Add PARSE_URL function #90

plugins/src/main/doc/functions.adoc

@@ -152,6 +152,7 @@ Expression support most of the standard scalar and aggregate functions.
 * https://github.com/nadment/hop-expression/blob/master/plugins/src/main/doc/nullifzero.adoc[NULLIFZERO]
 * https://github.com/nadment/hop-expression/blob/master/plugins/src/main/doc/numberformat.adoc[NUMBERFORMAT]
 * https://github.com/nadment/hop-expression/blob/master/plugins/src/main/doc/nvl2.adoc[NVL2]
+* https://github.com/nadment/hop-expression/blob/master/plugins/src/main/doc/parse_url.adoc[PARSE_URL]
 * https://github.com/nadment/hop-expression/blob/master/plugins/src/main/doc/pi.adoc[PI]
 * https://github.com/nadment/hop-expression/blob/master/plugins/src/main/doc/power.adoc[POWER]
 * https://github.com/nadment/hop-expression/blob/master/plugins/src/main/doc/previous_day.adoc[PREVIOUS_DAY]

plugins/src/main/doc/parse_url.adoc

@@ -0,0 +1,44 @@
+////
+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.
+////
+= PARSE_URL
+
+Returns the specified part of the URL or the value for the specified QUERY key.
+
+== Syntax
+----
+PARSE_URL(url, part [, key]) 
+----
+
+Return:: String
+
+== Usage
+
+* `part` must be one of HOST, PORT, PATH, QUERY, REF, PROTOCOL, FRAGMENT, AUTHORITY, FILE, USERINFO.
+* Use `key` specifies which query to extract (case-sensitive).
+* If a requested part or key is not found, NULL is returned.
+* Returns NULL if one of the arguments is NULL.
+
+== Example
+
+----
+PARSE_URL('http://hop.apache.org:80/path?id=1','HOST') → hop.apache.org
+PARSE_URL('http://hop.apache.org:80/path?id=1','PATH') → /path
+PARSE_URL('http://hop.apache.org:80/path?id=1&lang=fr','FILE') → /path?id=1&lang=fr
+PARSE_URL('http://hop.apache.org:80/path?id=1&lang=fr','QUERY') → id=1&lang=fr
+PARSE_URL('http://hop.apache.org:80/path?id=1&lang=fr','QUERY','id') → 1
+PARSE_URL('http://hop.apache.org:80/path?id=1#fragment','FRAGMENT') → fragment
+----

