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/*
* Copyright 2002-2022 the original author or authors.
*
* Licensed 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
*
* https://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.
*/
package org.springframework.web.util.pattern;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.StringJoiner;
import org.springframework.http.server.PathContainer;
import org.springframework.http.server.PathContainer.Element;
import org.springframework.http.server.PathContainer.Separator;
import org.springframework.lang.Nullable;
import org.springframework.util.CollectionUtils;
import org.springframework.util.MultiValueMap;
import org.springframework.util.StringUtils;
/**
* Representation of a parsed path pattern. Includes a chain of path elements
* for fast matching and accumulates computed state for quick comparison of
* patterns.
*
* {@code PathPattern} matches URL paths using the following rules:
*
* - {@code ?} matches one character
* - {@code *} matches zero or more characters within a path segment
* - {@code **} matches zero or more path segments until the end of the path
* {spring} matches a path segment and captures it as a variable named "spring"{spring:[a-z]+} matches the regexp {@code [a-z]+} as a path variable named "spring"{*spring} matches zero or more path segments until the end of the path
* and captures it as a variable named "spring"
*
* Note: In contrast to
* {@link org.springframework.util.AntPathMatcher}, {@code **} is supported only
* at the end of a pattern. For example {@code /pages/{**}} is valid but
* {@code /pages/{**}/details} is not. The same applies also to the capturing
* variant {*spring}. The aim is to eliminate ambiguity when
* comparing patterns for specificity.
*
*
Examples
*
* - {@code /pages/t?st.html} — matches {@code /pages/test.html} as well as
* {@code /pages/tXst.html} but not {@code /pages/toast.html}
* - {@code /resources/*.png} — matches all {@code .png} files in the
* {@code resources} directory
* /resources/** — matches all files
* underneath the {@code /resources/} path, including {@code /resources/image.png}
* and {@code /resources/css/spring.css}/resources/{*path} — matches all files
* underneath the {@code /resources/}, as well as {@code /resources}, and captures
* their relative path in a variable named "path"; {@code /resources/image.png}
* will match with "path" → "/image.png", and {@code /resources/css/spring.css}
* will match with "path" → "/css/spring.css"/resources/{filename:\\w+}.dat will match {@code /resources/spring.dat}
* and assign the value {@code "spring"} to the {@code filename} variable
*
* @author Andy Clement
* @author Rossen Stoyanchev
* @since 5.0
* @see PathContainer
*/
public class PathPattern implements Comparable {
private static final PathContainer EMPTY_PATH = PathContainer.parsePath("");
/**
* Comparator that sorts patterns by specificity as follows:
*
* - Null instances are last.
*
- Catch-all patterns are last.
*
- If both patterns are catch-all, consider the length (longer wins).
*
- Compare wildcard and captured variable count (lower wins).
*
- Consider length (longer wins)
*
*/
public static final Comparator SPECIFICITY_COMPARATOR =
Comparator.nullsLast(
Comparator.
comparingInt(p -> p.isCatchAll() ? 1 : 0)
.thenComparingInt(p -> p.isCatchAll() ? scoreByNormalizedLength(p) : 0)
.thenComparingInt(PathPattern::getScore)
.thenComparingInt(PathPattern::scoreByNormalizedLength)
);
/** The text of the parsed pattern. */
private final String patternString;
/** The parser used to construct this pattern. */
private final PathPatternParser parser;
/** The options to use to parse a pattern. */
private final PathContainer.Options pathOptions;
/** If this pattern has no trailing slash, allow candidates to include one and still match successfully. */
private final boolean matchOptionalTrailingSeparator;
/** Will this match candidates in a case-sensitive way? (case sensitivity at parse time). */
private final boolean caseSensitive;
/** First path element in the parsed chain of path elements for this pattern. */
@Nullable
private final PathElement head;
/** How many variables are captured in this pattern. */
private int capturedVariableCount;
/**
* The normalized length is trying to measure the 'active' part of the pattern. It is computed
* by assuming all captured variables have a normalized length of 1. Effectively this means changing
* your variable name lengths isn't going to change the length of the active part of the pattern.
* Useful when comparing two patterns.
