Support body limit

[fiznool]

This is something supported by the regular express body parser. It would be nice to limit the body size, e.g.

app.use(xmlBodyParser({ limit: '1MB' }));

I'd be keen to help out with a PR if you could point me in the right direction. The README mentions using raw-body - is this the way forward?

[macedigital]

Yes, raw-body integration is planned (soon-ish).

The only thing I'm not 100% sure of is how the option passing should work:

• use a flat-map, pass raw-body and xml2js options in the same config object
• use a separate key for passing options for raw-body
• use a second argument exclusively for raw-body options

Actually, option 3 looks like the cleanest solution to me, as it preserves the established api and will never cause issues if either dependency would introduce an option with the same name.

@fiznool let me know what you think. 👍 if you would provide a PR.

[fiznool]

@macedigital I think mirroring the original express-body-parser options, with an extra xmlOptions property in the object would be best.

{
  limit: '1MB',
  xmlOptions: {
    async: true,
    // etc
  }
}

Regarding a PR, I've decided not to use this module after all, it turns out that XML parsing with body-parser is actually pretty easy. I've included a code snippet below in case this is useful for anybody.

Regardless, thanks @macedigital for this module!

var express = require('express'),
    typeis = require('type-is');

var app = express();

var xmlParseOptions = {
  async: false,   // Setting to `true` causes issues with exceptions
  explicitArray: false,
  trim: true,
  normalize: true,
  normalizeTags: true,
  mergeAttrs: true,
  charkey: 'value',
  attrNameProcessors: [function(attr) {
    return '@' + attr;
  }]
};

app.use(bodyParser.text({
  type: '*/xml',
  limit: '1MB'
}));

app.use(function(req, res, next) {
  if(!typeis.hasBody(req) || !typeis(req, '*.xml')) {
    return next();
  }
   // Parse as XML
  var parser = new xml2js.Parser(xmlParseOptions);
  parser.parseString(req.body, function(err, xml) {
    if(err) {
      err.status = 400;
      return next(err);
    }
    req.body = xml || req.body;
    next();
  });
});

[macedigital]

I created a gist https://gist.github.com/macedigital/3799eec3c25a29692a25ee021457b171, so this alternative solution doesn't get lost. If time permits, support for limiting body size will arrive soon.

[fiznool]

Just to mention that I published body-parser-xml a while ago, which fully supports the payload size limiting option, along with every other option that the mainbody-parser package supports.