[#4331] Helper methods to get charset from Content-Type header of HttpMessage

Motivation:

HttpHeaders already has specific methods for such popular and simple headers like "Host", but if I need to convert POST raw body to string I need to parse complex ContentType header in my code.

Modifications:

Add getCharset and getCharsetAsString methods to parse charset from Content-Length header.

Result:

Easy to use utility method.

NOTICE.txt

@@ -219,3 +219,11 @@ the HTTP/2 HPACK algorithm written by Twitter. It can be obtained at:
   * HOMEPAGE:
     * https://github.com/twitter/hpack
 
+This product contains a modified portion of 'Apache Commons Lang', a Java library
+provides utilities for the java.lang API, which can be obtained at:
+
+  * LICENSE:
+    * license/LICENSE.commons-lang.txt (Apache License 2.0)
+  * HOMEPAGE:
+    * https://commons.apache.org/proper/commons-lang/
+

codec-http/src/main/java/io/netty/handler/codec/http/HttpUtil.java

@@ -16,9 +16,13 @@
 package io.netty.handler.codec.http;
 
 import io.netty.buffer.ByteBuf;
+import io.netty.util.AsciiString;
+import io.netty.util.CharsetUtil;
 
 import java.net.URI;
 import java.util.ArrayList;
+import java.nio.charset.Charset;
+import java.nio.charset.UnsupportedCharsetException;
 import java.util.Iterator;
 import java.util.List;
 
@@ -35,6 +39,7 @@ public final class HttpUtil {
      */
     @Deprecated
     static final EmptyHttpHeaders EMPTY_HEADERS = new EmptyHttpHeaders();
+    private static final AsciiString CHARSET_EQUALS = AsciiString.of(HttpHeaderValues.CHARSET + "=");
 
     private HttpUtil() { }
 
@@ -325,6 +330,57 @@ public final class HttpUtil {
         }
     }
 
+    /**
+     * Fetch charset from message's Content-Type header.
+     *
+     * @return the charset from message's Content-Type header or {@link io.netty.util.CharsetUtil#ISO_8859_1}
+     * if charset is not presented or unparsable
+     */
+    public static Charset getCharset(HttpMessage message) {
+        return getCharset(message, CharsetUtil.ISO_8859_1);
+    }
+
+    /**
+     * Fetch charset from message's Content-Type header.
+     *
+     * @return the charset from message's Content-Type header or {@code defaultCharset}
+     * if charset is not presented or unparsable
+     */
+    public static Charset getCharset(HttpMessage message, Charset defaultCharset) {
+        CharSequence charsetCharSequence = getCharsetAsString(message);
+        if (charsetCharSequence != null) {
+            try {
+                return Charset.forName(charsetCharSequence.toString());
+            } catch (UnsupportedCharsetException unsupportedException) {
+                return defaultCharset;
+            }
+        } else {
+            return defaultCharset;
+        }
+    }
+
+    /**
+     * Fetch charset string from message's Content-Type header.
+     *
+     * A lot of sites/possibly clients have charset="CHARSET", for example charset="utf-8". Or "utf8" instead of "utf-8"
+     * This is not according to standard, but this method provide an ability to catch desired mistakes manually in code
+     *
+     * @return the charset string from message's Content-Type header or {@code null} if charset is not presented
+     */
+    public static CharSequence getCharsetAsString(HttpMessage message) {
+        CharSequence contentTypeValue = message.headers().get(HttpHeaderNames.CONTENT_TYPE);
+        if (contentTypeValue != null) {
+            int indexOfCharset = AsciiString.indexOfIgnoreCaseAscii(contentTypeValue, CHARSET_EQUALS, 0);
+            if (indexOfCharset != AsciiString.INDEX_NOT_FOUND) {
+                int indexOfEncoding = indexOfCharset + CHARSET_EQUALS.length();
+                if (indexOfEncoding < contentTypeValue.length()) {
+                    return contentTypeValue.subSequence(indexOfEncoding, contentTypeValue.length());
+                }
+            }
+        }
+        return null;
+    }
+
     static void encodeAscii0(CharSequence seq, ByteBuf buf) {
         int length = seq.length();
         for (int i = 0 ; i < length; i++) {

codec-http/src/test/java/io/netty/handler/codec/http/HttpUtilTest.java

@@ -15,16 +15,16 @@
  */
 package io.netty.handler.codec.http;
 
-import io.netty.util.AsciiString;
+import io.netty.util.CharsetUtil;
 import org.junit.Test;
 