*/
private int normalizedLength;
/**
* Does the pattern end with '<separator>'.
*/
private boolean endsWithSeparatorWildcard = false;
/**
* Score is used to quickly compare patterns. Different pattern components are given different
* weights. A 'lower score' is more specific. Current weights:
*
* - Captured variables are worth 1
*
- Wildcard is worth 100
*
*/
private int score;
/** Does the pattern end with {*...}. */
private boolean catchAll = false;
PathPattern(String patternText, PathPatternParser parser, @Nullable PathElement head) {
this.patternString = patternText;
this.parser = parser;
this.pathOptions = parser.getPathOptions();
this.matchOptionalTrailingSeparator = parser.isMatchOptionalTrailingSeparator();
this.caseSensitive = parser.isCaseSensitive();
this.head = head;
// Compute fields for fast comparison
PathElement elem = head;
while (elem != null) {
this.capturedVariableCount += elem.getCaptureCount();
this.normalizedLength += elem.getNormalizedLength();
this.score += elem.getScore();
if (elem instanceof CaptureTheRestPathElement || elem instanceof WildcardTheRestPathElement) {
this.catchAll = true;
}
if (elem instanceof SeparatorPathElement && elem.next instanceof WildcardPathElement && elem.next.next == null) {
this.endsWithSeparatorWildcard = true;
}
elem = elem.next;
}
}
/**
* Return the original String that was parsed to create this PathPattern.
*/
public String getPatternString() {
return this.patternString;
}
/**
* Whether the pattern string contains pattern syntax that would require
* use of {@link #matches(PathContainer)}, or if it is a regular String that
* could be compared directly to others.
* @since 5.2
*/
public boolean hasPatternSyntax() {
return (this.score > 0 || this.catchAll || this.patternString.indexOf('?') != -1);
}
/**
* Whether this pattern matches the given path.
* @param pathContainer the candidate path to attempt to match against
* @return {@code true} if the path matches this pattern
*/
public boolean matches(PathContainer pathContainer) {
if (this.head == null) {
return !hasLength(pathContainer) ||
(this.matchOptionalTrailingSeparator && pathContainerIsJustSeparator(pathContainer));
}
else if (!hasLength(pathContainer)) {
if (this.head instanceof WildcardTheRestPathElement || this.head instanceof CaptureTheRestPathElement) {
pathContainer = EMPTY_PATH; // Will allow CaptureTheRest to bind the variable to empty
}
else {
return false;
}
}
MatchingContext matchingContext = new MatchingContext(pathContainer, false);
return this.head.matches(0, matchingContext);
}
/**
* Match this pattern to the given URI path and return extracted URI template
* variables as well as path parameters (matrix variables).
* @param pathContainer the candidate path to attempt to match against
* @return info object with the extracted variables, or {@code null} for no match
*/
@Nullable
public PathMatchInfo matchAndExtract(PathContainer pathContainer) {
if (this.head == null) {
return (hasLength(pathContainer) &&
!(this.matchOptionalTrailingSeparator && pathContainerIsJustSeparator(pathContainer)) ?
null : PathMatchInfo.EMPTY);
}
else if (!hasLength(pathContainer)) {
if (this.head instanceof WildcardTheRestPathElement || this.head instanceof CaptureTheRestPathElement) {
pathContainer = EMPTY_PATH; // Will allow CaptureTheRest to bind the variable to empty
}
else {
return null;
}
}
MatchingContext matchingContext = new MatchingContext(pathContainer, true);
return this.head.matches(0, matchingContext) ? matchingContext.getPathMatchResult() : null;
}
/**
* Match the beginning of the given path and return the remaining portion
* not covered by this pattern. This is useful for matching nested routes
* where the path is matched incrementally at each level.
