source: src/django_gheat/gheat/models.py@ 9638

from gheat import managers
import datetime
import binascii
import hashlib

from django.core import validators
from django.core.files.storage import FileSystemStorage
from django.db import models
from django.dispatch import receiver
from django.utils.encoding import smart_unicode
from django.utils.translation import ugettext_lazy as _


# http://djangosnippets.org/snippets/976/
class OverwriteStorage(FileSystemStorage):
    def get_available_name(self, name):
        """
        Returns a filename that's free on the target storage system, and
        available for new content to be written to.
        """
        # If the filename already exists, remove it as if it was a true file system
        if self.exists(name):
            self.delete(name)
        return name

class BinaryField(models.Field):
  MAGIC = '###MAGIC###'
  description = _('Binary object using base64 (up to %(max_length)s)')

  __metaclass__ = models.SubfieldBase

  def __init__(self, *args, **kwargs):
    # base64 roughly max the binary size with with 4 times
    kwargs['max_length'] = kwargs['max_length'] * 4 + len(self.MAGIC)
    super(BinaryField, self).__init__(*args, **kwargs)
    self.validators.append(validators.MaxLengthValidator(self.max_length))

  def to_python(self,value):
    if value.startswith(self.MAGIC):
      return binascii.a2b_base64(value[len(self.MAGIC):])
    else:
      return value

  def get_db_prep_value(self, value, connection, prepared=False):
    target = self.MAGIC + binascii.b2a_base64(value)
    if len(target) > self.max_length:
      raise ValueError(len(target))
    return target

  def get_prep_lookup(self, lookup_type, value):
    raise TypeError('Lookup type %r not supported.' % lookup_type)

  def get_internal_type(self):
    return 'TextField'

class TileCache(models.Model):
  key = models.CharField(max_length=34,unique=True)
  data = BinaryField(max_length=10000)
  creation_time = models.DateTimeField(auto_now_add=True)

  def __unicode__(self):
    return self.key

  @staticmethod
  def make_key(source):
    return hashlib.md5(source).hexdigest()

class WirelessClient(models.Model):
  mac = models.CharField(max_length=17, unique=True)
  def __unicode__(self):
    return self.mac


class Organization(models.Model):
  fullname = models.CharField(max_length=100,unique=True)
  name = models.CharField(max_length=100,unique=True)
  def __unicode__(self):
    return self.fullname

  @staticmethod
  def get_name_by_ssid(ssid):
    """ Try to determine the organization via the SSID """
    ssid = ssid.lower()
    name = None
    if ssid.startswith('ap') and ssid.endswith('wleiden.net'):
      name = 'WirelessLeiden'
    elif ssid.startswith('il-') and ssid.endswith('wleiden.net'):
      name = 'WirelessLeiden'
    elif ssid.startswith('ap') and 'wirelessleiden' in ssid:
      name = 'WirelessLeiden'
    elif ssid.startswith('ap-') and 'westeinder' in ssid:
      name = 'WirelessPlassen'
    elif ssid.endswith('walphen.net'):
      name = 'WirelessAlphen'
    elif 'wirelessarnhem' in ssid:
      name = 'WirelessArnhem'
    return name

  @staticmethod
  def get_by_ssid(ssid):
    name = Organization.get_name_by_ssid(ssid)
    if not name:
      return None
    else:
      return Organization.objects.get(name=name)


class Node(models.Model):
  name = models.CharField(max_length=50, unique=True)
  latitude = models.FloatField(null=True,blank=True)
  longitude = models.FloatField(null=True,blank=True)
  organization = models.ForeignKey(Organization,null=True, blank=True)

  def __unicode__(self):
    return "%s - %s" % (self.name, self.organization)

class Accespoint(models.Model):
  mac = models.CharField(max_length=17)
  ssid = models.CharField(max_length=64)
  organization = models.ForeignKey(Organization,null=True, blank=True)
  encryptie = models.BooleanField()
  class Meta:
    unique_together = ('mac', 'ssid')
  def __unicode__(self):
    return "%s - %s" % (self.mac, self.ssid)


  def save(self, *args, **kwargs):
    self.organization = self.get_organization(self.ssid)
    super(Accespoint, self).save(*args, **kwargs)

class Gebruiker(models.Model):
  naam = models.CharField(max_length=64)
  email = models.CharField(max_length=64)
  def __unicode__(self):
    return "%s - %s" % (self.naam, self.email)

class Apparatuur(models.Model):
  antenne = models.CharField(max_length=64)
  kaart = models.CharField(max_length=64)
  def __unicode__(self):
    return "%s - %s" % (self.antenne, self.kaart)
  class Meta:
    verbose_name_plural = 'Apparatuur'

class MeetRondje(models.Model):
  datum = models.DateTimeField(blank=True,null=True,default=datetime.datetime.now)
  naam = models.CharField(max_length=64)
  gebruiker = models.ForeignKey(Gebruiker)
  apparatuur = models.ForeignKey(Apparatuur)
  def __unicode__(self):
    return "%s - %s" % (self.gebruiker.naam, self.naam)
  class Meta:
    verbose_name_plural = 'MeetRondjes'

class MeetBestand(models.Model):
  meetrondje = models.ForeignKey(MeetRondje)
  bestand = models.FileField(upload_to='scan-data/%Y/%m/%d',storage=OverwriteStorage())
  is_imported = models.BooleanField(default=False)
  class Meta:
    verbose_name_plural = 'MeetBestanden'
  def __unicode__(self):
    return "%s - %s" % (self.meetrondje, self.bestand)
  

class Meting(models.Model):
  meetrondje = models.ForeignKey(MeetRondje)
  accespoint = models.ForeignKey(Accespoint)
  latitude = models.FloatField()
  longitude = models.FloatField()
  signaal = models.IntegerField(max_length=3)
  objects = managers.MetingManager()
  def __unicode__(self):
    return "%s @ %.5f,%.5f : %s" % (self.accespoint.ssid, float(self.latitude), float(self.longitude), self.signaal)
  class Meta:
    # This implies that you cannot have multiple messurements on the same
    # location for a single 'run', thus the data needs cleaned before to make
    # this properly hold.
    unique_together = ('meetrondje', 'accespoint', 'latitude', 'longitude'),
    verbose_name_plural = 'Metingen'