+import java.nio.charset.StandardCharsets;
 import java.util.List;
 
 import static io.netty.handler.codec.http.HttpHeadersTestUtils.of;
-import static org.hamcrest.CoreMatchers.is;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertThat;
+import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 
 public class HttpUtilTest {
@@ -54,10 +54,38 @@ public class HttpUtilTest {
     }
 
     @Test
-    public void testEquansIgnoreCase() {
+    public void testGetCharsetAsRawString() {
-        assertThat(AsciiString.contentEqualsIgnoreCase(null, null), is(true));
+        HttpMessage message = new DefaultHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK);
-        assertThat(AsciiString.contentEqualsIgnoreCase(null, "foo"), is(false));
+        message.headers().set(HttpHeaderNames.CONTENT_TYPE, "text/html; charset=\"utf8\"");
-        assertThat(AsciiString.contentEqualsIgnoreCase("bar", null), is(false));
+        assertEquals("\"utf8\"", HttpUtil.getCharsetAsString(message));
-        assertThat(AsciiString.contentEqualsIgnoreCase("FoO", "fOo"), is(true));
+
+        message.headers().set(HttpHeaderNames.CONTENT_TYPE, "text/html");
+        assertNull(HttpUtil.getCharsetAsString(message));
+    }
+
+    @Test
+    public void testGetCharset() {
+        HttpMessage message = new DefaultHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK);
+        message.headers().set(HttpHeaderNames.CONTENT_TYPE, "text/html; charset=utf-8");
+        assertEquals(CharsetUtil.UTF_8, HttpUtil.getCharset(message));
+
+        message.headers().set(HttpHeaderNames.CONTENT_TYPE, "TEXT/HTML; CHARSET=UTF-8");
+        assertEquals(CharsetUtil.UTF_8, HttpUtil.getCharset(message));
+    }
+
+    @Test
+    public void testGetCharset_defaultValue() {
+        HttpMessage message = new DefaultHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK);
+        message.headers().set(HttpHeaderNames.CONTENT_TYPE, "text/html");
+        assertEquals(CharsetUtil.ISO_8859_1, HttpUtil.getCharset(message));
+
+        message.headers().set(HttpHeaderNames.CONTENT_TYPE, "text/html");
+        assertEquals(CharsetUtil.UTF_8, HttpUtil.getCharset(message, StandardCharsets.UTF_8));
+
+        message.headers().set(HttpHeaderNames.CONTENT_TYPE, "text/html; charset=UTFFF");
+        assertEquals(CharsetUtil.ISO_8859_1, HttpUtil.getCharset(message));
+
+        message.headers().set(HttpHeaderNames.CONTENT_TYPE, "text/html; charset=UTFFF");
+        assertEquals(CharsetUtil.UTF_8, HttpUtil.getCharset(message, StandardCharsets.UTF_8));
     }
 }

common/src/main/java/io/netty/util/AsciiString.java

@@ -48,6 +48,8 @@ public final class AsciiString implements CharSequence, Comparable<CharSequence>
     public static final AsciiString EMPTY_STRING = new AsciiString("");
     private static final char MAX_CHAR_VALUE = 255;
 
+    public static final int INDEX_NOT_FOUND = -1;
+
     /**
      * If this value is modified outside the constructor then call {@link #arrayChanged()}.
      */
@@ -1382,7 +1384,7 @@ public final class AsciiString implements CharSequence, Comparable<CharSequence>
      * Determine if {@code a} contains {@code b} in a case insensitive manner.
      */
     public static boolean containsIgnoreCase(CharSequence a, CharSequence b) {
-        return contains(a, b, CaseInsensativeCharEqualityComparator.INSTANCE);
+        return contains(a, b, AsciiCaseInsensitiveCharEqualityComparator.INSTANCE);
     }
 
     /**
@@ -1497,9 +1499,10 @@ public final class AsciiString implements CharSequence, Comparable<CharSequence>
         }
     }
 
-    private static final class CaseInsensativeCharEqualityComparator implements CharEqualityComparator {
+    private static final class AsciiCaseInsensitiveCharEqualityComparator implements CharEqualityComparator {
-        static final CaseInsensativeCharEqualityComparator INSTANCE = new CaseInsensativeCharEqualityComparator();
+        static final AsciiCaseInsensitiveCharEqualityComparator
-        private CaseInsensativeCharEqualityComparator() { }
+                INSTANCE = new AsciiCaseInsensitiveCharEqualityComparator();
+        private AsciiCaseInsensitiveCharEqualityComparator() { }
 
         @Override
         public boolean equals(char a, char b) {
@@ -1507,6 +1510,19 @@ public final class AsciiString implements CharSequence, Comparable<CharSequence>
         }
     }
 
