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htmlparser.lua
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163 lines (132 loc) · 4 KB
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-- vim: ft=lua ts=2 sw=2
local esc = function(s) return string.gsub(s, "([%^%$%(%)%%%.%[%]%*%+%-%?])", "%%" .. "%1") end
local str = tostring
local char = string.char
local err = function(s) io.stderr:write(s) end
local out = function(s) io.stdout:write(s) end
local ElementNode = require("htmlparser.ElementNode")
local voidelements = require("htmlparser.voidelements")
local HtmlParser = {}
local tpr = {
-- Here we're replacing confusing sequences
-- (things looking like tags, but appearing where tags can't)
-- with definitelly invalid utf sequence, and later we'll replace them back
["<"] = char(208,209,208,209),
[">"] = char(209,208,209,208),
}
local function parse(text,limit)
local text=str(text)
local limit = limit or htmlparser_looplimit or 1000
local tpl = false
local function g(id,...)
local arg={...}
arg[id]=tpr[arg[id]]
tpl=true
return table.concat(arg)
end
text = text
:gsub(
"(<)"..
"([^>]-)"..
"(<)",
function(...)return g(3,...)end
):gsub(
"("..tpr["<"]..")"..
"([^%w%s])"..
"([^%2]-)"..
"(%2)"..
"(>)"..
"([^>]-)"..
"(>)",
function(...)return g(5,...)end
):gsub(
[=[(['"])]=]..
[=[([^'">%s]-)]=]..
"(>)"..
[=[([^'">%s]-)]=]..
[=[(['"])]=],
function(...)return g(3,...)end
)
local index = 0
local root = ElementNode:new(index, str(text))
local node, descend, tpos, opentags = root, true, 1, {}
while true do
if index == limit then
err("[HTMLParser] [ERR] Main loop reached loop limit ("..limit.."). Please, consider increasing it or check the code for errors")
break
end
local openstart, name
openstart, tpos, name = root._text:find(
"<" .. -- an uncaptured starting "<"
"([%w-]+)" .. -- name = the first word, directly following the "<"
"[^>]*>", -- include, but not capture everything up to the next ">"
tpos)
if not name then break end
index = index + 1
local tag = ElementNode:new(index, str(name), node, descend, openstart, tpos)
node = tag
local tagloop
local tagst, apos = tag:gettext(), 1
while true do
if tagloop == limit then
err("[HTMLParser] [ERR] tag parsing loop reached loop limit ("..limit.."). Please, consider increasing it or check the code for errors")
break
end
local start, k, eq, quote, v
start, apos, k, eq, quote = tagst:find(
"%s+" .. -- some uncaptured space
"([^%s=/>]+)" .. -- k = an unspaced string up to an optional "=" or the "/" or ">"
"(=?)" .. -- eq = the optional; "=", else ""
"(['\"]?)", -- quote = an optional "'" or '"' following the "=", or ""
apos)
if not k or k == "/>" or k == ">" then break end
if eq == "=" then
pattern = "=([^%s>]*)"
if quote ~= "" then
pattern = quote .. "([^" .. quote .. "]*)" .. quote
end
start, apos, v = tagst:find(pattern, apos)
end
v=v or ""
if tpl then
for rk,rv in pairs(tpr) do
v = v:gsub(rv,rk)
end
end
tag:addattribute(k, v)
tagloop = (tagloop or 0) + 1
end
if voidelements[tag.name:lower()] then
descend = false
tag:close()
else
opentags[tag.name] = opentags[tag.name] or {}
table.insert(opentags[tag.name], tag)
end
local closeend = tpos
local closingloop
while true do
if closingloop == limit then
err("[HTMLParser] [ERR] tag closing loop reached loop limit ("..limit.."). Please, consider increasing it or check the code for errors")
break
end
local closestart, closing, closename
closestart, closeend, closing, closename = root._text:find("[^<]*<(/?)([%w-]+)", closeend)
if not closing or closing == "" then break end
tag = table.remove(opentags[closename] or {}) or tag -- kludges for the cases of closing void or non-opened tags
closestart = root._text:find("<", closestart)
tag:close(closestart, closeend + 1)
node = tag.parent
descend = true
closingloop = (closingloop or 0) + 1
end
end
if tpl then
for k,v in pairs(tpr) do
root._text = root._text:gsub(v,k)
end
end
return root
end
HtmlParser.parse = parse
return HtmlParser