[WIP] Compare content type charsets case-insensitively

[lilsweetcaligula]

Work In Progress. The solution depends on changes fastify/fast-content-type-parse#11

Refs: #4583

Checklist

• run npm run test and npm run benchmark
• tests and/or benchmarks are included
• documentation is changed or added
• commit message and code follows the Developer's Certification of Origin
  and the Code of conduct

[lilsweetcaligula]

https://github.com/fastify/fast-content-type-parse/pull/11/files#r1180833385

[climba03003]

I don't understand why compare with lower-case require such complicated changes.

fastify/lib/contentTypeParser.js

Lines 364 to 381 in f1737b3

	function compareContentType (contentType, parserListItem) {
	if (parserListItem.isEssence) {
	// we do essence check
	return contentType.type.indexOf(parserListItem) !== -1
	} else {
	// when the content-type includes parameters
	// we do a full-text search
	// reject essence content-type before checking parameters
	if (contentType.type.indexOf(parserListItem.type) === -1) return false
	for (const key of parserListItem.parameterKeys) {
	// reject when missing parameters
	if (!(key in contentType.parameters)) return false
	// reject when parameters do not match
	if (contentType.parameters[key] !== parserListItem.parameters[key]) return false
	}
	return true
	}
	}

function compareContentType (contentType, parserListItem) {
  if (parserListItem.isEssence) {
    // we do essence check
    return contentType.type.indexOf(parserListItem) !== -1
  } else {
    // when the content-type includes parameters
    // we do a full-text search
    // reject essence content-type before checking parameters
    if (contentType.type.indexOf(parserListItem.type) === -1) return false
    for (const key of parserListItem.parameterKeys) {
      // reject when missing parameters
      if (!(key in contentType.parameters)) return false
      // when key is charset, compare with lowercase
      if (key.length === 7 && key === 'charset' && contentType.parameters[key].toLowerCase() !== parserListItem.parameters[key].toLowerCase()) return false
      // reject when parameters do not match
      else if (contentType.parameters[key] !== parserListItem.parameters[key]) return false
    }
    return true
  }
}