2 * Copyright (c) 2021 PANTHEON.tech, s.r.o. and others. All rights reserved.
4 * This program and the accompanying materials are made available under the
5 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
6 * and is available at http://www.eclipse.org/legal/epl-v10.html
8 package org.opendaylight.restconf.api;
10 import static com.google.common.base.Verify.verify;
11 import static com.google.common.base.Verify.verifyNotNull;
12 import static java.util.Objects.requireNonNull;
14 import com.google.common.collect.ImmutableList;
15 import com.google.common.collect.ImmutableList.Builder;
16 import java.text.ParseException;
17 import java.util.HexFormat;
18 import java.util.function.Supplier;
19 import org.eclipse.jdt.annotation.NonNull;
20 import org.eclipse.jdt.annotation.Nullable;
21 import org.opendaylight.restconf.api.ApiPath.ApiIdentifier;
22 import org.opendaylight.restconf.api.ApiPath.ListInstance;
23 import org.opendaylight.restconf.api.ApiPath.Step;
24 import org.opendaylight.yangtools.yang.common.YangNames;
25 import org.slf4j.Logger;
26 import org.slf4j.LoggerFactory;
29 * Parser for a sequence of {@link ApiPath}'s {@link Step}s.
32 private static final Logger LOG = LoggerFactory.getLogger(ApiPathParser.class);
35 * A lenient interpretation: '//' is '/', i.e. there is no segment.
37 private static final class Lenient extends ApiPathParser {
39 int parseStep(final String str, final int offset, final int limit) throws ParseException {
40 return offset == limit ? limit : super.parseStep(str, offset, limit);
45 * A lenient interpretation: '//' is '/', i.e. there is no segment, but also log offenders
47 private static final class Logging extends ApiPathParser {
49 private interface LogMethod {
50 void logLeniency(String format, Object arg0, Object arg1);
53 private final LogMethod method;
55 Logging(final LogMethod method) {
56 this.method = requireNonNull(method);
60 int parseStep(final String str, final int offset, final int limit) throws ParseException {
61 if (offset == limit) {
62 method.logLeniency("Ignoring duplicate slash in '{}' at offset", str, offset);
65 return super.parseStep(str, offset, limit);
69 private static final Supplier<org.opendaylight.restconf.api.ApiPathParser> URL_FACTORY;
72 // Select the correct parser implementation where consecutive slashes are concerned. We default to lenient
73 // interpretation and treat them as a single slash, but allow this to be overridden through a system property.
74 final String prop = System.getProperty("org.opendaylight.restconf.url.consecutive-slashes", "reject");
75 final String treatment;
78 treatment = "are treated as a single slash";
79 URL_FACTORY = Lenient::new;
82 treatment = "are treated as a single slash and will be logged";
83 URL_FACTORY = () -> new Logging(LOG::debug);
86 treatment = "are treated as a single slash and will be warned about";
87 URL_FACTORY = () -> new Logging(LOG::warn);
90 treatment = "will be rejected";
91 URL_FACTORY = ApiPathParser::new;
94 LOG.warn("Unknown property value '{}', assuming 'reject'", prop);
95 treatment = "will be rejected";
96 URL_FACTORY = ApiPathParser::new;
99 LOG.info("Consecutive slashes in REST URLs {}", treatment);
102 private final Builder<Step> steps = ImmutableList.builder();
105 * State tracking for creating substrings:
107 * Usually we copy spans 'src', in which case subStart captures 'start' argument to String.substring(...).
108 * If we encounter a percent escape we need to interpret as part of the string, we start building the string in
109 * subBuilder -- in which case subStart is set to -1.
111 * Note that StringBuilder is lazily-instantiated, as we have no percents at all
113 private int subStart;
114 private StringBuilder subBuilder;
116 // Lazily-allocated when we need to decode UTF-8. Since we touch this only when we are not expecting
117 private Utf8Buffer buf;
119 // the offset of the character returned from last peekBasicLatin()
120 private int nextOffset;
122 private ApiPathParser() {
126 static @NonNull ApiPathParser newStrict() {
127 return new ApiPathParser();
130 static @NonNull ApiPathParser newUrl() {
131 return URL_FACTORY.get();
135 // steps : step ("/" step)*
136 final @NonNull ImmutableList<@NonNull Step> parseSteps(final String str) throws ParseException {
139 // First process while we are seeing a slash
141 final int slash = str.indexOf('/', idx);
143 final int next = parseStep(str, idx, slash);
144 verify(next == slash, "Unconsumed bytes: %s next %s limit", next, slash);
151 // Now process the tail of the string
152 final int length = str.length();
153 final int next = parseStep(str, idx, length);
154 verify(next == length, "Unconsumed trailing bytes: %s next %s limit", next, length);
156 return steps.build();
160 // step : identifier (":" identifier)? ("=" key-value ("," key-value)*)?