+    private static final class GeneralCaseInsensitiveCharEqualityComparator implements CharEqualityComparator {
+        static final GeneralCaseInsensitiveCharEqualityComparator
+                INSTANCE = new GeneralCaseInsensitiveCharEqualityComparator();
+        private GeneralCaseInsensitiveCharEqualityComparator() { }
+
+        @Override
+        public boolean equals(char a, char b) {
+            //For motivation, why we need two checks, see comment in String#regionMatches
+            return Character.toUpperCase(a) == Character.toUpperCase(b) ||
+                Character.toLowerCase(a) == Character.toLowerCase(b);
+        }
+    }
+
     private static boolean contains(CharSequence a, CharSequence b, CharEqualityComparator cmp) {
         if (a == null || b == null || a.length() < b.length()) {
             return false;
@@ -1531,6 +1547,201 @@ public final class AsciiString implements CharSequence, Comparable<CharSequence>
         return false;
     }
 
+    private static boolean regionMatchesCharSequences(final CharSequence cs, final int csStart,
+                                         final CharSequence string, final int start, final int length,
+                                         CharEqualityComparator charEqualityComparator) {
+        //general purpose implementation for CharSequences
+        if (csStart < 0 || length > cs.length() - csStart) {
+            return false;
+        }
+        if (start < 0 || length > string.length() - start) {
+            return false;
+        }
+
+        int csIndex = csStart;
+        int csEnd = csIndex + length;
+        int stringIndex = start;
+
+        while (csIndex < csEnd) {
+            char c1 = cs.charAt(csIndex++);
+            char c2 = string.charAt(stringIndex++);
+
+            if (!charEqualityComparator.equals(c1, c2)) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    /**
+     * This methods make regionMatches operation correctly for any chars in strings
+     * @param cs the {@code CharSequence} to be processed
+     * @param ignoreCase specifies if case should be ignored.
+     * @param csStart the starting offset in the {@code cs} CharSequence
+     * @param string the {@code CharSequence} to compare.
+     * @param start the starting offset in the specified {@code string}.
+     * @param length the number of characters to compare.
+     * @return {@code true} if the ranges of characters are equal, {@code false} otherwise.
+     */
+    public static boolean regionMatches(final CharSequence cs, final boolean ignoreCase, final int csStart,
+                                        final CharSequence string, final int start, final int length) {
+        if (cs == null || string == null) {
+            return false;
+        }
+
+        if (cs instanceof String && string instanceof String) {
+            return ((String) cs).regionMatches(ignoreCase, csStart, (String) string, start, length);
+        }
+
+        if (cs instanceof AsciiString) {
+            return ((AsciiString) cs).regionMatches(ignoreCase, csStart, string, start, length);
+        }
+
+        return regionMatchesCharSequences(cs, csStart, string, start, length,
+                                            ignoreCase ? GeneralCaseInsensitiveCharEqualityComparator.INSTANCE :
+                                                    DefaultCharEqualityComparator.INSTANCE);
+    }
+
+    /**
+     * This is optimized version of regionMatches for string with ASCII chars only
+     * @param cs the {@code CharSequence} to be processed
+     * @param ignoreCase specifies if case should be ignored.
+     * @param csStart the starting offset in the {@code cs} CharSequence
+     * @param string the {@code CharSequence} to compare.
+     * @param start the starting offset in the specified {@code string}.
+     * @param length the number of characters to compare.
+     * @return {@code true} if the ranges of characters are equal, {@code false} otherwise.
+     */
+    public static boolean regionMatchesAscii(final CharSequence cs, final boolean ignoreCase, final int csStart,
+                                        final CharSequence string, final int start, final int length) {
+        if (cs == null || string == null) {
+            return false;
+        }
+
+        if (!ignoreCase && cs instanceof String && string instanceof String) {
+            //we don't call regionMatches from String for ignoreCase==true. It's a general purpose method,
+            //which make complex comparison in case of ignoreCase==true, which is useless for ASCII-only strings.
+            //To avoid applying this complex ignore-case comparison, we will use regionMatchesCharSequences
+            return ((String) cs).regionMatches(false, csStart, (String) string, start, length);
+        }
+
+        if (cs instanceof AsciiString) {
+            return ((AsciiString) cs).regionMatches(ignoreCase, csStart, string, start, length);
+        }
+
+        return regionMatchesCharSequences(cs, csStart, string, start, length,
