title: Unzip File in Dataflow Before Reading
body: <p>Our client is uploading files into GCS, but they are zipped. Is there any way, using the Java Dataflow SDK, in which we can run through all the zipped files, unzip the file, combine all the resulting .csv files into one file, and then only do the <code>TextIO</code> transforms? </p>
  
  <p><strong>EDIT</strong> </p>
  
  <p>To answer jkffs's questions, </p>
  
  <ol>
  <li>Well I don't really <em>need</em> to combine them all into a single file, it would just be much easier from a reading perspective. </li>
  <li>They are ZIP files, not GZ or BZ or anything else. Each ZIP contains multiple files. The files names are not really significant, and yes, I would actually prefer it TextIO transparently decompresses and concatenates all the files, on a per-archive basis. </li>
  </ol>
  
  <p>Hope that helps!</p>