server.js

/**
 * Created by anatal on 3/17/17.
 */

const AWS = require('aws-sdk');
const express = require('express');
const bodyParser = require('body-parser');
const cp = require('child_process');
const mozlog = require('mozlog')({
  app: 'speech-proxy',
})('server');
const request = require('request');
const Joi = require('joi');
const fs = require('fs');
const uuid = require('uuid/v4');
const fileType = require('file-type');
const StatsD = require('hot-shots');

const app = express();
const metrics = new StatsD({
  prefix: 'speech-proxy.'
});

// eslint-disable-next-line no-control-regex
const regexUA = RegExp('^[a-zA-Z0-9-_ \t\\/.;:]{0,1024}$');

const languages = (() => {
  const contents = fs.readFileSync('languages.json');
  return JSON.parse(contents.toString('utf8').toLowerCase());
})();

const configSchema = Joi.object({
  asr_url: Joi.string(),
  port: Joi.number(),
  s3_bucket: Joi.string().optional(),
});

const config = {
  asr_url: process.env.ASR_URL,
  port: process.env.PORT || 9001,
  s3_bucket: process.env.S3_BUCKET,
};

mozlog.info('config', config);

Joi.assert(config, configSchema);

const validateHeaders = (headers) => {
  // validate the language
  if (headers['accept-language-stt'] !== undefined) {
    const lang_header = headers['accept-language-stt'].toLowerCase();

    // if the passed language contains anything different from two (eg. pt)
    // or five (eg. pt-br) chars, or eleven (eg. cmn-Hans-CN)
    // or six (eg.fil-PH)  we deny
    if (
      lang_header.length !== 2 &&
      lang_header.length !== 5 &&
      lang_header.length !== 11 &&
      lang_header.length !== 6
    ) {
      return 'accept-language-stt';
    }

    // if the passed language contains five chars, (eg. pt-br)
    // we try to match the exact key in the json, and if we find, we accept
    if (
      (lang_header.length === 11 ||
        lang_header.length === 5 ||
        lang_header.length === 6) &&
      languages[lang_header] === undefined
    ) {
      return 'accept-language-stt';
    }

    // if the passed language contains two chars, we try to find a correspondent
    // substring in the json's key and if it matches, we accept
    if (lang_header.length === 2) {
      let match_lang = false;
      for (const lang in languages) {
        if (lang.substring(0, 2) === lang_header) {
          match_lang = true;
          break;
        }
      }
      if (!match_lang) {
        return 'accept-language-stt';
      }
    }
  }

  // validate storesample
  if (
    headers['store-sample'] !== undefined &&
    headers['store-sample'] !== '1' &&
    headers['store-sample'] !== '0'
  ) {
    return 'store-sample';
  }

  // validate storetranscription
  if (
    headers['store-transcription'] !== undefined &&
    headers['store-transcription'] !== '1' &&
    headers['store-transcription'] !== '0'
  ) {
    return 'store-transcription';
  }

  // validate producttag
  if (
    headers['product-tag'] !== undefined &&
    (!regexUA.test(headers['product-tag']) ||
    filterProductTag(headers['product-tag']) === 'unknown')
  ) {
    return 'product-tag';
  }

  return null;
};

const filterProductTag = (productTag) => {
  let tag = '';
  switch(productTag) {
  case 'vf':
    tag = 'voice-fill';
    break;
  case 'fxv':
    tag = 'firefox-voice';
    break;
  case 'fxr':
    tag = 'firefox-reality';
    break;
  case 'wsa':
    tag = 'webspeech-api';
    break;
  default:
    tag = 'unknown';
  }
  return tag;
};

const filterLanguage = (language) => {

  // if undefined, retorna english
  if (language === undefined) {
    return 'unk (en-us)';
  } else {
    const lang_header = language.toLowerCase();

    // if the passed language contains anything different from two (eg. pt)
    // or five (eg. pt-br) chars, or eleven (eg. cmn-Hans-CN)
    // or six (eg.fil-PH)  we deny
    if (
      lang_header.length !== 2 &&
      lang_header.length !== 5 &&
      lang_header.length !== 11 &&
      lang_header.length !== 6
    ) {
      return 'bad-lang';
    }

