ok2c commented on code in PR #731: URL: https://github.com/apache/httpcomponents-client/pull/731#discussion_r2679385304
########## httpclient5/src/main/java/org/apache/hc/client5/http/impl/AlpnHeaderSupport.java: ########## @@ -0,0 +1,183 @@ +/* + * ==================================================================== + * 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.hc.client5.http.impl; + + +import java.nio.charset.StandardCharsets; +import java.util.ArrayList; +import java.util.Collections; +import java.util.List; + +import org.apache.hc.core5.annotation.Contract; +import org.apache.hc.core5.annotation.Internal; +import org.apache.hc.core5.annotation.ThreadingBehavior; +import org.apache.hc.core5.http.message.MessageSupport; +import org.apache.hc.core5.http.message.ParserCursor; +import org.apache.hc.core5.util.Args; + +/** + * Codec for the HTTP {@code ALPN} header field (RFC 7639). + * + * @since 5.6 + */ +@Contract(threading = ThreadingBehavior.IMMUTABLE) +@Internal +public final class AlpnHeaderSupport { + + private static final char[] HEXADECIMAL = "0123456789ABCDEF".toCharArray(); + + private AlpnHeaderSupport() { + } + + /** + * Formats a list of raw ALPN protocol IDs into a single {@code ALPN} header value. + */ + public static String formatValue(final List<String> protocolIds) { + Args.notEmpty(protocolIds, "protocolIds"); + final StringBuilder sb = new StringBuilder(); + boolean first = true; + for (final String id : protocolIds) { + if (!first) { + sb.append(", "); + } + sb.append(encodeId(id)); + first = false; + } + return sb.toString(); + } + + /** + * Parses an {@code ALPN} header value into decoded protocol IDs. + */ + public static List<String> parseValue(final String value) { + if (value == null || value.isEmpty()) { + return Collections.emptyList(); + } + final List<String> out = new ArrayList<>(); + final ParserCursor cursor = new ParserCursor(0, value.length()); + MessageSupport.parseTokens(value, cursor, token -> { + if (!token.isEmpty()) { + out.add(decodeId(token)); + } + }); + return out; + } + + /** + * Encodes a single raw protocol ID to canonical token form. + */ + public static String encodeId(final String id) { + Args.notBlank(id, "id"); + final byte[] bytes = id.getBytes(StandardCharsets.UTF_8); + final StringBuilder sb = new StringBuilder(bytes.length); + for (final byte b0 : bytes) { + final int b = b0 & 0xFF; + if (b == '%' || !isTchar(b)) { + appendPctEncoded(b, sb); + } else { + sb.append((char) b); + } + } + return sb.toString(); + } + + /** + * Decodes percent-encoded token to raw ID using UTF-8. + * Accepts lowercase hex; malformed/incomplete sequences are left literal. + */ + public static String decodeId(final String token) { Review Comment: @arturobernalg what is the reason having to re-implement percent coding and not using `PercentCodec` from core? -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
