JavaScript Requires Chilkat v11.0.0+

Unzip One File to a Stream

See more Zip Examples

Demonstrates how to unzip a particular file contained within a .zip archive to a Chilkat stream. JavaScript

var success = false;

//  This example requires the Chilkat API to have been previously unlocked.
//  See Global Unlock Sample for sample code.

var zip = new CkZip();

//  First open a .zip.
success = zip.OpenZip("qa_data/hamlet.zip");
if (success == false) {
    console.log(zip.LastErrorText);
    return;
}

//  Find the entry to be unzipped to a stream..
var entry = new CkZipEntry();
success = zip.EntryMatching("*hamlet.xml",entry);
if (success == false) {
    console.log(zip.LastErrorText);
    return;
}

//  There are three ways we can unzip (inflate) to a stream.
//  
//  1) Set a sink file on the stream object and call UnzipToStream synchronously.
//     This unzips to the stream's sink (which is to simply unzip to a file in the filesystem).
//  
//  2) Create a stream object and call UnzipToStreamAsync.  This starts the unzip in a background
//     thread (after Task.Run is called).  Your application can then read the unzipped (inflated) file
//     directly from the stream.
//  
//  3) (not shown in this example) Unzip to a stream object that is the source of something else.
//     

//  ----------------------------------------------------------------
//  Case 1: Unzip to a file by setting the sink of streamA to a file.
var streamA = new CkStream();
streamA.SinkFile = "qa_output/hamletA.xml";

success = entry.UnzipToStream(streamA);
if (success !== true) {
    console.log(entry.LastErrorText);
    return;
}

//  Close the stream to close the output file.
success = streamA.WriteClose();

//  ----------------------------------------------------------------
//  Case 2a: Uzip to a stream asynchronously. 
var streamB = new CkStream();

// unzipTask: CkTask
var unzipTask = entry.UnzipToStreamAsync(streamB);
if (entry.LastMethodSuccess !== true) {
    console.log(entry.LastErrorText);
    return;
}

//  Start the background unzip thread.
unzipTask.Run();

//  Read the stream.  (this is reading the unzipped file data)
var sb = new CkStringBuilder();
while (streamB.EndOfStream !== true) {
    //  Each call to ReadSb appends to the contents of sb.
    streamB.ReadSb(sb);
}

sb.WriteFile("qa_output/hamletB.xml","utf-8",false);

console.log("Success.");

//  ----------------------------------------------------------------
//  Case 2b: Uzip to a stream asynchronously and emit output while reading. 
var streamC = new CkStream();

unzipTask = entry.UnzipToStreamAsync(streamC);
if (entry.LastMethodSuccess !== true) {
    console.log(entry.LastErrorText);
    return;
}

unzipTask.Run();

while (streamC.EndOfStream !== true) {
    var s = streamC.ReadString();
    console.log(s);
}

console.log("Success.");