn't exist, creating it", logger.DEBUG)
                ek.ek(os.makedirs, path)
            except (OSError, IOError), e:
                logger.log(u"Failed creating " + path + " : " + ex(e), logger.ERROR)
                return False

        # not Windows, create all missing folders and set permissions
        else:
            sofar = ''
            folder_list = path.split(os.path.sep)

            # look through each subfolder and make sure they all exist
            for cur_folder in folder_list:
                sofar += cur_folder + os.path.sep

                # if it exists then just keep walking down the line
                if ek.ek(os.path.isdir, sofar):
                    continue

                try:
                    logger.log(u"Folder " + sofar + " didn't exist, creating it", logger.DEBUG)
                    ek.ek(os.mkdir, sofar)
                    # use normpath to remove end separator, otherwise checks permissions against itself
                    chmodAsParent(ek.ek(os.path.normpath, sofar))
                    # do the library update for synoindex
                    notifiers.synoindex_notifier.addFolder(sofar)
                except (OSError, IOError), e:
                    logger.log(u"Failed creating " + sofar + " : " + ex(e), logger.ERROR)
                    return False

    return True


def rename_ep_file(cur_path, new_path, old_path_length=0):
    """
    Creates all folders needed to move a file to its new location, renames it, then cleans up any folders
    left that are now empty.

    cur_path: The absolute path to the file you want to move/rename
    new_path: The absolute path to the destination for the file WITHOUT THE EXTENSION
    old_path_length: The length of media file path (old name) WITHOUT THE EXTENSION
    """

    new_dest_dir, new_dest_name = os.path.split(new_path) #@UnusedVariable

    if old_path_length == 0 or old_path_length > len(cur_path):
        # approach from the right
        cur_file_name, cur_file_ext = os.path.splitext(cur_path)  # @UnusedVariable
    else:
        # approach from the left
        cur_file_ext  = cur_path[old_path_length:]
        cur_file_name = cur_path[:old_path_length]
        
    if cur_file_ext[1:] in subtitleExtensions:
        #Extract subtitle language from filename
        sublang = os.path.splitext(cur_file_name)[1][1:]
        
        #Check if the language extracted from filename is a valid language
        try:
            language = subliminal.language.Language(sublang, strict=True)
            cur_file_ext = '.'+sublang+cur_file_ext 
        except ValueError:
            pass
        
    # put the extension on the incoming file
    new_path += cur_file_ext

    make_dirs(os.path.dirname(new_path))

    # move the file
    try:
        logger.log(u"Renaming file from " + cur_path + " to " + new_path)
        ek.ek(os.rename, cur_path, new_path)
    except (OSError, IOError), e:
        logger.log(u"Failed renaming " + cur_path + " to " + new_path + ": " + ex(e), logger.ERROR)
        return False

    # clean up any old folders that are empty
    delete_empty_folders(ek.ek(os.path.dirname, cur_path))

    return True


def delete_empty_folders(check_empty_dir, keep_dir=None):
    """
    Walks backwards up the path and deletes any empty folders found.

    check_empty_dir: The path to clean (absolute path to a folder)
    keep_dir: Clean until this path is reached
    """

    # treat check_empty_dir as empty when it only contains these items
    ignore_items = []

    logger.log(u"Trying to clean any empty folders under " + check_empty_dir)

    # as long as the folder exists and doesn't contain any files, delete it
    while ek.ek(os.path.isdir, check_empty_dir) and check_empty_dir != keep_dir:

        check_files = ek.ek(os.listdir, check_empty_dir)

        if not check_files or (len(check_files) <= len(ignore_items) and all([check_file in ignore_items for check_file in check_files])):
            # directory is empty or contains only ignore_items
            try:
                logger.log(u"Deleting empty folder: " + check_empty_dir)
                # need shutil.rmtree when ignore_items is really implemented
                ek.ek(os.rmdir, check_empty_dir)
                # do the library update for synoindex
                notifiers.synoindex_notifier.deleteFolder(check_empty_dir)
            except OSError, e:
                logger.log(u"Unable to delete " + check_empty_dir + ": " + repr(e) + " / " + str(e), logger.WARNING)
                break
            check_empty_dir = ek.ek(os.path.dirname, check_empty_dir)
        else:
            break

def chmodAsParent(childPath):
    if os.name == 'nt' or os.name == 'ce':
        return

    parentPath = ek.ek(os.path.dirname, childPath)
    
    if not parentPath:
        logger.log(u"No parent path provided in " + childPath + ", unable to get permissions from it", logger.DEBUG)
        return
    
    parentPathStat = ek.ek(os.stat, parentPath)
    parentMode = stat.S_IMODE(parentPathStat[stat.ST_MODE])
    
