If you retrieve a file, how do you ensure that file does not contain malicious data?

如果检索某个文件，如何确保该文件不包含恶意数据？

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These functions were included in PHP from the inception, but administrators haven't always activated them. The following functions can retrieve a file from the web.

这些函数一开始就包含于php中，但管理员有时可能不会激活它们。

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BookDownloadUpload. Allows you to retrieve information about a book, including the file attachment.

允许您检索关于图书的信息，包括文件附件。

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