    // if the passed language contains five chars, (eg. pt-br)
    // we try to match the exact key in the json, and if we find, we accept
    if (
      (lang_header.length === 11 ||
        lang_header.length === 5 ||
        lang_header.length === 6) &&
      languages[lang_header] === undefined
    ) {
      return 'bad-lang';
    }

    // if the passed language contains two chars, we try to find a correspondent
    // substring in the json's key and if it matches, we accept
    if (lang_header.length === 2) {
      let match_lang = false;
      for (const lang in languages) {
        if (lang.substring(0, 2) === lang_header) {
          match_lang = true;
          break;
        }
      }
      if (!match_lang) {
        return 'bad-lang';
      }
    }
  }

  return language;
};

const filterSampleTranscription = (value) => {
  // validate storesample
  let tag = '';
  switch(value) {
  case undefined:
    tag = 'unset (store)';
    break;
  case '1':
    tag = 'store';
    break;
  case '0':
    tag = 'no-store';
    break;
  default:
    tag = 'bad';
  }
  return tag;
};

const S3 = new AWS.S3({
  region: process.env.AWS_DEFAULT_REGION || 'us-east-1',
});

app.use((req, res, next) => {
  const request_start = Date.now();
  res.locals.request_id = uuid();

  mozlog.info('request.start', {
    request_id: res.locals.request_id,
    remote_addr: req.ip,
    method: req.method,
    path: req.originalUrl,
    referrer: req.get('Referrer'),
    user_agent: req.get('User-Agent'),
  });

  res.once('finish', () => {
    if (req.method === 'POST') {
      const header_validation = validateHeaders(req.headers);
      if (header_validation !== null) {
        metrics.increment('request.validorinvalid', { status: header_validation });
      } else {
        metrics.increment('request.validorinvalid', { status: 'valid' });
        metrics.increment('request.count', { status: res.statusCode });
        metrics.histogram('request.latency', Date.now() - request_start, { status: res.statusCode });
        metrics.increment('request.productTag', { productTag: filterProductTag(req.headers['product-tag']) });
        metrics.increment('request.language', { language: filterLanguage(req.headers['accept-language-stt']) });
        metrics.increment('request.storesample', { storeSample: filterSampleTranscription(req.headers['store-sample']) });
        metrics.increment('request.storetranscription', { storeTranscription: filterSampleTranscription(req.headers['store-transcription']) });
      }
    }

    mozlog.info('request.finish', {
      request_id: res.locals.request_id,
      remote_addr: req.ip,
      method: req.method,
      path: req.originalUrl,
      status: res.statusCode,
      body: res.get('Content-Length'),
      time: Date.now() - request_start,
      referrer: req.get('Referrer'),
      user_agent: req.get('User-Agent'),
    });
  });

  next();
});

app.use(function(req, res, next) {
  res.header('Access-Control-Allow-Origin', '*');
  res.header(
    'Access-Control-Allow-Headers',
    [
      'Accept',
      'Accept-Language-STT',
      'Content-Type',
      'Origin',
      'Product-Tag',
      'Store-Sample',
      'Store-Transcription',
      'User-Agent',
      'X-Requested-With',
    ].join(',')
  );

  // Prevent browsers mistaking user provided content as HTML
  res.header('X-Content-Type-Options', 'nosniff');
  res.header('X-Frame-Options', 'DENY');

  next();
});

app.use(
  bodyParser.raw({
    limit: 1024000,
    type: function() {
      return true;
    },
  })
);

app.get('/__version__', function(req, res, next) {
  fs.readFile('version.json', (read_error, version) => {
    if (read_error) {
      return next(read_error);
    }

    res.json(JSON.parse(version));
  });
});

app.get('/__lbheartbeat__', function(req, res) {
  res.json({message: 'Okay'});
});