    childPathStat = ek.ek(os.stat, childPath)
    childPath_mode = stat.S_IMODE(childPathStat[stat.ST_MODE])

    if ek.ek(os.path.isfile, childPath):
        childMode = fileBitFilter(parentMode)
    else:
        childMode = parentMode

    if childPath_mode == childMode:
        return

    childPath_owner = childPathStat.st_uid
    user_id = os.geteuid() # @UndefinedVariable - only available on UNIX

    if user_id !=0 and user_id != childPath_owner:
        logger.log(u"Not running as root or owner of " + childPath + ", not trying to set permissions", logger.DEBUG)
        return

    try:
        ek.ek(os.chmod, childPath, childMode)
        logger.log(u"Setting permissions for %s to %o as parent directory has %o" % (childPath, childMode, parentMode), logger.DEBUG)
    except OSError:
        logger.log(u"Failed to set permission for %s to %o" % (childPath, childMode), logger.ERROR)

def fileBitFilter(mode):
    for bit in [stat.S_IXUSR, stat.S_IXGRP, stat.S_IXOTH, stat.S_ISUID, stat.S_ISGID]:
        if mode & bit:
            mode -= bit

    return mode

def fixSetGroupID(childPath):
    if os.name == 'nt' or os.name == 'ce':
        return

    parentPath = ek.ek(os.path.dirname, childPath)
    parentStat = ek.ek(os.stat, parentPath)
    parentMode = stat.S_IMODE(parentStat[stat.ST_MODE])

    if parentMode & stat.S_ISGID:
        parentGID = parentStat[stat.ST_GID]
        childStat = ek.ek(os.stat, childPath)
        childGID = childStat[stat.ST_GID]

        if childGID == parentGID:
            return

        childPath_owner = childStat.st_uid
        user_id = os.geteuid() # @UndefinedVariable - only available on UNIX

        if user_id !=0 and user_id != childPath_owner:
            logger.log(u"Not running as root or owner of " + childPath + ", not trying to set the set-group-ID", logger.DEBUG)
            return

        try:
            ek.ek(os.chown, childPath, -1, parentGID) # @UndefinedVariable - only available on UNIX
            logger.log(u"Respecting the set-group-ID bit on the parent directory for %s" % (childPath), logger.DEBUG)
        except OSError:
            logger.log(u"Failed to respect the set-group-ID bit on the parent directory for %s (setting group ID %i)" % (childPath, parentGID), logger.ERROR)

def sanitizeSceneName (name, ezrss=False):
    """
    Takes a show name and returns the "scenified" version of it.
    
    ezrss: If true the scenified version will follow EZRSS's cracksmoker rules as best as possible
    
    Returns: A string containing the scene version of the show name given.
    """

    if not ezrss:
        bad_chars = u",:()'!?\u2019"
    # ezrss leaves : and ! in their show names as far as I can tell
    else:
        bad_chars = u",()'?\u2019"

    # strip out any bad chars
    for x in bad_chars:
        name = name.replace(x, "")

    # tidy up stuff that doesn't belong in scene names
    name = name.replace("- ", ".").replace(" ", ".").replace("&", "and").replace('/', '.')
    name = re.sub("\.\.*", ".", name)

    if name.endswith('.'):
        name = name[:-1]

    return name

def create_https_certificates(ssl_cert, ssl_key):
    """
    Create self-signed HTTPS certificares and store in paths 'ssl_cert' and 'ssl_key'
    """
    try:
        from lib.OpenSSL import crypto  # @UnresolvedImport
        from lib.certgen import createKeyPair, createCertRequest, createCertificate, TYPE_RSA, serial  # @UnresolvedImport
    except:
        logger.log(u"pyopenssl module missing, please install for https access", logger.WARNING)
        return False

    # Create the CA Certificate
    cakey = createKeyPair(TYPE_RSA, 1024)
    careq = createCertRequest(cakey, CN='Certificate Authority')
    cacert = createCertificate(careq, (careq, cakey), serial, (0, 60 * 60 * 24 * 365 * 10)) # ten years

    cname = 'SickBeard'
    pkey = createKeyPair(TYPE_RSA, 1024)
    req = createCertRequest(pkey, CN=cname)
    cert = createCertificate(req, (cacert, cakey), serial, (0, 60* 60 * 24 * 365 *10)) # ten years

