用于验证文件和特殊字符的正则表达式

Question

I have a regex which validates only file to upload .doc , .docx , .DOCX , .rtf , and .pdf . See below the regex code:

"^.+(.doc|.DOC|.docx|.DOCX|.rtf|.RTF|.pdf|.PDF)$" 

But in this scenario, I also want to validate the file name should not include more than one . .

For ex:

A file name should not be like this: abc.abc.doc it should be like this: abc.doc .

Answer 1

There are two general formulas for what you want to do.

First approach: say what you want

(?i)^[a-z0-9_-]+\.(?:docx?|rtf|pdf)$

The (?i) makes it case-insensitive so that you don't have to repeat doc , DOC etc. For instance, you could have a doC or DoC extension, but it is not mentioned in the original alternation.

The allowable chars for the prefix are specified in [a-z0-9_-] , so if you want more chars you can add them there.

Second approach: say what you don't want

Another approach is to allow all characters in the prefix except a dot and perhaps a number of "bad characters":

(?i)^[^.<>:"/\\|*?\t\r\n]+\.(?:docx?|rtf|pdf)$

Neither will be a perfect fit unless you know exactly what set of characters your file system will allow.

Answer 2

^[^.]+([.]doc|[.]DOC|[.]docx|[.]DOCX|[.]rtf|[.]RTF|[.]pdf|[.]PDF)$

[^.]+ matches one or more characters which are not a period.

EDIT: As Jongware mentioned, the periods inthe "OR" list should match the period literal.