Re: PROPOSAL: temp stream for post_data

From: Date: Tue, 27 Aug 2013 21:17:01 +0000
Subject: Re: PROPOSAL: temp stream for post_data
References: 1  Groups: php.internals 
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On 27-08-2013 14:08, Michael Wallner wrote:
Hi, I prepared a patch to replace sapi_globals' request_info post_data and raw_post_data with a temp stream and remove support for HTTP_RAW_POST_DATA. [1] PROS: * save up to 300% on post_data_len memory (on non-form POSTs) * a local siege (c=512/512, 2.4k form/2.2k json) showed no (negative) performance impact; see attached logs * reusable php://input stream * ... CONS: * no more $HTTP_RAW_POST_DATA, where BC could easily provided with a one-liner: $GLOBALS["HTTP_RAW_POST_DATA"]=file_get_contents("php://input"); * memory is cheap * ???
I think it's generally a good idea, but I have some concerns: * The whole point of PG(enable_post_data_reading) is to be able to read the input of the fly. If I read your patch correctly, the data is completely gobbled when you open php://input and then the temp file is reminded. This will result in a serious performance degradation on large inputs, as processing can only start after everything has been read. The behavior should be different if PG(enable_post_data_reading) is false. * I don't see SG(request_info).request_body being closed anywhere. Is this relying just on auto-cleanup? I recall that being problematic in debug mode unless you use php_stream_auto_cleanup(). * The php://input streams simply forward the calls to SG(request_info).request_body, so if you open two, the per-stream cursor position may not match the position of the wrapped stream (even if it matched, we wouldn't want one stream to affect the position of the other). I don't see any easy way out here; all I can think of is is duping the file descriptor for the temporary file in these situations. But then the book keeping for php://input would be more complicated. * The cast added php_stream_get_resource_id() seems unnecessary; may hide bugs. If you just want to be able to pass void* values, better to put an inline function there with a php_stream* parameter, that way you would have a compiler warning if you passed anything but a php_stream* or a void* (though this would break taking a pointer). -- Gustavo Lopes

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