From 5fc5eeae55f1c45bfc5e73528aa7526597933108 Mon Sep 17 00:00:00 2001
From: Abubakar Awan <abkawan6@gmail.com>
Date: Mon, 6 Jul 2026 20:24:46 +0500
Subject: [PATCH] add support for custom keyTo property in belongsTo relation
 generator and controller template

Signed-off-by: Abubakar Awan <abkawan6@gmail.com>
---
 .../relation/belongs-to-relation.generator.js | 21 ++++++++++++++++---
 ...roller-relation-template-belongs-to.ts.ejs |  2 +-
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/packages/cli/generators/relation/belongs-to-relation.generator.js b/packages/cli/generators/relation/belongs-to-relation.generator.js
index f5a1d46e180d..f26c7c3e8232 100644
--- a/packages/cli/generators/relation/belongs-to-relation.generator.js
+++ b/packages/cli/generators/relation/belongs-to-relation.generator.js
@@ -49,6 +49,7 @@ module.exports = class BelongsToRelationGenerator extends (
     );
 
     this.artifactInfo.relationPropertyName = options.relationName;
+    this.artifactInfo.keyTo = options.keyTo;
     this.artifactInfo.targetModelPrimaryKey =
       options.destinationModelPrimaryKey;
     this.artifactInfo.targetModelPrimaryKeyType =
@@ -85,7 +86,11 @@ module.exports = class BelongsToRelationGenerator extends (
     const relationName = options.relationName;
     const defaultRelationName = options.defaultRelationName;
     const foreignKeyName = options.foreignKeyName;
-    const fktype = options.destinationModelPrimaryKeyType;
+    const keyTo = options.keyTo;
+    const fktype = keyTo
+      ? relationUtils.getModelPropertyType(modelDir, targetModel, keyTo) ||
+        options.destinationModelPrimaryKeyType
+      : options.destinationModelPrimaryKeyType;
 
     const project = new relationUtils.AstLoopBackProject();
     const sourceFile = relationUtils.addFileToProject(
@@ -103,6 +108,7 @@ module.exports = class BelongsToRelationGenerator extends (
       defaultRelationName,
       foreignKeyName,
       fktype,
+      keyTo,
     );
 
     relationUtils.addProperty(sourceClass, modelProperty);
@@ -123,12 +129,19 @@ module.exports = class BelongsToRelationGenerator extends (
     defaultRelationName,
     foreignKeyName,
     fktype,
+    keyTo,
   ) {
+    const keyToOption = keyTo ? `, keyTo: '${keyTo}'` : '';
+
     // checks if relation name is customized
     let relationDecorator = [
       {
         name: 'belongsTo',
-        arguments: [`() =>  ${className}`],
+        arguments: [
+          keyTo
+            ? `() =>  ${className}, {keyTo: '${keyTo}'}`
+            : `() =>  ${className}`,
+        ],
       },
     ];
     // already checked if the relation name is the same as the source key before
@@ -136,7 +149,9 @@ module.exports = class BelongsToRelationGenerator extends (
       relationDecorator = [
         {
           name: 'belongsTo',
-          arguments: [`() =>  ${className}, {name: '${relationName}'}`],
+          arguments: [
+            `() =>  ${className}, {name: '${relationName}'${keyToOption}}`,
+          ],
         },
       ];
     }
diff --git a/packages/cli/generators/relation/templates/controller-relation-template-belongs-to.ts.ejs b/packages/cli/generators/relation/templates/controller-relation-template-belongs-to.ts.ejs
index 1451cb6cfb7b..e70f3ec0cb78 100644
--- a/packages/cli/generators/relation/templates/controller-relation-template-belongs-to.ts.ejs
+++ b/packages/cli/generators/relation/templates/controller-relation-template-belongs-to.ts.ejs
@@ -21,7 +21,7 @@ export class <%= controllerClassName %> {
   @get('/<%= sourceModelPath %>/{id}/<%= targetModelName %>', {
     responses: {
       '200': {
-        description: '<%= targetModelClassName %> belonging to <%= sourceModelClassName %>',
+        description: '<%= targetModelClassName %> belonging to <%= sourceModelClassName %><%= keyTo ? " (resolved via " + targetModelClassName + "." + keyTo + ")" : "" %>',
         content: {
           'application/json': {
             schema: getModelSchemaRef(<%= targetModelClassName %>),