app.get('/__heartbeat__', function(req, res) {
  let opusbytes = '';
  const hbfile = 'hb.raw';
  if (fs.existsSync(hbfile)) {
    opusbytes = fs.readFileSync(hbfile);
  }
  // send to the asr server
  request(
    {
      url: config.asr_url,
      method: 'POST',
      body: opusbytes,
      headers: {'Content-Type': 'application/octet-stream'},
      qs: {endofspeech: 'false', nbest: 10},
    },
    function(asrErr, asrRes) {
      // and send back the results to the client
      if (asrErr) {
        res.status(500);
        return res.end();
      } else if (asrRes.statusCode === 200) {
        res.status(200);
        return res.end();
      } else {
        res.status(500);
        return res.end();
      }
    }
  );
});

app.get('/', (req, res) => {
  res.json({message: 'Okay'});
});

app.post('*', function(req, res, next) {
  let decodeArgs;
  const header_validation = validateHeaders(req.headers);

  if (header_validation !== null) {
    // convert the headers to hex to log it
    const headers = JSON.stringify(req.headers);
    const hex = [];
    for (let n = 0, l = headers.length; n < l; n++) {
      const hexval = Number(headers.charCodeAt(n)).toString(16);
      hex.push(hexval);
    }

    mozlog.info('request.header.error', {
      request_id: res.locals.request_id,
      error: hex.join(''),
    });
    return res.status(400).json({message: 'Bad header:' + header_validation});
  }

  if (fileType(req.body) === null) {
    return res
      .status(400)
      .json({message: 'Body should be an Opus or Webm audio file'});
  } else if (
    fileType(req.body).ext === 'webm' ||
    fileType(req.body).ext === '3gp'
  ) {
    decodeArgs = [
      'ffmpeg',
      '-i',
      '-',
      '-c:v',
      'libvpx',
      '-f',
      's16le',
      '-ar',
      '16000',
      '-acodec',
      'pcm_s16le',
      '-',
    ];
  } else if (fileType(req.body).ext === 'opus') {
    decodeArgs = ['opusdec', '--rate', '16000', '-', '-'];
  } else {
    return res
      .status(400)
      .json({message: 'Body should be an Opus or Webm audio file'});
  }

  const args = decodeArgs;

  const opusdec_start = Date.now();
  mozlog.info('request.opusdec.start', {
    request_id: res.locals.request_id,
  });
  const opusdec = cp.spawn(args[0], args.slice(1), {
    stdio: ['pipe', 'pipe', 'pipe'],
  });

  opusdec.on('error', next);

  opusdec.stdin.write(req.body);
  opusdec.stdin.end();

  // no-op to not fill up the buffer
  const opsdec_stderr_buf = [];
  opusdec.stderr.on('data', function(data) {
    opsdec_stderr_buf.push(data);
  });

  const timestamp = new Date().toISOString();
  const key_uuid = uuid();
  const key_base = timestamp.split('T')[0] + '/' + key_uuid.slice(0, 2) + '/' + key_uuid;

  // assemble and store the metadata file
  const metadata = {
    language: req.headers['accept-language-stt'],
    storesample:
      req.headers['store-sample'] !== undefined
        ? req.headers['store-sample']
        : '0',
    storetranscription:
      req.headers['store-transcription'] !== undefined
        ? req.headers['store-transcription']
        : '0',
    useragent: req.headers['user-agent'],
    producttag: req.headers['product-tag'],
    datetime: timestamp,
  };

  if (config.s3_bucket) {
    const metadata_upload_params = {
      Body: JSON.stringify(metadata),
      Bucket: config.s3_bucket,
      ContentType: 'application/json',
      Key: key_base + '/metadata.json',
    };

    const s3_request_start = Date.now();

    mozlog.info('request.s3.audio.start', {
      request_id: res.locals.request_id,
      key: key_base + '/metadata.json',
    });

