Internet Explorer 8 + Deflate
- by Andreas Bonini
I have a very weird problem.. I really do hope someone has an answer because I wouldn't know where else to ask.
I am writing a cgi application in C++ which is executed by Apache and outputs HTML code. I am compressing the HTML output myself - from within my C++ application - since my web host doesn't support mod_deflate for some reason.
I tested this with Firefox 2, Firefox 3, Opera 9, Opera 10, Google Chrome, Safari, IE6, IE7, IE8, even wget.. It works with ANYTHING except IE8.
IE8 just says "Internet Explorer cannot display the webpage", with no information whatsoever. I know it's because of the compression only because it works if I disable it.
Do you know what I'm doing wrong?
I use zlib to compress it, and the exact code is:
/* Compress it */
int compressed_output_size = content.length() + (content.length() * 0.2) + 16;
char *compressed_output = (char *)Alloc(compressed_output_size);
int compressed_output_length;
Compress(compressed_output, compressed_output_size, (void *)content.c_str(), content.length(), &compressed_output_length);
/* Send the compressed header */
cout << "Content-Encoding: deflate\r\n";
cout << boost::format("Content-Length: %d\r\n") % compressed_output_length;
cgiHeaderContentType("text/html");
cout.write(compressed_output, compressed_output_length);
static void Compress(void *to, size_t to_size, void *from, size_t from_size, int *final_size)
{
int ret;
z_stream stream;
stream.zalloc = Z_NULL;
stream.zfree = Z_NULL;
stream.opaque = Z_NULL;
if ((ret = deflateInit(&stream, CompressionSpeed)) != Z_OK)
COMPRESSION_ERROR("deflateInit() failed: %d", ret);
stream.next_out = (Bytef *)to;
stream.avail_out = (uInt)to_size;
stream.next_in = (Bytef *)from;
stream.avail_in = (uInt)from_size;
if ((ret = deflate(&stream, Z_NO_FLUSH)) != Z_OK)
COMPRESSION_ERROR("deflate() failed: %d", ret);
if (stream.avail_in != 0)
COMPRESSION_ERROR("stream.avail_in is not 0 (it's %d)", stream.avail_in);
if ((ret = deflate(&stream, Z_FINISH)) != Z_STREAM_END)
COMPRESSION_ERROR("deflate() failed: %d", ret);
if ((ret = deflateEnd(&stream)) != Z_OK)
COMPRESSION_ERROR("deflateEnd() failed: %d", ret);
if (final_size)
*final_size = stream.total_out;
return;
}
