[CALCITE-5825] Add URL_ENCODE and URL_DECODE function (enabled in Spa…

…rk library)

core/src/main/java/org/apache/calcite/adapter/enumerable/RexImpTable.java

@@ -272,6 +272,8 @@
 import static org.apache.calcite.sql.fun.SqlLibraryOperators.UNIX_MICROS;
 import static org.apache.calcite.sql.fun.SqlLibraryOperators.UNIX_MILLIS;
 import static org.apache.calcite.sql.fun.SqlLibraryOperators.UNIX_SECONDS;
+import static org.apache.calcite.sql.fun.SqlLibraryOperators.URL_DECODE;
+import static org.apache.calcite.sql.fun.SqlLibraryOperators.URL_ENCODE;
 import static org.apache.calcite.sql.fun.SqlLibraryOperators.XML_TRANSFORM;
 import static org.apache.calcite.sql.fun.SqlStdOperatorTable.ABS;
 import static org.apache.calcite.sql.fun.SqlStdOperatorTable.ACOS;
@@ -894,6 +896,10 @@ Builder populate2() {
       // Compression Operators
       defineMethod(COMPRESS, BuiltInMethod.COMPRESS.method, NullPolicy.ARG0);
 
+      // Url Operators
+      defineMethod(URL_ENCODE, BuiltInMethod.URL_ENCODE.method, NullPolicy.STRICT);
+      defineMethod(URL_DECODE, BuiltInMethod.URL_DECODE.method, NullPolicy.STRICT);
+
       // Xml Operators
       defineMethod(EXTRACT_VALUE, BuiltInMethod.EXTRACT_VALUE.method, NullPolicy.ARG0);
       defineMethod(XML_TRANSFORM, BuiltInMethod.XML_TRANSFORM.method, NullPolicy.ARG0);

core/src/main/java/org/apache/calcite/runtime/UrlFunctions.java

@@ -0,0 +1,58 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to you under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.calcite.runtime;
+
+import java.io.UnsupportedEncodingException;
+import java.net.URLDecoder;
+import java.net.URLEncoder;
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
+
+import static org.apache.calcite.util.Static.RESOURCE;
+
+/**
+ * A collection of functions used in Url processing.
+ */
+public class UrlFunctions {
+
+  private UrlFunctions() {
+  }
+
+  private static final Charset UTF_8 = StandardCharsets.UTF_8;
+
+  /** The "URL_DECODE(string)" function. */
+  public static String urlDecode(String value) {
+    String url;
+    try {
+      url = URLDecoder.decode(value, UTF_8.name());
+    } catch (UnsupportedEncodingException e) {
+      throw RESOURCE.charsetEncoding(value, UTF_8.name()).ex();
+    }
+    return url;
+  }
+
+  /** The "URL_ENCODE(string)" function. */
+  public static String urlEncode(String url) {
+    String value;
+    try {
+      value = URLEncoder.encode(url, UTF_8.name());
+    } catch (UnsupportedEncodingException e) {
+      throw RESOURCE.charsetEncoding(url, UTF_8.name()).ex();
+    }
+    return value;
+  }
+}

core/src/main/java/org/apache/calcite/sql/fun/SqlLibraryOperators.java

@@ -522,6 +522,22 @@ static RelDataType deriveTypeSplit(SqlOperatorBinding operatorBinding,
           ReturnTypes.VARBINARY_NULLABLE,
           OperandTypes.STRING, SqlFunctionCategory.STRING);
 
+  /** The "URL_DECODE(string)" function. */
+  @LibraryOperator(libraries = {SPARK})
+  public static final SqlFunction URL_DECODE =
+      SqlBasicFunction.create("URL_DECODE",
+          ReturnTypes.VARCHAR_NULLABLE,
+          OperandTypes.STRING,
+          SqlFunctionCategory.STRING);
+
+  /** The "URL_ENCODE(string)" function. */
+  @LibraryOperator(libraries = {SPARK})
+  public static final SqlFunction URL_ENCODE =
+      SqlBasicFunction.create("URL_ENCODE",
+          ReturnTypes.VARCHAR_NULLABLE,
+          OperandTypes.STRING,
+          SqlFunctionCategory.STRING);
+
   @LibraryOperator(libraries = {MYSQL})
   public static final SqlFunction EXTRACT_VALUE =
       SqlBasicFunction.create("EXTRACTVALUE",

