Add option "url_safe" to "to_base64" function

README.md

@@ -905,8 +905,12 @@ to_json("<sourceField>"[, pretty: "<boolean>"][, error_string: "<errorValue>"])
 
 Replaces the value with its Base64 encoding.
 
+Options:
+
+-`url_safe`: Whether to encode a URL. (Default: `false`)
+
 ```perl
-to_base64("<sourceField>")
+to_base64("<sourceField>"[, url_safe: "<boolean>"])
 ```
 
 [Example in Playground](https://metafacture.org/playground/?example=to_base64)

metafix/src/main/java/org/metafacture/metafix/FixMethod.java

@@ -680,7 +680,13 @@ public void apply(final Metafix metafix, final Record record, final List<String>
     to_base64 {
         @Override
         public void apply(final Metafix metafix, final Record record, final List<String> params, final Map<String, String> options) {
-            record.transform(params.get(0), s -> Base64.getEncoder().encodeToString(s.getBytes()));
+            final boolean urlSafe = getBoolean(options, "url_safe");
+            if (!urlSafe) {
+                record.transform(params.get(0), s -> Base64.getEncoder().encodeToString(s.getBytes()));
+            }
+            else {
+                record.transform(params.get(0), s -> Base64.getUrlEncoder().encodeToString(s.getBytes()));
+            }
         }
     },
     to_json {

metafix/src/test/java/org/metafacture/metafix/MetafixMethodTest.java

@@ -4084,6 +4084,28 @@ public void shouldTransformStringToBase64() {
         );
     }
 
+    @Test
+    public void shouldTransformUrlToBase64() {
+        MetafixTestHelpers.assertFix(streamReceiver, Arrays.asList(
+                "to_base64('data.title', url_safe:'true')"
+            ),
+            i -> {
+                i.startRecord("1");
+                i.startEntity("data");
+                i.literal("title", "https://www.youtube.com/watch?v=daLgsPSvD9A");
+                i.endEntity();
+                i.endRecord();
+            },
+            o -> {
+                o.get().startRecord("1");
+                o.get().startEntity("data");
+                o.get().literal("title", "aHR0cHM6Ly93d3cueW91dHViZS5jb20vd2F0Y2g_dj1kYUxnc1BTdkQ5QQ==");
+                o.get().endEntity();
+                o.get().endRecord();
+            }
+        );
+    }
+
     @Test // checkstyle-disable-line JavaNCSS
     public void shouldCreateVariableFromLiteralValue() {
         MetafixTestHelpers.assertFix(streamReceiver, Arrays.asList(