HostSuffix

public struct HostSuffix : URLMatchable

Type that matches a URL based on the suffix of the URL’s host propery.

Usage:

let url = URL(string: "https://example.com")!
HostSuffix(["example", "com"]).matches(url) //> true
HostSuffix(["com"]).matches(url)            //> true

See also

Host

  • Wraps the given domains to create a new HostSuffix value. It matches against suffixes of URL.host split into domain names.

    See also

    Host

    URL.host will be split into its composite domains before being compared with this collection.

    Declaration

    Swift

    public init(_ domains: [String])

    Parameters

    domains

    A collection of domains together representing a suffix of the host to match.

  • Wraps the given components to create a new HostSuffix value. It matches against suffixes of a URL’s host property.

    Given URL.host is a string, and the Host type wraps a string, why does HostSuffix wrap an collection of domains? Because matching a host suffix by string is a common security issue.

    Consider the URL “www.example.com”. We may wish to match only the “example.com” part so we naïvely create a value like HostSuffix("example.com"). This looks straight-forward, but also matches “hijackexample.com”. Even if we catch this and use the (easy to overlook) HostSuffix(".example.com") we now have a situation where “example.com” doesn’t match because it has no leading "." leading to non-obvious solutions (like Or(Host("example.com"), HostSuffix(".example.com"))) for what should be an obvious thing.

    Requiring an array of domains not only forces us to think through these issues but also has the virtuous property of making the naïve solution the correct one — HostSuffix(["example", "com"]) matches both “www.example.com” and “example.com” but does not match “hijackexample.com”.

    See also

    Host

    These domains will be joined with a "." when compared.

    Declaration

    Swift

    public init(_ domains: [Domain])

    Parameters

    domains

    A collection of domains together representing a suffix of the host to match.

  • Predicate that determines whether a HostSuffix matches a given URL.

    Declaration

    Swift

    public func matches(url: URL) -> Bool

    Parameters

    url

    The URL to be matched.

    Return Value

    true if the wrapped domains (joined by ".") equal a suffix of url.host. Otherwise, false.