erszcz / rxml

Experimental fork of esl/exml to get rid of C and use Rust / RustyXML

rxml

rxml is a fork of esl/exml which uses Rust for NIFs (native-implemented functions) and uses an XML parser written completely in Rust. Say bye-bye to C and Expat.

ToDo

To some extent in order of importance:

• prepare a branch / fork of MongooseIM which depends on this library for quick/convenient development iterations
• load test and compare with C/Expat-based esl/exml
• use Rustler - higher-level Erlang/Rust interface for maintainability
• use the ElementBuilder interface of RustyXML instead of the event based interface and completely get rid of src/exml_event.erl for maintainability
• use rebar3_rust for building
• clean up: remove c_src completely
• verify CData / attribute escaping differences across esl/exml, RustyXML, and the XMPP / XML standards - exml and RustyXML (un)escape differently, but does it matter?

exml

exml is an Erlang library helpful with parsing XML streams and doing some basic XML structures manipulation.

Building

exml is a rebar-compatible OTP application, run make or ./rebar compile in order to build it.

As a requirement, development headers for expat library are required.

Using

exml can parse both XML streams as well as single XML documents at once.

To parse a whole XML document:

{ok, Parser} = exml:parse(<<"<my_xml_doc/>">>).

To generate an XML document from Erlang terms:

El = #xmlel{name = <<"foo">>,
            attrs = [{<<"attr1">>, <<"bar">>}],
            children = [{xmlcdata, <<"Some Value">>}]},
exml:to_list(El).

or (pastable into erl shell):

El = {xmlel, <<"foo">>,
      [{<<"attr1">>, <<"bar">>}],
      [{xmlcdata, <<"Some Value">>}]}.
exml:to_list(El).

Which results in:

<foo attr1='bar'>Some Value</foo>

exml:to_binary/1 works similarly.

There're also exml:to_pretty_iolist/1,3 for a quick'n'dirty document preview (pastable into erl):

rr("include/exml.hrl").
El = #xmlel{name = <<"outer">>,
            attrs = [{<<"attr1">>, <<"val1">>},
                     {<<"attr2">>, <<"val-two">>}],
            children = [#xmlel{name = <<"inner-childless">>},
                        #xmlel{name = <<"inner-w-children">>,
                               children = [#xmlel{name = <<"a">>}]}]}.
io:format("~s", [exml:to_pretty_iolist(El)]).

which prints:

<outer attr2='val-two' attr1='val1'>
  <inner-childless/>
  <inner-w-children>
    <a/>
  </inner-w-children>
</outer>

For an example of using the streaming API see test/exml_stream_tests.erl.