relay/actor.py

   1 import aiohttp
   2 import aiohttp.web
   3 import asyncio
   4 import logging
   5 import uuid
   6 import urllib.parse
   7 import simplejson as json
   8 import re
   9 import cgi
  10 from Crypto.PublicKey import RSA
  11 from .database import DATABASE
  12
  13
  14 # generate actor keys if not present
  15 if "actorKeys" not in DATABASE:
  16     logging.info("No actor keys present, generating 4096-bit RSA keypair.")
  17
  18     privkey = RSA.generate(4096)
  19     pubkey = privkey.publickey()
  20
  21     DATABASE["actorKeys"] = {
  22         "publicKey": pubkey.exportKey('PEM'),
  23         "privateKey": privkey.exportKey('PEM')
  24     }
  25
  26
  27 PRIVKEY = RSA.importKey(DATABASE["actorKeys"]["privateKey"])
  28 PUBKEY = PRIVKEY.publickey()
  29
  30
  31 from . import app, CONFIG
  32 from .remote_actor import fetch_actor
  33
  34
  35 AP_CONFIG = CONFIG.get('ap', {'host': 'localhost'})
  36
  37
  38 async def actor(request):
  39     data = {
  40         "@context": "https://www.w3.org/ns/activitystreams",
  41         "endpoints": {
  42             "sharedInbox": "https://{}/inbox".format(request.host)
  43         },
  44         "followers": "https://{}/followers".format(request.host),
  45         "following": "https://{}/following".format(request.host),
  46         "inbox": "https://{}/inbox".format(request.host),
  47         "sharedInbox": "https://{}/inbox".format(request.host),
  48         "name": "ActivityRelay",
  49         "type": "Application",
  50         "id": "https://{}/actor".format(request.host),
  51         "publicKey": {
  52             "id": "https://{}/actor#main-key".format(request.host),
  53             "owner": "https://{}/actor".format(request.host),
  54             "publicKeyPem": DATABASE["actorKeys"]["publicKey"]
  55         },
  56         "summary": "ActivityRelay bot",
  57         "preferredUsername": "relay",
  58         "url": "https://{}/actor".format(request.host)
  59     }
  60     return aiohttp.web.json_response(data)
  61
  62
  63 app.router.add_get('/actor', actor)
  64
  65
  66 from .http_signatures import sign_headers
  67
  68
  69 get_actor_inbox = lambda actor: actor.get('endpoints', {}).get('sharedInbox', actor['inbox'])
  70
  71
  72 async def push_message_to_actor(actor, message, our_key_id):
  73     inbox = get_actor_inbox(actor)
  74
  75     url = urllib.parse.urlsplit(inbox)
  76
  77     # XXX: Digest
  78     data = json.dumps(message)
  79     headers = {
  80         '(request-target)': 'post {}'.format(url.path),
  81         'Content-Length': str(len(data)),
  82         'Content-Type': 'application/activity+json',
  83         'User-Agent': 'ActivityRelay'
  84     }
  85     headers['signature'] = sign_headers(headers, PRIVKEY, our_key_id)
  86
  87     logging.debug('%r >> %r', inbox, message)
  88
  89     async with aiohttp.ClientSession() as session:
  90         async with session.post(inbox, data=data, headers=headers) as resp:
  91             resp_payload = await resp.text()
  92             logging.debug('%r >> resp %r', inbox, resp_payload)
  93
  94
  95 async def follow_remote_actor(actor_uri):
  96     logging.info('following: %r', actor_uri)
  97
  98     actor = await fetch_actor(actor_uri)
  99
 100     message = {
 101         "@context": "https://www.w3.org/ns/activitystreams",
 102         "type": "Follow",
 103         "to": [actor['id']],
 104         "object": actor['id'],
 105         "id": "https://{}/activities/{}".format(AP_CONFIG['host'], uuid.uuid4()),
 106         "actor": "https://{}/actor".format(AP_CONFIG['host'])
 107     }
 108     await push_message_to_actor(actor, message, "https://{}/actor#main-key".format(AP_CONFIG['host']))
 109
 110
 111 async def unfollow_remote_actor(actor_uri):
 112     logging.info('unfollowing: %r', actor_uri)
 113
 114     actor = await fetch_actor(actor_uri)
 115
 116     message = {
 117         "@context": "https://www.w3.org/ns/activitystreams",
 118         "type": "Undo",
 119         "to": [actor['id']],
 120         "object": {
 121              "type": "Follow",
 122              "object": actor_uri,
 123              "actor": actor['id'],
 124              "id": "https://{}/activities/{}".format(AP_CONFIG['host'], uuid.uuid4())
 125         },
 126         "id": "https://{}/activities/{}".format(AP_CONFIG['host'], uuid.uuid4()),