+                                          ignoreCase ? AsciiCaseInsensitiveCharEqualityComparator.INSTANCE :
+                                                      DefaultCharEqualityComparator.INSTANCE);
+    }
+
+    /**
+     * <p>Case in-sensitive find of the first index within a CharSequence
+     * from the specified position.</p>
+     *
+     * <p>A {@code null} CharSequence will return {@code -1}.
+     * A negative start position is treated as zero.
+     * An empty ("") search CharSequence always matches.
+     * A start position greater than the string length only matches
+     * an empty search CharSequence.</p>
+     *
+     * <pre>
+     * AsciiString.indexOfIgnoreCase(null, *, *)          = -1
+     * AsciiString.indexOfIgnoreCase(*, null, *)          = -1
+     * AsciiString.indexOfIgnoreCase("", "", 0)           = 0
+     * AsciiString.indexOfIgnoreCase("aabaabaa", "A", 0)  = 0
+     * AsciiString.indexOfIgnoreCase("aabaabaa", "B", 0)  = 2
+     * AsciiString.indexOfIgnoreCase("aabaabaa", "AB", 0) = 1
+     * AsciiString.indexOfIgnoreCase("aabaabaa", "B", 3)  = 5
+     * AsciiString.indexOfIgnoreCase("aabaabaa", "B", 9)  = -1
+     * AsciiString.indexOfIgnoreCase("aabaabaa", "B", -1) = 2
+     * AsciiString.indexOfIgnoreCase("aabaabaa", "", 2)   = 2
+     * AsciiString.indexOfIgnoreCase("abc", "", 9)        = -1
+     * </pre>
+     *
+     * @param str  the CharSequence to check, may be null
+     * @param searchStr  the CharSequence to find, may be null
+     * @param startPos  the start position, negative treated as zero
+     * @return the first index of the search CharSequence (always &ge; startPos),
+     *  -1 if no match or {@code null} string input
+     * @throws NullPointerException if {@code cs} or {@code string} is {@code null}.
+     */
+    public static int indexOfIgnoreCase(final CharSequence str, final CharSequence searchStr, int startPos) {
+        if (str == null || searchStr == null) {
+            return INDEX_NOT_FOUND;
+        }
+        if (startPos < 0) {
+            startPos = 0;
+        }
+        int searchStrLen = searchStr.length();
+        final int endLimit = str.length() - searchStrLen + 1;
+        if (startPos > endLimit) {
+            return INDEX_NOT_FOUND;
+        }
+        if (searchStrLen == 0) {
+            return startPos;
+        }
+        for (int i = startPos; i < endLimit; i++) {
+            if (regionMatches(str, true, i, searchStr, 0, searchStrLen)) {
+                return i;
+            }
+        }
+        return INDEX_NOT_FOUND;
+    }
+
+    /**
+     * <p>Case in-sensitive find of the first index within a CharSequence
+     * from the specified position. This method optimized and works correctly for ASCII CharSequences only</p>
+     *
+     * <p>A {@code null} CharSequence will return {@code -1}.
+     * A negative start position is treated as zero.
+     * An empty ("") search CharSequence always matches.
+     * A start position greater than the string length only matches
+     * an empty search CharSequence.</p>
+     *
+     * <pre>
+     * AsciiString.indexOfIgnoreCase(null, *, *)          = -1
+     * AsciiString.indexOfIgnoreCase(*, null, *)          = -1
+     * AsciiString.indexOfIgnoreCase("", "", 0)           = 0
+     * AsciiString.indexOfIgnoreCase("aabaabaa", "A", 0)  = 0
+     * AsciiString.indexOfIgnoreCase("aabaabaa", "B", 0)  = 2
+     * AsciiString.indexOfIgnoreCase("aabaabaa", "AB", 0) = 1
+     * AsciiString.indexOfIgnoreCase("aabaabaa", "B", 3)  = 5
+     * AsciiString.indexOfIgnoreCase("aabaabaa", "B", 9)  = -1
+     * AsciiString.indexOfIgnoreCase("aabaabaa", "B", -1) = 2
+     * AsciiString.indexOfIgnoreCase("aabaabaa", "", 2)   = 2
+     * AsciiString.indexOfIgnoreCase("abc", "", 9)        = -1
+     * </pre>
+     *
+     * @param str  the CharSequence to check, may be null
+     * @param searchStr  the CharSequence to find, may be null
+     * @param startPos  the start position, negative treated as zero
+     * @return the first index of the search CharSequence (always &ge; startPos),
+     *  -1 if no match or {@code null} string input
+     * @throws NullPointerException if {@code cs} or {@code string} is {@code null}.
+     */
+    public static int indexOfIgnoreCaseAscii(final CharSequence str, final CharSequence searchStr, int startPos) {
+        if (str == null || searchStr == null) {
+            return INDEX_NOT_FOUND;
+        }
+        if (startPos < 0) {
+            startPos = 0;
+        }
+        int searchStrLen = searchStr.length();
+        final int endLimit = str.length() - searchStrLen + 1;
+        if (startPos > endLimit) {
+            return INDEX_NOT_FOUND;
+        }
+        if (searchStrLen == 0) {
+            return startPos;
+        }
+        for (int i = startPos; i < endLimit; i++) {
+            if (regionMatchesAscii(str, true, i, searchStr, 0, searchStrLen)) {
+                return i;
+            }
+        }
+        return INDEX_NOT_FOUND;
+    }
+
     private static boolean equalsIgnoreCase(byte a, byte b) {
         return a == b || toLowerCase(a) == toLowerCase(b);
     }