    # Save the key and certificate to disk
    try:
        open(ssl_key, 'w').write(crypto.dump_privatekey(crypto.FILETYPE_PEM, pkey))
        open(ssl_cert, 'w').write(crypto.dump_certificate(crypto.FILETYPE_PEM, cert))
    except:
        logger.log(u"Error creating SSL key and certificate", logger.ERROR)
        return False

    return True

if __name__ == '__main__':
    import doctest
    doctest.testmod()


def parse_json(data):
    """
    Parse json data into a python object

    data: data string containing json

    Returns: parsed data as json or None
    """

    try:
        parsedJSON = json.loads(data)
    except ValueError:
        logger.log(u"Error trying to decode json data:" + data, logger.ERROR)
        return None

    return parsedJSON


def parse_xml(data, del_xmlns=False):
    """
    Parse data into an xml elementtree.ElementTree

    data: data string containing xml
    del_xmlns: if True, removes xmlns namesspace from data before parsing

    Returns: parsed data as elementtree or None
    """

    if del_xmlns:
        data = re.sub(' xmlns="[^"]+"', '', data)

    try:
        parsedXML = etree.fromstring(data)
    except Exception, e:
        logger.log(u"Error trying to parse xml data: " + data + " to Elementtree, Error: " + ex(e), logger.DEBUG)
        parsedXML = None

    return parsedXML


def get_xml_text(element, mini_dom=False):
    """
    Get all text inside a xml element

    element: A xml element either created with elementtree.ElementTree or xml.dom.minidom
    mini_dom: Default False use elementtree, True use minidom

    Returns: text
    """

    text = ""

    if mini_dom:
        node = element
        for child in node.childNodes:
            if child.nodeType in (Node.CDATA_SECTION_NODE, Node.TEXT_NODE):
                text += child.data
    else:
        if element is not None:
            for child in [element] + element.findall('.//*'):
                if child.text:
                    text += child.text

    return text.strip()

 
def backupVersionedFile(old_file, version):
    numTries = 0

    new_file = old_file + '.' + 'v' + str(version)

    while not ek.ek(os.path.isfile, new_file):
        if not ek.ek(os.path.isfile, old_file):
            logger.log(u"Not creating backup, " + old_file + " doesn't exist", logger.DEBUG)
            break

        try:
            logger.log(u"Trying to back up " + old_file + " to " + new_file, logger.DEBUG)
            shutil.copy(old_file, new_file)
            logger.log(u"Backup done", logger.DEBUG)
            break
        except Exception, e:
            logger.log(u"Error while trying to back up " + old_file + " to " + new_file + " : " + ex(e), logger.WARNING)
            numTries += 1
            time.sleep(1)
            logger.log(u"Trying again.", logger.DEBUG)

        if numTries >= 10:
            logger.log(u"Unable to back up " + old_file + " to " + new_file + " please do it manually.", logger.ERROR)
            return False

    return True


# try to convert to int, if it fails the default will be returned
def tryInt(s, s_default = 0):
    try: return int(s)
    except: return s_default

# generates a md5 hash of a file
def md5_for_file(filename, block_size=2**16):
    try:    
        with open(filename,'rb') as f:
            md5 = hashlib.md5()
            while True:
                data = f.read(block_size)
                if not data:
                    break
                md5.update(data)
            f.close()
            return md5.hexdigest()
    except Exception:
        return None
    
def get_lan_ip():
    """
    Simple function to get LAN localhost_ip 
    http://stackoverflow.com/questions/11735821/python-get-localhost-ip
    """

    if os.name != "nt":
        import fcntl
        import struct
    
        def get_interface_ip(ifname):
            s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
            return socket.inet_ntoa(fcntl.ioctl(s.fileno(), 0x8915, struct.pack('256s',
                                    ifname[:15]))[20:24])
    
    ip = socket.gethostbyname(socket.gethostname())
    if ip.startswith("127.") and os.name != "nt":
        interfaces = [
            "eth0",
            "eth1",
            "eth2",
            "wlan0",
            "wlan1",
            "wifi0",
            "ath0",
            "ath1",
            "ppp0",
            ]
        for ifname in interfaces:
            try:
                ip = get_interface_ip(ifname)
                print ifname, ip 
                break
            except IOError:
                pass
    return ip

def check_url(url):
    """
    Check if a URL exists without downloading the whole file.
    We only check the URL header.
    """
    # see also http://stackoverflow.com/questions/2924422
    # http://stackoverflow.com/questions/1140661
    good_codes = [httplib.OK, httplib.FOUND, httplib.MOVED_PERMANENTLY]

    host, path = urlparse.urlparse(url)[1:3]    # elems [1] and [2]
    try:
        conn = httplib.HTTPConnection(host)
        conn.request('HEAD', path)
        return conn.getresponse().status in good_codes
    except StandardError:
        return None
        

"""
Encryption
==========
By Pedro Jose Pereira Vieito <pvieito@gmail.com> (@pvieito)

* If encryption_version==0 then return data without encryption
* The keys should be unique for each device

