#1727 added new functions to the functions library:

* fn:trim()
* fn:url-encode()
* fn:url-decode()
* fn:base64-encode()
* fn:base64-decode()

Signed-off-by: Thomas Jäckle <thomas.jaeckle@beyonnex.io>

placeholders/src/main/java/org/eclipse/ditto/placeholders/ImmutableFunctionExpression.java

@@ -37,6 +37,11 @@ final class ImmutableFunctionExpression implements FunctionExpression {
             new PipelineFunctionSubstringAfter(),  // fn:substring-after(':')
             new PipelineFunctionLower(),           // fn:lower()
             new PipelineFunctionUpper(),           // fn:upper()
+            new PipelineFunctionTrim(),            // fn:trim()
+            new PipelineFunctionUrlEncode(),       // fn:url-encode()
+            new PipelineFunctionUrlDecode(),       // fn:url-decode()
+            new PipelineFunctionBase64Encode(),    // fn:base64-encode()
+            new PipelineFunctionBase64Decode(),    // fn:base64-decode()
             new PipelineFunctionDelete(),          // fn:delete()
             new PipelineFunctionReplace(),         // fn:replace('from', 'to')
             new PipelineFunctionSplit()            // fn:split(' ')

placeholders/src/main/java/org/eclipse/ditto/placeholders/PipelineFunctionBase64Decode.java

@@ -0,0 +1,76 @@
+/*
+ * Copyright (c) 2023 Contributors to the Eclipse Foundation
+ *
+ * See the NOTICE file(s) distributed with this work for additional
+ * information regarding copyright ownership.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
+package org.eclipse.ditto.placeholders;
+
+import java.util.Base64;
+import java.util.Collections;
+import java.util.List;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * Provides the {@code fn:base64-decode()} function implementation.
+ */
+@Immutable
+final class PipelineFunctionBase64Decode implements PipelineFunction {
+
+    private static final String FUNCTION_NAME = "base64-decode";
+
+    @Override
+    public String getName() {
+        return FUNCTION_NAME;
+    }
+
+    @Override
+    public Base64DecodeSignature getSignature() {
+        return Base64DecodeSignature.INSTANCE;
+    }
+
+    @Override
+    public PipelineElement apply(final PipelineElement value, final String paramsIncludingParentheses,
+            final ExpressionResolver expressionResolver) {
+
+        // check if signature matches (empty params!)
+        validateOrThrow(paramsIncludingParentheses);
+        return value.map(v -> new String(Base64.getDecoder().decode(v)));
+    }
+
+    private void validateOrThrow(final String paramsIncludingParentheses) {
+        if (!PipelineFunctionParameterResolverFactory.forEmptyParameters().test(paramsIncludingParentheses)) {
+            throw PlaceholderFunctionSignatureInvalidException.newBuilder(paramsIncludingParentheses, this)
+                    .build();
+        }
+    }
+
+    /**
+     * Describes the signature of the {@code base64-decode()} function.
+     */
+    private static final class Base64DecodeSignature implements Signature {
+
+        private static final Base64DecodeSignature INSTANCE = new Base64DecodeSignature();
+
+        private Base64DecodeSignature() {
+        }
+
+        @Override
+        public List<ParameterDefinition<?>> getParameterDefinitions() {
+            return Collections.emptyList();
+        }
+
+        @Override
+        public String toString() {
+            return renderSignature();
+        }
+    }
+
+}

placeholders/src/main/java/org/eclipse/ditto/placeholders/PipelineFunctionBase64Encode.java

@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2023 Contributors to the Eclipse Foundation
+ *
+ * See the NOTICE file(s) distributed with this work for additional
+ * information regarding copyright ownership.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
+package org.eclipse.ditto.placeholders;
+
+import java.nio.charset.StandardCharsets;
+import java.util.Base64;
+import java.util.Collections;
+import java.util.List;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * Provides the {@code fn:base64-encode()} function implementation.
+ */
+@Immutable
+final class PipelineFunctionBase64Encode implements PipelineFunction {
+
+    private static final String FUNCTION_NAME = "base64-encode";
+
+    @Override
+    public String getName() {
+        return FUNCTION_NAME;
+    }
+
+    @Override
+    public Base64EncodeSignature getSignature() {
+        return Base64EncodeSignature.INSTANCE;
+    }
+
+    @Override
+    public PipelineElement apply(final PipelineElement value, final String paramsIncludingParentheses,
+            final ExpressionResolver expressionResolver) {
+
+        // check if signature matches (empty params!)
+        validateOrThrow(paramsIncludingParentheses);
+        return value.map(v -> Base64.getEncoder().encodeToString(v.getBytes(StandardCharsets.UTF_8)));
+    }
+
+    private void validateOrThrow(final String paramsIncludingParentheses) {
+        if (!PipelineFunctionParameterResolverFactory.forEmptyParameters().test(paramsIncludingParentheses)) {
+            throw PlaceholderFunctionSignatureInvalidException.newBuilder(paramsIncludingParentheses, this)
+                    .build();
+        }
+    }
+
+    /**
+     * Describes the signature of the {@code base64-encode()} function.
+     */
+    private static final class Base64EncodeSignature implements Signature {
+
+        private static final Base64EncodeSignature INSTANCE = new Base64EncodeSignature();
+
+        private Base64EncodeSignature() {
+        }
+
+        @Override
+        public List<ParameterDefinition<?>> getParameterDefinitions() {
+            return Collections.emptyList();
+        }
+
+        @Override
+        public String toString() {
+            return renderSignature();
+        }
+    }
+
+}

