michael@0: /*
michael@0:  * ====================================================================
michael@0:  * Licensed to the Apache Software Foundation (ASF) under one
michael@0:  * or more contributor license agreements.  See the NOTICE file
michael@0:  * distributed with this work for additional information
michael@0:  * regarding copyright ownership.  The ASF licenses this file
michael@0:  * to you under the Apache License, Version 2.0 (the
michael@0:  * "License"); you may not use this file except in compliance
michael@0:  * with the License.  You may obtain a copy of the License at
michael@0:  *
michael@0:  *   http://www.apache.org/licenses/LICENSE-2.0
michael@0:  *
michael@0:  * Unless required by applicable law or agreed to in writing,
michael@0:  * software distributed under the License is distributed on an
michael@0:  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
michael@0:  * KIND, either express or implied.  See the License for the
michael@0:  * specific language governing permissions and limitations
michael@0:  * under the License.
michael@0:  * ====================================================================
michael@0:  *
michael@0:  * This software consists of voluntary contributions made by many
michael@0:  * individuals on behalf of the Apache Software Foundation.  For more
michael@0:  * information on the Apache Software Foundation, please see
michael@0:  * <http://www.apache.org/>.
michael@0:  *
michael@0:  */
michael@0: 
michael@0: package ch.boye.httpclientandroidlib.message;
michael@0: 
michael@0: import ch.boye.httpclientandroidlib.HeaderElement;
michael@0: import ch.boye.httpclientandroidlib.NameValuePair;
michael@0: import ch.boye.httpclientandroidlib.util.CharArrayBuffer;
michael@0: 
michael@0: /**
michael@0:  * Basic implementation for formatting header value elements.
michael@0:  * Instances of this class are stateless and thread-safe.
michael@0:  * Derived classes are expected to maintain these properties.
michael@0:  *
michael@0:  * @since 4.0
michael@0:  */
michael@0: public class BasicHeaderValueFormatter implements HeaderValueFormatter {
michael@0: 
michael@0:     /**
michael@0:      * A default instance of this class, for use as default or fallback.
michael@0:      * Note that {@link BasicHeaderValueFormatter} is not a singleton, there
michael@0:      * can be many instances of the class itself and of derived classes.
michael@0:      * The instance here provides non-customized, default behavior.
michael@0:      */
michael@0:     public final static
michael@0:         BasicHeaderValueFormatter DEFAULT = new BasicHeaderValueFormatter();
michael@0: 
michael@0: 
michael@0:     /**
michael@0:      * Special characters that can be used as separators in HTTP parameters.
michael@0:      * These special characters MUST be in a quoted string to be used within
michael@0:      * a parameter value .
michael@0:      */
michael@0:     public final static String SEPARATORS = " ;,:@()<>\\\"/[]?={}\t";
michael@0: 
michael@0: 
michael@0:     /**
michael@0:      * Unsafe special characters that must be escaped using the backslash
michael@0:      * character
michael@0:      */
michael@0:     public final static String UNSAFE_CHARS = "\"\\";
michael@0: 
michael@0: 
michael@0: 
michael@0:     // public default constructor
michael@0: 
michael@0: 
michael@0: 
michael@0:     /**
michael@0:      * Formats an array of header elements.
michael@0:      *
michael@0:      * @param elems     the header elements to format
michael@0:      * @param quote     <code>true</code> to always format with quoted values,
michael@0:      *                  <code>false</code> to use quotes only when necessary
michael@0:      * @param formatter         the formatter to use, or <code>null</code>
michael@0:      *                          for the {@link #DEFAULT default}
michael@0:      *
michael@0:      * @return  the formatted header elements
michael@0:      */
michael@0:     public final static
michael@0:         String formatElements(final HeaderElement[] elems,
michael@0:                               final boolean quote,
michael@0:                               HeaderValueFormatter formatter) {
michael@0:         if (formatter == null)
michael@0:             formatter = BasicHeaderValueFormatter.DEFAULT;
michael@0:         return formatter.formatElements(null, elems, quote).toString();
michael@0:     }
michael@0: 
michael@0: 
michael@0:     // non-javadoc, see interface HeaderValueFormatter
michael@0:     public CharArrayBuffer formatElements(CharArrayBuffer buffer,
michael@0:                                           final HeaderElement[] elems,
michael@0:                                           final boolean quote) {
michael@0:         if (elems == null) {
michael@0:             throw new IllegalArgumentException
michael@0:                 ("Header element array must not be null.");
michael@0:         }
michael@0: 
michael@0:         int len = estimateElementsLen(elems);
michael@0:         if (buffer == null) {
michael@0:             buffer = new CharArrayBuffer(len);
michael@0:         } else {
michael@0:             buffer.ensureCapacity(len);
michael@0:         }
michael@0: 
michael@0:         for (int i=0; i<elems.length; i++) {
michael@0:             if (i > 0) {
michael@0:                 buffer.append(", ");
michael@0:             }
michael@0:             formatHeaderElement(buffer, elems[i], quote);
michael@0:         }
michael@0: 
michael@0:         return buffer;
michael@0:     }
michael@0: 
michael@0: 
michael@0:     /**
michael@0:      * Estimates the length of formatted header elements.
