add Url.Update

url/examples.json

@@ -14,6 +14,15 @@
             }]
         }
     }],
+    "update": [{
+        "title": "Update a short URL",
+        "run_check": false,
+        "request": {
+            "shortURL": "https://m3o.one/u/f8f3f83f3f83g",
+            "destinationURL": "https://mynewsite.com/this-is-a-rather-long-web-address"
+        },
+        "response": {}
+    }],
     "shorten": [{
         "title": "Shorten a long URL",
         "run_check": false,

url/handler/url.go

@@ -70,6 +70,47 @@ func (e *Url) Delete(ctx context.Context, req *url.DeleteRequest, rsp *url.Delet
 	return nil
 }
 
+func (e *Url) Update(ctx context.Context, req *url.UpdateRequest, rsp *url.UpdateResponse) error {
+	tenantId, ok := tenant.FromContext(ctx)
+	if !ok {
+		return errors.Unauthorized("url.shorten", "not authorized")
+	}
+
+	id := strings.Replace(req.ShortURL, e.hostPrefix, "", -1)
+
+	// check the owner has this short url
+	records, err := store.Read("urlOwner/" + tenantId + "/" + id)
+	if err != nil {
+		return err
+	}
+
+	if len(records) == 0 {
+		return errors.NotFound("url.update", "not found")
+	}
+
+	uri := new(url.URLPair)
+	if err := records[0].Decode(uri); err != nil {
+		return err
+	}
+
+	// set the destination url
+	uri.DestinationURL = req.DestinationURL
+
+	// write a global key
+	key := "url/" + id
+	if err := store.Write(store.NewRecord(key, uri)); err != nil {
+		return err
+	}
+
+	// write per owner key
+	key = "urlOwner/" + tenantId + "/" + id
+	if err := store.Write(store.NewRecord(key, uri)); err != nil {
+		return err
+	}
+
+	return nil
+}
+
 func (e *Url) Shorten(ctx context.Context, req *url.ShortenRequest, rsp *url.ShortenResponse) error {
 	tenantId, ok := tenant.FromContext(ctx)
 	if !ok {