You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
86 lines
2.0 KiB
Go
86 lines
2.0 KiB
Go
package urn
|
|
|
|
import (
|
|
"encoding/json"
|
|
"fmt"
|
|
"strings"
|
|
)
|
|
|
|
const errInvalidURN = "invalid URN: %s"
|
|
|
|
// URN represents an Uniform Resource Name.
|
|
//
|
|
// The general form represented is:
|
|
//
|
|
// urn:<id>:<ss>
|
|
//
|
|
// Details at https://tools.ietf.org/html/rfc2141.
|
|
type URN struct {
|
|
prefix string // Static prefix. Equal to "urn" when empty.
|
|
ID string // Namespace identifier
|
|
SS string // Namespace specific string
|
|
norm string // Normalized namespace specific string
|
|
}
|
|
|
|
// Normalize turns the receiving URN into its norm version.
|
|
//
|
|
// Which means: lowercase prefix, lowercase namespace identifier, and immutate namespace specific string chars (except <hex> tokens which are lowercased).
|
|
func (u *URN) Normalize() *URN {
|
|
return &URN{
|
|
prefix: "urn",
|
|
ID: strings.ToLower(u.ID),
|
|
SS: u.norm,
|
|
}
|
|
}
|
|
|
|
// Equal checks the lexical equivalence of the current URN with another one.
|
|
func (u *URN) Equal(x *URN) bool {
|
|
return *u.Normalize() == *x.Normalize()
|
|
}
|
|
|
|
// String reassembles the URN into a valid URN string.
|
|
//
|
|
// This requires both ID and SS fields to be non-empty.
|
|
// Otherwise it returns an empty string.
|
|
//
|
|
// Default URN prefix is "urn".
|
|
func (u *URN) String() string {
|
|
var res string
|
|
if u.ID != "" && u.SS != "" {
|
|
if u.prefix == "" {
|
|
res += "urn"
|
|
}
|
|
res += u.prefix + ":" + u.ID + ":" + u.SS
|
|
}
|
|
|
|
return res
|
|
}
|
|
|
|
// Parse is responsible to create an URN instance from a byte array matching the correct URN syntax.
|
|
func Parse(u []byte) (*URN, bool) {
|
|
urn, err := NewMachine().Parse(u)
|
|
if err != nil {
|
|
return nil, false
|
|
}
|
|
|
|
return urn, true
|
|
}
|
|
|
|
// MarshalJSON marshals the URN to JSON string form (e.g. `"urn:oid:1.2.3.4"`).
|
|
func (u URN) MarshalJSON() ([]byte, error) {
|
|
return json.Marshal(u.String())
|
|
}
|
|
|
|
// MarshalJSON unmarshals a URN from JSON string form (e.g. `"urn:oid:1.2.3.4"`).
|
|
func (u *URN) UnmarshalJSON(bytes []byte) error {
|
|
var str string
|
|
if err := json.Unmarshal(bytes, &str); err != nil {
|
|
return err
|
|
}
|
|
if value, ok := Parse([]byte(str)); !ok {
|
|
return fmt.Errorf(errInvalidURN, str)
|
|
} else {
|
|
*u = *value
|
|
}
|
|
return nil
|
|
} |