正则表达式问题用于字符串验证

Question

I am trying to validate following type of string using regular expressions in PHP. Using PHP 5.5.9.

String is in following format:

/[sometext]/course/[sometext1]/[sometext2]

What I need is a regex that will accept string that is only in that format and nothing else. Meaning these would be invalid:

/aaa/course/bbb/ccc/
/aaa/course/bbb/ccc/ddd

What I have so far is this:

/\/(?P<domain>.+?)\/course\/(?P<courseid>.+?)\/(?P<reportname>.+?)/

Any ideas?

Update:

With the help from all posters and especially wiktor-stribi%c5%bcew I got this one that works:

 $regex = '#^/(?P<domain>[^/]+)/course/(?P<courseid>[^/]+)/(?P<reportname>[^/]+)$#';

Answer 1

You can use the following regular expression:

^\/(?P<domain>[^\/]+)\/course\/(?P<courseid>[^\/]+)\/(?P<reportname>[^\/]+)$

PHP:

$re = '~^/(?P<domain>[^/]+)/course/(?P<courseid>[^/]+)/(?P<reportname>[^/]+)$~';

See the regex demo

The [^\/] is a negated character class that matches any character but /.

The ^ and $ are usually enough to make sure your input starts and ends with the current pattern (you can replace them with \A and \z respectively to make sure the \z matches at the very end of the string, or use ^/$ with the /D modifier).

Even if you use lazy .+? dot matching, the . can overflow several / delimiters if it is necessary to return a valid match.