cdn loaded latex math

lua/luarails.lua

@@ -0,0 +1,104 @@
+-- Guardrails and safe patterns for plugin development
+
+-- Safe string operations
+function safe_concat(...)
+    local result = {}
+    for i, v in ipairs({...}) do
+        if v ~= nil then
+            table.insert(result, tostring(v))
+        end
+    end
+    return table.concat(result)
+end
+
+-- Safe table operations
+function table_contains(tbl, value)
+    for _, v in ipairs(tbl) do
+        if v == value then return true end
+    end
+    return false
+end
+
+function table_keys(tbl)
+    local keys = {}
+    for k, _ in pairs(tbl) do
+        table.insert(keys, k)
+    end
+    return keys
+end
+
+function table_values(tbl)
+    local values = {}
+    for _, v in pairs(tbl) do
+        table.insert(values, v)
+    end
+    return values
+end
+
+-- Safe string escaping
+function escape_html(str)
+    if str == nil then return "" end
+    local s = tostring(str)
+    s = string.gsub(s, "&", "&")
+    s = string.gsub(s, "<", "&lt;")
+    s = string.gsub(s, ">", "&gt;")
+    s = string.gsub(s, '"', "&quot;")
+    s = string.gsub(s, "'", "&#39;")
+    return s
+end
+
+-- Pattern validation
+function is_valid_filename(name)
+    if name == nil or name == "" then return false end
+    -- Block directory traversal
+    if string.match(name, "%.%.") then return false end
+    if string.match(name, "/") or string.match(name, "\\\\") then return false end
+    return true
+end
+
+-- Safe error handling wrapper
+function try_catch(fn, catch_fn)
+    local status, err = pcall(fn)
+    if not status and catch_fn then
+        catch_fn(err)
+    end
+    return status
+end
+
+-- Request validation
+function validate_request(req, required_fields)
+    if type(req) ~= "table" then return false, "Request must be a table" end
+    for _, field in ipairs(required_fields) do
+        if req[field] == nil then
+            return false, "Missing required field: " .. field
+        end
+    end
+    return true, nil
+end
+
+-- Rate limiting helper (simple in-memory)
+_rate_limits = _rate_limits or {}
+function check_rate_limit(key, max_calls, window_seconds)
+    local now = os.time()
+    if _rate_limits[key] == nil then
+        _rate_limits[key] = {count = 1, window_start = now}
+        return true
+    end
+    
+    local rl = _rate_limits[key]
+    if now - rl.window_start > window_seconds then
+        -- Reset window
+        rl.count = 1
+        rl.window_start = now
+        return true
+    end
+    
+    if rl.count >= max_calls then
+        return false
+    end
+    
+    rl.count = rl.count + 1
+    return true
+end
+
+log("Lua guardrails initialized")