* @param pathContainer the candidate path to attempt to match against
* @return info object with the match result or {@code null} for no match
*/
@Nullable
public PathRemainingMatchInfo matchStartOfPath(PathContainer pathContainer) {
if (this.head == null) {
return new PathRemainingMatchInfo(EMPTY_PATH, pathContainer);
}
else if (!hasLength(pathContainer)) {
return null;
}
MatchingContext matchingContext = new MatchingContext(pathContainer, true);
matchingContext.setMatchAllowExtraPath();
boolean matches = this.head.matches(0, matchingContext);
if (!matches) {
return null;
}
else {
PathContainer pathMatched;
PathContainer pathRemaining;
if (matchingContext.remainingPathIndex == pathContainer.elements().size()) {
pathMatched = pathContainer;
pathRemaining = EMPTY_PATH;
}
else {
pathMatched = pathContainer.subPath(0, matchingContext.remainingPathIndex);
pathRemaining = pathContainer.subPath(matchingContext.remainingPathIndex);
}
return new PathRemainingMatchInfo(pathMatched, pathRemaining, matchingContext.getPathMatchResult());
}
}
/**
* Determine the pattern-mapped part for the given path.
* For example:
* - '{@code /docs/cvs/commit.html}' and '{@code /docs/cvs/commit.html} → ''
* - '{@code /docs/*}' and '{@code /docs/cvs/commit}' → '{@code cvs/commit}'
* - '{@code /docs/cvs/*.html}' and '{@code /docs/cvs/commit.html} → '{@code commit.html}'
* - '{@code /docs/**}' and '{@code /docs/cvs/commit} → '{@code cvs/commit}'
*
* Notes:
*
* - Assumes that {@link #matches} returns {@code true} for
* the same path but does not enforce this.
*
- Duplicate occurrences of separators within the returned result are removed
*
- Leading and trailing separators are removed from the returned result
*
* @param path a path that matches this pattern
* @return the subset of the path that is matched by pattern or "" if none
* of it is matched by pattern elements
*/
public PathContainer extractPathWithinPattern(PathContainer path) {
List pathElements = path.elements();
int pathElementsCount = pathElements.size();
int startIndex = 0;
// Find first path element that is not a separator or a literal (i.e. the first pattern based element)
PathElement elem = this.head;
while (elem != null) {
if (!elem.isLiteral()) {
break;
}
elem = elem.next;
startIndex++;
}
if (elem == null) {
// There is no pattern piece
return PathContainer.parsePath("");
}
// Skip leading separators that would be in the result
while (startIndex < pathElementsCount && (pathElements.get(startIndex) instanceof Separator)) {
startIndex++;
}
int endIndex = pathElements.size();
// Skip trailing separators that would be in the result
while (endIndex > 0 && (pathElements.get(endIndex - 1) instanceof Separator)) {
endIndex--;
}
boolean multipleAdjacentSeparators = false;
for (int i = startIndex; i < (endIndex - 1); i++) {
if ((pathElements.get(i) instanceof Separator) && (pathElements.get(i+1) instanceof Separator)) {
multipleAdjacentSeparators=true;
break;
}
}
PathContainer resultPath = null;
if (multipleAdjacentSeparators) {
// Need to rebuild the path without the duplicate adjacent separators
StringBuilder sb = new StringBuilder();
int i = startIndex;
while (i < endIndex) {
Element e = pathElements.get(i++);
sb.append(e.value());
if (e instanceof Separator) {
while (i < endIndex && (pathElements.get(i) instanceof Separator)) {
i++;
}
}
}
resultPath = PathContainer.parsePath(sb.toString(), this.pathOptions);
}
else if (startIndex >= endIndex) {
resultPath = PathContainer.parsePath("");
}
else {
resultPath = path.subPath(startIndex, endIndex);
}
return resultPath;
}
/**
* Compare this pattern with a supplied pattern: return -1,0,+1 if this pattern
* is more specific, the same or less specific than the supplied pattern.
* The aim is to sort more specific patterns first.
*/
@Override
public int compareTo(@Nullable PathPattern otherPattern) {
int result = SPECIFICITY_COMPARATOR.compare(this, otherPattern);
return (result == 0 && otherPattern != null ?
this.patternString.compareTo(otherPattern.patternString) : result);
}
/**
* Combine this pattern with another.
