note 8753 modified in function.gzcompress by felipe

No, it doesn't return gzip compressed data -- specifically, the CRC is messed up. However, after massaging the output a lot, I have come up with a solution. I also commented it a lot, pointing out odd things. <?php // Start the output buffer ob_start(); ob_implicit_flush(0); // Output stuff here... // Get the contents of the output buffer $contents = ob_get_contents(); ob_end_clean(); // Tell the browser that they are going to get gzip data // Of course, you already checked if they support gzip or x-gzip // and if they support x-gzip, you'd change the header to say // x-gzip instead, right? header("Content-Encoding: gzip"); // Display the header of the gzip file // Thanks ck@medienkombinat.de! // Only display this once echo "\x1f\x8b\x08\x00\x00\x00\x00\x00"; // Figure out the size and CRC of the original for later $Size = strlen($contents); $Crc = crc32($contents); // Compress the data $contents = gzcompress($contents, 9); // We can't just output it here, since the CRC is messed up. // If I try to "echo $contents" at this point, the compressed // data is sent, but not completely. There are four bytes at // the end that are a CRC. Three are sent. The last one is // left in limbo. Also, if we "echo $contents", then the next // byte we echo will not be sent to the client. I am not sure // if this is a bug in 4.0.2 or not, but the best way to avoid // this is to put the correct CRC at the end of the compressed // data. (The one generated by gzcompress looks WAY wrong.) // This will stop Opera from crashing, gunzip will work, and // other browsers won't keep loading indefinately. // // Strip off the old CRC (it's there, but it won't be displayed // all the way -- very odd) $contents = substr($contents, 0, strlen($contents) - 4); // Show only the compressed data echo $contents; // Output the CRC, then the size of the original gzip_PrintFourChars($Crc); gzip_PrintFourChars($Size); // Done. You can append further data by gzcompressing // another string and reworking the CRC and Size stuff for // it too. Repeat until done. function gzip_PrintFourChars($Val) { for ($i = 0; $i < 4; $i ++) { echo chr($Val % 256); $Val = floor($Val / 256); } } ?> --was-- No, it doesn't return gzip compressed data -- specifically, the CRC is messed up. However, after massaging the output a lot, I have come up with a solution. I also commented it a lot, pointing out odd things. // Start the output buffer ob_start(); ob_implicit_flush(0); // Output stuff here... // Get the contents of the output buffer $contents = ob_get_contents(); ob_end_clean(); // Tell the browser that they are going to get gzip data // Of course, you already checked if they support gzip or x-gzip // and if they support x-gzip, you'd change the header to say // x-gzip instead, right? header("Content-Encoding: gzip"); // Display the header of the gzip file // Thanks ck@medienkombinat.de! // Only display this once echo "\x1f\x8b\x08\x00\x00\x00\x00\x00"; // Figure out the size and CRC of the original for later $Size = strlen($contents); $Crc = crc32($contents); // Compress the data $contents = gzcompress($contents, 9); // We can't just output it here, since the CRC is messed up. // If I try to "echo $contents" at this point, the compressed // data is sent, but not completely. There are four bytes at // the end that are a CRC. Three are sent. The last one is // left in limbo. Also, if we "echo $contents", then the next // byte we echo will not be sent to the client. I am not sure // if this is a bug in 4.0.2 or not, but the best way to avoid // this is to put the correct CRC at the end of the compressed // data. (The one generated by gzcompress looks WAY wrong.) // This will stop Opera from crashing, gunzip will work, and // other browsers won't keep loading indefinately. // // Strip off the old CRC (it's there, but it won't be displayed // all the way -- very odd) $contents = substr($contents, 0, strlen($contents) - 4); // Show only the compressed data echo $contents; // Output the CRC, then the size of the original gzip_PrintFourChars($Crc); gzip_PrintFourChars($Size); // Done. You can append further data by gzcompressing // another string and reworking the CRC and Size stuff for // it too. Repeat until done. function gzip_PrintFourChars($Val) { for ($i = 0; $i < 4; $i ++) { echo chr($Val % 256); $Val = floor($Val / 256); } } ?> http://php.net/manual/en/function.gzcompress.php