michael@0:      *
michael@0:      * @param elems     the header elements to format, or <code>null</code>
michael@0:      *
michael@0:      * @return  a length estimate, in number of characters
michael@0:      */
michael@0:     protected int estimateElementsLen(final HeaderElement[] elems) {
michael@0:         if ((elems == null) || (elems.length < 1))
michael@0:             return 0;
michael@0: 
michael@0:         int result = (elems.length-1) * 2; // elements separated by ", "
michael@0:         for (int i=0; i<elems.length; i++) {
michael@0:             result += estimateHeaderElementLen(elems[i]);
michael@0:         }
michael@0: 
michael@0:         return result;
michael@0:     }
michael@0: 
michael@0: 
michael@0: 
michael@0:     /**
michael@0:      * Formats a header element.
michael@0:      *
michael@0:      * @param elem      the header element to format
michael@0:      * @param quote     <code>true</code> to always format with quoted values,
michael@0:      *                  <code>false</code> to use quotes only when necessary
michael@0:      * @param formatter         the formatter to use, or <code>null</code>
michael@0:      *                          for the {@link #DEFAULT default}
michael@0:      *
michael@0:      * @return  the formatted header element
michael@0:      */
michael@0:     public final static
michael@0:         String formatHeaderElement(final HeaderElement elem,
michael@0:                                    boolean quote,
michael@0:                                    HeaderValueFormatter formatter) {
michael@0:         if (formatter == null)
michael@0:             formatter = BasicHeaderValueFormatter.DEFAULT;
michael@0:         return formatter.formatHeaderElement(null, elem, quote).toString();
michael@0:     }
michael@0: 
michael@0: 
michael@0:     // non-javadoc, see interface HeaderValueFormatter
michael@0:     public CharArrayBuffer formatHeaderElement(CharArrayBuffer buffer,
michael@0:                                                final HeaderElement elem,
michael@0:                                                final boolean quote) {
michael@0:         if (elem == null) {
michael@0:             throw new IllegalArgumentException
michael@0:                 ("Header element must not be null.");
michael@0:         }
michael@0: 
michael@0:         int len = estimateHeaderElementLen(elem);
michael@0:         if (buffer == null) {
michael@0:             buffer = new CharArrayBuffer(len);
michael@0:         } else {
michael@0:             buffer.ensureCapacity(len);
michael@0:         }
michael@0: 
michael@0:         buffer.append(elem.getName());
michael@0:         final String value = elem.getValue();
michael@0:         if (value != null) {
michael@0:             buffer.append('=');
michael@0:             doFormatValue(buffer, value, quote);
michael@0:         }
michael@0: 
michael@0:         final int parcnt = elem.getParameterCount();
michael@0:         if (parcnt > 0) {
michael@0:             for (int i=0; i<parcnt; i++) {
michael@0:                 buffer.append("; ");
michael@0:                 formatNameValuePair(buffer, elem.getParameter(i), quote);
michael@0:             }
michael@0:         }
michael@0: 
michael@0:         return buffer;
michael@0:     }
michael@0: 
michael@0: 
michael@0:     /**
michael@0:      * Estimates the length of a formatted header element.