*/
public PathPattern combine(PathPattern pattern2string) {
// If one of them is empty the result is the other. If both empty the result is ""
if (!StringUtils.hasLength(this.patternString)) {
if (!StringUtils.hasLength(pattern2string.patternString)) {
return this.parser.parse("");
}
else {
return pattern2string;
}
}
else if (!StringUtils.hasLength(pattern2string.patternString)) {
return this;
}
// /* + /hotel => /hotel
// /*.* + /*.html => /*.html
// However:
// /usr + /user => /usr/user
// /{foo} + /bar => /{foo}/bar
if (!this.patternString.equals(pattern2string.patternString) && this.capturedVariableCount == 0 &&
matches(PathContainer.parsePath(pattern2string.patternString))) {
return pattern2string;
}
// /hotels/* + /booking => /hotels/booking
// /hotels/* + booking => /hotels/booking
if (this.endsWithSeparatorWildcard) {
return this.parser.parse(concat(
this.patternString.substring(0, this.patternString.length() - 2),
pattern2string.patternString));
}
// /hotels + /booking => /hotels/booking
// /hotels + booking => /hotels/booking
int starDotPos1 = this.patternString.indexOf("*."); // Are there any file prefix/suffix things to consider?
if (this.capturedVariableCount != 0 || starDotPos1 == -1 || getSeparator() == '.') {
return this.parser.parse(concat(this.patternString, pattern2string.patternString));
}
// /*.html + /hotel => /hotel.html
// /*.html + /hotel.* => /hotel.html
String firstExtension = this.patternString.substring(starDotPos1 + 1); // looking for the first extension
String p2string = pattern2string.patternString;
int dotPos2 = p2string.indexOf('.');
String file2 = (dotPos2 == -1 ? p2string : p2string.substring(0, dotPos2));
String secondExtension = (dotPos2 == -1 ? "" : p2string.substring(dotPos2));
boolean firstExtensionWild = (firstExtension.equals(".*") || firstExtension.isEmpty());
boolean secondExtensionWild = (secondExtension.equals(".*") || secondExtension.isEmpty());
if (!firstExtensionWild && !secondExtensionWild) {
throw new IllegalArgumentException(
"Cannot combine patterns: " + this.patternString + " and " + pattern2string);
}
return this.parser.parse(file2 + (firstExtensionWild ? secondExtension : firstExtension));
}
@Override
public boolean equals(@Nullable Object other) {
if (!(other instanceof PathPattern)) {
return false;
}
PathPattern otherPattern = (PathPattern) other;
return (this.patternString.equals(otherPattern.getPatternString()) &&
getSeparator() == otherPattern.getSeparator() &&
this.caseSensitive == otherPattern.caseSensitive);
}
@Override
public int hashCode() {
return (this.patternString.hashCode() + getSeparator()) * 17 + (this.caseSensitive ? 1 : 0);
}
@Override
public String toString() {
return this.patternString;
}
int getScore() {
return this.score;
}
boolean isCatchAll() {
return this.catchAll;
}
/**
* The normalized length is trying to measure the 'active' part of the pattern. It is computed
* by assuming all capture variables have a normalized length of 1. Effectively this means changing
* your variable name lengths isn't going to change the length of the active part of the pattern.
* Useful when comparing two patterns.
*/
int getNormalizedLength() {
return this.normalizedLength;
}
char getSeparator() {
return this.pathOptions.separator();
}
int getCapturedVariableCount() {
return this.capturedVariableCount;
}
String toChainString() {
StringJoiner stringJoiner = new StringJoiner(" ");
PathElement pe = this.head;
while (pe != null) {
stringJoiner.add(pe.toString());
pe = pe.next;
}
return stringJoiner.toString();
}
/**
* Return the string form of the pattern built from walking the path element chain.
* @return the string form of the pattern
*/
String computePatternString() {
StringBuilder sb = new StringBuilder();
PathElement pe = this.head;
while (pe != null) {
sb.append(pe.getChars());
pe = pe.next;
}
return sb.toString();
}
@Nullable
PathElement getHeadSection() {
return this.head;
}
/**
* Join two paths together including a separator if necessary.
* Extraneous separators are removed (if the first path
* ends with one and the second path starts with one).
