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|
--- DOM module for LuaXML
-- @module luaxml-domobject
-- @author Michal Hoftich <michal.h21@gmail.com
local dom = {}
local xml = require("luaxml-mod-xml")
local handler = require("luaxml-mod-handler")
local css_query = require("luaxml-cssquery")
local void = {area = true, base = true, br = true, col = true, hr = true, img = true, input = true, link = true, meta = true, param = true}
local escapes = {
[">"] = ">",
["<"] = "<",
["&"] = "&",
['"'] = """,
["'"] = "'",
["`"] = "`"
}
local function escape(search, text)
return text:gsub(search, function(ch)
return escapes[ch] or ""
end)
end
local function escape_element(text)
return escape("([<>&])", text)
end
local function escape_attr(text)
return escape("([<>&\"'`])", text)
end
local actions = {
TEXT = {text = "%s"},
COMMENT = {start = "<!-- ", text = "%s", stop = " -->"},
ELEMENT = {start = "<%s%s>", stop = "</%s>", void = "<%s%s />"},
DECL = {start = "<?%s %s?>"},
DTD = {start = "<!DOCTYPE ", text = "%s" , stop=">"}
}
--- It serializes the DOM object back to the XML.
-- This function is mainly used for internal purposes, it is better to
-- use the `DOM_Object:serialize()`.
-- @param parser DOM object
-- @param current Element which should be serialized
-- @param level
-- @param output
-- @return table Table with XML strings. It can be concenated using table.concat() function to get XML string corresponding to the DOM_Object.
local function serialize_dom(parser, current,level, output)
local output = output or {}
local function get_action(typ, action)
local ac = actions[typ] or {}
local format = ac[action] or ""
return format
end
local function insert(format, ...)
table.insert(output, string.format(format, ...))
end
local function prepare_attributes(attr)
local t = {}
local attr = attr or {}
for k, v in pairs(attr) do
t[#t+1] = string.format("%s='%s'", k, escape_attr(v))
end
if #t == 0 then return "" end
-- add space before attributes
return " " .. table.concat(t, " ")
end
local function start(typ, el, attr)
local format = get_action(typ, "start")
insert(format, el, prepare_attributes(attr))
end
local function text(typ, text)
local format = get_action(typ, "text")
insert(format, escape_element(text))
end
local function stop(typ, el)
local format = get_action(typ, "stop")
insert(format,el)
end
local level = level or 0
local spaces = string.rep(" ",level)
local root= current or parser._handler.root
local name = root._name or "unnamed"
local xtype = root._type or "untyped"
local text_content = root._text or ""
local attributes = root._attr or {}
-- if xtype == "TEXT" then
-- print(spaces .."TEXT : " .. root._text)
-- elseif xtype == "COMMENT" then
-- print(spaces .. "Comment : ".. root._text)
-- else
-- print(spaces .. xtype .. " : " .. name)
-- end
-- for k, v in pairs(attributes) do
-- print(spaces .. " ".. k.."="..v)
-- end
if xtype == "DTD" then
text_content = string.format('%s %s "%s" "%s"', name, attributes["_type"] or "", attributes._name, attributes._uri )
-- remove unused fields
text_content = text_content:gsub('"nil"','')
text_content = text_content:gsub('%s*$','')
attributes = {}
elseif xtype == "ELEMENT" and void[name] then
local format = get_action(xtype, "void")
insert(format, name, prepare_attributes(attributes))
return output
end
start(xtype, name, attributes)
text(xtype,text_content)
local children = root._children or {}
for _, child in ipairs(children) do
output = serialize_dom(parser,child, level + 1, output)
end
stop(xtype, name)
return output
end
--- XML parsing function
-- Parse the XML text and create the DOM object.
