Swaps over Nostr

- Separation between SwapManager and its transport:
   Legacy transpport uses http, Nostr uses websockets
 - The transport uses a context to open/close connections.
   This context is not async, because it needs to be called
   from the GUI
 - Swapserver fees values are initialized to None instead
   of 0, so that any attempt to use them before the swap
   manager is initialized will raise an exception.
 - Remove swapserver fees disk caching (swap_pairs file)
 - Regtests use http transport
 - Android uses http transport (until QML is ready)

electrum/plugins/swapserver/server.py

@@ -15,7 +15,7 @@ if TYPE_CHECKING:
     from electrum.wallet import Abstract_Wallet
 
 
-class SwapServer(Logger, EventListener):
+class HttpSwapServer(Logger, EventListener):
     """
     public API:
     - getpairs
@@ -57,7 +57,7 @@ class SwapServer(Logger, EventListener):
 
     async def get_pairs(self, r):
         sm = self.sm
-        sm.init_pairs()
+        sm.server_update_pairs()
         pairs = {
             "info": [],
             "warnings": [],

electrum/plugins/swapserver/swapserver.py

@@ -29,7 +29,7 @@ from typing import TYPE_CHECKING
 
 from electrum.plugin import BasePlugin, hook
 
-from .server import SwapServer
+from .server import HttpSwapServer
 
 if TYPE_CHECKING:
     from electrum.simple_config import SimpleConfig
@@ -49,12 +49,6 @@ class SwapServerPlugin(BasePlugin):
         # we use the first wallet loaded
         if self.server is not None:
             return
-        if self.config.NETWORK_OFFLINE:
-            return
-
-        self.server = SwapServer(self.config, wallet)
         sm = wallet.lnworker.swap_manager
-        for coro in [
-            self.server.run(),
-        ]:
-            asyncio.run_coroutine_threadsafe(daemon.taskgroup.spawn(coro), daemon.asyncio_loop)
+        sm.is_server = True
+        sm.http_server = HttpSwapServer(self.config, wallet)