placeholders/src/main/java/org/eclipse/ditto/placeholders/PipelineFunctionTrim.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright (c) 2023 Contributors to the Eclipse Foundation
+ *
+ * See the NOTICE file(s) distributed with this work for additional
+ * information regarding copyright ownership.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
+package org.eclipse.ditto.placeholders;
+
+import java.util.Collections;
+import java.util.List;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * Provides the {@code fn:trim()} function implementation.
+ */
+@Immutable
+final class PipelineFunctionTrim implements PipelineFunction {
+
+    private static final String FUNCTION_NAME = "trim";
+
+    @Override
+    public String getName() {
+        return FUNCTION_NAME;
+    }
+
+    @Override
+    public TrimFunctionSignature getSignature() {
+        return TrimFunctionSignature.INSTANCE;
+    }
+
+    @Override
+    public PipelineElement apply(final PipelineElement value, final String paramsIncludingParentheses,
+            final ExpressionResolver expressionResolver) {
+
+        // check if signature matches (empty params!)
+        validateOrThrow(paramsIncludingParentheses);
+        return value.map(String::trim);
+    }
+
+    private void validateOrThrow(final String paramsIncludingParentheses) {
+        if (!PipelineFunctionParameterResolverFactory.forEmptyParameters().test(paramsIncludingParentheses)) {
+            throw PlaceholderFunctionSignatureInvalidException.newBuilder(paramsIncludingParentheses, this)
+                    .build();
+        }
+    }
+
+    /**
+     * Describes the signature of the {@code trim()} function.
+     */
+    private static final class TrimFunctionSignature implements Signature {
+
+        private static final TrimFunctionSignature INSTANCE = new TrimFunctionSignature();
+
+        private TrimFunctionSignature() {
+        }
+
+        @Override
+        public List<ParameterDefinition<?>> getParameterDefinitions() {
+            return Collections.emptyList();
+        }
+
+        @Override
+        public String toString() {
+            return renderSignature();
+        }
+    }
+
+}

placeholders/src/main/java/org/eclipse/ditto/placeholders/PipelineFunctionUrlDecode.java

@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2023 Contributors to the Eclipse Foundation
+ *
+ * See the NOTICE file(s) distributed with this work for additional
+ * information regarding copyright ownership.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
+package org.eclipse.ditto.placeholders;
+
+import java.io.UnsupportedEncodingException;
+import java.net.URLDecoder;
+import java.nio.charset.StandardCharsets;
+import java.util.Collections;
+import java.util.List;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * Provides the {@code fn:url-decode()} function implementation.
+ */
+@Immutable
+final class PipelineFunctionUrlDecode implements PipelineFunction {
+
+    private static final String FUNCTION_NAME = "url-decode";
+
+    @Override
+    public String getName() {
+        return FUNCTION_NAME;
+    }
+
+    @Override
+    public UrlDecodeSignature getSignature() {
+        return UrlDecodeSignature.INSTANCE;
+    }
+
+    @Override
+    public PipelineElement apply(final PipelineElement value, final String paramsIncludingParentheses,
+            final ExpressionResolver expressionResolver) {
+
+        // check if signature matches (empty params!)
+        validateOrThrow(paramsIncludingParentheses);
+        return value.map(v -> {
+            try {
+                return URLDecoder.decode(v, StandardCharsets.UTF_8.name());
+            } catch (final UnsupportedEncodingException e) {
+                return URLDecoder.decode(v);
+            }
+        });
+    }
+
+    private void validateOrThrow(final String paramsIncludingParentheses) {
+        if (!PipelineFunctionParameterResolverFactory.forEmptyParameters().test(paramsIncludingParentheses)) {
+            throw PlaceholderFunctionSignatureInvalidException.newBuilder(paramsIncludingParentheses, this)
+                    .build();
+        }
+    }
+
+    /**
+     * Describes the signature of the {@code url-decode()} function.
+     */
+    private static final class UrlDecodeSignature implements Signature {
+
+        private static final UrlDecodeSignature INSTANCE = new UrlDecodeSignature();
+
+        private UrlDecodeSignature() {
+        }
+
+        @Override
+        public List<ParameterDefinition<?>> getParameterDefinitions() {
+            return Collections.emptyList();
+        }
+
+        @Override
+        public String toString() {
+            return renderSignature();
+        }
+    }
+
+}