 127         "actor": "https://{}/actor".format(AP_CONFIG['host'])
 128     }
 129     await push_message_to_actor(actor, message, "https://{}/actor#main-key".format(AP_CONFIG['host']))
 130
 131
 132 tag_re = re.compile(r'(<!--.*?-->|<[^>]*>)')
 133 def strip_html(data):
 134     no_tags = tag_re.sub('', data)
 135     return cgi.escape(no_tags)
 136
 137
 138 def distill_inboxes(actor):
 139     global DATABASE
 140
 141     inbox = get_actor_inbox(actor)
 142     targets = [target for target in DATABASE.get('relay-list', []) if target != inbox]
 143
 144     assert inbox not in targets
 145
 146     return targets
 147
 148
 149 def distill_object_id(activity):
 150     logging.debug('>> determining object ID for %r', activity['object'])
 151     obj = activity['object']
 152
 153     if isinstance(obj, str):
 154         return obj
 155
 156     return obj['id']
 157
 158
 159 async def handle_relay(actor, data, request):
 160     object_id = distill_object_id(data)
 161
 162     # don't relay mastodon announces -- causes LRP fake direction issues
 163     if data['type'] == 'Announce' and length(data.get('cc', [])) > 0:
 164         return
 165
 166     message = {
 167         "@context": "https://www.w3.org/ns/activitystreams",
 168         "type": "Announce",
 169         "to": ["https://{}/actor/followers".format(request.host)],
 170         "actor": "https://{}/actor".format(request.host),
 171         "object": object_id,
 172         "id": "https://{}/activities/{}".format(request.host, uuid.uuid4())
 173     }
 174
 175     logging.debug('>> relay: %r', message)
 176
 177     inboxes = distill_inboxes(actor)
 178
 179     futures = [push_message_to_actor({'inbox': inbox}, message, 'https://{}/actor#main-key'.format(request.host)) for inbox in inboxes]
 180     asyncio.ensure_future(asyncio.gather(*futures))
 181
 182
 183 async def handle_follow(actor, data, request):
 184     global DATABASE
 185
 186     following = DATABASE.get('relay-list', [])
 187     inbox = get_actor_inbox(actor)
 188
 189     if inbox not in following:
 190         following += [inbox]
 191         DATABASE['relay-list'] = following
 192
 193     message = {
 194         "@context": "https://www.w3.org/ns/activitystreams",
 195         "type": "Accept",
 196         "to": [actor["id"]],
 197         "actor": "https://{}/actor".format(request.host),
 198
 199         # this is wrong per litepub, but mastodon < 2.4 is not compliant with that profile.
 200         "object": {
 201              "type": "Follow",
 202              "id": data["id"],
 203              "object": "https://{}/actor".format(request.host),
 204              "actor": actor["id"]
 205         },
 206
 207         "id": "https://{}/activities/{}".format(request.host, uuid.uuid4()),
 208     }
 209
 210     asyncio.ensure_future(push_message_to_actor(actor, message, 'https://{}/actor#main-key'.format(request.host)))
 211
 212     if data['object'].endswith('/actor'):
 213         asyncio.ensure_future(follow_remote_actor(actor['id']))
 214
 215
 216 async def handle_undo(actor, data, request):
 217     global DATABASE
 218
 219     child = data['object']
 220     if child['type'] == 'Follow':
 221         following = DATABASE.get('relay-list', [])
 222
 223         inbox = get_actor_inbox(actor)
 224
 225         if inbox in following:
 226             following.remove(inbox)
 227             DATABASE['relay-list'] = following
 228
 229         if child['object'].endswith('/actor'):
 230             await unfollow_remote_actor(actor['id'])
 231
 232
 233 processors = {
 234     'Announce': handle_relay,
 235     'Create': handle_relay,
 236     'Follow': handle_follow,
 237     'Undo': handle_undo
 238 }
 239
 240
 241 async def inbox(request):
 242     data = await request.json()
 243
 244     if 'actor' not in data or not request['validated']:
 245         raise aiohttp.web.HTTPUnauthorized(body='access denied', content_type='text/plain')
 246
 247     actor = await fetch_actor(data["actor"])
 248     actor_uri = 'https://{}/actor'.format(request.host)
 249
 250     logging.debug(">> payload %r", data)
 251
 252     processor = processors.get(data['type'], None)
 253     if processor:
 254         await processor(actor, data, request)
 255
 256     return aiohttp.web.Response(body=b'{}', content_type='application/activity+json')
 257
 258
 259 app.router.add_post('/inbox', inbox)