    S3.putObject(metadata_upload_params, (s3_error) => {
      if (s3_error) {
        mozlog.info('request.s3.audio.error', {
          request_id: res.locals.request_id,
          key: key_base + '/metadata.json',
          status: s3_error.statusCode,
          body: req.body.length,
          time: Date.now() - s3_request_start,
        });
        return next(s3_error);
      }

      mozlog.info('request.s3.audio.finish', {
        request_id: res.locals.request_id,
        key: key_base + '/metadata.json',
        status: 200,
        body: req.body.length,
        time: Date.now() - s3_request_start,
      });
    });
  }

  opusdec.on('close', function(code) {
    mozlog.info('request.opusdec.finish', {
      request_id: res.locals.request_id,
      time: Date.now() - opusdec_start,
      stderr: Buffer.concat(opsdec_stderr_buf).toString('utf8'),
    });
    if (code !== 0) {
      next(new Error('opusdec exited with code %d', code));
    }
  });

  if (config.s3_bucket && metadata.storesample === '1') {
    const audio_upload_params = {
      Body: req.body,
      Bucket: config.s3_bucket,
      ContentType: 'audio/opus',
      Key: key_base + '/audio.opus',
    };

    const s3_request_start = Date.now();

    mozlog.info('request.s3.audio.start', {
      request_id: res.locals.request_id,
      key: key_base + '/audio.opus',
    });

    S3.putObject(audio_upload_params, (s3_error) => {
      if (s3_error) {
        mozlog.info('request.s3.audio.error', {
          request_id: res.locals.request_id,
          key: key_base + '/audio.opus',
          status: s3_error.statusCode,
          body: req.body.length,
          time: Date.now() - s3_request_start,
        });
        return next(s3_error);
      }

      mozlog.info('request.s3.audio.finish', {
        request_id: res.locals.request_id,
        key: key_base + '/audio.opus',
        status: 200,
        body: req.body.length,
        time: Date.now() - s3_request_start,
      });
    });
  }

  const asr_request_start = Date.now();

  mozlog.info('request.asr.start', {
    request_id: res.locals.request_id,
  });

  // send to the asr server
  request(
    {
      url: config.asr_url,
      method: 'POST',
      body: opusdec.stdout,
      headers: {
        'Content-Type': 'application/octet-stream',
        'Accept-Language': metadata.language,
      },
      qs: {endofspeech: 'false', nbest: 10},
    },
    function(asrErr, asrRes, asrBody) {
      // and send back the results to the client
      if (asrErr) {
        mozlog.info('request.asr.error', {
          request_id: res.locals.request_id,
          time: Date.now() - asr_request_start,
        });
        return next(asrErr);
      }

      const resBody = asrBody && asrBody.toString('utf8');
      try {
        res.json(JSON.parse(resBody));
      } catch (e) {
        mozlog.info('request.asr.error', {
          request_id: res.locals.request_id,
          time: Date.now() - asr_request_start,
        });
        return res.status(500).json({error: 'Internal STT Server Error'});
      }

      mozlog.info('request.asr.finish', {
        request_id: res.locals.request_id,
        status: 200,
        time: Date.now() - asr_request_start,
      });

      if (config.s3_bucket && metadata.storetranscription === '1') {
        const json_upload_params = {
          Body: resBody,
          Bucket: config.s3_bucket,
          ContentType: 'application/json',
          Key: key_base + '/transcript.json',
        };

        const s3_request_start = Date.now();

        mozlog.info('request.s3.json.start', {
          request_id: res.locals.request_id,
          key: key_base + '/transcript.json',
        });

        S3.putObject(json_upload_params, (s3_error) => {
          if (s3_error) {
            mozlog.info('request.s3.json.error', {
              request_id: res.locals.request_id,
              key: key_base + '/transcript.json',
              status: s3_error.statusCode,
              time: Date.now() - s3_request_start,
            });
            return next(s3_error);
          }

          mozlog.info('request.s3.json.finish', {
            request_id: res.locals.request_id,
            key: key_base + '/transcript.json',
            status: 200,
            time: Date.now() - s3_request_start,
          });
        });
      }
    }
  );
});

app.use((err, req, res, next) => {
  const reqId = res.locals && res.locals.request_id ?
    res.locals.request_id :
    '???';

  mozlog.info('request.error', {
    request_id: reqId,
    error: err,
  });

  res.status(500).json({
    message: err,
  });

  next();
});

const server = app.listen(config.port);
mozlog.info('listen');

process.on('SIGINT', () => {
  server.close();
});
process.on('SIGTERM', () => {
  server.close();
});
server.once('close', () => {
  mozlog.info('shutdown');
});