core/src/main/java/org/apache/calcite/util/BuiltInMethod.java

@@ -97,6 +97,7 @@
 import org.apache.calcite.runtime.SpatialTypeFunctions;
 import org.apache.calcite.runtime.SqlFunctions;
 import org.apache.calcite.runtime.SqlFunctions.FlatProductInputType;
+import org.apache.calcite.runtime.UrlFunctions;
 import org.apache.calcite.runtime.Utilities;
 import org.apache.calcite.runtime.XmlFunctions;
 import org.apache.calcite.schema.FilterableTable;
@@ -385,6 +386,8 @@ public enum BuiltInMethod {
   SHA512(SqlFunctions.class, "sha512", String.class),
   THROW_UNLESS(SqlFunctions.class, "throwUnless", boolean.class, String.class),
   COMPRESS(CompressionFunctions.class, "compress", String.class),
+  URL_DECODE(UrlFunctions.class, "urlDecode", String.class),
+  URL_ENCODE(UrlFunctions.class, "urlEncode", String.class),
   EXTRACT_VALUE(XmlFunctions.class, "extractValue", String.class, String.class),
   XML_TRANSFORM(XmlFunctions.class, "xmlTransform", String.class, String.class),
   EXTRACT_XML(XmlFunctions.class, "extractXml", String.class, String.class, String.class),

site/_docs/reference.md

@@ -2854,6 +2854,8 @@ BigQuery's type system uses confusingly different names for types and functions:
 | b | UNIX_MILLIS(timestamp)                         | Returns the number of milliseconds since 1970-01-01 00:00:00
 | b | UNIX_SECONDS(timestamp)                        | Returns the number of seconds since 1970-01-01 00:00:00
 | b | UNIX_DATE(date)                                | Returns the number of days since 1970-01-01
+| s | URL_DECODE(string)                             | Decodes a *string* in 'application/x-www-form-urlencoded' format using a specific encoding scheme
+| s | URL_ENCODE(string)                             | Translates a *string* into 'application/x-www-form-urlencoded' format using a specific encoding scheme
 | o | XMLTRANSFORM(xml, xslt)                        | Applies XSLT transform *xslt* to XML string *xml* and returns the result
 
 Note:

testkit/src/main/java/org/apache/calcite/test/SqlOperatorTest.java

@@ -5491,6 +5491,48 @@ private static void checkIf(SqlOperatorFixture f) {
         "07000000789c4bad48cc2dc84905000bc002ed", "VARBINARY NOT NULL");
   }
 
+  @Test void testUrlDecode() {
+    final SqlOperatorFixture f0 = fixture().setFor(SqlLibraryOperators.URL_DECODE);
+    f0.checkFails("^URL_DECODE('https://calcite.apache.org')^",
+        "No match found for function signature URL_DECODE\\(<CHARACTER>\\)",
+        false);
+    final SqlOperatorFixture f = f0.withLibrary(SqlLibrary.SPARK);
+    f.checkString("URL_DECODE('https%3A%2F%2Fcalcite.apache.org')",
+        "https://calcite.apache.org",
+        "VARCHAR NOT NULL");
+    f.checkString("URL_DECODE('http%3A%2F%2Ftest%3Fa%3Db%26c%3Dd')",
+        "http://test?a=b&c=d",
+        "VARCHAR NOT NULL");
+    f.checkString("URL_DECODE('http%3A%2F%2F%E4%BD%A0%E5%A5%BD')",
+        "http://\u4F60\u597D",
+        "VARCHAR NOT NULL");
+    f.checkString("URL_DECODE('test')",
+        "test",
+        "VARCHAR NOT NULL");
+    f.checkNull("URL_DECODE(cast(null as varchar))");
+  }
+
+  @Test void testUrlEncode() {
+    final SqlOperatorFixture f0 = fixture().setFor(SqlLibraryOperators.URL_ENCODE);
+    f0.checkFails("^URL_ENCODE('https://calcite.apache.org')^",
+        "No match found for function signature URL_ENCODE\\(<CHARACTER>\\)",
+        false);
+    final SqlOperatorFixture f = f0.withLibrary(SqlLibrary.SPARK);
+    f.checkString("URL_ENCODE('https://calcite.apache.org')",
+        "https%3A%2F%2Fcalcite.apache.org",
+        "VARCHAR NOT NULL");
+    f.checkString("URL_ENCODE('http://test?a=b&c=d')",
+        "http%3A%2F%2Ftest%3Fa%3Db%26c%3Dd",
+        "VARCHAR NOT NULL");
+    f.checkString("URL_ENCODE(_UTF8'http://\u4F60\u597D')",
+        "http%3A%2F%2F%E4%BD%A0%E5%A5%BD",
+        "VARCHAR NOT NULL");
+    f.checkString("URL_ENCODE('test')",
+        "test",
+        "VARCHAR NOT NULL");
+    f.checkNull("URL_ENCODE(cast(null as varchar))");
+  }
+
   @Test void testExtractValue() {
     SqlOperatorFixture f = fixture().withLibrary(SqlLibrary.MYSQL);
     f.checkNull("ExtractValue(NULL, '//b')");