common/src/test/java/io/netty/util/AsciiStringCharacterTest.java

@@ -24,9 +24,11 @@ import java.util.Random;
 
 import static io.netty.util.AsciiString.contains;
 import static io.netty.util.AsciiString.containsIgnoreCase;
+import static org.hamcrest.CoreMatchers.is;
 import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertThat;
 import static org.junit.Assert.assertTrue;
 
 /**
@@ -231,4 +233,43 @@ public class AsciiStringCharacterTest {
         assertTrue(new AsciiString(new byte[] { 5 }).parseBoolean());
         assertTrue(new AsciiString(new byte[] { 2, 0 }).parseBoolean());
     }
+
+    @Test
+    public void testEqualsIgnoreCase() {
+        assertThat(AsciiString.contentEqualsIgnoreCase(null, null), is(true));
+        assertThat(AsciiString.contentEqualsIgnoreCase(null, "foo"), is(false));
+        assertThat(AsciiString.contentEqualsIgnoreCase("bar", null), is(false));
+        assertThat(AsciiString.contentEqualsIgnoreCase("FoO", "fOo"), is(true));
+    }
+
+    @Test
+    public void testIndexOfIgnoreCase() {
+        assertEquals(-1, AsciiString.indexOfIgnoreCase(null, "abc", 1));
+        assertEquals(-1, AsciiString.indexOfIgnoreCase("abc", null, 1));
+        assertEquals(0, AsciiString.indexOfIgnoreCase("", "", 0));
+        assertEquals(0, AsciiString.indexOfIgnoreCase("aabaabaa", "A", 0));
+        assertEquals(2, AsciiString.indexOfIgnoreCase("aabaabaa", "B", 0));
+        assertEquals(1, AsciiString.indexOfIgnoreCase("aabaabaa", "AB", 0));
+        assertEquals(5, AsciiString.indexOfIgnoreCase("aabaabaa", "B", 3));
+        assertEquals(-1, AsciiString.indexOfIgnoreCase("aabaabaa", "B", 9));
+        assertEquals(2, AsciiString.indexOfIgnoreCase("aabaabaa", "B", -1));
+        assertEquals(2, AsciiString.indexOfIgnoreCase("aabaabaa", "", 2));
+        assertEquals(-1, AsciiString.indexOfIgnoreCase("abc", "", 9));
+        assertEquals(0, AsciiString.indexOfIgnoreCase("ãabaabaa", "Ã", 0));
+    }
+
+    @Test
+    public void testIndexOfIgnoreCaseAscii() {
+        assertEquals(-1, AsciiString.indexOfIgnoreCaseAscii(null, "abc", 1));
+        assertEquals(-1, AsciiString.indexOfIgnoreCaseAscii("abc", null, 1));
+        assertEquals(0, AsciiString.indexOfIgnoreCaseAscii("", "", 0));
+        assertEquals(0, AsciiString.indexOfIgnoreCaseAscii("aabaabaa", "A", 0));
+        assertEquals(2, AsciiString.indexOfIgnoreCaseAscii("aabaabaa", "B", 0));
+        assertEquals(1, AsciiString.indexOfIgnoreCaseAscii("aabaabaa", "AB", 0));
+        assertEquals(5, AsciiString.indexOfIgnoreCaseAscii("aabaabaa", "B", 3));
+        assertEquals(-1, AsciiString.indexOfIgnoreCaseAscii("aabaabaa", "B", 9));
+        assertEquals(2, AsciiString.indexOfIgnoreCaseAscii("aabaabaa", "B", -1));
+        assertEquals(2, AsciiString.indexOfIgnoreCaseAscii("aabaabaa", "", 2));
+        assertEquals(-1, AsciiString.indexOfIgnoreCaseAscii("abc", "", 9));
+    }
 }

license/LICENSE.commons-lang.txt

@@ -0,0 +1,177 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
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