enhancement: asset field support

.gitignore

@@ -274,3 +274,4 @@ src/main/resources/
 /.vscode/
 /docs/
 INTEGRATION-TESTS-GUIDE.md
+src/main/java/com/demo/*

CHANGELOG.md

@@ -1,5 +1,10 @@
 # CHANGELOG
 
+## v2.5.0
+
+### Feb 12, 2026
+- Enhancement: assetFields method added
+
 ## v2.4.0
 
 ### Feb 02, 2026

pom.xml

@@ -5,7 +5,7 @@
     <modelVersion>4.0.0</modelVersion>
     <groupId>com.contentstack.sdk</groupId>
     <artifactId>java</artifactId>
-    <version>2.4.0</version>
+    <version>2.5.0</version>
     <packaging>jar</packaging>
     <name>contentstack-java</name>
     <description>Java SDK for Contentstack Content Delivery API</description>

src/main/java/com/contentstack/sdk/Asset.java

@@ -1,6 +1,7 @@
 package com.contentstack.sdk;
 
 import org.jetbrains.annotations.NotNull;
+import org.json.JSONArray;
 import org.json.JSONObject;
 import retrofit2.Retrofit;
 import lombok.Getter;
@@ -544,6 +545,19 @@ public Asset includeMetadata() {
         return this;
     }
 
+    public Asset assetFields(String... fields) {
+        if (fields != null && fields.length > 0) {
+            JSONArray array = new JSONArray();
+            for (String field : fields) {
+                array.put(field);
+            }
+            if (!array.isEmpty()) {
+                urlQueries.put("asset_fields[]", array);
+            }
+        }
+        return this;
+    }
+
     /**
      * Fetch.
      *

src/main/java/com/contentstack/sdk/AssetLibrary.java

@@ -2,6 +2,7 @@
 
 import org.jetbrains.annotations.NotNull;
 import org.json.JSONObject;
+import org.json.JSONArray;
 
 import java.util.*;
 import java.util.logging.Logger;
@@ -33,7 +34,8 @@ protected void setStackInstance(@NotNull Stack stack) {
 
     //Sanitization of keys
     private boolean isValidKey(String key) {
-        return key.matches("^[a-zA-Z0-9_.]+$");
+        // Fixed regex: allow alphanumeric, underscore, dot, and square brackets at the end, escaped properly
+        return key.matches("^[a-zA-Z0-9_.]+(\\[\\])?$");
     }
 
     //Sanitization of values
@@ -265,6 +267,19 @@ public AssetLibrary limit (@NotNull int number) {
         return this;
     }
 
+    public AssetLibrary assetFields(String... fields) {
+        if (fields != null && fields.length > 0) {
+            JSONArray array = new JSONArray();
+            for (String field : fields) {
+                array.put(field);
+            }
+            if (!array.isEmpty()) {
+                urlQueries.put("asset_fields[]", array);
+            }
+        }
+        return this;
+    }
+
     /**
      * Fetch all.
      *

src/main/java/com/contentstack/sdk/CSHttpConnection.java

@@ -102,7 +102,9 @@ public String setFormParamsGET(HashMap<String, Object> params) {
         if (params != null && params.size() > 0) {
             String urlParams = null;
             urlParams = info.equalsIgnoreCase(Constants.REQUEST_CONTROLLER.QUERY.name())
-                    || info.equalsIgnoreCase(Constants.REQUEST_CONTROLLER.ENTRY.name()) ? getParams(params) : null;
+                    || info.equalsIgnoreCase(Constants.REQUEST_CONTROLLER.ENTRY.name())
+                    || info.equalsIgnoreCase(Constants.REQUEST_CONTROLLER.ASSET.name())
+                    || info.equalsIgnoreCase(Constants.REQUEST_CONTROLLER.ASSETLIBRARY.name()) ? getParams(params) : null;
             if (urlParams == null) {
                 for (Map.Entry<String, Object> e : params.entrySet()) {
                     if (urlParams == null) {
@@ -124,7 +126,7 @@ private String getParams(HashMap<String, Object> params) {
             Object value = e.getValue();
             try {
                 if (key.equalsIgnoreCase("include[]") || key.equalsIgnoreCase("only[BASE][]")
-                        || key.equalsIgnoreCase("except[BASE][]")) {
+                        || key.equalsIgnoreCase("except[BASE][]") || key.equalsIgnoreCase("asset_fields[]")) {
                     urlParams = convertUrlParam(urlParams, value, key);
                 } else if (key.equalsIgnoreCase("only")) {
                     JSONObject onlyJSON = (JSONObject) value;

src/main/java/com/contentstack/sdk/Entry.java

@@ -904,6 +904,19 @@ public Entry exceptWithReferenceUid(@NotNull List<String> fieldUid, @NotNull Str
         return this;
     }
 
+
+    public Entry assetFields(String... fields) {
+        if (fields != null && fields.length > 0) {
+            JSONArray array = new JSONArray();
+            for (String field : fields) {
+                array.put(field);
+            }
+            if (!array.isEmpty()) {
+                params.put("asset_fields[]", array);
+            }
+        }
+        return this;
+    }
     /**
      * Fetches the latest version of the entries from Contentstack.com content stack
      *

src/main/java/com/contentstack/sdk/Query.java

@@ -1146,6 +1146,19 @@ public Query search(@NotNull String value) {
         return this;
     }
 
+    public Query assetFields(String... fields) {
+        if (fields != null && fields.length > 0) {
+            JSONArray array = new JSONArray();
+            for (String field : fields) {
+                array.put(field);
+            }
+            if (!array.isEmpty()) {
+                urlQueries.put("asset_fields[]", array);
+            }
+        }
+        return this;
+    }
+
     /**
      * Execute a Query and Caches its result (Optional)
      *

src/test/java/com/contentstack/sdk/TestAsset.java

@@ -182,6 +182,133 @@ void testIncludeMetadata() {
         assertEquals(true, asset.urlQueries.get("include_metadata"));
     }
 
