Модуль:VarQuery

Для документации этого модуля может быть создана страница Модуль:VarQuery/doc

local p = {}
local cargo = mw.ext.cargo -- используем Cargo API
local getArgs = require('Module:Arguments').getArgs
local split = require('Module:Split')
local Json = require('Module:Json')
local Variables = require('Module:Variables')

local i18n = {
	error = {
		multiple_results = 'More than one result.',
		no_results = 'No results found.',
		no_table = 'No table given',
	}
}

--- Validates the given rows.
local function validate(rows, surpress)
	local errorMsg
	if type(rows) == 'string' then
		errorMsg = rows
		mw.logObject(rows)
	end
	local nrows = #rows
	if nrows ~= 1 then
		if nrows == 0 then
			errorMsg = (i18n.error.no_results)
		else
			errorMsg = (i18n.error.multiple_results)
		end
	end
	if errorMsg then
		if surpress then
			mw.log(errorMsg)
		else
			error(errorMsg)
		end
		return false
	end
	return true
end

--- Clear already existing variables that could interfere with the new ones.
local function clear_variables(prefix, fields)
	for _, field in ipairs(split(fields, '%s*,%s*')) do
		local var_key = prefix .. field
		if Variables.varExists(var_key) then
			Variables.varDefine(var_key, '')
		end
	end
end

--- Write the row values to the corresponding variables.
local function write_variables(prefix, row)
	for key, value in pairs(row) do
		if type(value) == 'table' then
			write_variables(prefix .. key .. '_', value)
		elseif key == 'extradata' then
			write_variables(prefix .. key .. '_', Json.parse(mw.text.decode(value)))
		else
			local var_key = prefix .. key
			Variables.varDefine(var_key, value)
		end
	end
end

function p.main(frame)
	local args = getArgs(frame)
	local fields = args['field'] or args['fields'] or 'pagename'
	local prefix = args['prefix'] or 'cargo_'
	
	if args.fromArgs then
		clear_variables(prefix, fields)
		write_variables(prefix, args)
		return
	end
	
	local table = args['table'] or args['tables']
	assert(table, i18n.error.no_table)

	clear_variables(prefix, fields)
	local rows = cargo.query(table, fields, {
		where = args.where,
		groupBy = args['group by'],
		orderBy = args['order by'],
		limit = 1,
		format = 'table'
	})
	
	if validate(rows, args.failquiet) then
		write_variables(prefix, rows[1])
	end
end

return p