relay/actor.py

   1 import aiohttp
   2 import aiohttp.web
   3 import asyncio
   4 import logging
   5 import uuid
   6 import re
   7 import urllib.parse
   8 import simplejson as json
   9 import cgi
  10 from Crypto.PublicKey import RSA
  11 from .database import DATABASE
  12 from .http_debug import http_debug
  13
  14 from cachetools import LFUCache
  15
  16
  17 # generate actor keys if not present
  18 if "actorKeys" not in DATABASE:
  19     logging.info("No actor keys present, generating 4096-bit RSA keypair.")
  20
  21     privkey = RSA.generate(4096)
  22     pubkey = privkey.publickey()
  23
  24     DATABASE["actorKeys"] = {
  25         "publicKey": pubkey.exportKey('PEM'),
  26         "privateKey": privkey.exportKey('PEM')
  27     }
  28
  29
  30 PRIVKEY = RSA.importKey(DATABASE["actorKeys"]["privateKey"])
  31 PUBKEY = PRIVKEY.publickey()
  32
  33
  34 from . import app, CONFIG
  35 from .remote_actor import fetch_actor
  36
  37
  38 AP_CONFIG = CONFIG.get('ap', {'host': 'localhost','blocked_instances':[]})
  39 CACHE_SIZE = CONFIG.get('cache-size', 16384)
  40
  41
  42 CACHE = LFUCache(CACHE_SIZE)
  43
  44
  45 async def actor(request):
  46     data = {
  47         "@context": "https://www.w3.org/ns/activitystreams",
  48         "endpoints": {
  49             "sharedInbox": "https://{}/inbox".format(request.host)
  50         },
  51         "followers": "https://{}/followers".format(request.host),
  52         "following": "https://{}/following".format(request.host),
  53         "inbox": "https://{}/inbox".format(request.host),
  54         "name": "ActivityRelay",
  55         "type": "Application",
  56         "id": "https://{}/actor".format(request.host),
  57         "publicKey": {
  58             "id": "https://{}/actor#main-key".format(request.host),
  59             "owner": "https://{}/actor".format(request.host),
  60             "publicKeyPem": DATABASE["actorKeys"]["publicKey"]
  61         },
  62         "summary": "ActivityRelay bot",
  63         "preferredUsername": "relay",
  64         "url": "https://{}/actor".format(request.host)
  65     }
  66     return aiohttp.web.json_response(data)
  67
  68
  69 app.router.add_get('/actor', actor)
  70
  71
  72 from .http_signatures import sign_headers
  73
  74
  75 get_actor_inbox = lambda actor: actor.get('endpoints', {}).get('sharedInbox', actor['inbox'])
  76
  77
  78 async def push_message_to_actor(actor, message, our_key_id):
  79     inbox = get_actor_inbox(actor)
  80
  81     url = urllib.parse.urlsplit(inbox)
  82
  83     # XXX: Digest
  84     data = json.dumps(message)
  85     headers = {
  86         '(request-target)': 'post {}'.format(url.path),
  87         'Content-Length': str(len(data)),
  88         'Content-Type': 'application/activity+json',
  89         'User-Agent': 'ActivityRelay'
  90     }
  91     headers['signature'] = sign_headers(headers, PRIVKEY, our_key_id)
  92     headers.pop('(request-target)')
  93
  94     logging.debug('%r >> %r', inbox, message)
  95
  96     async with aiohttp.ClientSession(trace_configs=[http_debug()]) as session:
  97         async with session.post(inbox, data=data, headers=headers) as resp:
  98             if resp.status == 202:
  99                 return
 100             resp_payload = await resp.text()
 101             logging.debug('%r >> resp %r', inbox, resp_payload)
 102
 103
 104 async def follow_remote_actor(actor_uri):
 105     logging.info('following: %r', actor_uri)
 106
 107     actor = await fetch_actor(actor_uri)
 108
 109     message = {
 110         "@context": "https://www.w3.org/ns/activitystreams",
 111         "type": "Follow",
 112         "to": [actor['id']],
 113         "object": actor['id'],
 114         "id": "https://{}/activities/{}".format(AP_CONFIG['host'], uuid.uuid4()),
 115         "actor": "https://{}/actor".format(AP_CONFIG['host'])
 116     }
 117     await push_message_to_actor(actor, message, "https://{}/actor#main-key".format(AP_CONFIG['host']))
 118
 119
 120 async def unfollow_remote_actor(actor_uri):
 121     logging.info('unfollowing: %r', actor_uri)
 122
 123     actor = await fetch_actor(actor_uri)
 124
 125     message = {
 126         "@context": "https://www.w3.org/ns/activitystreams",
 127         "type": "Undo",
 128         "to": [actor['id']],
 129         "object": {
 130              "type": "Follow",
 131              "object": actor_uri,
 132              "actor": actor['id'],
 133              "id": "https://{}/activities/{}".format(AP_CONFIG['host'], uuid.uuid4())
 134         },
 135         "id": "https://{}/activities/{}".format(AP_CONFIG['host'], uuid.uuid4()),
 136         "actor": "https://{}/actor".format(AP_CONFIG['host'])
