Enable dynamic_add_media to take the file data instead of a path

src/script/common/c_converter.cpp

@@ -483,6 +483,17 @@ bool check_field_or_nil(lua_State *L, int index, int type, const char *fieldname
 
 bool getstringfield(lua_State *L, int table,
 		const char *fieldname, std::string &result)
+{
+	std::string_view sv;
+	if (getstringfield(L, table, fieldname, sv)) {
+		result = sv;
+		return true;
+	}
+	return false;
+}
+
+bool getstringfield(lua_State *L, int table,
+		const char *fieldname, std::string_view &result)
 {
 	lua_getfield(L, table, fieldname);
 	bool got = false;
@@ -491,7 +502,7 @@ bool getstringfield(lua_State *L, int table,
 		size_t len = 0;
 		const char *ptr = lua_tolstring(L, -1, &len);
 		if (ptr) {
-			result.assign(ptr, len);
+			result = std::string_view(ptr, len);
 			got = true;
 		}
 	}

src/script/common/c_converter.h

@@ -27,7 +27,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #pragma once
 
 #include <vector>
-#include <unordered_map>
+#include <string_view>
 
 #include "irrlichttypes_bloated.h"
 #include "common/c_types.h"
@@ -67,11 +67,11 @@ v3s16              getv3s16field_default(lua_State *L, int table,
 
 bool               getstringfield(lua_State *L, int table,
                              const char *fieldname, std::string &result);
+bool               getstringfield(lua_State *L, int table,
+                             const char *fieldname, std::string_view &result);
 size_t             getstringlistfield(lua_State *L, int table,
                              const char *fieldname,
                              std::vector<std::string> *result);
-void               read_groups(lua_State *L, int index,
-                             std::unordered_map<std::string, int> &result);
 bool               getboolfield(lua_State *L, int table,
                              const char *fieldname, bool &result);
 bool               getfloatfield(lua_State *L, int table,

src/script/lua_api/l_server.cpp

@@ -548,19 +548,22 @@ int ModApiServer::l_dynamic_add_media(lua_State *L)
 	Server *server = getServer(L);
 	const bool at_startup = !getEnv(L);
 
-	std::string filename, filepath, to_player;
-	bool ephemeral = false;
+	std::string tmp;
+	Server::DynamicMediaArgs args;
 
 	if (lua_istable(L, 1)) {
-		getstringfield(L, 1, "filename", filename);
-		getstringfield(L, 1, "filepath", filepath);
-		getstringfield(L, 1, "to_player", to_player);
-		getboolfield(L, 1, "ephemeral", ephemeral);
+		getstringfield(L, 1, "filename", args.filename);
+		if (getstringfield(L, 1, "filepath", tmp))
+			args.filepath = tmp;
+		args.data.emplace();
+		if (!getstringfield(L, 1, "filedata", *args.data))
+			args.data.reset();
+		getstringfield(L, 1, "to_player", args.to_player);
+		getboolfield(L, 1, "ephemeral", args.ephemeral);
 	} else {
-		filepath = readParam<std::string>(L, 1);
+		tmp = readParam<std::string>(L, 1);
+		args.filepath = tmp;
 	}
-	if (filepath.empty())
-		luaL_typerror(L, 1, "non-empty string");
 	if (at_startup) {
 		if (!lua_isnoneornil(L, 2))
 			throw LuaError("must be called without callback at load-time");
@@ -572,13 +575,27 @@ int ModApiServer::l_dynamic_add_media(lua_State *L)
 		luaL_checktype(L, 2, LUA_TFUNCTION);
 	}
 
-	CHECK_SECURE_PATH(L, filepath.c_str(), false);
+	// validate
+	if (args.filepath) {
+		if (args.filepath->empty())
+			throw LuaError("filepath must be non-empty");
+		if (args.data)
+			throw LuaError("cannot provide both filepath and filedata");
+	} else if (args.data) {
+		if (args.filename.empty())
+			throw LuaError("filename required");
+	} else {
+		throw LuaError("either filepath or filedata must be provided");
+	}
 
-	u32 token = server->getScriptIface()->allocateDynamicMediaCallback(L, 2);
+	if (args.filepath)
+		CHECK_SECURE_PATH(L, args.filepath->c_str(), false);
 
-	bool ok = server->dynamicAddMedia(filename, filepath, token, to_player, ephemeral);
+	args.token = server->getScriptIface()->allocateDynamicMediaCallback(L, 2);
+
+	bool ok = server->dynamicAddMedia(args);
 	if (!ok)
-		server->getScriptIface()->freeDynamicMediaCallback(token);
+		server->getScriptIface()->freeDynamicMediaCallback(args.token);
 	lua_pushboolean(L, ok);
 
 	return 1;

src/server.cpp

@@ -381,6 +381,13 @@ Server::~Server()
 	if (m_mod_storage_database)
 		m_mod_storage_database->endSave();
 
