feat: initial backend implementation of multihost synchronization (#562)

internal/api/syncapi/uriutil.go

@@ -0,0 +1,60 @@
+package syncapi
+
+import (
+	"errors"
+	"net/url"
+)
+
+var ErrNotBackrestURI = errors.New("not a backrest URI")
+
+func CreateRemoteRepoURI(instanceUrl string) (string, error) {
+	u, err := url.Parse(instanceUrl)
+	if err != nil {
+		return "", err
+	}
+
+	if u.Scheme == "http" {
+		u.Scheme = "backrest"
+	} else if u.Scheme == "https" {
+		u.Scheme = "sbackrest"
+	} else {
+		return "", errors.New("unsupported scheme")
+	}
+
+	return u.String(), nil
+}
+
+func IsBackrestRemoteRepoURI(repoUri string) bool {
+	u, err := url.Parse(repoUri)
+	if err != nil {
+		return false
+	}
+
+	return u.Scheme == "backrest"
+}
+
+func InstanceForBackrestURI(repoUri string) (string, error) {
+	u, err := url.Parse(repoUri)
+	if err != nil {
+		return "", err
+	}
+
+	if u.Scheme != "backrest" {
+		return "", errors.New("not a backrest URI")
+	}
+
+	return u.Hostname(), nil
+}
+
+func RepoForBackrestURI(repoUri string) (string, error) {
+	u, err := url.Parse(repoUri)
+	if err != nil {
+		return "", err
+	}
+
+	if u.Scheme != "backrest" {
+		return "", errors.New("not a backrest URI")
+	}
+
+	return u.Path, nil
+}