com.rabbitmq.jms.util.UriCodec Maven / Gradle / Ivy
/* Copyright (c) 2013 Pivotal Software, Inc. All rights reserved. */
package com.rabbitmq.jms.util;
import java.io.UnsupportedEncodingException;
import java.util.Arrays;
/**
* Helper class to encode/decode (pieces of) URI strings
*
* Static methods are provided to encode and decode parts of a URI. Works only with UTF-8 and US-ASCII character encodings.
* The results are undefined for all other encodings.
*
*
* Encoding a string involves encoding each character not allowed in that part of the URI string. Non-allowed characters are
* converted to a sequence of ‘percent-encoded’ bytes (octets). A percent-encoded octet is ‘%xx’
* where xx are two hexadecimal digits. The octets percent-encoded for a character depend upon the character
* encoding used: in the case of UTF-8 this might be up to four octets, but for US-ASCII encoding this would be only one octet.
* Decoding reconstructs the characters from the percent-encoded octets.
*
*
* The character encoding used to decode a string must be that used encode it, or the results are undefined.
*
*
* Coding and decoding a URI depends which part of the URI you are accessing. Notice, for example, that in the
* userinfo part, colons are allowed asis, but that in the first relative path segment they are not.
*
*
* This class only provides string-to-string encoding and decoding methods for (some) parts of a URI string.
* It does not syntactically validate the encoded or decoded strings for each part. So, for example,
* it will encode a scheme part which contains colons (replacing them with percent-encoded octets), even though
* percent-encoded octets are not allowed in schemes.
*
*
* [NB: The algorithmic assumption is made throughout that all valid characters are represented by a single byte
* in the US-ASCII codepage and that these coincide with their representation in UTF-8.]
*
*
* URI Specification
*
*
* RFC 2396 - Uniform Resource Identifiers (URI): Generic Syntax
* is obsoleted by RFC 3986 -
* Uniform Resource Identifier (URI): Generic Syntax which describes in (A)BNF the
* valid form of an encoded URI.
*
*
* Here is the appendix from RFC 3986 which gives the ABNF.
* ABNF itself is defined in RFC
* 2234 - Augmented BNF for Syntax Specifications: ABNF where furthermore the following
* non-terminals are defined: ALPHA (letters), DIGIT (decimal digits), and
* HEXDIG (hexadecimal digits).
*
* [NB: ‘;’ indicates a line comment, as in the original, but I have replaced the
* solidus ‘/’ (alternative) operator by the graphemically more pleasing vertical
* bar ‘|’.]
*
*/
public abstract class UriCodec { // Prevent me declaring instances.
private UriCodec() {} // Prevent anyone else declaring instances; also prohibits extensions.
/**
* Encode a string for the userinfo part of a URI string.
* @param ui - uncoded input
* @param encodingScheme - must be one of "UTF-8" or "US-ASCII"
* @return ui encoded (with % encodings if necessary)
*/
public static String encUserinfo(String ui, String encodingScheme) {
return genericEncode(USERINFO_C_BA, ui, encodingScheme);
}
/**
* @param rawui - encoded userinfo part
* @param encodingScheme - must be one of "UTF-8" of "US-ASCII"
* @return rawui decoded (with % encodings replaced by characters they represent)
*/
public static String decUserinfo(String rawui, String encodingScheme) {
return genericDecode(rawui, encodingScheme);
}
/**
* Encode a string for the scheme part of a URI string.
* @param ui - uncoded input
* @param encodingScheme - must be one of "UTF-8" or "US-ASCII"
* @return ui encoded (with % encodings if necessary)
*/
public static String encScheme(String ui, String encodingScheme) {
return genericEncode(SCHEME_C_BA, ui, encodingScheme);
}
/**
* @param rawui - encoded scheme part
* @param encodingScheme - must be one of "UTF-8" of "US-ASCII"
* @return rawui decoded (with % encodings replaced by characters they represent)
*/
public static String decScheme(String rawui, String encodingScheme) {
return genericDecode(rawui, encodingScheme);
}
/**
* Encode a string for a segment part of a URI string.
* @param ui - uncoded input
* @param encodingScheme - must be one of "UTF-8" or "US-ASCII"
* @return ui encoded (with % encodings if necessary)
*/
public static String encSegment(String ui, String encodingScheme) {
return genericEncode(SEGMENT_C_BA, ui, encodingScheme);
}
/**
* @param rawui - encoded segment part
* @param encodingScheme - must be one of "UTF-8" of "US-ASCII"
* @return rawui decoded (with % encodings replaced by characters they represent)
*/
public static String decSegment(String rawui, String encodingScheme) {
return genericDecode(rawui, encodingScheme);
}
/**
* Encode a string for the host part of a URI string.
* @param ui - uncoded input
* @param encodingScheme - must be one of "UTF-8" or "US-ASCII"
* @return ui encoded (with % encodings if necessary)
*/
public static String encHost(String ui, String encodingScheme) {
return genericEncode(HOST_C_BA, ui, encodingScheme);
}
/**
* @param rawui - encoded host part
* @param encodingScheme - must be one of "UTF-8" of "US-ASCII"
* @return rawui decoded (with % encodings replaced by characters they represent)
*/
public static String decHost(String rawui, String encodingScheme) {
return genericDecode(rawui, encodingScheme);
}
/**
* Encode a string for the path part of a URI string.
