Class CompressionPlugin

packages/server/src/adapters/node/compression-plugin.ts:21–98

 * @see {@link https://orpc.dev/docs/plugins/compression Compression Plugin Docs}
 */
export class CompressionPlugin<T extends Context> implements NodeHttpHandlerPlugin<T> {
  private readonly compressionHandler: ReturnType<typeof compression>

  constructor(options: CompressionPluginOptions = {}) {
    this.compressionHandler = compression({
      ...options,
      filter: (req, res) => {
        const hasContentDisposition = res.hasHeader('content-disposition')
        const contentType = res.getHeader('content-type')?.toString()

        /**
         * Never compress Event Iterator responses.
         */
        if (!hasContentDisposition && contentType?.startsWith('text/event-stream')) {
          return false
        }

        return options.filter
          ? options.filter(req, res)
          : compression.filter(req, res)
      },
    })
  }

  initRuntimeAdapter(options: NodeHttpHandlerOptions<T>): void {
    options.adapterInterceptors ??= []

    /**
     * use `unshift` to ensure this runs before user-defined adapter interceptors
     */
    options.adapterInterceptors.unshift(async (options) => {
      let resolve: (value: Awaited<ReturnType<typeof options.next>>) => void
      let reject: (reason?: any) => void
      const promise = new Promise<Awaited<ReturnType<typeof options.next>>>((res, rej) => {
        resolve = res
        reject = rej
      })

      /**
       * These methods are proxied by the compression handler, so we need to
       * store the original methods to call them after compression is done
       * to prevent side effects to other code outside of this plugin.
       * https://github.com/expressjs/compression/blob/master/index.js#L97-L153
       */
      const originalWrite = options.response.write
      const originalEnd = options.response.end
      const originalOn = options.response.on

      this.compressionHandler(
        options.request as any,
        options.response as any,
        async (err) => {
          /* v8 ignore next 3 - this never happen in realtime: https://github.com/expressjs/compression/blob/master/index.js#L243 */
          if (err) {
            reject(err)
          }
          else {
            try {