cNetwork: Exported lookup functions to Lua API.

Also added an example in the NetworkTest plugin.

MCServer/Plugins/NetworkTest/Info.lua

@@ -36,6 +36,27 @@ g_PluginInfo =
 						},
 					},  -- ParameterCombinations
 				},  -- client
+				
+				lookup =
+				{
+					HelpString = "Looks up the IP addresses corresponding to the given hostname  (google.com by default)",
+					Handler = HandleConsoleNetLookup,
+					ParameterCombinations =
+					{
+						{
+							Params = "",
+							Help = "Looks up the IP addresses of google.com.",
+						},
+						{
+							Params = "Hostname",
+							Help = "Looks up the IP addresses of the specified hostname.",
+						},
+						{
+							Params = "IP",
+							Help = "Looks up the canonical name of the specified IP.",
+						},
+					},
+				},  -- lookup
 			},  -- Subcommands
 		},  -- net
 	},

MCServer/Plugins/NetworkTest/NetworkTest.lua

@@ -61,3 +61,45 @@ end
 
 
 
+
+function HandleConsoleNetLookup(a_Split)
+	-- Get the name to look up:
+	local Addr = a_Split[3] or "google.com"
+	
+	-- Create the callbacks "personalised" for the host:
+	local Callbacks =
+	{
+		OnNameResolved = function (a_Hostname, a_IP)
+			LOG(a_Hostname .. " resolves to " .. a_IP)
+		end,
+		
+		OnError = function (a_Query, a_ErrorCode, a_ErrorMsg)
+			LOG("Failed to retrieve information for " .. a_Query .. ": " .. a_ErrorCode .. " (" .. a_ErrorMsg .. ")")
+			assert(a_Query == Addr)
+		end,
+		
+		OnFinished = function (a_Query)
+			LOG("Resolving " .. a_Query .. " has finished.")
+			assert(a_Query == Addr)
+		end,
+	}
+	
+	-- Queue both name and IP DNS queries;
+	-- we don't distinguish between an IP and a hostname in this command so we don't know which one to use:
+	local res = cNetwork:HostnameToIP(Addr, Callbacks)
+	if not(res) then
+		LOGWARNING("cNetwork:HostnameToIP call failed immediately")
+		return true
+	end
+	res = cNetwork:IPToHostname(Addr, Callbacks)
+	if not(res) then
+		LOGWARNING("cNetwork:IPToHostname call failed immediately")
+		return true
+	end
+	
+	return true, "DNS query has been queued."
+end
+
+
+
+

src/Bindings/CMakeLists.txt

@@ -8,6 +8,7 @@ SET (SRCS
 	Bindings.cpp
 	DeprecatedBindings.cpp
 	LuaChunkStay.cpp
+	LuaNameLookup.cpp
 	LuaState.cpp
 	LuaTCPLink.cpp
 	LuaWindow.cpp
@@ -25,6 +26,7 @@ SET (HDRS
 	DeprecatedBindings.h
 	LuaChunkStay.h
 	LuaFunctions.h
+	LuaNameLookup.h
 	LuaState.h
 	LuaTCPLink.h
 	LuaWindow.h

src/Bindings/LuaNameLookup.cpp

@@ -0,0 +1,88 @@
+
+// LuaNameLookup.cpp
+
+// Implements the cLuaNameLookup class used as the cNetwork API callbacks for name and IP lookups from Lua
+
+#include "Globals.h"
+#include "LuaNameLookup.h"
+
+
+
+
+
+cLuaNameLookup::cLuaNameLookup(const AString & a_Query, cPluginLua & a_Plugin, int a_CallbacksTableStackPos):
+	m_Plugin(a_Plugin),
+	m_Callbacks(a_Plugin.GetLuaState(), a_CallbacksTableStackPos),
+	m_Query(a_Query)
+{
+}
+
+
+
+
+
+void cLuaNameLookup::OnNameResolved(const AString & a_Name, const AString & a_IP)
+{
+	// Check if we're still valid:
+	if (!m_Callbacks.IsValid())
+	{
+		return;
+	}
+
+	// Call the callback:
+	cPluginLua::cOperation Op(m_Plugin);
+	if (!Op().Call(cLuaState::cTableRef(m_Callbacks, "OnNameResolved"), a_Name, a_IP))
+	{
+		LOGINFO("cNetwork name lookup OnNameResolved callback failed in plugin %s looking up %s. %s resolves to %s.",
+			m_Plugin.GetName().c_str(), m_Query.c_str(), a_Name.c_str(), a_IP.c_str()
+		);
+	}
+}
+
+
+
+
+
+void cLuaNameLookup::OnError(int a_ErrorCode, const AString & a_ErrorMsg)
+{
+	// Check if we're still valid:
+	if (!m_Callbacks.IsValid())
+	{
+		return;
+	}
+
+	// Call the callback:
+	cPluginLua::cOperation Op(m_Plugin);
+	if (!Op().Call(cLuaState::cTableRef(m_Callbacks, "OnError"), m_Query, a_ErrorCode, a_ErrorMsg))
+	{
+		LOGINFO("cNetwork name lookup OnError callback failed in plugin %s looking up %s. The error is %d (%s)",
+			m_Plugin.GetName().c_str(), m_Query.c_str(), a_ErrorCode, a_ErrorMsg.c_str()
+		);
+	}
+}
+
+
+
+
+
+void cLuaNameLookup::OnFinished(void)
+{
+	// Check if we're still valid:
+	if (!m_Callbacks.IsValid())
+	{
+		return;
+	}
+
+	// Call the callback:
+	cPluginLua::cOperation Op(m_Plugin);
+	if (!Op().Call(cLuaState::cTableRef(m_Callbacks, "OnFinished"), m_Query))
+	{
+		LOGINFO("cNetwork name lookup OnFinished callback failed in plugin %s, looking up %s.",
+			m_Plugin.GetName().c_str(), m_Query.c_str()
+		);
+	}
+}
+
+
+
+

