Ported URL encoding utils from Commons HttpClient

git-svn-id: https://svn.apache.org/repos/asf/jakarta/httpcomponents/httpclient/trunk@528509 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/http/client/utils/URLUtils.java

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+/*
+ * $HeadURL$
+ * $Revision$
+ * $Date$
+ *
+ * ====================================================================
+ *
+ *  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.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ *
+ */
+package org.apache.http.client.utils;
+
+import java.io.UnsupportedEncodingException;
+
+import org.apache.commons.codec.net.URLCodec;
+import org.apache.http.NameValuePair;
+import org.apache.http.util.CharArrayBuffer;
+
+/**
+ * The home for utility methods that handle various URL encoding tasks.
+ * 
+ * @author Michael Becke
+ * @author <a href="mailto:oleg at ural.ru">Oleg Kalnichevski</a>
+ * 
+ * @since 2.0 final
+ */
+public class URLUtils {
+
+    /** Default content encoding chatset */
+    private static final String DEFAULT_CHARSET = "ISO-8859-1";
+
+    /**
+     * Form-urlencoding routine.
+     *
+     * The default encoding for all forms is `application/x-www-form-urlencoded'. 
+     * A form data set is represented in this media type as follows:
+     *
+     * The form field names and values are escaped: space characters are replaced 
+     * by `+', and then reserved characters are escaped as per [URL]; that is, 
+     * non-alphanumeric characters are replaced by `%HH', a percent sign and two 
+     * hexadecimal digits representing the ASCII code of the character. Line breaks, 
+     * as in multi-line text field values, are represented as CR LF pairs, i.e. `%0D%0A'.
+     * 
+     * <p>
+     * if the given charset is not supported, ISO-8859-1 is used instead.
+     * </p>
+     * 
+     * @param pairs the values to be encoded
+     * @param charset the character set of pairs to be encoded
+     * 
+     * @return the urlencoded pairs
+     * 
+     * @since 4.0
+     */
+     public static String formUrlEncode(final NameValuePair[] pairs, final String charset) {
+        try {
+            return doFormUrlEncode(pairs, charset);
+        } catch (UnsupportedEncodingException e) {
+            try {
+                return doFormUrlEncode(pairs, DEFAULT_CHARSET);
+            } catch (UnsupportedEncodingException fatal) {
+                // Should never happen. ISO-8859-1 must be supported on all JVMs
+                throw new Error("HttpClient requires " + DEFAULT_CHARSET + " support");
+            }
+        }
+    }
+
+    /**
+     * Form-urlencoding routine.
+     *
+     * The default encoding for all forms is `application/x-www-form-urlencoded'. 
+     * A form data set is represented in this media type as follows:
+     *
+     * The form field names and values are escaped: space characters are replaced 
+     * by `+', and then reserved characters are escaped as per [URL]; that is, 
+     * non-alphanumeric characters are replaced by `%HH', a percent sign and two 
+     * hexadecimal digits representing the ASCII code of the character. Line breaks, 
+     * as in multi-line text field values, are represented as CR LF pairs, i.e. `%0D%0A'.
+     * 
+     * @param pairs the values to be encoded
+     * @param charset the character set of pairs to be encoded
+     * 
+     * @return the urlencoded pairs
+     * @throws UnsupportedEncodingException if charset is not supported
+     * 
+     * @since 2.0 final
+     */
+     private static String doFormUrlEncode(
+             final NameValuePair[] pairs, 
+             final String charset) throws UnsupportedEncodingException {
+        CharArrayBuffer buf = new CharArrayBuffer(32);
+        for (int i = 0; i < pairs.length; i++) {
+            URLCodec codec = new URLCodec();
+            NameValuePair pair = pairs[i];
+            if (pair.getName() != null) {
+                if (i > 0) {
+                    buf.append("&");
+                }
+                buf.append(codec.encode(pair.getName(), charset));
+                buf.append("=");
+                if (pair.getValue() != null) {
+                    buf.append(codec.encode(pair.getValue(), charset));
+                }
+            }
+        }
+        return buf.toString();
+    }
+    
+    /**
+     * This class should not be instantiated.
+     */
+    private URLUtils() {
+    }
+
+}