Prevent accidentally using full Drive URL as folder ID (#144)

* Prevent accidentally using full Drive URL as folder ID

core/src/main/java/google/registry/model/registrar/Registrar.java

@@ -868,7 +868,9 @@ public class Registrar extends ImmutableObject implements Buildable, Jsonifiable
       return this;
     }
 
-    public Builder setDriveFolderId(String driveFolderId) {
+    public Builder setDriveFolderId(@Nullable String driveFolderId) {
+      checkArgument(driveFolderId == null || !driveFolderId.contains("/"),
+          "Drive folder ID must not be a full URL");
       getInstance().driveFolderId = driveFolderId;
       return this;
     }

core/src/main/java/google/registry/tools/CreateOrUpdateRegistrarCommand.java

@@ -237,7 +237,7 @@ abstract class CreateOrUpdateRegistrarCommand extends MutatingCommand {
   @Nullable
   @Parameter(
       names = "--drive_folder_id",
-      description = "Id of this registrar's folder in Drive",
+      description = "Id (not full URL) of this registrar's folder in Drive",
       converter = OptionalStringParameter.class,
       validateWith = OptionalStringParameter.class)
   Optional<String> driveFolderId;

core/src/main/resources/google/registry/ui/soy/registrar/RegistrarCreateConsole.soy

@@ -240,12 +240,12 @@
         {param required: true /}
       {/call}
       {call registry.soy.forms.inputFieldRowWithValue}
-        {param label: 'DRIVE ID' /}
+        {param label: 'Drive ID' /}
         {param name: 'driveId' /}
         {param value: $driveId /}
         {param placeholder: 'required' /}
         {param description kind="text"}
-          Id of this registrar's folder in Drive.
+          ID (not full URL) of this registrar's folder in Google Drive.
         {/param}
         {param required: true /}
       {/call}

core/src/test/java/google/registry/model/registrar/RegistrarTest.java

@@ -452,6 +452,14 @@ public class RegistrarTest extends EntityTestCase {
         () -> registrar.asBuilder().setAllowedTldsUncached(ImmutableSet.of("bad")));
   }
 
+  @Test
+  public void testFailure_driveFolderId_asFullUrl() {
+    IllegalArgumentException thrown =
+        assertThrows(IllegalArgumentException.class, () -> registrar.asBuilder().setDriveFolderId(
+            "https://drive.google.com/drive/folders/1j3v7RZkU25DjbTx2-Q93H04zKOBau89M"));
+    assertThat(thrown).hasMessageThat().isEqualTo("Drive folder ID must not be a full URL");
+  }
+
   @Test
   public void testFailure_nullEmail() {
     NullPointerException thrown =