Adds an Onionoo module for looking up Tor relays

Adds a new torrelay command that can be used to search for a Tor relay
by fingerprint/nickname and also a new channel setting that allows relay
details to be automatically looked up when a 40-char hex fingerprint
appears in the channel.

modules/onionoo.py

@@ -0,0 +1,61 @@
+#--depends-on commands
+#--depends-on config
+
+import re
+from src import EventManager, ModuleManager, utils
+
+REGEX_SHA1_HEX = re.compile("[A-Fa-f0-9]{40}")
+URL_ONIONOO_DETAILS = "https://onionoo.torproject.org/details"
+URL_RELAY_SEARCH_SEARCH = "https://metrics.torproject.org/rs.html#search/"
+URL_RELAY_SEARCH_DETAILS = "https://metrics.torproject.org/rs.html#details/"
+
+def _get_relays_details(search):
+    page = utils.http.request(
+        URL_ONIONOO_DETAILS, get_params={"search": search}, json=True)
+    if page and "relays" in page.data:
+        return page.data["relays"]
+    raise utils.EventsResultsError()
+
+def _format_relay_summary_message(relays, search):
+    if len(relays) > 1:
+        raise utils.EventError(f"There were {len(relays)} relays found for "
+                               f"this query. {URL_RELAY_SEARCH_SEARCH}{search}")
+    if not relays:
+        raise utils.EventError("There were no relays found for this query.")
+    details = relays[0]
+    nickname = details["nickname"]
+    consensus_weight = details["consensus_weight"]
+    flags = " ".join(details["flags"])
+    url = URL_RELAY_SEARCH_DETAILS + details["fingerprint"]
+    return f"{nickname} - CW: {consensus_weight} [{flags}] {url}"
+
+@utils.export("channelset", utils.BoolSetting("auto-torrelay",
+    "Disable/Enable automatically getting Tor relay info from fingerprints"))
+class Module(ModuleManager.BaseModule):
+    _name = "Onionoo"
+
+    @utils.hook("command.regex")
+    @utils.kwarg("ignore_action", False)
+    @utils.kwarg("priority", EventManager.PRIORITY_MONITOR)
+    @utils.kwarg("command", "torrelay")
+    @utils.kwarg("pattern", REGEX_SHA1_HEX)
+    def channel_message(self, event):
+        if event["target"].get_setting("auto-torrelay", False):
+            event.eat()
+            search = event["match"].group(0)
+            try:
+                relays = _get_relays_details(search)
+                event["stdout"].write(
+                    _format_relay_summary_message(relays, search))
+            except utils.EventError:
+                pass
+
+    @utils.hook("received.command.torrelay", min_args=1)
+    def torrelay(self, event):
+        """
+        :help: Get summary information about a Tor relay
+        :usage: <fingerprint|nickname>
+        """
+        search = event["args"]
+        relays = _get_relays_details(search)
+        event["stdout"].write(_format_relay_summary_message(relays, search))