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             resp_payload = await resp.text()
  99             logging.debug('%r >> resp %r', inbox, resp_payload)
 100
 101
 102 async def follow_remote_actor(actor_uri):
 103     logging.info('following: %r', actor_uri)
 104
 105     actor = await fetch_actor(actor_uri)
 106
 107     message = {
 108         "@context": "https://www.w3.org/ns/activitystreams",
 109         "type": "Follow",
 110         "to": [actor['id']],
 111         "object": actor['id'],
 112         "id": "https://{}/activities/{}".format(AP_CONFIG['host'], uuid.uuid4()),
 113         "actor": "https://{}/actor".format(AP_CONFIG['host'])
 114     }
 115     await push_message_to_actor(actor, message, "https://{}/actor#main-key".format(AP_CONFIG['host']))
 116
 117
 118 async def unfollow_remote_actor(actor_uri):
 119     logging.info('unfollowing: %r', actor_uri)
 120
 121     actor = await fetch_actor(actor_uri)
 122
 123     message = {
 124         "@context": "https://www.w3.org/ns/activitystreams",
 125         "type": "Undo",
 126         "to": [actor['id']],
 127         "object": {
 128              "type": "Follow",
 129              "object": actor_uri,
 130              "actor": actor['id'],
 131              "id": "https://{}/activities/{}".format(AP_CONFIG['host'], uuid.uuid4())
 132         },
 133         "id": "https://{}/activities/{}".format(AP_CONFIG['host'], uuid.uuid4()),
 134         "actor": "https://{}/actor".format(AP_CONFIG['host'])
 135     }
 136     await push_message_to_actor(actor, message, "https://{}/actor#main-key".format(AP_CONFIG['host']))
 137
 138
 139 tag_re = re.compile(r'(<!--.*?-->|<[^>]*>)')
 140 def strip_html(data):
 141     no_tags = tag_re.sub('', data)
 142     return cgi.escape(no_tags)
 143
 144
 145 def distill_inboxes(actor):
 146     global DATABASE
 147
 148     inbox = get_actor_inbox(actor)
 149     targets = [target for target in DATABASE.get('relay-list', []) if target != inbox]
 150
 151     assert inbox not in targets
 152
 153     return targets
 154
 155
 156 def distill_object_id(activity):
 157     logging.debug('>> determining object ID for %r', activity['object'])
 158     obj = activity['object']
 159
 160     if isinstance(obj, str):
 161         return obj
 162
 163     return obj['id']
 164
 165
 166 async def handle_relay(actor, data, request):
 167     global CACHE
 168
 169     object_id = distill_object_id(data)
 170
 171     if object_id in CACHE:
 172         logging.debug('>> already relayed %r as %r', object_id, CACHE[object_id])
 173         return
 174
 175     # don't relay mastodon announces -- causes LRP fake direction issues
 176     if data['type'] == 'Announce' and len(data.get('cc', [])) > 0:
 177         return
 178
 179     activity_id = "https://{}/activities/{}".format(request.host, uuid.uuid4())
 180
 181     message = {
 182         "@context": "https://www.w3.org/ns/activitystreams",
 183         "type": "Announce",
 184         "to": ["https://{}/actor/followers".format(request.host)],
 185         "actor": "https://{}/actor".format(request.host),
 186         "object": object_id,
 187         "id": activity_id
 188     }
 189
 190     logging.debug('>> relay: %r', message)
 191
 192     inboxes = distill_inboxes(actor)
 193
 194     futures = [push_message_to_actor({'inbox': inbox}, message, 'https://{}/actor#main-key'.format(request.host)) for inbox in inboxes]
 195     asyncio.ensure_future(asyncio.gather(*futures))
 196
 197     CACHE[object_id] = activity_id
 198
 199
 200 async def handle_follow(actor, data, request):
 201     global DATABASE
 202
 203     following = DATABASE.get('relay-list', [])
 204     inbox = get_actor_inbox(actor)
 205
 206     if urllib.parse.urlsplit(inbox).hostname in AP_CONFIG['blocked_instances']:
 207         return
 208
 209     if inbox not in following:
 210         following += [inbox]
 211         DATABASE['relay-list'] = following
 212
 213         if data['object'].endswith('/actor'):
 214             asyncio.ensure_future(follow_remote_actor(actor['id']))
 215
 216     message = {
 217         "@context": "https://www.w3.org/ns/activitystreams",
 218         "type": "Accept",
 219         "to": [actor["id"]],
 220         "actor": "https://{}/actor".format(request.host),
 221
 222         # this is wrong per litepub, but mastodon < 2.4 is not compliant with that profile.
 223         "object": {
 224              "type": "Follow",
 225              "id": data["id"],
 226              "object": "https://{}/actor".format(request.host),
 227              "actor": actor["id"]
 228         },
 229
 230         "id": "https://{}/activities/{}".format(request.host, uuid.uuid4()),
 231     }
 232
 233     asyncio.ensure_future(push_message_to_actor(actor, message, 'https://{}/actor#main-key'.format(request.host)))
 234
 235
 236 async def handle_undo(actor, data, request):
 237     global DATABASE
 238
 239     child = data['object']
 240     if child['type'] == 'Follow':
 241         following = DATABASE.get('relay-list', [])
 242
 243         inbox = get_actor_inbox(actor)
 244
 245         if inbox in following:
 246             following.remove(inbox)
 247             DATABASE['relay-list'] = following
 248
 249         if child['object'].endswith('/actor'):
 250             await unfollow_remote_actor(actor['id'])
 251
 252
 253 processors = {
 254     'Announce': handle_relay,
 255     'Create': handle_relay,
 256     'Follow': handle_follow,
 257     'Undo': handle_undo
 258 }
 259
 260
 261 async def inbox(request):
 262     data = await request.json()
 263
 264     if 'actor' not in data or not request['validated']:
 265         raise aiohttp.web.HTTPUnauthorized(body='access denied', content_type='text/plain')
 266
 267     actor = await fetch_actor(data["actor"])
 268     actor_uri = 'https://{}/actor'.format(request.host)
 269
 270     logging.debug(">> payload %r", data)
 271
 272     processor = processors.get(data['type'], None)
 273     if processor:
 274         await processor(actor, data, request)
 275
 276     return aiohttp.web.Response(body=b'{}', content_type='application/activity+json')
 277
 278
 279 app.router.add_post('/inbox', inbox)