src/Bindings/LuaNameLookup.h

@@ -0,0 +1,46 @@
+
+// LuaNameLookup.h
+
+// Declares the cLuaNameLookup class used as the cNetwork API callbacks for name and IP lookups from Lua
+
+
+
+
+
+#pragma once
+
+#include "../OSSupport/Network.h"
+#include "PluginLua.h"
+
+
+
+
+
+class cLuaNameLookup:
+	public cNetwork::cResolveNameCallbacks
+{
+public:
+	/** Creates a new instance of the lookup callbacks for the specified query,
+	attached to the specified lua plugin and wrapping the callbacks that are in a table at the specified stack pos. */
+	cLuaNameLookup(const AString & a_Query, cPluginLua & a_Plugin, int a_CallbacksTableStackPos);
+
+protected:
+	/** The plugin for which the link is created. */
+	cPluginLua & m_Plugin;
+
+	/** The Lua table that holds the callbacks to be invoked. */
+	cLuaState::cRef m_Callbacks;
+
+	/** The query used to start the lookup (either hostname or IP). */
+	AString m_Query;
+
+
+	// cNetwork::cResolveNameCallbacks overrides:
+	virtual void OnNameResolved(const AString & a_Name, const AString & a_IP) override;
+	virtual void OnError(int a_ErrorCode, const AString & a_ErrorMsg) override;
+	virtual void OnFinished(void) override;
+};
+
+
+
+

src/Bindings/LuaTCPLink.h

@@ -10,7 +10,6 @@
 #pragma once
 
 #include "../OSSupport/Network.h"
-#include "LuaState.h"
 #include "PluginLua.h"
 
 
@@ -22,7 +21,7 @@ class cLuaTCPLink:
 	public cTCPLink::cCallbacks
 {
 public:
-	/** Creates a new instance of the link, attached to the specified lua state and wrapping the callbacks that are in a table at the specified stack pos. */
+	/** Creates a new instance of the link, attached to the specified plugin and wrapping the callbacks that are in a table at the specified stack pos. */
 	cLuaTCPLink(cPluginLua & a_Plugin, int a_CallbacksTableStackPos);
 
 	/** Sends the data contained in the string to the remote peer.

src/Bindings/ManualBindings_Network.cpp

@@ -9,6 +9,7 @@
 #include "tolua++/include/tolua++.h"
 #include "LuaState.h"
 #include "LuaTCPLink.h"
+#include "LuaNameLookup.h"
 
 
 
@@ -71,6 +72,86 @@ static int tolua_cNetwork_Connect(lua_State * L)
 
 
 
+static int tolua_cNetwork_HostnameToIP(lua_State * L)
+{
+	// Function signature:
+	// cNetwork:HostnameToIP(Host, Callbacks) -> bool
+
+	cLuaState S(L);
+	if (
+		!S.CheckParamUserTable(1, "cNetwork") ||
+		!S.CheckParamString(2) ||
+		!S.CheckParamTable(3) ||
+		!S.CheckParamEnd(4)
+	)
+	{
+		return 0;
+	}
+	
+	// Get the plugin instance:
+	cPluginLua * Plugin = GetLuaPlugin(L);
+	if (Plugin == nullptr)
+	{
+		// An error message has been already printed in GetLuaPlugin()
+		S.Push(false);
+		return 1;
+	}
+
+	// Read the params:
+	AString Host;
+	S.GetStackValue(2, Host);
+
+	// Try to look up:
+	bool res = cNetwork::HostnameToIP(Host, std::make_shared<cLuaNameLookup>(Host, *Plugin, 3));
+	S.Push(res);
+
+	return 1;
+}
+
+
+
+
+
+static int tolua_cNetwork_IPToHostname(lua_State * L)
+{
+	// Function signature:
+	// cNetwork:IPToHostname(IP, Callbacks) -> bool
+
+	cLuaState S(L);
+	if (
+		!S.CheckParamUserTable(1, "cNetwork") ||
+		!S.CheckParamString(2) ||
+		!S.CheckParamTable(3) ||
+		!S.CheckParamEnd(4)
+	)
+	{
+		return 0;
+	}
+	
+	// Get the plugin instance:
+	cPluginLua * Plugin = GetLuaPlugin(L);
+	if (Plugin == nullptr)
+	{
+		// An error message has been already printed in GetLuaPlugin()
+		S.Push(false);
+		return 1;
+	}
+
+	// Read the params:
+	AString Host;
+	S.GetStackValue(2, Host);
+
+	// Try to look up:
+	bool res = cNetwork::IPToHostName(Host, std::make_shared<cLuaNameLookup>(Host, *Plugin, 3));
+	S.Push(res);
+
+	return 1;
+}
+
+
+
+
+
 ////////////////////////////////////////////////////////////////////////////////
 // cTCPLink bindings (routed through cLuaTCPLink):
 
@@ -258,9 +339,9 @@ void ManualBindings::BindNetwork(lua_State * tolua_S)
 	// Fill in the functions (alpha-sorted):
 	tolua_beginmodule(tolua_S, "cNetwork");
 		tolua_function(tolua_S, "Connect",      tolua_cNetwork_Connect);
-		/*
 		tolua_function(tolua_S, "HostnameToIP", tolua_cNetwork_HostnameToIP);
 		tolua_function(tolua_S, "IPToHostname", tolua_cNetwork_IPToHostname);
+		/*
 		tolua_function(tolua_S, "Listen",       tolua_cNetwork_Listen);
 		*/
 	tolua_endmodule(tolua_S);