 137     }
 138     await push_message_to_actor(actor, message, "https://{}/actor#main-key".format(AP_CONFIG['host']))
 139
 140
 141 tag_re = re.compile(r'(<!--.*?-->|<[^>]*>)')
 142 def strip_html(data):
 143     no_tags = tag_re.sub('', data)
 144     return cgi.escape(no_tags)
 145
 146
 147 def distill_inboxes(actor):
 148     global DATABASE
 149
 150     inbox = get_actor_inbox(actor)
 151     targets = [target for target in DATABASE.get('relay-list', []) if target != inbox]
 152
 153     assert inbox not in targets
 154
 155     return targets
 156
 157
 158 def distill_object_id(activity):
 159     logging.debug('>> determining object ID for %r', activity['object'])
 160     obj = activity['object']
 161
 162     if isinstance(obj, str):
 163         return obj
 164
 165     return obj['id']
 166
 167
 168 async def handle_relay(actor, data, request):
 169     global CACHE
 170
 171     object_id = distill_object_id(data)
 172
 173     if object_id in CACHE:
 174         logging.debug('>> already relayed %r as %r', object_id, CACHE[object_id])
 175         return
 176
 177     # don't relay mastodon announces -- causes LRP fake direction issues
 178     if data['type'] == 'Announce' and len(data.get('cc', [])) > 0:
 179         return
 180
 181     activity_id = "https://{}/activities/{}".format(request.host, uuid.uuid4())
 182
 183     message = {
 184         "@context": "https://www.w3.org/ns/activitystreams",
 185         "type": "Announce",
 186         "to": ["https://{}/actor/followers".format(request.host)],
 187         "actor": "https://{}/actor".format(request.host),
 188         "object": object_id,
 189         "id": activity_id
 190     }
 191
 192     logging.debug('>> relay: %r', message)
 193
 194     inboxes = distill_inboxes(actor)
 195
 196     futures = [push_message_to_actor({'inbox': inbox}, message, 'https://{}/actor#main-key'.format(request.host)) for inbox in inboxes]
 197     asyncio.ensure_future(asyncio.gather(*futures))
 198
 199     CACHE[object_id] = activity_id
 200
 201
 202 async def handle_follow(actor, data, request):
 203     global DATABASE
 204
 205     following = DATABASE.get('relay-list', [])
 206     inbox = get_actor_inbox(actor)
 207
 208     if urllib.parse.urlsplit(inbox).hostname in AP_CONFIG['blocked_instances']:
 209         return
 210
 211     if inbox not in following:
 212         following += [inbox]
 213         DATABASE['relay-list'] = following
 214
 215         if data['object'].endswith('/actor'):
 216             asyncio.ensure_future(follow_remote_actor(actor['id']))
 217
 218     message = {
 219         "@context": "https://www.w3.org/ns/activitystreams",
 220         "type": "Accept",
 221         "to": [actor["id"]],
 222         "actor": "https://{}/actor".format(request.host),
 223
 224         # this is wrong per litepub, but mastodon < 2.4 is not compliant with that profile.
 225         "object": {
 226              "type": "Follow",
 227              "id": data["id"],
 228              "object": "https://{}/actor".format(request.host),
 229              "actor": actor["id"]
 230         },
 231
 232         "id": "https://{}/activities/{}".format(request.host, uuid.uuid4()),
 233     }
 234
 235     asyncio.ensure_future(push_message_to_actor(actor, message, 'https://{}/actor#main-key'.format(request.host)))
 236
 237
 238 async def handle_undo(actor, data, request):
 239     global DATABASE
 240
 241     child = data['object']
 242     if child['type'] == 'Follow':
 243         following = DATABASE.get('relay-list', [])
 244
 245         inbox = get_actor_inbox(actor)
 246
 247         if inbox in following:
 248             following.remove(inbox)
 249             DATABASE['relay-list'] = following
 250
 251         if child['object'].endswith('/actor'):
 252             await unfollow_remote_actor(actor['id'])
 253
 254
 255 processors = {
 256     'Announce': handle_relay,
 257     'Create': handle_relay,
 258     'Follow': handle_follow,
 259     'Undo': handle_undo
 260 }
 261
 262
 263 async def inbox(request):
 264     data = await request.json()
 265
 266     if 'actor' not in data or not request['validated']:
 267         raise aiohttp.web.HTTPUnauthorized(body='access denied', content_type='text/plain')
 268
 269     actor = await fetch_actor(data["actor"])
 270     actor_uri = 'https://{}/actor'.format(request.host)
 271
 272     logging.debug(">> payload %r", data)
 273
 274     processor = processors.get(data['type'], None)
 275     if processor:
 276         await processor(actor, data, request)
 277
 278     return aiohttp.web.Response(body=b'{}', content_type='application/activity+json')
 279
 280
 281 app.router.add_post('/inbox', inbox)