Bug #55781 [Opn->Fbk]: exif_read_file assumes only stdio supports stat(), performs slow seek to end

Edit report at https://bugs.php.net/bug.php?id=55781&edit=1 ID: 55781 Updated by: kalle@php.net Reported by: tom at punkave dot com Summary: exif_read_file assumes only stdio supports stat(), performs slow seek to end -Status: Open +Status: Feedback Type: Bug Package: EXIF related Operating System: All PHP Version: 5.3.8 Block user comment: N Private report: N New Comment: I'm not sure whether or not this is possible, as the http wrapper do not support stat() calls, which means we would need to add specific code for different protocols in ext/exif, or just for http(s). We could look into adding support for stat on the HTTP wrapper, however I'm not sure which data we could translate into what. I personally lean a little towards the first one, but for the overall good of the PHP codebase, I think the second option is most beneficial for other extensions at the same time that could need such. Previous Comments: ------------------------------------------------------------------------ [2011-09-25 18:17:30] tom at punkave dot com Description: ------------ Per Twitter exchange with @pierrejoye The exif_read_file function checks whether the file is accessed over stdio. If it is accessed over stdio, VCWD_STAT() is used to get the size of the file efficiently. If it is accessed by any other means, this pattern is used: php_stream_seek(ImageInfo->infile, 0, SEEK_END); ImageInfo->FileSize = php_stream_tell(ImageInfo- >infile); php_stream_seek(ImageInfo->infile, 0, SEEK_SET); Moving the seek pointer to the end can trigger slow, bandwidth-hungry network operations for remote stream wrappers, such as S3 wrappers. Please test whether the stream implements the stat operation and, if so, use it to avoid this performance hit. I was able to work around the problem by teaching my stream wrapper to specifically tolerate the "seek to the end / ftell / seek to the start" pattern and return cached data. ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=55781&edit=1