Question

i have a C# application where i am using SharpZipLib to deflate a very long string and then send the data over to a PHP Service in a Base64 string of the deflated byte[].

For some reason, when trying to Inflate it on the PHP side, it is returning an error: ‘gzinflate: data error’.

How to inflate a gzipped string in PHP?

Here is the C# code:

    byte[] sIn = System.Text.UTF8Encoding.UTF8.GetBytes(data);

    MemoryStream rawDataStream = new MemoryStream();
    GZipOutputStream gzipOut = new GZipOutputStream(rawDataStream);
    gzipOut.IsStreamOwner = false;

    gzipOut.Write(sIn, 0, sIn.Length);
    gzipOut.Close();

    byte[] compressed = rawDataStream.ToArray();

    // data sent to the php service
    string b64 = Convert.ToBase64String(compressed);

PHP code:

    $inflated = base64_decode($_POST['data']);

    // crash here
    $inflated = gzinflate($inflated);

Thanks in advance!

Answer 1

Can’t really say why it fails for you with GZipOutStream though I’m guessing it is doing something else then just a pure deflate-compression. I changed your code to use DeflateStream from System.IO.Compression instead and then it worked like a charm.

byte[] sIn = UTF8Encoding.UTF8.GetBytes("testing some shit");

MemoryStream rawDataStream = new MemoryStream();
DeflateStream gzipOut = new DeflateStream(rawDataStream, CompressionMode.Compress);

gzipOut.Write(sIn, 0, sIn.Length);
gzipOut.Close();

byte[] compressed = rawDataStream.ToArray();

// data sent to the php service
string b64 = Convert.ToBase64String(compressed);

Edit

Since the question was about using compression for a Windows Phone project I tried using the DeflateStream from SharpCompress as well and it works just fine, you just have to change which namespace you are using, the classes are the same.