-- @return DOM_Object
local parse = function(
xmltext --- String to be parsed
)
local domHandler = handler.domHandler()
--- @type DOM_Object
local DOM_Object = xml.xmlParser(domHandler)
-- preserve whitespace
DOM_Object.options.stripWS = nil
DOM_Object:parse(xmltext)
DOM_Object.current = DOM_Object._handler.root
DOM_Object.__index = DOM_Object
DOM_Object.css_query = css_query()
local function save_methods(element)
setmetatable(element,DOM_Object)
local children = element._children or {}
for _, x in ipairs(children) do
save_methods(x)
end
end
local parser = setmetatable({}, DOM_Object)
--- Returns root element of the DOM_Object
-- @return DOM_Object
function DOM_Object:root_node()
return self._handler.root
end
--- Get current node type
-- @param el [optional] node to get the type of
function DOM_Object:get_node_type(
el --- [optional] element to test
)
local el = el or self
return el._type
end
--- Test if the current node is an element.
-- You can pass different element as parameter
-- @return boolean
function DOM_Object:is_element(
el --- [optional] element to test
)
local el = el or self
return self:get_node_type(el) == "ELEMENT" -- @bool
end
--- Test if current node is text
-- @return boolean
function DOM_Object:is_text(
el --- [optional] element to test
)
local el = el or self
return self:get_node_type(el) == "TEXT"
end
local lower = string.lower
--- Return name of the current element
-- @return string
function DOM_Object:get_element_name(
el --- [optional] element to test
)
local el = el or self
return el._name or "unnamed"
end
--- Get value of an attribute
-- @return string
function DOM_Object:get_attribute(
name --- Attribute name
)
local el = self
if self:is_element(el) then
local attr = el._attr or {}
return attr[name]
end
end
--- Set value of an attribute
-- @return boolean
function DOM_Object:set_attribute(
name --- Attribute name
, value --- Value to be set
)
local el = self
if self:is_element(el) then
el._attr[name] = value
return true
end
end
--- Serialize the current node back to XML
-- @return string
function DOM_Object:serialize(
current --- [optional] element to be serialized
)
local current = current
-- if no current element is added and self is not plain parser object
-- (_type is then nil), use the current object as serialized root
if not current and self._type then
current = self
end
return table.concat(serialize_dom(self, current))
end
--- Get text content from the node and all of it's children
-- @return string
function DOM_Object:get_text(
current --- [optional] element which should be converted to text
)
local current = current or self
local text = {}
for _, el in ipairs(current:get_children()) do
if el:is_text() then
text[#text+1] = el._text or ""
elseif el:is_element() then
text[#text+1] = el:get_text()
end
end
return table.concat(text)
end
--- Retrieve elements from the given path.
-- The path is list of elements separated by space,
-- starting from the top element of the current element
-- @return table of elements which match the path
function DOM_Object:get_path(
path --- path to be traversed
, current --- [optional] element which should be traversed. Default element is the root element of the DOM_Object
)
local function traverse_path(path_elements, current, t)
local t = t or {}
if #path_elements == 0 then
-- for _, x in ipairs(current._children or {}) do
-- table.insert(t,x)
-- end
table.insert(t,current)
return t
end
local current_path = table.remove(path_elements, 1)
for _, x in ipairs(self:get_children(current)) do
if self:is_element(x) then
local name = string.lower(self:get_element_name(x))
if name == current_path then
t = traverse_path(path_elements, x, t)
end
end
end
return t
end
local current = current or self:root_node() -- self._handler.root
local path_elements = {}
local path = string.lower(path)
for el in path:gmatch("([^%s]+)") do table.insert(path_elements, el) end
return traverse_path(path_elements, current)
end
--- Select elements chidlren using CSS selector syntax
-- @return table with elements matching the selector.
