Downloading and Unpacking a Gz File into a Stream

export class GZipStreamClient extends Ctx.Tag('GZipStreamClient')<
  GZipStreamClient,
  {
    readonly read: (uri: string) => St.Stream<string, GzipStreamError>;
  }
>() {}

export class GzipStreamError extends S.TaggedError<GzipStreamError>()('GzipStreamError', {
  message: S.string
}) {}

export const GZipStreamClientLive = GZipStreamClient.of({
  read: (uri: string) =>
    F.pipe(
      Ef.try({
        try: () => new URL(uri),
        catch: (err) => new GzipStreamError({ message: (err as Error).toString() })
      }),
      Ef.flatMap((url) => {
        if (url.protocol !== 'https:' && url.protocol !== 'http:') {
          return Ef.fail(new GzipStreamError({ message: `unknown protocol ${url.protocol}` }));
        }

        return Ef.succeed(url);
      }),
      Ef.flatMap(() => Http.client.Client),
      Ef.flatMap((client) => client(Http.request.get(uri))),
      Ef.provide(Platform.NodeHttpClient.layer),
      Http.response.arrayBuffer,
      St.pipeThrough(
        NodeSink.fromWritable(
          () => createGunzip(),
          (err) => new GzipStreamError({ message: (err as Error).message })
        )
      ),
      St.mapError((err: GzipStreamError | Http.error.HttpClientError) => {
        if (err._tag === 'ResponseError' || err._tag === 'RequestError') {
          return new GzipStreamError({ message: `response error ${err.reason.toLowerCase()}` });
        }

        return err;
      })
    )
});

describe('Gzip file processing', async () => {
  it('should be able to download and unpack gzip files', async ({ expect }) =>
    F.pipe(
      GZipStreamClient,
      Ef.map((client) => client.read('http://ftp.debian.org/debian/dists/stable/main/Contents-amd64.gz')),
      Ef.flatMap((s) => St.runCollect(s)),
      Ef.provide(PlatformNode.NodeContext.layer),
      Ef.provideService(GZipStreamClient, GZipStreamClientLive),
      Ef.map((chunk) => expect(chunk.length).toBeGreaterThan(0)),
      Ef.runPromise
    ));
});