+	// Clean up files
+	for (auto &it : m_media) {
+		if (it.second.delete_at_shutdown) {
+			fs::DeleteSingleFileOrEmptyDirectory(it.second.path);
+		}
+	}
+
 	// Delete things in the reverse order of creation
 	delete m_emerge;
 	delete m_env;
@@ -3568,22 +3575,65 @@ void Server::deleteParticleSpawner(const std::string &playername, u32 id)
 	SendDeleteParticleSpawner(peer_id, id);
 }
 
-bool Server::dynamicAddMedia(std::string filename, std::string filepath,
-	const u32 token, const std::string &to_player, bool ephemeral)
+namespace {
+	std::string writeToTempFile(std::string_view content)
+	{
+		auto filepath = fs::CreateTempFile();
+		if (filepath.empty())
+			return "";
+		std::ofstream os(filepath, std::ios::binary);
+		if (!os.good())
+			return "";
+		os << content;
+		os.close();
+		if (os.fail()) {
+			fs::DeleteSingleFileOrEmptyDirectory(filepath);
+			return "";
+		}
+		return filepath;
+	}
+}
+
+bool Server::dynamicAddMedia(const DynamicMediaArgs &a)
 {
-	if (filename.empty())
-		filename = fs::GetFilenameFromPath(filepath.c_str());
+	std::string filename = a.filename;
+	std::string filepath;
+
+	// Deal with file -or- data, as provided
+	// (Note: caller must ensure validity, so sanity_check is okay)
+	if (a.filepath) {
+		sanity_check(!a.data);
+		filepath = *a.filepath;
+		if (filename.empty())
+			filename = fs::GetFilenameFromPath(filepath.c_str());
+	} else {
+		sanity_check(a.data);
+		sanity_check(!filename.empty());
+
+		// Write the file to disk. addMediaFile() will read it right back but this
+		// is the best way without turning the media loading code into spaghetti.
+		filepath = writeToTempFile(*a.data);
+		if (filepath.empty()) {
+			errorstream << "Server: failed writing media file \""
+				<< filename << "\" to disk" << std::endl;
+			return false;
+		}
+		verbosestream << "Server: \"" << filename << "\" temporarily written to "
+			<< filepath << std::endl;
+	}
+
+	// Do some checks
 	auto it = m_media.find(filename);
 	if (it != m_media.end()) {
 		// Allow the same path to be "added" again in certain conditions
-		if (ephemeral || it->second.path != filepath) {
+		if (a.ephemeral || it->second.path != filepath) {
 			errorstream << "Server::dynamicAddMedia(): file \"" << filename
 				<< "\" already exists in media cache" << std::endl;
 			return false;
 		}
 	}
 
-	if (!m_env && (!to_player.empty() || ephemeral)) {
+	if (!m_env && (!a.to_player.empty() || a.ephemeral)) {
 		errorstream << "Server::dynamicAddMedia(): "
 			"adding ephemeral or player-specific media at startup is nonsense"
 			<< std::endl;
@@ -3595,35 +3645,37 @@ bool Server::dynamicAddMedia(std::string filename, std::string filepath,
 	bool ok = addMediaFile(filename, filepath, &filedata, &raw_hash);
 	if (!ok)
 		return false;
+	assert(!filedata.empty());
 
-	if (ephemeral) {
-		// Create a copy of the file and swap out the path, this removes the
-		// requirement that mods keep the file accessible at the original path.
-		filepath = fs::CreateTempFile();
-		bool ok = ([&] () -> bool {
-			if (filepath.empty())
+	const auto &media_it = m_media.find(filename);
+	assert(media_it != m_media.end());
+
+	if (a.ephemeral) {
+		if (!a.data) {
+			// Create a copy of the file and swap out the path, this removes the
+			// requirement that mods keep the file accessible at the original path.
+			filepath = writeToTempFile(filedata);
+			if (filepath.empty()) {
+				errorstream << "Server: failed creating a copy of media file \""
+					<< filename << "\"" << std::endl;
+				m_media.erase(filename);
 				return false;
-			std::ofstream os(filepath.c_str(), std::ios::binary);
-			if (!os.good())
-				return false;
-			os << filedata;
-			os.close();
-			return !os.fail();
-		})();
-		if (!ok) {
-			errorstream << "Server: failed to create a copy of media file "
-				<< "\"" << filename << "\"" << std::endl;
-			m_media.erase(filename);
-			return false;
+			}
+			verbosestream << "Server: \"" << filename << "\" temporarily copied to "
+				<< filepath << std::endl;
+			media_it->second.path = filepath;
 		}
-		verbosestream << "Server: \"" << filename << "\" temporarily copied to "
-			<< filepath << std::endl;
 
