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<@NonNull 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;
76 URL_FACTORY = switch (prop) {
78 treatment = "are treated as a single slash";
82 treatment = "are treated as a single slash and will be logged";
83 yield () -> new Logging(LOG::debug);
86 treatment = "are treated as a single slash and will be warned about";
87 yield () -> new Logging(LOG::warn);
90 treatment = "will be rejected";
91 yield ApiPathParser::new;
94 LOG.warn("Unknown property value '{}', assuming 'reject'", prop);
95 treatment = "will be rejected";
96 yield ApiPathParser::new;
100 LOG.info("Consecutive slashes in REST URLs {}", treatment);
103 private final Builder<Step> steps = ImmutableList.builder();
106 * State tracking for creating substrings:
108 * Usually we copy spans 'src', in which case subStart captures 'start' argument to String.substring(...).
109 * If we encounter a percent escape we need to interpret as part of the string, we start building the string in
110 * subBuilder -- in which case subStart is set to -1.
112 * Note that StringBuilder is lazily-instantiated, as we have no percents at all
114 private int subStart;
115 private StringBuilder subBuilder;
117 // Lazily-allocated when we need to decode UTF-8. Since we touch this only when we are not expecting
118 private Utf8Buffer buf;
120 // the offset of the character returned from last peekBasicLatin()
121 private int nextOffset;
123 private ApiPathParser() {
127 static @NonNull ApiPathParser newStrict() {
128 return new ApiPathParser();
131 static @NonNull ApiPathParser newUrl() {
132 return URL_FACTORY.get();
136 // steps : step ("/" step)*
137 final @NonNull ImmutableList<@NonNull Step> parseSteps(final String str) throws ParseException {
140 // First process while we are seeing a slash
142 final int slash = str.indexOf('/', idx);
144 final int next = parseStep(str, idx, slash);
145 verify(next == slash, "Unconsumed bytes: %s next %s limit", next, slash);
152 // Now process the tail of the string
153 final int length = str.length();
154 final int next = parseStep(str, idx, length);
155 verify(next == length, "Unconsumed trailing bytes: %s next %s limit", next, length);
157 return steps.build();
161 // step : identifier (":" identifier)? ("=" key-value ("," key-value)*)?
162 // Note: visible for subclasses
163 int parseStep(final String str, final int offset, final int limit) throws ParseException {
164 int idx = startIdentifier(str, offset, limit);
165 while (idx < limit) {
166 final char ch = peekBasicLatin(str, idx, limit);
168 return parseStep(endSub(str, idx), str, nextOffset, limit);
169 } else if (ch == '=') {
170 return parseStep(null, endSub(str, idx), str, nextOffset, limit);
172 idx = continueIdentifer(idx, ch);
175 steps.add(new ApiIdentifier(null, endSub(str, idx)));
179 // Starting at second identifier
180 private int parseStep(final @Nullable String module, final String str, final int offset, final int limit)
181 throws ParseException {
182 int idx = startIdentifier(str, offset, limit);
183 while (idx < limit) {
184 final char ch = peekBasicLatin(str, idx, limit);
186 return parseStep(module, endSub(str, idx), str, nextOffset, limit);
188 idx = continueIdentifer(idx, ch);
191 steps.add(new ApiIdentifier(module, endSub(str, idx)));
195 // Starting at first key-value
196 private int parseStep(final @Nullable String module, final @NonNull String identifier,
197 final String str, final int offset, final int limit) throws ParseException {
198 final var values = ImmutableList.<String>builder();
202 while (idx < limit) {
203 final char ch = str.charAt(idx);
205 values.add(endSub(str, idx));
207 } else if (ch != '%') {
211 // Save current string content and capture current index for reporting
212 final var sb = flushSub(str, idx);
213 final int errorOffset = idx;
217 buf = utf = new Utf8Buffer();
221 utf.appendByte(parsePercent(str, idx, limit));
223 } while (idx < limit && str.charAt(idx) == '%');
225 utf.flushTo(sb, errorOffset);
229 steps.add(new ListInstance(module, identifier, values.add(endSub(str, idx)).build()));
233 private int startIdentifier(final String str, final int offset, final int limit) throws ParseException {
234 if (offset == limit) {
235 throw new ParseException("Identifier may not be empty", offset);
239 final char ch = peekBasicLatin(str, offset, limit);
240 if (!YangNames.IDENTIFIER_START.matches(ch)) {
241 throw new ParseException("Expecting [a-zA-Z_], not '" + ch + "'", offset);
247 private int continueIdentifer(final int offset, final char ch) throws ParseException {
248 if (YangNames.NOT_IDENTIFIER_PART.matches(ch)) {
249 throw new ParseException("Expecting [a-zA-Z_.-], not '" + ch + "'", offset);
255 // Assert current character comes from the Basic Latin block, i.e. 00-7F.
256 // Callers are expected to pick up 'nextIdx' to resume parsing at the next character
257 private char peekBasicLatin(final String str, final int offset, final int limit) throws ParseException {
258 final char ch = str.charAt(offset);
260 final byte b = parsePercent(str, offset, limit);
262 throw new ParseException("Expecting %00-%7F, not " + str.substring(offset, limit), offset);
265 flushSub(str, offset);
266 nextOffset = offset + 3;
270 if (ch < 0 || ch > 127) {
271 throw new ParseException("Unexpected character '" + ch + "'", offset);
273 nextOffset = offset + 1;
277 private void startSub(final int offset) {
281 private void append(final char ch) {
282 // We are not reusing string, append the char, otherwise
283 if (subStart == -1) {
284 verifyNotNull(subBuilder).append(ch);
288 private @NonNull String endSub(final String str, final int end) {
289 return subStart != -1 ? str.substring(subStart, end) : verifyNotNull(subBuilder).toString();
292 private @NonNull StringBuilder flushSub(final String str, final int end) {
295 subBuilder = sb = new StringBuilder();
297 if (subStart != -1) {
299 sb.append(str, subStart, end);
305 private static byte parsePercent(final String str, final int offset, final int limit) throws ParseException {
306 if (limit - offset < 3) {
307 throw new ParseException("Incomplete escape '" + str.substring(offset, limit) + "'", offset);
309 return (byte) (parseHex(str, offset + 1) << 4 | parseHex(str, offset + 2));
312 @SuppressWarnings("checkstyle:AvoidHidingCauseException")
313 private static int parseHex(final String str, final int offset) throws ParseException {
315 return HexFormat.fromHexDigit(str.charAt(offset));
316 } catch (NumberFormatException e) {
317 // There is no way to preserve the cause which CheckStyle would recognize
318 throw new ParseException(e.getMessage(), offset);