+    // ========== ASSET FIELDS TESTS (CDA asset_fields[] parameter) ==========
+
+    @Test
+    void testAssetFieldsWithSupportedValues() {
+        Asset result = asset.assetFields("user_defined_fields", "embedded", "ai_suggested", "visual_markups");
+        assertSame(asset, result);
+        assertTrue(asset.urlQueries.has("asset_fields[]"));
+        Object val = asset.urlQueries.get("asset_fields[]");
+        assertTrue(val instanceof JSONArray);
+        JSONArray arr = (JSONArray) val;
+        assertEquals(4, arr.length());
+        assertEquals("user_defined_fields", arr.get(0));
+        assertEquals("embedded", arr.get(1));
+        assertEquals("ai_suggested", arr.get(2));
+        assertEquals("visual_markups", arr.get(3));
+    }
+
+    @Test
+    void testAssetFieldsReturnsThis() {
+        Asset result = asset.assetFields("user_defined_fields");
+        assertSame(asset, result);
+    }
+
+    @Test
+    void testAssetFieldsWithNoArgsDoesNotSetParam() {
+        asset.assetFields();
+        assertFalse(asset.urlQueries.has("asset_fields[]"));
+    }
+
+    @Test
+    void testAssetFieldsWithNullDoesNotSetParam() {
+        asset.assetFields((String[]) null);
+        assertFalse(asset.urlQueries.has("asset_fields[]"));
+    }
+
+    @Test
+    void testAssetFieldsChainingWithOtherMethods() {
+        Asset result = asset.assetFields("embedded", "visual_markups")
+            .includeMetadata()
+            .includeDimension();
+        assertSame(asset, result);
+        assertTrue(asset.urlQueries.has("asset_fields[]"));
+        assertTrue(asset.urlQueries.has("include_metadata"));
+        assertTrue(asset.urlQueries.has("include_dimension"));
+        JSONArray arr = asset.urlQueries.getJSONArray("asset_fields[]");
+        assertEquals(2, arr.length());
+        assertEquals("embedded", arr.get(0));
+        assertEquals("visual_markups", arr.get(1));
+    }
+
+    /**
+     * Usage: stack.asset(assetUid).assetFields(...).fetch()
+     * Verifies the full chain sets asset_fields[] on the asset before fetch.
+     */
+    @Test
+    void testUsageSingleAssetFetchWithAssetFields() throws IllegalAccessException {
+        Stack stack = Contentstack.stack("api_key", "delivery_token", "env");
+        Asset asset = stack.asset("asset_uid_123")
+            .assetFields("embedded", "visual_markups");
+        assertTrue(asset.urlQueries.has("asset_fields[]"));
+        JSONArray arr = asset.urlQueries.getJSONArray("asset_fields[]");
+        assertEquals(2, arr.length());
+        assertEquals("embedded", arr.get(0));
+        assertEquals("visual_markups", arr.get(1));
+    }
+
+
+    @Test
+    void testAssetFieldsSingleField() {
+        asset.assetFields("embedded");
+        assertTrue(asset.urlQueries.has("asset_fields[]"));
+        JSONArray arr = asset.urlQueries.getJSONArray("asset_fields[]");
+        assertEquals(1, arr.length());
+        assertEquals("embedded", arr.get(0));
+    }
+
+    @Test
+    void testAssetFieldsEmptyVarargsArrayDoesNotSetParam() {
+        asset.assetFields(new String[0]);
+        assertFalse(asset.urlQueries.has("asset_fields[]"));
+    }
+
+    @Test
+    void testAssetFieldsDuplicateValuesAllowed() {
+        asset.assetFields("embedded", "embedded");
+        JSONArray arr = asset.urlQueries.getJSONArray("asset_fields[]");
+        assertEquals(2, arr.length());
+        assertEquals("embedded", arr.get(0));
+        assertEquals("embedded", arr.get(1));
+    }
+
+    @Test
+    void testAssetFieldsSecondCallOverwrites() {
+        asset.assetFields("user_defined_fields", "embedded");
+        asset.assetFields("ai_suggested");
+        JSONArray arr = asset.urlQueries.getJSONArray("asset_fields[]");
+        assertEquals(1, arr.length());
+        assertEquals("ai_suggested", arr.get(0));
+    }
+
+    @Test
+    void testAssetFieldsWithEmptyStringInArray() {
+        asset.assetFields("valid", "", "embedded");
+        JSONArray arr = asset.urlQueries.getJSONArray("asset_fields[]");
+        assertEquals(3, arr.length());
+        assertEquals("valid", arr.get(0));
+        assertEquals("", arr.get(1));
+        assertEquals("embedded", arr.get(2));
+    }
+
+    @Test
+    void testAssetFieldsWithNullInArray() {
+        asset.assetFields("valid", null, "embedded");
+        JSONArray arr = asset.urlQueries.getJSONArray("asset_fields[]");
+        assertEquals(3, arr.length());
+        assertEquals("valid", arr.get(0));
+        assertEquals("embedded", arr.get(2));
+    }
+
+    @Test
+    void testAssetFieldsSingleEmptyStringSetsParam() {
+        asset.assetFields("");
+        assertTrue(asset.urlQueries.has("asset_fields[]"));
+        assertEquals(1, asset.urlQueries.getJSONArray("asset_fields[]").length());
+        assertEquals("", asset.urlQueries.getJSONArray("asset_fields[]").get(0));
+    }
+
     // ========== CHAINING TESTS ==========
 
     @Test