161 // Note: visible for subclasses
162 int parseStep(final String str, final int offset, final int limit) throws ParseException {
163 int idx = startIdentifier(str, offset, limit);
164 while (idx < limit) {
165 final char ch = peekBasicLatin(str, idx, limit);
167 return parseStep(endSub(str, idx), str, nextOffset, limit);
168 } else if (ch == '=') {
169 return parseStep(null, endSub(str, idx), str, nextOffset, limit);
171 idx = continueIdentifer(idx, ch);
174 steps.add(new ApiIdentifier(null, endSub(str, idx)));
178 // Starting at second identifier
179 private int parseStep(final @Nullable String module, final String str, final int offset, final int limit)
180 throws ParseException {
181 int idx = startIdentifier(str, offset, limit);
182 while (idx < limit) {
183 final char ch = peekBasicLatin(str, idx, limit);
185 return parseStep(module, endSub(str, idx), str, nextOffset, limit);
187 idx = continueIdentifer(idx, ch);
190 steps.add(new ApiIdentifier(module, endSub(str, idx)));
194 // Starting at first key-value
195 private int parseStep(final @Nullable String module, final @NonNull String identifier,
196 final String str, final int offset, final int limit) throws ParseException {
197 final var values = ImmutableList.<String>builder();
201 while (idx < limit) {
202 final char ch = str.charAt(idx);
204 values.add(endSub(str, idx));
206 } else if (ch != '%') {
210 // Save current string content and capture current index for reporting
211 final var sb = flushSub(str, idx);
212 final int errorOffset = idx;
216 buf = utf = new Utf8Buffer();
220 utf.appendByte(parsePercent(str, idx, limit));
222 } while (idx < limit && str.charAt(idx) == '%');
224 utf.flushTo(sb, errorOffset);
228 steps.add(new ListInstance(module, identifier, values.add(endSub(str, idx)).build()));
232 private int startIdentifier(final String str, final int offset, final int limit) throws ParseException {
233 if (offset == limit) {
234 throw new ParseException("Identifier may not be empty", offset);
238 final char ch = peekBasicLatin(str, offset, limit);
239 if (!YangNames.IDENTIFIER_START.matches(ch)) {
240 throw new ParseException("Expecting [a-zA-Z_], not '" + ch + "'", offset);
246 private int continueIdentifer(final int offset, final char ch) throws ParseException {
247 if (YangNames.NOT_IDENTIFIER_PART.matches(ch)) {
248 throw new ParseException("Expecting [a-zA-Z_.-], not '" + ch + "'", offset);
254 // Assert current character comes from the Basic Latin block, i.e. 00-7F.
255 // Callers are expected to pick up 'nextIdx' to resume parsing at the next character
256 private char peekBasicLatin(final String str, final int offset, final int limit) throws ParseException {
257 final char ch = str.charAt(offset);
259 final byte b = parsePercent(str, offset, limit);
261 throw new ParseException("Expecting %00-%7F, not " + str.substring(offset, limit), offset);
264 flushSub(str, offset);
265 nextOffset = offset + 3;
269 if (ch < 0 || ch > 127) {
270 throw new ParseException("Unexpected character '" + ch + "'", offset);
272 nextOffset = offset + 1;
276 private void startSub(final int offset) {
280 private void append(final char ch) {
281 // We are not reusing string, append the char, otherwise
282 if (subStart == -1) {
283 verifyNotNull(subBuilder).append(ch);
287 private @NonNull String endSub(final String str, final int end) {
288 return subStart != -1 ? str.substring(subStart, end) : verifyNotNull(subBuilder).toString();
291 private @NonNull StringBuilder flushSub(final String str, final int end) {
294 subBuilder = sb = new StringBuilder();
296 if (subStart != -1) {
298 sb.append(str, subStart, end);
304 private static byte parsePercent(final String str, final int offset, final int limit) throws ParseException {
305 if (limit - offset < 3) {
306 throw new ParseException("Incomplete escape '" + str.substring(offset, limit) + "'", offset);
308 return (byte) (parseHex(str, offset + 1) << 4 | parseHex(str, offset + 2));
311 @SuppressWarnings("checkstyle:AvoidHidingCauseException")
312 private static int parseHex(final String str, final int offset) throws ParseException {
314 return HexFormat.fromHexDigit(str.charAt(offset));
315 } catch (NumberFormatException e) {
316 // There is no way to preserve the cause which CheckStyle would recognize
317 throw new ParseException(e.getMessage(), offset);