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Added loop limit, added kludge for template engines, documented loop limit, added error messages, fixes #42
This commit is contained in:
Vadim A. Misbakh-Soloviov
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71c0a65006
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12
README.md
12
README.md
@ -2,25 +2,27 @@
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Parse HTML text into a tree of elements with selectors
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[1]: http://wscherphof.github.com/lua-set/
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[2]: http://api.jquery.com/category/selectors/
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[1]: https://api.jquery.com/category/selectors/
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## Install
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Htmlparser is a listed [LuaRock](http://luarocks.org/repositories/rocks/). Install using [LuaRocks](http://www.luarocks.org/): `luarocks install htmlparser`
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### Dependencies
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Htmlparser depends on [Lua 5.2](http://www.lua.org/download.html) (while work with LuaJIT, which provides 5.1-compatible ABI), and on the ["lua-set"][1] package, which is installed along automatically. To be able to run the tests, [lunitx](https://github.com/dcurrie/lunit) also comes along as a LuaRock
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Htmlparser depends on [Lua 5.1-5.3](https://www.lua.org/download.html) or [LuaJIT](https://luajit.org/download.html), which provides 5.1-compatible ABI.
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To be able to run the tests, [lunitx](https://github.com/dcurrie/lunit) also comes along as a LuaRock
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## Usage
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Start off with
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```lua
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pcall(require, "luarocks.loader")
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local htmlparser = require("htmlparser")
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```
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Then, parse some html:
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```lua
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local root = htmlparser.parse(htmlstring)
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```
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Optionally, you can pass loop-limit value (integer). This value means the deepness of the tree, after which parser will give up. Default value is 1000.
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Also, global variable `htmlparser_looplimit` is supported (while this optional argument takes priority over global value)
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The input to parse may be the contents of a complete html document, or any valid html snippet, as long as all tags are correctly opened and closed.
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Now, find specific contained elements by selecting:
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```lua
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@ -43,7 +45,7 @@ end
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The root element is a container for the top level elements in the parsed text, i.e. the `<html>` element in a parsed html document would be a child of the returned root element.
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## Selectors
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Supported selectors are a subset of [jQuery's selectors][2]:
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Supported selectors are a subset of [jQuery's selectors][1]:
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- `"*"` all contained elements
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- `"element"` elements with the given tagname
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@ -1,47 +1,108 @@
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-- vim: ft=lua ts=2
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local esc = function(s) return string.gsub(s, "([%^%$%(%)%%%.%[%]%*%+%-%?])", "%%" .. "%1") end
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local str = tostring
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local char = string.char
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local err = function(s) io.stderr:write(s) end
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local out = function(s) io.stdout:write(s) end
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local ElementNode = require("htmlparser.ElementNode")
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local voidelements = require("htmlparser.voidelements")
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local HtmlParser = {}
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local tpl_rep={
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-- Replace table for template engines syntax that can confuse us.
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-- Here we're replacing confusing sequences
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-- (things looking like tags, but appearing where tags can't)
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-- with definitelly invalid utf sequence, and later we'll replace them back
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["<%"] = char(208,209),
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["%>"] = char(209,208),
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}
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local tpl_rep_rev = {}
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local function parse(text)
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local text=str(text)
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local limit = limit or htmlparser_looplimit or 1000
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local tpl = false
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for k,v in pairs(tpl_rep) do
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local mtc="("..esc(k)..")"
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if text:match(mtc) then
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tpl=true
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text=text:gsub(mtc,tpl_rep)
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tpl_rep_rev[v]=k;
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end
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end
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local index = 0
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local root = ElementNode:new(index, text)
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local root = ElementNode:new(index, str(text))
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local node, descend, tpos, opentags = root, true, 1, {}
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while true do
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if index == limit then
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err("[HTMLParser] [ERR] Main loop reached loop limit ("..limit.."). Please, consider increasing it or check the code for errors")
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break
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end
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local openstart, name
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openstart, tpos, name = string.find(root._text,
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openstart, tpos, name = root._text:find(
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"<" .. -- an uncaptured starting "<"
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"([%w-]+)" .. -- name = the first word, directly following the "<"
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"[^>]*>", -- include, but not capture everything up to the next ">"
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tpos)
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if not name then break end
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index = index + 1
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local tag = ElementNode:new(index, name, node, descend, openstart, tpos)
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local tag = ElementNode:new(index, str(name), node, descend, openstart, tpos)
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node = tag
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local tagloop
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local tagst, apos = tag:gettext(), 1
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while true do
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if tagloop == limit then
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err("[HTMLParser] [ERR] tag parsing loop reached loop limit ("..limit.."). Please, consider increasing it or check the code for errors")
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break
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end
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local start, k, eq, quote, v
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start, apos, k, eq, quote = string.find(tagst,
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start, apos, k, eq, quote = tagst:find(
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"%s+" .. -- some uncaptured space
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"([^%s=/>]+)" .. -- k = an unspaced string up to an optional "=" or the "/" or ">"
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"(=?)" .. -- eq = the optional; "=", else ""
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"(['\"]?)", -- quote = an optional "'" or '"' following the "=", or ""
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apos)
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if not k or k == "/>" or k == ">" then break end
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if eq == "=" then
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local pattern = "=([^%s>]*)"
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if quote ~= "" then
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pattern = quote .. "([^" .. quote .. "]*)" .. quote
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end
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start, apos, v = string.find(tagst, pattern, apos)
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end
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tag:addattribute(k, v or "")
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start, apos, v = tagst:find(pattern, apos)
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end
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if voidelements[string.lower(tag.name)] then
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v=v or ""
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if tpl then
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for rk,rv in pairs(tpl_rep_rev) do
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local mtc="("..esc(rk)..")"
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if text:match(mtc) then
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v = v:gsub(mtc,tpl_rep_rev)
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end
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end
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end
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tag:addattribute(k, v)
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tagloop = (tagloop or 0) + 1
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end
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if voidelements[tag.name:lower()] then
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descend = false
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tag:close()
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else
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@ -50,15 +111,33 @@ local function parse(text)
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end
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local closeend = tpos
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local closingloop
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while true do
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if closingloop == limit then
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err("[HTMLParser] [ERR] tag closing loop reached loop limit ("..limit.."). Please, consider increasing it or check the code for errors")
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break
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end
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local closestart, closing, closename
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closestart, closeend, closing, closename = string.find(root._text, "[^<]*<(/?)([%w-]+)", closeend)
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closestart, closeend, closing, closename = root._text:find("[^<]*<(/?)([%w-]+)", closeend)
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if not closing or closing == "" then break end
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tag = table.remove(opentags[closename] or {}) or tag -- kludges for the cases of closing void or non-opened tags
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closestart = string.find(root._text, "<", closestart)
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closestart = root._text:find("<", closestart)
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tag:close(closestart, closeend + 1)
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node = tag.parent
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descend = true
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closingloop = (closingloop or 0) + 1
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end
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end
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if tpl then
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for k,v in pairs(tpl_rep_rev) do
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local mtc="("..esc(k)..")"
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if text:match(mtc) then
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root._text = root._text:gsub(mtc,tpl_rep_rev)
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end
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end
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end
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