fastify/lib/contentTypeParser.js

'use strict'

const lru = require('tiny-lru')
const secureJson = require('secure-json-parse')
const {
  kDefaultJsonParse,
  kContentTypeParser,
  kBodyLimit,
  kState
} = require('./symbols')
const {
  codes: {
    FST_ERR_CTP_INVALID_TYPE,
    FST_ERR_CTP_EMPTY_TYPE,
    FST_ERR_CTP_ALREADY_PRESENT,
    FST_ERR_CTP_INVALID_HANDLER,
    FST_ERR_CTP_INVALID_PARSE_TYPE,
    FST_ERR_CTP_BODY_TOO_LARGE,
    FST_ERR_CTP_INVALID_MEDIA_TYPE,
    FST_ERR_CTP_INVALID_CONTENT_LENGTH,
    FST_ERR_CTP_EMPTY_JSON_BODY
  }
} = require('./errors')

function ContentTypeParser (bodyLimit, onProtoPoisoning, onConstructorPoisoning) {
  this[kDefaultJsonParse] = getDefaultJsonParser(onProtoPoisoning, onConstructorPoisoning)
  this.customParsers = {}
  this.customParsers['application/json'] = new Parser(true, false, bodyLimit, this[kDefaultJsonParse])
  this.customParsers['text/plain'] = new Parser(true, false, bodyLimit, defaultPlainTextParser)
  this.parserList = ['application/json', 'text/plain']
  this.cache = lru(100)
}

ContentTypeParser.prototype.add = function (contentType, opts, parserFn) {
  if (typeof contentType !== 'string') throw new FST_ERR_CTP_INVALID_TYPE()
  if (contentType.length === 0) throw new FST_ERR_CTP_EMPTY_TYPE()
  if (typeof parserFn !== 'function') throw new FST_ERR_CTP_INVALID_HANDLER()

  if (this.hasParser(contentType)) {
    throw new FST_ERR_CTP_ALREADY_PRESENT(contentType)
  }

  if (opts.parseAs !== undefined) {
    if (opts.parseAs !== 'string' && opts.parseAs !== 'buffer') {
      throw new FST_ERR_CTP_INVALID_PARSE_TYPE(opts.parseAs)
    }
  }

  const parser = new Parser(
    opts.parseAs === 'string',
    opts.parseAs === 'buffer',
    opts.bodyLimit,
    parserFn
  )

  if (contentType === '*') {
    this.parserList.push('')
    this.customParsers[''] = parser
  } else {
    if (contentType !== 'application/json') {
      this.parserList.unshift(contentType)
    }
    this.customParsers[contentType] = parser
  }
}

ContentTypeParser.prototype.hasParser = function (contentType) {
  if (contentType === 'application/json') {
    return this.customParsers['application/json'].fn !== this[kDefaultJsonParse]
  }
  if (contentType === 'text/plain') {
    return this.customParsers['text/plain'].fn !== defaultPlainTextParser
  }
  return contentType in this.customParsers
}

ContentTypeParser.prototype.getParser = function (contentType) {
  for (var i = 0; i < this.parserList.length; i++) {
    if (contentType.indexOf(this.parserList[i]) > -1) {
      var parser = this.customParsers[this.parserList[i]]
      this.cache.set(contentType, parser)
      return parser
    }
  }

  return this.customParsers['']
}

ContentTypeParser.prototype.run = function (contentType, handler, request, reply) {
  var parser = this.cache.get(contentType) || this.getParser(contentType)
  if (parser === undefined) {
    reply.send(new FST_ERR_CTP_INVALID_MEDIA_TYPE(contentType))
  } else {
    if (parser.asString === true || parser.asBuffer === true) {
      rawBody(
        request,
        reply,
        reply.context._parserOptions,
        parser,
        done
      )
    } else {
      var result = parser.fn(request.raw, done)
      if (result && typeof result.then === 'function') {
        result.then(body => done(null, body), done)
      }
    }
  }

