In the Caddyfile, a **matcher token** immediately following the directive can limit that directive's scope. The matcher token can be one of these forms:
1.**`*`** to match all requests (wildcard; default).
2.**`/path`** start with a forward slash to match a request path.
3.**`@name`** to specify a _named matcher_.
Matcher tokens are [usually optional](/docs/caddyfile/directives#matchers). If a matcher token is omitted, it is the same as a wildcard matcher (`*`).
#### Examples
This directive applies to [all](#wildcard-matchers) HTTP requests:
The wildcard matcher `*` matches all requests, and is only needed if a matcher token is required. For example, if the first argument you want to give a directive also happens to be a path, it would look exactly like a path matcher! So you can use a wildcard matcher to disambiguate, for example:
Path matcher tokens must start with a forward slash `/`.
[Path matching](/docs/caddyfile/matchers#path) is an exact match by default; you must append a `*` for a fast prefix match. Note that `/foo*` will match `/foo` and `/foo/` as well as `/foobar`; you might actually want `/foo/*` instead.
### Named matchers
Defining a matcher with a unique name gives you more flexibility, allowing you to combine [any available matchers](#standard-matchers) into a set:
This proxies only the requests that have a header field named "Connection" containing the word "Upgrade", and another field named "Upgrade" with a value of "websocket".
Like directives, named matcher definitions must go inside the site blocks that use them.
A named matcher definition constitutes a _matcher set_. Matchers in a set are AND'ed together; i.e. all must match. For example, if you have both a `header` and `path` matcher in the set, both must match.
By any [CEL (Common Expression Language)](https://github.com/google/cel-spec) expression that returns `true` or `false`.
As a special case, Caddy [placeholders](/docs/conventions#placeholders) (or [Caddyfile shorthands](/docs/caddyfile/concepts#placeholders)) may be used in these CEL expressions, as they are preprocessed and converted to regular CEL function calls before being interpreted by the CEL environment.
-`root` defines the directory in which to look for files. Default is the current working directory, or the `root` [variable](/docs/modules/http.handlers.vars) (`{http.vars.root}`) if set (can be set via the [`root` directive](/docs/caddyfile/directives/root)).
-`split_path` will cause the path to be split at the first delimiter in the list that is found in each filepath to try. For each split value, the left-hand side of the split including the delimiter itself will be the filepath that is tried. For example, `/remote.php/dav/` using a delimiter of `.php` would try the file `/remote.php`. Each delimiter must appear at the end of a URI path component in order to be used as a split delimiter. This is a niche setting and is mostly used when serving PHP sites.
Like `header`, but supports regular expressions. Capture groups can be accessed via placeholder like `{http.regexp.name.capture_group}` where `name` is the name of the regular expression (optional, but recommended) and `capture_group` is either the name or number of the capture group in the expression. Capture group `0` is the full regexp match, `1` is the first capture group, `2` is the second capture group, and so on.
Matches request by the `Host` header field of the request. It is not common to use this in the Caddyfile, since most site blocks already indicate hosts in the address of the site. This matcher is mostly used in site blocks that don't define specific hostnames.
Like `path`, but supports regular expressions. Capture groups can be accessed via placeholder like `{http.regexp.name.capture_group}` where `name` is the name of the regular expression (optional, but recommended) and `capture_group` is either the name or number of the capture group in the expression. Capture group `0` is the full regexp match, `1` is the first capture group, `2` is the second capture group, and so on.
By query string parameters. Should be a sequence of `key=value` pairs. Keys are matched exactly, case-sensitively. Values are matched exactly, but also support `*` to match any value.
