Add support for web assembly and lambda functions in transformations

Author: nitzanj

cloudinary-core/src/main/java/com/cloudinary/BaseParam.java

@@ -0,0 +1,22 @@
+package com.cloudinary;
+
+import com.cloudinary.utils.StringUtils;
+
+import java.util.List;
+
+public class BaseParam {
+    private String param;
+
+    protected BaseParam(List<String> components) {
+        this.param = StringUtils.join(components, ":");
+    }
+
+    protected BaseParam(String... components) {
+        this.param = StringUtils.join(components, ":");
+    }
+
+    @Override
+    public String toString() {
+        return param;
+    }
+}

cloudinary-core/src/main/java/com/cloudinary/CustomAction.java

@@ -0,0 +1,31 @@
+package com.cloudinary;
+
+import com.cloudinary.utils.Base64Coder;
+
+/**
+ * Helper class to generate a custom action params to be used in {@link Transformation#customAction(CustomAction)}.
+ */
+public class CustomAction extends BaseParam{
+
+    private CustomAction(String... components) {
+        super(components);
+    }
+
+    /**
+     * Generate a web-assembly custom action param to send to {@link Transformation#customAction(CustomAction)}
+     * @param publicId The public id of the web-assembly file
+     * @return A new instance of custom action param
+     */
+    public static CustomAction wasm(String publicId){
+        return new CustomAction("wasm", publicId);
+    }
+
+    /**
+     * Generate a remote lambda custom action param to send to {@link Transformation#customAction(CustomAction)}
+     * @param url   The public url of the aws lambda function
+     * @return A new instance of custom action param
+     */
+    public static CustomAction remote(String url){
+        return new CustomAction("remote", Base64Coder.encodeURLSafeString(url));
+    }
+}

cloudinary-core/src/main/java/com/cloudinary/Transformation.java

@@ -634,6 +634,7 @@ public String generate(Map options) {
                 "dl", "delay",
                 "dn", "density",
                 "f", "fetch_format",
+                "fn", "custom_action",
                 "fps", "fps",
                 "g", "gravity",
                 "l", "overlay",
@@ -841,4 +842,12 @@ public T variables(Expression...variables) {
         return param("variables", variables);
     }
 
+    /**
+     * Set a custom action, such as a call to a lambda function or a web-assembly function.
+     * @param action The custom action to perform, see {@link CustomAction}.
+     * @return The transformation for chaining
+     */
+    public T customAction(CustomAction action) {
+        return param("custom_action", action.toString());
+    }
 }

cloudinary-core/src/main/java/com/cloudinary/utils/Base64Coder.java

@@ -280,6 +280,10 @@ public static byte[] decode(char[] in, int iOff, int iLen) {
     private Base64Coder() {
     }
 
+    public static String encodeURLSafeString(String s) {
+        return encodeURLSafeString(s.getBytes());
+    }
+
     public static String encodeURLSafeString(byte[] digest) {
         char[] encode = encode(digest);
         for (int i = 0; i < encode.length; i++) {

cloudinary-core/src/test/java/com/cloudinary/test/CloudinaryTest.java

@@ -25,6 +25,8 @@
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
+import static com.cloudinary.CustomAction.remote;
+import static com.cloudinary.CustomAction.wasm;
 import static com.cloudinary.utils.ObjectUtils.asMap;
 import static com.cloudinary.utils.ObjectUtils.emptyMap;
 import static org.junit.Assert.*;
@@ -1101,6 +1103,13 @@ public void testKeyframeInterval(){
         assertEquals("", new Transformation().keyframeInterval(null).generate());
     }
 
+    @Test
+    public void testCustomAction(){
+        assertEquals("fn_wasm:blur_wasm", new Transformation().customAction(wasm("blur_wasm")).generate());
+        assertEquals("fn_remote:aHR0cHM6Ly9kZjM0cmE0YS5leGVjdXRlLWFwaS51cy13ZXN0LTIuYW1hem9uYXdzLmNvbS9kZWZhdWx0L2Nsb3VkaW5hcnlBY3Rpb24=",
+                new Transformation().customAction(remote("https://df34ra4a.execute-api.us-west-2.amazonaws.com/default/cloudinaryAction")).generate());
+    }
+
     public static Map<String, String> getUrlParameters(URI uri) throws UnsupportedEncodingException {
         Map<String, String> params = new HashMap<String, String>();
         for (String param : uri.getRawQuery().split("&")) {