# HG changeset patch
# User Kim Alvefur <zash@zash.se>
# Date 1737036300 -3600
# Node ID ac60c21015c7e5528bca5054bb291e428a7b9b0e
# Parent  ff13dd315e68dcde2a3ef5a7b4d2893182767318
core.configmanager: Add ways to read config values from files

Inspired by something MattJ said

Allows retrieving config values from files which are expected to be
relative to the config directory, extending on the ENV_ method of
retrieving config values from outside the config file.

- FileLine retrieves the first line, stripping any trailing newline
- FileContents reads the whole file
- FileLines reads lines into an array

diff -r ff13dd315e68 -r ac60c21015c7 CHANGES
--- a/CHANGES	Thu Jan 16 11:35:19 2025 +0000
+++ b/CHANGES	Thu Jan 16 15:05:00 2025 +0100
@@ -60,6 +60,7 @@
 
 - The configuration file now supports referring and appending to options previously set
 - Direct usage of the Lua API in the config file is deprecated, but can now be accessed via Lua.* instead
+- Convenience functions for reading values from files
 
 ## Changes
 
diff -r ff13dd315e68 -r ac60c21015c7 core/configmanager.lua
--- a/core/configmanager.lua	Thu Jan 16 11:35:19 2025 +0000
+++ b/core/configmanager.lua	Thu Jan 16 15:05:00 2025 +0100
@@ -161,15 +161,43 @@
 		end;
 	};
 
+	-- For reading config values out of files.
+	local function filereader(basepath, defaultmode)
+		return function(filename, mode)
+			local f, err = io.open(resolve_relative_path(basepath, filename));
+			if not f then error(err, 2); end
+			local content, err = f:read(mode or defaultmode);
+			f:close();
+			if not content then error(err, 2); end
+			return content;
+		end
+	end
+
+	-- Collect lines into an array
+	local function linereader(basepath)
+		return function(filename)
+			local ret = {};
+			for line in io.lines(resolve_relative_path(basepath, filename)) do
+				t_insert(ret, line);
+			end
+			return ret;
+		end
+	end
+
 	parser = {};
 	function parser.load(data, config_file, config_table)
 		local set_options = {}; -- set_options[host.."/"..option_name] = true (when the option has been set already in this file)
 		local warnings = {};
 		local env;
+		local config_path = config_file:gsub("[^"..path_sep.."]+$", "");
+
 		-- The ' = true' are needed so as not to set off __newindex when we assign the functions below
 		env = setmetatable({
 			Host = true, host = true, VirtualHost = true,
 			Component = true, component = true,
+			FileContents = true,
+			FileLine = true,
+			FileLines = true,
 			Include = true, include = true, RunScript = true }, {
 				__index = function (_, k)
 					if k:match("^ENV_") then
@@ -293,7 +321,6 @@
 				end
 				local path_pos, glob = file:match("()([^"..path_sep.."]+)$");
 				local path = file:sub(1, math_max(path_pos-2,0));
-				local config_path = config_file:gsub("[^"..path_sep.."]+$", "");
 				if #path > 0 then
 					path = resolve_relative_path(config_path, path);
 				else
@@ -308,7 +335,7 @@
 				return;
 			end
 			-- Not a wildcard, so resolve (potentially) relative path and run through config parser
-			file = resolve_relative_path(config_file:gsub("[^"..path_sep.."]+$", ""), file);
+			file = resolve_relative_path(config_path, file);
 			local f, err = io.open(file);
 			if f then
 				local ret, err = parser.load(f:read("*a"), file, config_table);
@@ -325,9 +352,13 @@
 		env.include = env.Include;
 
 		function env.RunScript(file)
-			return dofile(resolve_relative_path(config_file:gsub("[^"..path_sep.."]+$", ""), file));
+			return dofile(resolve_relative_path(config_path, file));
 		end
 
+		env.FileContents = filereader(config_path, "*a");
+		env.FileLine = filereader(config_path, "*l");
+		env.FileLines = linereader(config_path);
+
 		local chunk, err = envload(data, "@"..config_file, env);
 
 		if not chunk then
diff -r ff13dd315e68 -r ac60c21015c7 spec/scansion/admins.txt
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/spec/scansion/admins.txt	Thu Jan 16 15:05:00 2025 +0100
@@ -0,0 +1,1 @@
+admin@localhost
diff -r ff13dd315e68 -r ac60c21015c7 spec/scansion/prosody.cfg.lua
--- a/spec/scansion/prosody.cfg.lua	Thu Jan 16 11:35:19 2025 +0000
+++ b/spec/scansion/prosody.cfg.lua	Thu Jan 16 15:05:00 2025 +0100
@@ -1,6 +1,6 @@
 --luacheck: ignore
 
-admins = { "admin@localhost" }
+admins = FileLines("admins.txt")
 
 network_backend = ENV_PROSODY_NETWORK_BACKEND or "epoll"
 network_settings = Lua.require"prosody.util.json".decode(ENV_PROSODY_NETWORK_SETTINGS or "{}")