webvideo-clip-web-api/src/controllers/ClipController.ts

import {
  createVideoClipper,
  VideoType,
  CreateVideoClipperParams,
} from '@modal/webvideo-clip-core';
import { constants } from 'http2';
import { RouteHandlerMethod } from 'fastify';

export type ClipArgs = {
  url?: unknown,
  start?: string | number,
  end?: string | number,
}

const DURATION_STRING_REGEXP = /^\d\d:[0-5]\d:[0-5]\d(\.\d+)?$/;

const validateRequestBody = (body: ClipArgs) => {
  const messages = [] as string[];
  const { url, start, end } = body;
  if (typeof url !== 'string') {
    messages.push('URL is required.');
  }

  const typeofStart = typeof start;
  if (typeofStart !== 'undefined') {
    if (!['string', 'number'].includes(typeofStart)) {
      messages.push('Invalid end value.');
    } else if (typeofStart === 'string' && !DURATION_STRING_REGEXP.test(start as string)) {
      messages.push('Invalid start value.');
    }
  }

  const typeofEnd = typeof end;
  if (typeofEnd !== 'undefined') {
    if (!['string', 'number'].includes(typeofEnd)) {
      messages.push('Invalid end value.');
    } else if (typeofEnd === 'string' && !DURATION_STRING_REGEXP.test(end as string)) {
      messages.push('Invalid end value.');
    }
  }

  return messages;
};

const getVideoType = (url: string) => {
  if (url.startsWith('https://www.youtube.com')) {
    return VideoType.YOUTUBE;
  }

  return null;
};

export const clip: RouteHandlerMethod = async (request, reply) => {
  const validationMessages = validateRequestBody(request.body as ClipArgs);
  if (validationMessages.length > 0) {
    reply
      .status(constants.HTTP_STATUS_BAD_REQUEST)
      .send({
        errors: validationMessages,
      });
    return;
  }
  const videoType = getVideoType((request.body as ClipArgs).url as string);
  if (videoType === null) {
    reply
      .status(constants.HTTP_STATUS_UNPROCESSABLE_ENTITY)
      .send({
        message: 'Unsupported URL.',
      });
  }

  const { url, start, end } = request.body as ClipArgs;
  const videoClipperArgs = {
    type: videoType,
    url,
    start,
    end,
    downloaderExecutablePath: process.env.YOUTUBE_DOWNLOADER_EXECUTABLE_PATH,
  } as CreateVideoClipperParams;
  const clipper = createVideoClipper(videoClipperArgs);
  clipper.on('process', (arg: Record<string, unknown>) => {
    request.server.log.info(`${arg.type as string}:${arg.phase as string}`);
    if (typeof arg.command === 'string') {
      request.server.log.debug(`> ${arg.command}`);
    }
  });

  let clipResult: Record<string, unknown>;
  clipper.on('success', (result: Record<string, unknown>) => {
    clipResult = result;
  });

  let theError: Error;
  clipper.on('error', (error: Error) => {
    theError = error;
  });

  clipper.on('end', () => {
    if (theError) {
      reply
        .status(constants.HTTP_STATUS_INTERNAL_SERVER_ERROR)
        .send({
          message: theError.message,
        });
      return;
    }

    reply
      .header('Content-Type', clipResult.type as string)
      .send(clipResult.output as Buffer);
  });

  clipper.process();
};