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合理配置 php.ini

如何配置php.ini实现PHP文件上传功能。其中涉及到php.ini配置文件中的upload_tmp_dir、upload_max_filesize、post_max_size等选项,这些选项是文件上传成败的关键。我以php.5.3 的版本为例说明。

打开php.ini 配置文件,查找 file_uploads ,在这个区域有以下3个选项:

file_uploads = On

是否允许HTTP文件上传。默认值为On允许HTTP文件上传,此选项不能设置为Off。

upload_tmp_dir =

文件上传的临时存放目录。如果没指定则PHP会使用系统默认的临时目录。该选项默认为空,此选项在手动配置PHP运行环境时,也容易遗忘,如果不配置这个选项,文件上传功能就无法实现,你必须给这个选项赋值,比如upload_tmp_dir = "/home/tmp" ,代表在home目录下有一个tmp目录,并且给这目录赋予所有用户读写权限。

upload_max_filesize = 2M

上传文件的最大尺寸。这个选项默认值为2M,即文件上传的大小为2M,如果你想上传一个50M的文件,你必须设定 upload_max_filesize = 50M。
但是仅设置upload_max_filesize = 50M 还是无法实现大文件的上传功能,我们还必须修改php.ini文件中的 post_max_size 选项。

max_file_uploads = 20 

设置一次最多允许上传文件的数量

继续在 php.ini 中查找 Data Handling ,在这个区域有1个选项:

post_max_size = 8M

指通过表单POST给PHP的所能接收的最大值,包括表单里的所有值。默认为8M。如果POST数据超出限制,那么$_POST和$_FILES将会为空。
要上传大文件,你必须设定该选项值大于upload_max_filesize选项的值,例如你设置了upload_max_filesize = 50M ,这里可以把post_max_size = 100M。
另外如果启用了内存限制,那么该值应当小于memory_limit 选项的值。

继续在 php.ini 中查找 Resource Limits ,在这个区域有3个选项:

max_execution_time = 30

每个PHP页面运行的最大时间值(单位秒),默认30秒。当我们上传一个较大的文件,例如50M的文件,很可能要几分钟才能上传完,但php默认页面最久执行时间为30秒,超过30秒,该脚本就停止执行,这就导致出现无法打开网页的情况。因此我们可以把值设置的较大些,如 max_execution_time = 600。 如果设置为0,则表示无时间限制。

max_input_time = 60

每个PHP脚本解析请求数据所用的时间(单位秒),默认60秒。当我们上传大文件时,可以将这个值设置的较大些。 如果设置为0,则表示无时间限制。

memory_limit = 128M

这个选项用来设置单个PHP脚本所能申请到的最大内存空间。这有助于防止写得不好的脚本消耗光服务器上的可用内存。如果不需要任何内存上的限制将其设为 -1。
php5.2.0以前的版本默认8M; php.5.2.0版本默认为16M。php 5.2.0之后的版本默认为 128M;

php.ini 配置上传文件功能示例

假设要上传一个50M的大文件。配置 php.ini 如下:
file_uploads = On
upload_tmp_dir = "/home/fileuploadtmp"
upload_max_filesize = 50M
post_max_size = 100M
max_execution_time = 600
max_input_time = 600
memory_limit = 128M
提示:需要保持 memory_limit > post_max_size > upload_max_filesize
此例仅供参考,你可以根据实际情况调整。



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