Add 4 additional electrum server config settings.

Author: evoskuil

include/bitcoin/server/settings.hpp

@@ -90,9 +90,21 @@ class BCS_API settings
         using base = network::settings::tls_server;
         using base::base;
 
-        // Maximum number of headers the server will return in single request.
-        // Recommended to be multiple of difficulty retarget period, e.g. 2016.
+        /// Maximum number of headers the server will return in single request.
+        /// Recommended to be a multiple of the difficulty retarget period.
         uint32_t maximum_headers{ 10 * 2016 };
+
+        /// Maximum cumulative number of address subscriptions per channel.
+        uint32_t maximum_subscriptions{ 1'000'000 };
+
+        /// Arbitrary server name returned by server.version.
+        std::string server_name{ BC_USER_AGENT };
+
+        /// Arbitrary string returned by server.donation_address.
+        std::string donation_address{};
+
+        /// Arbitrary string returned by server.banner.
+        std::string banner_message{};
     };
 
     /// html (http/s) document server settings (has directory/default).

src/parser.cpp

@@ -1132,7 +1132,27 @@ options_metadata parser::load_settings() THROWS
     (
         "electrum.maximum_headers",
         value<uint32_t>(&configured.server.electrum.maximum_headers),
-        "The maximum allowed header request cound, defaults to '20160'."
+        "The maximum allowed headers returned per request, defaults to '20160'."
+    )
+    (
+        "electrum.maximum_subscriptions",
+        value<uint32_t>(&configured.server.electrum.maximum_subscriptions),
+        "The maximum allowed address subscriptions per channel, defaults to '1000000'."
+    )
+    (
+        "electrum.server_name",
+        value<std::string>(&configured.server.electrum.server_name),
+        "String returned by server.version, defaults to '" BC_USER_AGENT "'."
+    )
+    (
+        "electrum.donation_address",
+        value<std::string>(&configured.server.electrum.donation_address),
+        "String returned by server.donation_address, defaults to empty."
+    )
+    (
+        "electrum.banner_message",
+        value<std::string>(&configured.server.electrum.banner_message),
+        "String returned by server.banner, defaults to empty."
     )
 
     /* [stratum_v1] */

test/settings.cpp

@@ -233,6 +233,10 @@ BOOST_AUTO_TEST_CASE(server__electrum_server__defaults__expected)
 
     // electrum_server
     BOOST_REQUIRE_EQUAL(server.maximum_headers, 10u * 2016u);
+    BOOST_REQUIRE_EQUAL(server.maximum_subscriptions, 1'000'000u);
+    BOOST_REQUIRE_EQUAL(server.server_name, BC_USER_AGENT);
+    BOOST_REQUIRE(server.donation_address.empty());
+    BOOST_REQUIRE(server.banner_message.empty());
 }
 
 BOOST_AUTO_TEST_CASE(server__stratum_v1_server__defaults__expected)