-		m_media[filename].path = filepath;
-		m_media[filename].no_announce = true;
-		// stepPendingDynMediaCallbacks will clean this up later.
-	} else if (!to_player.empty()) {
-		m_media[filename].no_announce = true;
+		media_it->second.no_announce = true;
+		// stepPendingDynMediaCallbacks will clean the file up later
+	} else if (a.data) {
+		// data is in a temporary file but not ephemeral, so the cleanup point
+		// is different.
+		media_it->second.delete_at_shutdown = true;
+	}
+	if (!a.to_player.empty()) {
+		// only sent to one player (who must be online), so shouldn't announce.
+		media_it->second.no_announce = true;
 	}
 
 	std::unordered_set<session_t> delivered, waiting;
@@ -3631,18 +3683,18 @@ bool Server::dynamicAddMedia(std::string filename, std::string filepath,
 	// Push file to existing clients
 	if (m_env) {
 		NetworkPacket pkt(TOCLIENT_MEDIA_PUSH, 0);
-		pkt << raw_hash << filename << static_cast<bool>(ephemeral);
+		pkt << raw_hash << filename << static_cast<bool>(a.ephemeral);
 
 		NetworkPacket legacy_pkt = pkt;
 
 		// Newer clients get asked to fetch the file (asynchronous)
-		pkt << token;
+		pkt << a.token;
 		// Older clients have an awful hack that just throws the data at them
 		legacy_pkt.putLongString(filedata);
 
 		ClientInterface::AutoLock clientlock(m_clients);
 		for (auto &pair : m_clients.getClientList()) {
-			if (pair.second->getState() == CS_DefinitionsSent && !ephemeral) {
+			if (pair.second->getState() == CS_DefinitionsSent && !a.ephemeral) {
 				/*
 					If a client is in the DefinitionsSent state it is too late to
 					transfer the file via sendMediaAnnouncement() but at the same
@@ -3663,7 +3715,7 @@ bool Server::dynamicAddMedia(std::string filename, std::string filepath,
 				continue;
 
 			const session_t peer_id = pair.second->peer_id;
-			if (!to_player.empty() && getPlayerName(peer_id) != to_player)
+			if (!a.to_player.empty() && getPlayerName(peer_id) != a.to_player)
 				continue;
 
 			if (proto_ver < 40) {
@@ -3686,15 +3738,15 @@ bool Server::dynamicAddMedia(std::string filename, std::string filepath,
 	// Run callback for players that already had the file delivered (legacy-only)
 	for (session_t peer_id : delivered) {
 		if (auto player = m_env->getPlayer(peer_id))
-			getScriptIface()->on_dynamic_media_added(token, player->getName());
+			getScriptIface()->on_dynamic_media_added(a.token, player->getName());
 	}
 
 	// Save all others in our pending state
-	auto &state = m_pending_dyn_media[token];
+	auto &state = m_pending_dyn_media[a.token];
 	state.waiting_players = std::move(waiting);
 	// regardless of success throw away the callback after a while
 	state.expiry_timer = 60.0f;
-	if (ephemeral)
+	if (a.ephemeral)
 		state.filename = filename;
 
 	return true;

src/server.h

@@ -44,6 +44,8 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include <map>
 #include <vector>
 #include <unordered_set>
+#include <optional>
+#include <string_view>
 
 class ChatEvent;
 struct ChatEventChat;
@@ -87,13 +89,17 @@ struct MediaInfo
 {
 	std::string path;
 	std::string sha1_digest; // base64-encoded
-	bool no_announce; // true: not announced in TOCLIENT_ANNOUNCE_MEDIA (at player join)
+	// true = not announced in TOCLIENT_ANNOUNCE_MEDIA (at player join)
+	bool no_announce;
+	// does what it says. used by some cases of dynamic media.
+	bool delete_at_shutdown;
 
 	MediaInfo(const std::string &path_="",
 	          const std::string &sha1_digest_=""):
 		path(path_),
 		sha1_digest(sha1_digest_),
-		no_announce(false)
+		no_announce(false),
+		delete_at_shutdown(false)
 	{
 	}
 };
@@ -258,8 +264,15 @@ public:
 
 	void deleteParticleSpawner(const std::string &playername, u32 id);
 
-	bool dynamicAddMedia(std::string filename, std::string filepath, u32 token,
-		const std::string &to_player, bool ephemeral);
+	struct DynamicMediaArgs {
+		std::string filename;
+		std::optional<std::string> filepath;
+		std::optional<std::string_view> data;
+		u32 token;
+		std::string to_player;
+		bool ephemeral = false;
+	};
+	bool dynamicAddMedia(const DynamicMediaArgs &args);
 
 	ServerInventoryManager *getInventoryMgr() const { return m_inventory_mgr.get(); }
 	void sendDetachedInventory(Inventory *inventory, const std::string &name, session_t peer_id);