michael@0:      *
michael@0:      * @param elem      the header element to format, or <code>null</code>
michael@0:      *
michael@0:      * @return  a length estimate, in number of characters
michael@0:      */
michael@0:     protected int estimateHeaderElementLen(final HeaderElement elem) {
michael@0:         if (elem == null)
michael@0:             return 0;
michael@0: 
michael@0:         int result = elem.getName().length(); // name
michael@0:         final String value = elem.getValue();
michael@0:         if (value != null) {
michael@0:             // assume quotes, but no escaped characters
michael@0:             result += 3 + value.length(); // ="value"
michael@0:         }
michael@0: 
michael@0:         final int parcnt = elem.getParameterCount();
michael@0:         if (parcnt > 0) {
michael@0:             for (int i=0; i<parcnt; i++) {
michael@0:                 result += 2 +                   // ; <param>
michael@0:                     estimateNameValuePairLen(elem.getParameter(i));
michael@0:             }
michael@0:         }
michael@0: 
michael@0:         return result;
michael@0:     }
michael@0: 
michael@0: 
michael@0: 
michael@0: 
michael@0:     /**
michael@0:      * Formats a set of parameters.
michael@0:      *
michael@0:      * @param nvps      the parameters to format
michael@0:      * @param quote     <code>true</code> to always format with quoted values,
michael@0:      *                  <code>false</code> to use quotes only when necessary
michael@0:      * @param formatter         the formatter to use, or <code>null</code>
michael@0:      *                          for the {@link #DEFAULT default}
michael@0:      *
michael@0:      * @return  the formatted parameters
michael@0:      */
michael@0:     public final static
michael@0:         String formatParameters(final NameValuePair[] nvps,
michael@0:                                 final boolean quote,
michael@0:                                 HeaderValueFormatter formatter) {
michael@0:         if (formatter == null)
michael@0:             formatter = BasicHeaderValueFormatter.DEFAULT;
michael@0:         return formatter.formatParameters(null, nvps, quote).toString();
michael@0:     }
michael@0: 
michael@0: 
michael@0:     // non-javadoc, see interface HeaderValueFormatter
michael@0:     public CharArrayBuffer formatParameters(CharArrayBuffer buffer,
michael@0:                                             NameValuePair[] nvps,
michael@0:                                             boolean quote) {
michael@0:         if (nvps == null) {
michael@0:             throw new IllegalArgumentException
michael@0:                 ("Parameters must not be null.");
michael@0:         }
michael@0: 
michael@0:         int len = estimateParametersLen(nvps);
michael@0:         if (buffer == null) {
michael@0:             buffer = new CharArrayBuffer(len);
michael@0:         } else {
michael@0:             buffer.ensureCapacity(len);
michael@0:         }
michael@0: 
michael@0:         for (int i = 0; i < nvps.length; i++) {
michael@0:             if (i > 0) {
michael@0:                 buffer.append("; ");
michael@0:             }
michael@0:             formatNameValuePair(buffer, nvps[i], quote);
michael@0:         }
michael@0: 
michael@0:         return buffer;
michael@0:     }
michael@0: 
michael@0: 
michael@0:     /**
michael@0:      * Estimates the length of formatted parameters.
michael@0:      *
michael@0:      * @param nvps      the parameters to format, or <code>null</code>
michael@0:      *
michael@0:      * @return  a length estimate, in number of characters
michael@0:      */
michael@0:     protected int estimateParametersLen(final NameValuePair[] nvps) {
michael@0:         if ((nvps == null) || (nvps.length < 1))
michael@0:             return 0;
michael@0: 
michael@0:         int result = (nvps.length-1) * 2; // "; " between the parameters
michael@0:         for (int i=0; i<nvps.length; i++) {
michael@0:             result += estimateNameValuePairLen(nvps[i]);
michael@0:         }
michael@0: 
michael@0:         return result;
michael@0:     }
michael@0: 
michael@0: 
michael@0:     /**
michael@0:      * Formats a name-value pair.
