views.py: implement hostname checks according to I2P Naming Rules

http://www.i2p2.i2p/naming.html

web/postkey/views.py

@@ -1,20 +1,51 @@
 from django.shortcuts import render_to_response
 from django.http import HttpResponseRedirect
+from django import forms
 from django.forms import ModelForm
 from django.template import RequestContext
 
 from web.postkey.models import i2phost
+import re
 
 class AddForm(ModelForm):
 	class Meta:
 		model = i2phost
 		fields = ('name', 'b64hash')
+	def clean_name(self):
+		data = self.cleaned_data['name']
+		# convert hostname to lowercase
+		data = data.lower()
+		# Must end with '.i2p'.
+		if re.match(r'.*\.i2p$', data) == None:
+			raise forms.ValidationError('Hostname doesn\'t ends with .i2p')
+		# Base 32 hostnames (*.b32.i2p) are not allowed
+		if re.match(r'.*\.b32\.i2p$', data):
+			 raise forms.ValidationError('Base 32 hostnames are not allowed')
+		# Must contain only [a-z] [0-9] '.' and '-'
+		h = re.match(r'([a-z0-9.-]+)\.i2p$', data)
+		if h == None:
+			raise forms.ValidationError('Illegal characters in hostname')
+		else:
+			namepart = h.groups()[0]
+		# Must not contain '..'
+		if re.search(r'\.\.', namepart):
+			raise forms.ValidationError('".." in hostname')
+		# Must not contain '.-' or '-.' (as of 0.6.1.33)
+		if re.search(r'(\.-)|(-\.)', namepart):
+			raise forms.ValidationError('Hostname contain ".-" or "-."')
+		# Must not contain '--' except in 'xn--' for IDN
+		if re.search(r'(?<!^xn)--', namepart):
+			raise forms.ValidationError('Hostname contain "--" and it\'s not an IDN')
+		# Certain hostnames reserved for project use are not allowed
+		if re.search(r'(^|\.)(proxy|router|console)$', namepart):
+			raise forms.ValidationError('Trying to use reserved hostname')
+		return data
 
 def index(request):
 	if request.method == 'POST':
 		form = AddForm(request.POST)
 		if form.is_valid():
-			form.save()
+			#form.save()
 			return HttpResponseRedirect('/postkey/success/')
 	else:
 		form = AddForm()