feat(logic): add some functions to deal with urls

x/logic/util/url.go

@@ -0,0 +1,37 @@
+package util
+
+import (
+	"net/url"
+)
+
+// UrlMatches is a function that returns a function that matches the given url against the given other item.
+//
+// The function matches the components of the given url against the components of the given other url. If the component
+// of the given other url is empty, it is considered to match the component of the given url.
+// For example:
+//   - matchUrl("http://example.com/foo")("http://example.com/foo") -> true
+//   - matchUrl("http://example.com/foo")("http://example.com/foo?bar=baz") -> false
+//   - matchUrl("tel:123456789")("tel:") -> true
+//
+// The function is curried, and is a binary relation that is reflexive, associative (but not commutative).
+func UrlMatches(this *url.URL) func(*url.URL) bool {
+	return func(that *url.URL) bool {
+		return (that.Scheme == "" || that.Scheme == this.Scheme) &&
+			(that.Opaque == "" || that.Opaque == this.Opaque) &&
+			(that.User == nil || that.User.String() == "" || that.User.String() == this.User.String()) &&
+			(that.Host == "" || that.Host == this.Host) &&
+			(that.Path == "" || that.Path == this.Path) &&
+			(that.RawQuery == "" || that.RawQuery == this.RawQuery) &&
+			(that.Fragment == "" || that.Fragment == this.Fragment)
+	}
+}
+
+// ParseUrlMust parses the given url and panics if it fails.
+// You have been warned.
+func ParseUrlMust(s string) *url.URL {
+	u, err := url.Parse(s)
+	if err != nil {
+		panic(err)
+	}
+	return u
+}