Match Patterns

Host permissions and content script matching are based on a set of URLs defined by match patterns. A match pattern is essentially a URL that begins with a permitted scheme (http, https, file, or ftp, and that can contain '*' characters. The special pattern <all_urls> matches any URL that starts with a permitted scheme. Each match pattern has 3 parts:

  • scheme — for example, http or file or *

Note

Access to file URLs is not automatic. The user must visit the Extensions management page and opt in to file access for each Extension that requests it.

  • _host_ — for example, www.google.com or *.google.com or *; if the scheme is file, there is no host part.
  • _path_ — for example, /*, /foo*, or /foo/bar. The path must be present in a host permission, but is always treated as /*.

The basic syntax:

<url-pattern> := <scheme>://<host><path>
<scheme> := '*' | 'http' | 'https' | 'file' | 'ftp'
<host> := '*' | '*.' <any char except '/' and '*'>+
<path> := '/' <any chars>

The meaning of * depends on whether it is in the scheme, host, or path part. If the scheme is *, then it matches either http or https, and not file, or ftp. If the host is just *, then it matches any host. If the host is *.hostname, then it matches the specified host or any of the subdomains. In the path section, each * matches 0 or more characters. The following table shows some valid patterns.

Pattern What it does Examples of matching URLs
http://*/* Matches any URL that uses the http scheme http://www.google.com http://example.org/foo/bar.html
http://*/foo* Matches any URL that uses the http scheme, on any host, as long as the path starts with /foo http://example.com/foo/bar.html http://www.google.com/foo
https://*.google.com/foo*bar Matches any URL that uses the https scheme, is on a google.com host (such as www.google.com, docs.google.com, or google.com), as long as the path starts with /foo and ends with bar https://www.google.com/foo/baz/bar https://docs.google.com/foobar
http://example.org/foo/bar.html Matches the specified URL http://example.org/foo/bar.html
file:///foo* Matches any local file whose path starts with /foo file:///foo/bar.html file:///foo
http://127.0.0.1/* Matches any URL that uses the http scheme and is on the host 127.0.0.1 http://127.0.0.1 http://127.0.0.1/foo/bar.html
*://mail.google.com/* Matches any URL that starts with http://mail.google.com or https://mail.google.com. http://mail.google.com/foo/baz/bar https://mail.google.com/foobar
<all_urls> Matches any URL that uses a permitted scheme. (See the beginning of this section for the list of permitted schemes.) http://example.org/foo/bar.html file:///bar/baz.html

Here are some examples of _invalid_ pattern matches:

Bad pattern Why it is bad
http://www.foo.com No _path_
http://*foo/bar '*' in the host can be followed only by a '.' or '/'
http://foo.*.bar/baz If '*' is in the _host_, it must be the first character
http:/bar Missing _scheme_ separator ('/' should be "//")
foo://* Invalid _scheme_

Some schemes are not supported in all contexts.

Note

Portions of this page are modifications based on work created and shared by Google and used according to terms described in the Creative Commons Attribution 4.0 International License.
The original page is found here.

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