* @param ui - uncoded input
* @param encodingScheme - must be one of "UTF-8" or "US-ASCII"
* @return ui encoded (with % encodings if necessary)
*/
public static String encPath(String ui, String encodingScheme) {
return genericEncode(PATH_C_BA, ui, encodingScheme);
}
/**
* @param rawui - encoded path part
* @param encodingScheme - must be one of "UTF-8" of "US-ASCII"
* @return rawui decoded (with % encodings replaced by characters they represent)
*/
public static String decPath(String rawui, String encodingScheme) {
return genericDecode(rawui, encodingScheme);
}
private static String genericDecode(String rawstr, String encodingScheme) {
try {
int starState = 0;
int n=0; int hiHex = 0;
byte[] bytes = new byte[rawstr.length()]; // invariant: n bytes are set
for (byte b : rawstr.getBytes(encodingScheme)) {
switch (starState) {
case 0 : if (b!='%') bytes[n++] = b;
else { starState = 1; } break;
case 1 : starState = 2; hiHex = hex(b); break;
case 2 : starState = 0; bytes[n++] = (byte) (hiHex*16 + hex(b)); break;
default : break;
}
} // n is length of 'set' byte array
return new String(bytes, 0, n, encodingScheme);
} catch (UnsupportedEncodingException e) {
return rawstr;
}
}
private static int hex(int b) {
return (b < 48) ? 0
:(b < 58) ? (b-48) // 48..57 -> 0..9
:(b < 65) ? 0
:(b < 71) ? (b-55) // 65..70 -> 10..15
:(b < 97) ? 0
:(b < 103) ? (b-87) // 97..102 -> 10..15
: 0;
}
private static String genericEncode(byte[] charClass, String str, String encodingScheme) {
try {
StringBuilder sb = new StringBuilder();
for (byte b : str.getBytes(encodingScheme)) {
if (inClass(b,charClass)) sb.append(Character.toChars(b));
else addEscaped(sb, b);
}
return sb.toString();
} catch (UnsupportedEncodingException e) {
return str;
}
}
private static void addEscaped(StringBuilder sb, int b) {
int ind = (b+256)%256; // to range 0<=ind<=255
sb.append('%').append(HIHEX[ind]).append(LOHEX[ind]);
}
private static boolean inClass(byte b, byte[] sortedBytes) {
return Arrays.binarySearch(sortedBytes, b) >= 0;
}
private static final String DIGIT = "0123456789";
private static final String ALPHA = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
private static final String SUB_DELIMS = "!$&'()*+,;="; // sub-delims
private static final String UNRESERVED = ALPHA + DIGIT + "-._~"; // unreserved
private static final String SCHEME_C = ALPHA + DIGIT + "+-."; // scheme
private static final String PCHAR_C = UNRESERVED + SUB_DELIMS + ":@"; // pchar
private static final String SEGMENT_C = PCHAR_C; // segment
private static final String PATH_C = SEGMENT_C + "/"; // path
private static final String USERINFO_C = UNRESERVED + SUB_DELIMS + ":"; // userinfo
private static final String HOST_C = UNRESERVED + SUB_DELIMS + ":[]."; // host
// sorted array optimisations
private static final byte[] SCHEME_C_BA = bytesOf(SCHEME_C);
private static final byte[] USERINFO_C_BA = bytesOf(USERINFO_C);
private static final byte[] HOST_C_BA = bytesOf(HOST_C);
private static final byte[] PCHAR_C_BA = bytesOf(PCHAR_C);
private static final byte[] SEGMENT_C_BA = PCHAR_C_BA;
private static final byte[] PATH_C_BA = bytesOf(PATH_C);
private static final char[] LOHEX = new char[] { '0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'
, '0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'
, '0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'
, '0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'
, '0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'
, '0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'
, '0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'
, '0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'
, '0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'
, '0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'
, '0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'
, '0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'
, '0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'
, '0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'
, '0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'
, '0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'
};
private static final char[] HIHEX = new char[] { '0','0','0','0','0','0','0','0','0','0','0','0','0','0','0','0'
, '1','1','1','1','1','1','1','1','1','1','1','1','1','1','1','1'
, '2','2','2','2','2','2','2','2','2','2','2','2','2','2','2','2'
, '3','3','3','3','3','3','3','3','3','3','3','3','3','3','3','3'
, '4','4','4','4','4','4','4','4','4','4','4','4','4','4','4','4'
, '5','5','5','5','5','5','5','5','5','5','5','5','5','5','5','5'
, '6','6','6','6','6','6','6','6','6','6','6','6','6','6','6','6'
, '7','7','7','7','7','7','7','7','7','7','7','7','7','7','7','7'
, '8','8','8','8','8','8','8','8','8','8','8','8','8','8','8','8'
, '9','9','9','9','9','9','9','9','9','9','9','9','9','9','9','9'
, 'A','A','A','A','A','A','A','A','A','A','A','A','A','A','A','A'
, 'B','B','B','B','B','B','B','B','B','B','B','B','B','B','B','B'
, 'C','C','C','C','C','C','C','C','C','C','C','C','C','C','C','C'
, 'D','D','D','D','D','D','D','D','D','D','D','D','D','D','D','D'
, 'E','E','E','E','E','E','E','E','E','E','E','E','E','E','E','E'
, 'F','F','F','F','F','F','F','F','F','F','F','F','F','F','F','F'
};
private static final byte[] bytesOf(String str) {
try {
byte[] result = str.getBytes("UTF-8");
Arrays.sort(result, 0, result.length);
return result;
} catch (Exception e) {
throw new RuntimeException("Cannot generate byte array for URI conversion.", e);
}
}
}