不带多部分/表单数据的PHP中通过HTTP PUT发送二进制文件的内存影响

Question

I recently wrote a code where I send a normal PUT request which has contents of a binary file in the request body with the Content-Type header set to the mime type of said file. In the server, I handle that by just reading the raw request body in a variable, employing some validation: size (using strlen ) and mime types (using finfo->buffer ) and then copying the contents to a file (using file_put_contents ).

The usual (or popular, I guess) way of uploading files would be using multipart/form-data encoding, which would be handled automatically by PHP. In that case, PHP would write the contents in a temporary file, which I believe exists in a storage device rather than memory.

Now, I went through the code in https://github.com/php/php-src/blob/master/main/rfc1867.c , and it seemed to put the request body in memory anyways.

My question is:

0) Does PHP store the full request body in memory (at least once), regardless of the enctype it gets?

1) Does getting all the raw body and writing it to a file (using file_put_contents ) uses more memory compared to using php's internal multipart/form-data handling mechanism to upload a file?

1a) Does php's copy-on-write mechanism help me here? that is to say am I allocating new blocks of memory when I store the raw body content in some variable (and not a file)? Or am I just pointing to the request data that is already on the memory (if there is) ?

2) If what I'm doing does impact memory, do you have any suggestions for improvement that does not involve using multipart/form-data ?

PS: I do not need to send anything else (eg, metadata) with the file, nor do I have the need to send multiple files in a single request.

PPS: Sorry if my post is incomprehensible, I'd be happy to provide other details if anything seems confusing or incomplete.

EDIT

• Added Question 0.
• Slightly Modified questions in hopes of making it less confusing.

Answer 1

1) Does getting all the raw body and writing it to a file (using file_put_contents makes me use more memory rather than letting PHP handle it?

Yeah, tons. With file_put_contents() alone, you need the full data in-memory before writing it. It's meant for more of a utility for small files and such.

1a) Does php's copy-on-write mechanism help me here? that is to say am I allocating new blocks of memory when I store the raw body content in some variable (and not a file)?

I'm not familiar with specifically what you're referring to, but yes if you store the body content in a variable, a copy of it is sitting in memory.

2) If what I'm doing does impact memory, do you have any suggestions for improvement that does not involve using multipart/form-data ?

Yes! Check out the php://input stream. This will allow you to access the raw POST body.

http://php.net/manual/en/wrappers.php.php#wrappers.php.input