如何修正正则表达式，避免匹配administrator并实现可选/规则

Hey there! Let's tackle that regex issue you're facing. The problem with your current pattern is that it doesn't restrict what comes right after "admin" — so "administrator" gets matched because "admin" is at the start, and the rest is incorrectly captured as the controller.

The Solution #

We need to enforce that after "admin", either the string ends, or the next character is a / (if there's any后续 content). Here's an adjusted regex that meets all your requirements:

preg_match("/^admin(?:\/(?P<controller>[a-z-]+)?\/?(?P<action>[a-z-]+)?)?$/i", $input_line, $output_array);

Breakdown of the Pattern #

Let's break down what each part does to make it clear:

• ^admin: Strictly matches the start of the string followed by "admin"
• (?:\/...)?: An optional non-capturing group that ensures any content after "admin" must start with /
  • \/: The mandatory leading slash if there's后续 content
  • (?P<controller>[a-z-]+)?: Optional named capture group for the controller (allows letters and hyphens, can be empty for cases like admin/)
  • \/?: Optional slash separating the controller and action
  • (?P<action>[a-z-]+)?: Optional named capture group for the action (also allows letters and hyphens, can be empty)
• $: Matches the end of the string, preventing extra characters after valid paths

What It Matches #

• ✅ admin (exact match)
• ✅ admin/ (admin followed by just a slash)
• ✅ admin/users (admin with controller)
• ✅ admin/users/index (admin with controller and action)

What It Rejects #

• ❌ administrator (admin is followed by letters instead of a slash or end of string)
• ❌ home (doesn't start with admin)

If you want a slightly more strict version that avoids trailing slashes except for the admin/ case, you could use this pattern instead:

preg_match("/^admin(?:\/(?P<controller>[a-z-]+)(?:\/(?P<action>[a-z-]+))?)?$|^admin\/$/i", $input_line, $output_array);

This one explicitly allows admin/ while disallowing trailing slashes on paths with controllers/actions (like admin/users/).

内容的提问来源于stack exchange，提问作者Chad