htmerl
=====
An OTP library for parsing HTML documents.
This library attempts to follow the [HTML 5.2 specification](https://www.w3.org/TR/html52/)
for tokenizing and parsing the HTML syntax as closely as possible.
This means that common errors that browsers accept are also accepted here and sanitized.
The output from `htmerl:sax/2` is identical to the XML SAX events produced
by `xmerl_sax_parser` except that here all values and names are UTF-8 binary
and not lists.
Usage
-----
There are two ways to use `htmerl`.
Firstly, to build a tree directly from the parsed input. Notice here that the missing "head" element was added.
```erlang
1> htmerl:simple(<<"<!DOCTYPE html><html><body>Hello</body></html>">>).
{htmlDocument,<<"html">>,<<>>,<<>>,
[{htmlElement,<<"html">>,<<"http://www.w3.org/1999/xhtml">>,
[],
[{htmlElement,<<"head">>,<<"http://www.w3.org/1999/xhtml">>,
[],[]},
{htmlElement,<<"body">>,<<"http://www.w3.org/1999/xhtml">>,
[],
[{htmlText,<<"Hello">>,text}]}]}]}
```
Secondly, as a SAX parser. Calling `htmerl:sax/1` returns a list of SAX events.
`htmerl:sax/2` calls a user defined function.
```erlang
2> htmerl:sax(<<"<!DOCTYPE html><html><body>Hello</body></html>">>).
{ok,[startDocument,
{startDTD,<<"html">>,<<>>,<<>>},
endDTD,
{startPrefixMapping,<<>>,<<"http://www.w3.org/1999/xhtml">>},
{startElement,<<"http://www.w3.org/1999/xhtml">>,<<"html">>,
{<<>>,<<"html">>},
[]},
{startElement,<<"http://www.w3.org/1999/xhtml">>,<<"head">>,
{<<>>,<<"head">>},
[]},
{endElement,<<"http://www.w3.org/1999/xhtml">>,<<"head">>,
{<<>>,<<"head">>}},
{startElement,<<"http://www.w3.org/1999/xhtml">>,<<"body">>,
{<<>>,<<"body">>},
[]},
{characters,<<"Hello">>},
{endElement,<<"http://www.w3.org/1999/xhtml">>,<<"body">>,
{<<>>,<<"body">>}},
{endElement,<<"http://www.w3.org/1999/xhtml">>,<<"html">>,
{<<>>,<<"html">>}},
{endPrefixMapping,<<>>},
endDocument],
[]}
```
or with a user defined function and state
```erlang
3> F = fun(E, _, S) -> io:format("Event: ~p~n", [E]), S end,
Opts = [{event_fun, F}, {user_state, []}],
htmerl:sax(<<"<!DOCTYPE html><html><body>Hello</body></html>">>, Opts).
Event: startDocument
Event: {startDTD,<<"html">>,<<>>,<<>>}
Event: endDTD
Event: {startPrefixMapping,<<>>,<<"http://www.w3.org/1999/xhtml">>}
Event: {startElement,<<"http://www.w3.org/1999/xhtml">>,<<"html">>,
{<<>>,<<"html">>},
[]}
Event: {startElement,<<"http://www.w3.org/1999/xhtml">>,<<"head">>,
{<<>>,<<"head">>},
[]}
Event: {endElement,<<"http://www.w3.org/1999/xhtml">>,<<"head">>,
{<<>>,<<"head">>}}
Event: {startElement,<<"http://www.w3.org/1999/xhtml">>,<<"body">>,
{<<>>,<<"body">>},
[]}
Event: {characters,<<"Hello">>}
Event: {endElement,<<"http://www.w3.org/1999/xhtml">>,<<"body">>,
{<<>>,<<"body">>}}
Event: {endElement,<<"http://www.w3.org/1999/xhtml">>,<<"html">>,
{<<>>,<<"html">>}}
Event: {endPrefixMapping,<<>>}
Event: endDocument
{ok,[],[]}
```
Build
-----
$ rebar3 compile