Changes the accounts_frontiers RPC to return per account results (#3791)

* Changes the accounts_frontiers RPC to return per account results
* Adds an unit test for checking per account responses

Co-authored-by: Dimitrios Siganos <dimitris@siganos.org>

nano/node/json_handler.cpp

@@ -960,18 +960,25 @@ void nano::json_handler::accounts_create ()
 void nano::json_handler::accounts_frontiers ()
 {
 	boost::property_tree::ptree frontiers;
-	auto transaction (node.store.tx_begin_read ());
+	auto transaction = node.store.tx_begin_read ();
-	for (auto & accounts : request.get_child ("accounts"))
+	for (auto & account_from_request : request.get_child ("accounts"))
 	{
-		auto account (account_impl (accounts.second.data ()));
+		auto account = account_impl (account_from_request.second.data ());
 		if (!ec)
 		{
-			auto latest (node.ledger.latest (transaction, account));
+			auto latest = node.ledger.latest (transaction, account);
 			if (!latest.is_zero ())
 			{
 				frontiers.put (account.to_account (), latest.to_string ());
+				continue;
+			}
+			else
+			{
+				ec = nano::error_common::account_not_found;
 			}
 		}
+		frontiers.put (account_from_request.second.data (), boost::str (boost::format ("error: %1%") % ec.message ()));
+		ec = {};
 	}
 	response_l.add_child ("frontiers", frontiers);
 	response_errors ();

nano/rpc_test/rpc.cpp

@@ -3177,8 +3177,9 @@ TEST (rpc, accounts_representatives)
 	ASSERT_EQ (response_representative, nano::dev::genesis->account ().to_account ());
 }
 
-// Tests the accounts_representatives RPC for expected per account results with
+/**
-// two possible error conditions: bad account number and account not found.
+ * Test the RPC accounts_frontiers with 3 accounts, one good one, one with an invalid account ID and one with an account that does not exist.
+ */
 TEST (rpc, accounts_representatives_per_account_result_with_errors)
 {
 	nano::system system;
@@ -3235,21 +3236,50 @@ TEST (rpc, accounts_frontiers)
 	auto node = add_ipc_enabled_node (system);
 	system.wallet (0)->insert_adhoc (nano::dev::genesis_key.prv);
 	auto const rpc_ctx = add_rpc (system, node);
+
 	boost::property_tree::ptree request;
 	request.put ("action", "accounts_frontiers");
-	boost::property_tree::ptree entry;
+	boost::property_tree::ptree accounts_l;
-	boost::property_tree::ptree peers_l;
+	// Adds a valid account that will be found in the ledger.
-	entry.put ("", nano::dev::genesis_key.pub.to_account ());
+	boost::property_tree::ptree entry1;
-	peers_l.push_back (std::make_pair ("", entry));
+	entry1.put ("", nano::dev::genesis_key.pub.to_account ());
-	request.add_child ("accounts", peers_l);
+	accounts_l.push_back (std::make_pair ("", entry1));
+	// Adds a bad account number for getting an error response.
+	boost::property_tree::ptree entry2;
+	auto const bad_account_number = "nano_3e3j5tkog48pnny9dmfzj1r16pg8t1e76dz5tmac6iq689wyjfpiij4txtd1";
+	entry2.put ("", bad_account_number);
+	accounts_l.push_back (std::make_pair ("", entry2));
+	// Adds a valid account that isn't on the ledger for getting an error response.
+	boost::property_tree::ptree entry3;
+	auto const account_not_found = "nano_1os6txqxyuesnxrtshnfb5or1hesc1647wpk9rsr84pmki6eairwha79hk3j";
+	entry3.put ("", account_not_found);
+	accounts_l.push_back (std::make_pair ("", entry3));
+	request.add_child ("accounts", accounts_l);
 	auto response (wait_response (system, rpc_ctx, request));
-	for (auto & frontiers : response.get_child ("frontiers"))
+
+	auto get_error_message = [] (nano::error_common error_common) -> std::string {
+		std::error_code ec = error_common;
+		return boost::str (boost::format ("error: %1%") % ec.message ());
+	};
+
+	// create a map of expected replies, everytime we receive and echeck a reply, we remove it from this map
+	// in the end, this container should be empty, which would signify that all 3 replies were received correctly
+	std::map<std::string, std::string> reply_map{
+		{ nano::dev::genesis_key.pub.to_account (), nano::dev::genesis->hash ().to_string () },
+		{ bad_account_number, get_error_message (nano::error_common::bad_account_number) },
+		{ account_not_found, get_error_message (nano::error_common::account_not_found) },
+	};
+
+	for (auto & frontier : response.get_child ("frontiers"))
 	{
-		std::string account_text (frontiers.first);
+		std::string account_text = frontier.first;
-		ASSERT_EQ (nano::dev::genesis_key.pub.to_account (), account_text);
+		std::string frontier_text = frontier.second.get<std::string> ("");
-		std::string frontier_text (frontiers.second.get<std::string> (""));
+		ASSERT_EQ (frontier_text, reply_map[account_text]);
-		ASSERT_EQ (node->latest (nano::dev::genesis->account ()), nano::block_hash{ frontier_text });
+		reply_map.erase (account_text);
 	}
+
+	// we expect all replies to have been received and this container to be empty
+	ASSERT_EQ (reply_map.size (), 0);
 }
 
 TEST (rpc, accounts_pending)