michael@0:      *
michael@0:      * @param nvp       the name-value pair to format
michael@0:      * @param quote     <code>true</code> to always format with a quoted value,
michael@0:      *                  <code>false</code> to use quotes only when necessary
michael@0:      * @param formatter         the formatter to use, or <code>null</code>
michael@0:      *                          for the {@link #DEFAULT default}
michael@0:      *
michael@0:      * @return  the formatted name-value pair
michael@0:      */
michael@0:     public final static
michael@0:         String formatNameValuePair(final NameValuePair nvp,
michael@0:                                    final boolean quote,
michael@0:                                    HeaderValueFormatter formatter) {
michael@0:         if (formatter == null)
michael@0:             formatter = BasicHeaderValueFormatter.DEFAULT;
michael@0:         return formatter.formatNameValuePair(null, nvp, quote).toString();
michael@0:     }
michael@0: 
michael@0: 
michael@0:     // non-javadoc, see interface HeaderValueFormatter
michael@0:     public CharArrayBuffer formatNameValuePair(CharArrayBuffer buffer,
michael@0:                                                final NameValuePair nvp,
michael@0:                                                final boolean quote) {
michael@0:         if (nvp == null) {
michael@0:             throw new IllegalArgumentException
michael@0:                 ("NameValuePair must not be null.");
michael@0:         }
michael@0: 
michael@0:         int len = estimateNameValuePairLen(nvp);
michael@0:         if (buffer == null) {
michael@0:             buffer = new CharArrayBuffer(len);
michael@0:         } else {
michael@0:             buffer.ensureCapacity(len);
michael@0:         }
michael@0: 
michael@0:         buffer.append(nvp.getName());
michael@0:         final String value = nvp.getValue();
michael@0:         if (value != null) {
michael@0:             buffer.append('=');
michael@0:             doFormatValue(buffer, value, quote);
michael@0:         }
michael@0: 
michael@0:         return buffer;
michael@0:     }
michael@0: 
michael@0: 
michael@0:     /**
michael@0:      * Estimates the length of a formatted name-value pair.
michael@0:      *
michael@0:      * @param nvp       the name-value pair to format, or <code>null</code>
michael@0:      *
michael@0:      * @return  a length estimate, in number of characters
michael@0:      */
michael@0:     protected int estimateNameValuePairLen(final NameValuePair nvp) {
michael@0:         if (nvp == null)
michael@0:             return 0;
michael@0: 
michael@0:         int result = nvp.getName().length(); // name
michael@0:         final String value = nvp.getValue();
michael@0:         if (value != null) {
michael@0:             // assume quotes, but no escaped characters
michael@0:             result += 3 + value.length(); // ="value"
michael@0:         }
michael@0:         return result;
michael@0:     }
michael@0: 
michael@0: 
michael@0:     /**
michael@0:      * Actually formats the value of a name-value pair.
michael@0:      * This does not include a leading = character.
michael@0:      * Called from {@link #formatNameValuePair formatNameValuePair}.
michael@0:      *
michael@0:      * @param buffer    the buffer to append to, never <code>null</code>
michael@0:      * @param value     the value to append, never <code>null</code>
michael@0:      * @param quote     <code>true</code> to always format with quotes,
michael@0:      *                  <code>false</code> to use quotes only when necessary
michael@0:      */
michael@0:     protected void doFormatValue(final CharArrayBuffer buffer,
michael@0:                                  final String value,
michael@0:                                  boolean quote) {
michael@0: 
michael@0:         if (!quote) {
michael@0:             for (int i = 0; (i < value.length()) && !quote; i++) {
michael@0:                 quote = isSeparator(value.charAt(i));
michael@0:             }
michael@0:         }
michael@0: 
michael@0:         if (quote) {
michael@0:             buffer.append('"');
michael@0:         }
michael@0:         for (int i = 0; i < value.length(); i++) {
michael@0:             char ch = value.charAt(i);
michael@0:             if (isUnsafe(ch)) {
michael@0:                 buffer.append('\\');
michael@0:             }
michael@0:             buffer.append(ch);
michael@0:         }
michael@0:         if (quote) {
michael@0:             buffer.append('"');
michael@0:         }
michael@0:     }
michael@0: 
michael@0: 
michael@0:     /**
michael@0:      * Checks whether a character is a {@link #SEPARATORS separator}.
michael@0:      *
michael@0:      * @param ch        the character to check
michael@0:      *
michael@0:      * @return  <code>true</code> if the character is a separator,
michael@0:      *          <code>false</code> otherwise
michael@0:      */
michael@0:     protected boolean isSeparator(char ch) {
michael@0:         return SEPARATORS.indexOf(ch) >= 0;
michael@0:     }
michael@0: 
michael@0: 
michael@0:     /**
michael@0:      * Checks whether a character is {@link #UNSAFE_CHARS unsafe}.
michael@0:      *
michael@0:      * @param ch        the character to check
michael@0:      *
michael@0:      * @return  <code>true</code> if the character is unsafe,
michael@0:      *          <code>false</code> otherwise
michael@0:      */
michael@0:     protected boolean isUnsafe(char ch) {
michael@0:         return UNSAFE_CHARS.indexOf(ch) >= 0;
michael@0:     }
michael@0: 
michael@0: 
michael@0: } // class BasicHeaderValueFormatter