To add a new encryption_version:
  1) Code your new encryption_version        
  2) Update the last encryption_version available in webserve.py
  3) Remember to maintain old encryption versions and key generators for retrocompatibility
"""

# Key Generators
unique_key1 = hex(uuid.getnode()**2) # Used in encryption v1

# Encryption Functions
def encrypt(data, encryption_version=0, decrypt=False):
    
    # Version 1: Simple XOR encryption (this is not very secure, but works)
    if encryption_version == 1:
    	if decrypt:
        	return ''.join(chr(ord(x) ^ ord(y)) for (x,y) in izip(base64.decodestring(data), cycle(unique_key1)))
        else:
        	return base64.encodestring(''.join(chr(ord(x) ^ ord(y)) for (x,y) in izip(data, cycle(unique_key1)))).strip()
    # Version 0: Plain text
    else:
        return data
        
def decrypt(data, encryption_version=0):
	return encrypt(data, encryption_version, decrypt=True)

def full_sanitizeSceneName(name):
    return re.sub('[. -]', ' ', sanitizeSceneName(name)).lower().lstrip()

def _check_against_names(name, show):
    nameInQuestion = full_sanitizeSceneName(name)

    showNames = [show.name]
    showNames.extend(sickbeard.scene_exceptions.get_scene_exceptions(show.indexerid))

    for showName in showNames:
        nameFromList = full_sanitizeSceneName(showName)
        #logger.log(u"Comparing names: '"+nameFromList+"' vs '"+nameInQuestion+"'", logger.DEBUG)
        if nameFromList == nameInQuestion:
            return True

    return False

def get_show_by_name(name, showList, useIndexer=False):
    logger.log(u"Trying to get the indexerid for "+name, logger.DEBUG)

    if showList:
        for show in showList:
            if _check_against_names(name, show):
                logger.log(u"Matched "+name+" in the showlist to the show "+show.name, logger.DEBUG)
                return show

    if useIndexer:
        for indexer in indexerStrings:
            try:
                lINDEXER_API_PARMS = {'indexer': indexer}

                lINDEXER_API_PARMS['custom_ui'] = classes.ShowListUI

                t = indexer_api.indexerApi(**lINDEXER_API_PARMS)
                showObj = t[name]
            except (indexer_exceptions.indexer_exception, IOError):
                # if none found, search on all languages
                try:
                    lINDEXER_API_PARMS = {'indexer': indexer}

                    lINDEXER_API_PARMS['search_all_languages'] = True
                    lINDEXER_API_PARMS['custom_ui'] = classes.ShowListUI

                    t = indexer_api.indexerApi(**lINDEXER_API_PARMS)
                    showObj = t[name]
                except (indexer_exceptions.indexer_exception, IOError):
                    pass

                continue
            except (IOError):
                continue

            showResult = findCertainShow(sickbeard.showList, int(showObj["id"]))
            if showResult is not None:
                return showResult

    return None

def suffix(d):
    return 'th' if 11<=d<=13 else {1:'st',2:'nd',3:'rd'}.get(d%10, 'th')

def custom_strftime(format, t):
    return t.strftime(format).replace('{S}', str(t.day) + suffix(t.day))

def retry(ExceptionToCheck, default=None, tries=4, delay=3, backoff=2, logger=None):
    """Retry calling the decorated function using an exponential backoff.

    http://www.saltycrane.com/blog/2009/11/trying-out-retry-decorator-python/
    original from: http://wiki.python.org/moin/PythonDecoratorLibrary#Retry

    :param ExceptionToCheck: the exception to check. may be a tuple of
        excpetions to check
    :type ExceptionToCheck: Exception or tuple
    :param tries: number of times to try (not retry) before giving up
    :type tries: int
    :param delay: initial delay between retries in seconds
    :type delay: int
    :param backoff: backoff multiplier e.g. value of 2 will double the delay
        each retry
    :type backoff: int
    :param logger: logger to use. If None, print
    :type logger: logging.Logger instance
    """
    def deco_retry(f):
        def f_retry(*args, **kwargs):
            mtries, mdelay = tries, delay
            try_one_last_time = True
            while mtries > 1:
                try:
                    print args,kwargs
                    return f(*args, **kwargs)
                    try_one_last_time = False
                    break
                except ExceptionToCheck, e:
                    msg = "%s, Retrying in %d seconds..." % (str(e), mdelay)
                    if logger:
                        logger.warning(msg)
                    else:
                        print msg
                    time.sleep(mdelay)
                    mtries -= 1
                    mdelay *= backoff
            if try_one_last_time:
                try:
                    return f(*args, **kwargs)
                except ExceptionToCheck, e:
                    return default
            return
        return f_retry  # true decorator
    return deco_retry