plugins/src/main/java/org/apache/hop/expression/operator/ParseUrlFunction.java

@@ -0,0 +1,140 @@
+/*
+ * 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.hop.expression.operator;
+
+import com.jayway.jsonpath.internal.Utils;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+import org.apache.hop.expression.Function;
+import org.apache.hop.expression.FunctionPlugin;
+import org.apache.hop.expression.IExpression;
+import org.apache.hop.expression.OperatorCategory;
+import org.apache.hop.expression.type.OperandTypes;
+import org.apache.hop.expression.type.ReturnTypes;
+
+/** Returns the specified part of the URL or the value for the specified QUERY key. */
+@FunctionPlugin
+public class ParseUrlFunction extends Function {
+
+  public enum UrlPart {
+    HOST,
+    PORT,
+    PATH,
+    QUERY,
+    REF,
+    PROTOCOL,
+    FILE,
+    AUTHORITY,
+    USERINFO;
+  }
+
+  static Pattern keyToPattern(final String keyToExtract) {
+    return Pattern.compile("(&|^)" + keyToExtract + "=([^&]*)");
+  }
+
+  private static final Map<String, Pattern> cache = new ConcurrentHashMap<>();
+
+  public ParseUrlFunction() {
+    super(
+        "PARSE_URL",
+        ReturnTypes.STRING_NULLABLE,
+        OperandTypes.STRING_STRING.or(OperandTypes.STRING_STRING_STRING),
+        OperatorCategory.STRING,
+        "/docs/parse_url.html");
+  }
+
+  @Override
+  public Object eval(final IExpression[] operands) {
+    String url = operands[0].getValue(String.class);
+    if (url == null) return null;
+
+    String part = operands[1].getValue(String.class);
+    if (part == null) return null;
+
+    if (operands.length == 3) {
+      String key = operands[2].getValue(String.class);
+      if (key == null) {
+        return null;
+      }
+
+      return parseUrl(url, part, key);
+    }
+
+    return parseUrl(url, part);
+  }
+
+  public String parseUrl(String url, String partStr) {
+    UrlPart part;
+
+    URI uri;
+    try {
+      uri = new URI(url);
+    } catch (URISyntaxException e) {
+      return null;
+    }
+
+    try {
+      part = UrlPart.valueOf(partStr);
+    } catch (IllegalArgumentException e) {
+      return null;
+    }
+
+    switch (part) {
+      case HOST:
+        return uri.getHost();
+      case PORT:
+        return (uri.getPort() < 0) ? null : String.valueOf(uri.getPort());
+      case PATH:
+        String path = uri.getRawPath();
+        return (Utils.isEmpty(path)) ? null : path;
+      case QUERY:
+        return uri.getRawQuery();
+      case REF:
+        return uri.getRawFragment();
+      case PROTOCOL:
+        return uri.getScheme();
+      case FILE:
+        if (uri.getRawQuery() != null) {
+          return uri.getRawPath() + "?" + uri.getRawQuery();
+        } else {
+          return uri.getRawPath();
+        }
+      case AUTHORITY:
+        return uri.getRawAuthority();
+      case USERINFO:
+        return uri.getRawUserInfo();
+      default:
+        return null;
+    }
+  }
+
+  public String parseUrl(String url, String part, String keyToExtract) {
+    if (part.equals("QUERY")) {
+      String query = parseUrl(url, part);
+      if (query != null) {
+        Pattern pattern = cache.computeIfAbsent(keyToExtract, ParseUrlFunction::keyToPattern);
+        Matcher matcher = pattern.matcher(query);
+        return matcher.find() ? matcher.group(2) : null;
+      }
+    }
+    return null;
+  }
+}

plugins/src/test/java/org/apache/hop/core/expression/ScalarFunctionTest.java

@@ -400,6 +400,36 @@ public void Decode() throws Exception {
         "DECODE(FIELD_NUMBER,FIELD_INTEGER,1,2,2,4)");
   }
 
+  @Test
+  public void ParseUrl() throws Exception {
+    evalEquals("Parse_Url('http://hop.apache.org:80/path?query=1','PROTOCOL')", "http")
+        .returnType(Types.STRING);
+    evalEquals("Parse_Url('http://hop.apache.org:80/path?query=1','HOST')", "hop.apache.org");
+    evalEquals("Parse_Url('http://hop.apache.org:80/path?query=1','PORT')", "80");
+    evalEquals(
+        "Parse_Url('http://user:[email protected]:80/path?query=1','USERINFO')",
+        "user:password");
+    evalEquals(
+        "Parse_Url('http://user:[email protected]:80/path?query=1','AUTHORITY')",
+        "user:[email protected]:80");
+
+    evalEquals("Parse_Url('http://hop.apache.org:80/path?query=1','PATH')", "/path");
+    evalEquals(
+        "Parse_Url('http://hop.apache.org:80/path?query=1#fragment','FILE')", "/path?query=1");
+    evalEquals(
+        "Parse_Url('http://hop.apache.org:80/path?query=1&lang=fr','QUERY')", "query=1&lang=fr");
+    evalEquals("Parse_Url('http://hop.apache.org:80/path?query=1&id=2','QUERY','id')", "2");
+    evalEquals("Parse_Url('http://hop.apache.org:80/path?query=1#fragment', 'REF')", "fragment");
+
+    evalNull("Parse_Url(NULL_STRING,'PATH')");
+    evalNull("Parse_Url('http://hop.apache.org:80',NULL_STRING)");
+    evalNull("Parse_Url('http://hop.apache.org:80','PATH')");
+    evalNull("Parse_Url('http://hop.apache.org/path?query=1','PORT')");
+    evalNull("Parse_Url('http://hop.apache.org/path','QUERY')");
+    evalNull("Parse_Url('http://hop.apache.org/path?query=1','QUERY','xxx')");
+    evalNull("Parse_Url('http://hop.apache.org/path?query=1','QUERY',NULL_STRING)");
+  }
+
   @Test
   public void Pi() throws Exception {
     evalEquals("Pi()", PI).returnType(Types.NUMBER);