Implement 2nd-level domain verification when adding a subdomain

If user wants to register  a subdomain, he must prove he is owner of
2nd-level domain. He must create a file with random name generated by us
in webserver's document root in 2nd-level domain. Then we trying to
fetch this file. If it success, registration gets accepted.

pyi2phosts/postkey/urls.py

@@ -3,4 +3,5 @@ from django.conf.urls.defaults import *
 urlpatterns = patterns('pyi2phosts.postkey.views',
 		(r'^$', 'addkey'),
 		(r'^success/', 'success'),
+		(r'^subdomain/', 'subdomain'),
 )

pyi2phosts/postkey/views.py

@@ -1,5 +1,8 @@
 import re
 import datetime
+import string
+import random
+import urllib2
 
 from django import forms
 from django.shortcuts import render_to_response
@@ -33,8 +36,6 @@ class AddForm(forms.ModelForm):
 		# Another set of reserved hostnames (suggested by zzz)
 		if re.search(r'(^|\.)(i2p|i2p2|geti2p|mail|project|i2project|i2pproject|i2p-project).i2p$', data):
 			raise forms.ValidationError('Trying to use hostname from additional reserved set')
-		if data.count('.') > 1:
-			raise forms.ValidationError('Currently only 2-level domains are allowed')
 		return data
 	def clean_b64hash(self):
 		"""Validate base64 hash"""
@@ -51,16 +52,45 @@ class AddForm(forms.ModelForm):
 						field, self.data[field], self.errors[field].as_text())
 		return is_valid
 
+
+class SubdomainVerifyForm(forms.Form):
+	"""Form for displaying verification filename and code when verifying a subdomain"""
+	filename = forms.CharField(widget=forms.TextInput(attrs={
+		'size': '20',
+		'readonly': 'readonly',
+		'onclick': 'this.select();',
+		}))
+
+def save_host(request):
+	"""Function for saving hosts after validation or subdomain verification"""
+	# avoid race conditions
+	try:
+		h = i2phost.objects.get(name=request.session['hostname'])
+	except i2phost.DoesNotExist:
+		host = i2phost(name=request.session['hostname'],
+				b64hash=request.session['b64hash'],
+				description=request.session['description'],
+				date_added=datetime.datetime.utcnow())
+		host.save()
+		return redirect('pyi2phosts.postkey.views.success')
+	else:
+		log.warning('refusing to save already existed host: %s', request.session['hostname'])
+		request.session.flush()
+		return redirect('/')
+
 def addkey(request):
 	if request.method == 'POST':
 		form = AddForm(request.POST)
 		if form.is_valid():
-			log.debug('submit is valid, saving')
-			newhost = form.save(commit=False)
-			newhost.date_added = datetime.datetime.utcnow()
-			newhost.save()
 			request.session['hostname'] = form.cleaned_data['name']
-			return redirect('pyi2phosts.postkey.views.success')
+			request.session['b64hash'] = form.cleaned_data['b64hash']
+			request.session['description'] = form.cleaned_data['description']
+			if form.cleaned_data['name'].count('.') > 1:
+				return redirect('pyi2phosts.postkey.views.subdomain')
+			else:
+				log.debug('submit is valid, saving')
+				s = save_host(request)
+				return s
 	else:
 		form = AddForm()
 	return render_to_response('postkey.html', {
@@ -70,11 +100,63 @@ def addkey(request):
 
 def success(request):
 	if 'hostname' in request.session:
+		hn = request.session['hostname']
+		request.session.flush()
 		return render_to_response('success_submission.html', {
 			'title': settings.SITE_NAME,
-			'hostname': request.session['hostname'],
+			'hostname': hn,
 			})
 	else:
 		return redirect('/')
 
+def subdomain(request):
+	"""Subdomain verification"""
+	if request.method == 'POST':
+		form = SubdomainVerifyForm(request.POST)
+		if form.is_valid():
+			# do verification here, then redirect to success
+			proxy_handler = urllib2.ProxyHandler({'http': settings.EEPROXY_URL})
+			opener = urllib2.build_opener(proxy_handler)
+			if 'topdomain' in request.session and 'v_filename' in request.session:
+				url = 'http://' + request.session['topdomain'] + '/' + request.session['v_filename']
+			else:
+				log.warning('trying to call subdomain validation without a session')
+				return redirect('/')
+			log.info('starting http-verification of subdomain: %s', request.session['hostname'])
+			try:
+				log.debug('trying to open %s', url)
+				resp = opener.open(url, timeout=60)
+			except urllib2.URLError, e:
+				if hasattr(e, 'reason'):
+					log.warning('%s: failed to reach server, reason: %s', topdomain, e.reason)
+				elif hasattr(e, 'code'):
+					log.warning('%s can\'t finish the request, error code: %s',
+							request.session['topdomain'], e.code)
+					return render_to_response('subdomain_http_verify_failure.html', {
+						'title': settings.SITE_NAME,
+						'code': e.code,
+						})
+			else:
+				log.debug('subdomain verification success, saving host')
+				s = save_host(request)
+				return s
+	else:
+		# generate verification code and display info page to user
+		v_filename = ''.join([random.choice(string.letters + string.digits) for x in xrange(16)])
+		if 'hostname' in request.session:
+			m = re.match('.+\.(.+\.i2p$)', request.session['hostname'])
+			topdomain = m.group(1)
+		else:
+			return redirect('/')
+		# save needed variables in session data because otherwise it will be lost
+		request.session['v_filename'] = v_filename
+		request.session['topdomain'] = topdomain
+		form = SubdomainVerifyForm({'filename': v_filename})
+		return render_to_response('subdomain_http_verify.html', {
+			'title': settings.SITE_NAME,
+			'hostname': request.session['hostname'],
+			'topdomain': topdomain,
+			'form': form,
+			}, context_instance=RequestContext(request))
+
 log = get_logger(filename=settings.LOG_FILE, log_level=settings.LOG_LEVEL)

pyi2phosts/settings.py

@@ -113,6 +113,7 @@ LOG_LEVEL = 'debug'
 LOG_FILE = '/var/log/py-i2phosts/web.log'
 LATEST_DAY_COUNT = 30
 LATEST_HOSTS_COUNT = 40
+EEPROXY_URL = 'http://127.0.0.1:4444'
 
 
 # include local settings

pyi2phosts/templates/subdomain_http_verify.html

@@ -0,0 +1,20 @@
+{% extends "base.html" %}
+
+{% block content %}
+<p>
+You are trying to add a subdomain. Our policy permits subdomains registration only if you're own an
+upper domain (2nd-level domain). Before subdomain will be added, we must ensure that you're own an upper-level
+domain.
+</p>
+<p>
+Unfortunately, we can verify a 2nd-level domain ownage only via http, so if you're use the domain not for http,
+please run a webserver temporary. Create the following file in the webserver's document root and press "OK" button.
+This file should be accessible via http://{{ topdomain }}/&laquo;filename&raquo; (without quotes).
+</p>
+	<form action="/postkey/subdomain/" method="post">
+		{% csrf_token %}
+		{{ form.as_p }}
+		<input type="submit" value="OK" />
+	</form>
+
+{% endblock %}

pyi2phosts/templates/subdomain_http_verify_failure.html

@@ -0,0 +1,8 @@
+{% extends "base.html" %}
+
+{% block content %}
+<p>
+Verification failed. Webserver returned http code: {{ code }}
+</p>
+
+{% endblock %}