问题
In my site host, I have seen (via phpinfo) that
- post_max_size = 8Mb
- upload_max_filesize = 16Mb
This led me to think that I should be able to upload as file as big as 16Mb. However, when I do this through a post method (as normal), post_max_size takes over and declares that I sent too much.
What is the method which permits sending a file as big as 16Mb ? GET - PUT - other ?
Hope someone can clarify this for me.
Simon
回答1:
upload_max_filesize is the limit of any single file.
post_max_size is the limit of the entire body of the request, which could include multiple files.
Given post_max_size = 20M and upload_max_filesize = 6M you could upload up to 3 files of 6M each. If instead post_max_size = 6M and upload_max_filesize = 20M then you could only upload one 6M file before hitting post_max_size. It doesn't help to have upload_max_size > post_max_size.
It's not obvious how to recognize going over post_max_size. $_POST and $_FILES will be empty, but $_SERVER['CONTENT_LENGTH'] will be > 0. If the client just didn't upload any post variables or files, then $_SERVER['CONTENT_LENGTH'] will be 0.
回答2:
By POST file uploads are done (commonly, there are also other methods). Look into the method attribute of the form which contains the file-upload field ;)
The lowest limit of any related setting supersedes a higher setting:
- post_max_size
- upload_max_filesize
- memory_limit
See Handling file uploads: Common Pitfals which explains this in detail and how to calculate the values.
回答3:
The normal method to send a file upload is POST, thus also post_max_size should be 16 Mb or more.
Incidentally, also memory_limit plays a role. It should be bigger than 16Mb, but since the default value is 128Mb, you won't see this problem. Example php.ini configuration:
post_max_size = 16M
upload_max_filesize = 16M
memory_limit = 128M
Change these value in php.ini if you've access to it, otherwise you can try to change them in an .htaccess file.
php_value upload_max_filesize 16M
php_value post_max_size 16M
This will work only if the AllowOverride settings permit it. Otherwise, you've to ask to your hosting company.
回答4:
post_max_size:
- Sets max size of post data allowed. This setting also affects file upload
- To upload large files, this value must be larger than upload_max_filesize
- Generally speaking, memory_limit should be larger than post_max_size.
- PHP Default: 8M
upload_max_filesize:
- The maximum size of an uploaded file
- PHP Default: 2M
memory_limit > post_max_size > upload_max_filesize
PHP Default: 128M > 8M > 2M
By default, post_max_size should be 4 times greater than upload_max_filesize.
In turn
memory_limit should be 16 times greater than post_max_size
回答5:
Your server configuration settings allows users to upload files upto 16MB (because you have set upload_max_filesize = 16Mb) but the post_max_size accepts post data upto 8MB only. This is why it throws an error.
Quoted from the official PHP site:
To upload large files, post_max_size value must be larger than upload_max_filesize.
memory_limit should be larger than post_max_size
You should always set your post_max_size value greater than the upload_max_filesize value.
回答6:
change in php.ini max_input_vars 1000
来源：https://stackoverflow.com/questions/7754133/php-post-max-size-overrides-upload-max-filesize