function DOM_Object:query_selector(
selector --- String using the CSS selector syntax
)
local css_query = self.css_query
local css_parts = css_query:prepare_selector(selector)
return css_query:get_selector_path(self, css_parts)
end
--- Get table with children of the current element
-- @return table with children of the selected element
function DOM_Object:get_children(
el --- [optional] element to be selected
)
local el = el or self
local children = el._children or {}
return children
end
--- Get the parent element
-- @return DOM_Object parent element
function DOM_Object:get_parent(
el --- [optional] element to be selected
)
local el = el or self
return el._parent
end
--- Execute function on the current element and all it's children elements
-- @return nothing
function DOM_Object:traverse_elements(
fn, --- function which will be executed on the current element and all it's children
current --- [optional] element to be selected
)
local current = current or self --
-- Following situation may happen when this method is called directly on the parsed object
if not current:get_node_type() then
current = self:root_node()
end
local status = true
if self:is_element(current) or self:get_node_type(current) == "ROOT"then
local status = fn(current)
-- don't traverse child nodes when the user function return false
if status ~= false then
for _, child in ipairs(self:get_children(current)) do
self:traverse_elements(fn, child)
end
end
end
end
--- Execute function on list of elements returned by DOM_Object:get_path()
function DOM_Object:traverse_node_list(
nodelist --- table with nodes selected by DOM_Object:get_path()
, fn --- function to be executed
)
local nodelist = nodelist or {}
for _, node in ipairs(nodelist) do
for _, element in ipairs(node._children) do
fn(element)
end
end
end
--- Replace the current node with new one
-- @return boolean, message
function DOM_Object:replace_node(
new --- element which should replace the current element
)
local old = self
local parent = self:get_parent(old)
local id,msg = self:find_element_pos( old)
if id then
parent._children[id] = new
return true
end
return false, msg
end
--- Add child node to the current node
function DOM_Object:add_child_node(
child --- element to be inserted as a current node child
)
local parent = self
child._parent = parent
table.insert(parent._children, child)
end
--- Create copy of the current node
-- @return DOM_Object element
function DOM_Object:copy_node(
element --- [optional] element to be copied
)
local element = element or self
local t = {}
for k, v in pairs(element) do
if type(v) == "table" and k~="_parent" then
t[k] = self:copy_node(v)
else
t[k] = v
end
end
save_methods(t)
return t
end
--- Create a new element
-- @return DOM_Object element
function DOM_Object:create_element(
name, -- New tag name
attributes, -- Table with attributes
parent -- [optional] element which should be saved as the element's parent
)
local parent = parent or self
local new = {}
new._type = "ELEMENT"
new._name = name
new._attr = attributes or {}
new._children = {}
new._parent = parent
save_methods(new)
return new
end
--- Create new text node
-- @return DOM_Object text object
function DOM_Object:create_text_node(
text, -- string
parent -- [optional] element which should be saved as the element's parent
)
local parent = parent or self
local new = {}
new._type = "TEXT"
new._parent = parent
new._text = text
save_methods(new)
return new
end
--- Delete current node
function DOM_Object:remove_node(
element -- [optional] element to be removed
)
local element = element or self
local parent = self:get_parent(element)
local pos = self:find_element_pos(element)
-- if pos then table.remove(parent._children, pos) end
if pos then
-- table.remove(parent._children, pos)
parent._children[pos] = setmetatable({_type = "removed"}, DOM_Object)
end
end
--- Find the element position in the current node list
-- @return integer position of the current element in the element table
function DOM_Object:find_element_pos(
el -- [optional] element which should be looked up
)
local el = el or self
local parent = self:get_parent(el)
if not self:is_element(parent) and self:get_node_type(parent) ~= "ROOT" then return nil, "The parent isn't element" end
for i, x in ipairs(parent._children) do
if x == el then return i end
end
return false, "Cannot find element"
end
--- Get node list which current node is part of
-- @return table with elements
function DOM_Object:get_siblibgs(
el -- [optional] element for which the sibling element list should be retrieved
)
local el = el or self
local parent = el:get_parent()
if parent:is_element() then
return parent:get_children()
end
end
--- Get sibling node of the current node
-- @param change Distance from the current node
-- @return DOM_Object node
function DOM_Object:get_sibling_node( change)
local el = self
local pos = el:find_element_pos()
local siblings = el:get_siblibgs()
if pos and siblings then
return siblings[pos + change]
end
end
--- Get next node
-- @return DOM_Object node
function DOM_Object:get_next_node(
el --- [optional] node to be used
)
local el = el or self
return el:get_sibling_node(1)
end
--- Get previous node
-- @return DOM_Object node
function DOM_Object:get_prev_node(
el -- [optional] node to be used
)
local el = el or self
return el:get_sibling_node(-1)
end
-- include the methods to all xml nodes
save_methods(parser._handler.root)
-- parser:
return parser
end
--- @export
return {
parse = parse,
serialize_dom= serialize_dom
}
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