


PHP uses the finfo_file() function to implement the method of detecting the type of uploaded images
这篇文章主要介绍了PHP使用finfo_file()函数检测上传图片类型的实现方法,结合实例形式分析了finfo_file()函数的功能、使用方法及相关注意事项,需要的朋友可以参考下
在输入输出中,文件的交互必不可少,比如文件的上传什么的。这里我们来解决一个小问题,就是如何判断用户上传文件的文件类型。
举一个应用场面:在我们的Web应用中,比如用户上传头像,要求是png,jpg,gif格式,接收到图片后会根据图片格式类型做不同的头像切割处理,但个别用户会传一些只更改过文件后缀的非标准图片,比如nowamagic.jpg 强行修改成 nowamagic.png,这样程序无法对该类型图片进行切割,切割失败。这个时候就需要对文件进行检测,并且仅仅根据后缀来判断是不行的。
这种这么常见的需求,PHP肯定自带了某些函数来实现的,这个函数就是 finfo_file
。
finfo_file
(PHP >= 5.3.0, PECL fileinfo >= 0.1.0)
finfo_file -- finfo::file — Return information about a file,This function is used to get information about a file.
函数很简单,看看官方文档就大概清楚了,这里就举一个使用例子吧,就是上传一张图片,并判断它的类型:
<html> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <head> <title>文件上传</title> </head> <body> <form accept="" method="post" enctype="multipart/form-data"> <input type="file" name="img[]" /><br /> <input type="submit" name="s" /><br /> </form> <?php //上传文件信息 $img = $_FILES['img']; if ($img) { //文件存放目录,和本php文件同级 $dir = dirname(__file__); $filename = $img['name'][0]; $tempname = $img['tmp_name'][0]; $savepath = "$dir\\$filename"; $state = move_uploaded_file($tempname, $savepath); //如果上传成功,预览 if($state) { echo "<img src='$filename' alt='$filename' /> "; } $finfo = finfo_open(FILEINFO_MIME_TYPE); //$mime = finfo_file($finfo, dirname(__FILE__)."/".$filename); $mime = finfo_file($finfo, $savepath); echo $mime; } ?> </body> </html>
以上就是本文的全部内容,希望对大家的学习有所帮助。
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