  function done (error, body) {
    if (error) {
      reply.send(error)
    } else {
      request.body = body
      handler(request, reply)
    }
  }
}

function rawBody (request, reply, options, parser, done) {
  var asString = parser.asString
  var limit = options.limit === null ? parser.bodyLimit : options.limit
  var contentLength = request.headers['content-length'] === undefined
    ? NaN
    : Number.parseInt(request.headers['content-length'], 10)

  if (contentLength > limit) {
    reply.send(new FST_ERR_CTP_BODY_TOO_LARGE())
    return
  }

  var receivedLength = 0
  var body = asString === true ? '' : []
  var req = request.raw

  if (asString === true) {
    req.setEncoding('utf8')
  }

  req.on('data', onData)
  req.on('end', onEnd)
  req.on('error', onEnd)

  function onData (chunk) {
    receivedLength += chunk.length

    if (receivedLength > limit) {
      req.removeListener('data', onData)
      req.removeListener('end', onEnd)
      req.removeListener('error', onEnd)
      reply.send(new FST_ERR_CTP_BODY_TOO_LARGE())
      return
    }

    if (asString === true) {
      body += chunk
    } else {
      body.push(chunk)
    }
  }

  function onEnd (err) {
    req.removeListener('data', onData)
    req.removeListener('end', onEnd)
    req.removeListener('error', onEnd)

    if (err !== undefined) {
      err.statusCode = 400
      reply.code(err.statusCode).send(err)
      return
    }

    if (asString === true) {
      receivedLength = Buffer.byteLength(body)
    }
    if (!Number.isNaN(contentLength) && receivedLength !== contentLength) {
      reply.send(new FST_ERR_CTP_INVALID_CONTENT_LENGTH())
      return
    }

    if (asString === false) {
      body = Buffer.concat(body)
    }

    var result = parser.fn(req, body, done)
    if (result && typeof result.then === 'function') {
      result.then(body => done(null, body), done)
    }
  }
}

function getDefaultJsonParser (onProtoPoisoning, onConstructorPoisoning) {
  return defaultJsonParser

  function defaultJsonParser (req, body, done) {
    if (body === '' || body == null) {
      return done(new FST_ERR_CTP_EMPTY_JSON_BODY(), undefined)
    }

    try {
      var json = secureJson.parse(body, { protoAction: onProtoPoisoning, constructorAction: onConstructorPoisoning })
    } catch (err) {
      err.statusCode = 400
      return done(err, undefined)
    }
    done(null, json)
  }
}

function defaultPlainTextParser (req, body, done) {
  done(null, body)
}

function Parser (asString, asBuffer, bodyLimit, fn) {
  this.asString = asString
  this.asBuffer = asBuffer
  this.bodyLimit = bodyLimit
  this.fn = fn
}

function buildContentTypeParser (c) {
  const contentTypeParser = new ContentTypeParser()
  contentTypeParser[kDefaultJsonParse] = c[kDefaultJsonParse]
  Object.assign(contentTypeParser.customParsers, c.customParsers)
  contentTypeParser.parserList = c.parserList.slice()
  return contentTypeParser
}

function addContentTypeParser (contentType, opts, parser) {
  if (this[kState].started) {
    throw new Error('Cannot call "addContentTypeParser" when fastify instance is already started!')
  }

  if (typeof opts === 'function') {
    parser = opts
    opts = {}
  }

  if (!opts) opts = {}
  if (!opts.bodyLimit) opts.bodyLimit = this[kBodyLimit]

  if (Array.isArray(contentType)) {
    contentType.forEach((type) => this[kContentTypeParser].add(type, opts, parser))
  } else {
    this[kContentTypeParser].add(contentType, opts, parser)
  }

  return this
}

function hasContentTypeParser (contentType) {
  return this[kContentTypeParser].hasParser(contentType)
}

module.exports = ContentTypeParser
module.exports.helpers = {
  buildContentTypeParser,
  addContentTypeParser,
  hasContentTypeParser
}
module.exports[Symbol.for('internals')] = { rawBody }