* @param path1 first path
* @param path2 second path
* @return joined path that may include separator if necessary
*/
private String concat(String path1, String path2) {
boolean path1EndsWithSeparator = (path1.charAt(path1.length() - 1) == getSeparator());
boolean path2StartsWithSeparator = (path2.charAt(0) == getSeparator());
if (path1EndsWithSeparator && path2StartsWithSeparator) {
return path1 + path2.substring(1);
}
else if (path1EndsWithSeparator || path2StartsWithSeparator) {
return path1 + path2;
}
else {
return path1 + getSeparator() + path2;
}
}
/**
* Return if the container is not null and has more than zero elements.
* @param container a path container
* @return {@code true} has more than zero elements
*/
private boolean hasLength(@Nullable PathContainer container) {
return container != null && container.elements().size() > 0;
}
private static int scoreByNormalizedLength(PathPattern pattern) {
return -pattern.getNormalizedLength();
}
private boolean pathContainerIsJustSeparator(PathContainer pathContainer) {
return pathContainer.value().length() == 1 &&
pathContainer.value().charAt(0) == getSeparator();
}
/**
* Holder for URI variables and path parameters (matrix variables) extracted
* based on the pattern for a given matched path.
*/
public static class PathMatchInfo {
private static final PathMatchInfo EMPTY = new PathMatchInfo(Collections.emptyMap(), Collections.emptyMap());
private final Map uriVariables;
private final Map> matrixVariables;
PathMatchInfo(Map uriVars, @Nullable Map> matrixVars) {
this.uriVariables = Collections.unmodifiableMap(uriVars);
this.matrixVariables = (matrixVars != null ?
Collections.unmodifiableMap(matrixVars) : Collections.emptyMap());
}
/**
* Return the extracted URI variables.
*/
public Map getUriVariables() {
return this.uriVariables;
}
/**
* Return maps of matrix variables per path segment, keyed off by URI
* variable name.
*/
public Map> getMatrixVariables() {
return this.matrixVariables;
}
@Override
public String toString() {
return "PathMatchInfo[uriVariables=" + this.uriVariables + ", " +
"matrixVariables=" + this.matrixVariables + "]";
}
}
/**
* Holder for the result of a match on the start of a pattern.
* Provides access to the remaining path not matched to the pattern as well
* as any variables bound in that first part that was matched.
*/
public static class PathRemainingMatchInfo {
private final PathContainer pathMatched;
private final PathContainer pathRemaining;
private final PathMatchInfo pathMatchInfo;
PathRemainingMatchInfo(PathContainer pathMatched, PathContainer pathRemaining) {
this(pathMatched, pathRemaining, PathMatchInfo.EMPTY);
}
PathRemainingMatchInfo(PathContainer pathMatched, PathContainer pathRemaining,
PathMatchInfo pathMatchInfo) {
this.pathRemaining = pathRemaining;
this.pathMatched = pathMatched;
this.pathMatchInfo = pathMatchInfo;
}
/**
* Return the part of a path that was matched by a pattern.
* @since 5.3
*/
public PathContainer getPathMatched() {
return this.pathMatched;
}
/**
* Return the part of a path that was not matched by a pattern.
*/
public PathContainer getPathRemaining() {
return this.pathRemaining;
}
/**
* Return variables that were bound in the part of the path that was
* successfully matched or an empty map.
*/
public Map getUriVariables() {
return this.pathMatchInfo.getUriVariables();
}
/**
* Return the path parameters for each bound variable.
*/
public Map> getMatrixVariables() {
return this.pathMatchInfo.getMatrixVariables();
}
}
/**
* Encapsulates context when attempting a match. Includes some fixed state like the
* candidate currently being considered for a match but also some accumulators for
* extracted variables.
*/
class MatchingContext {
final PathContainer candidate;
final List pathElements;
final int pathLength;
@Nullable
private Map extractedUriVariables;
@Nullable
private Map> extractedMatrixVariables;
boolean extractingVariables;
boolean determineRemainingPath = false;
// if determineRemaining is true, this is set to the position in
// the candidate where the pattern finished matching - i.e. it
// points to the remaining path that wasn't consumed
int remainingPathIndex;
public MatchingContext(PathContainer pathContainer, boolean extractVariables) {
this.candidate = pathContainer;
this.pathElements = pathContainer.elements();
this.pathLength = this.pathElements.size();
this.extractingVariables = extractVariables;
}
public void setMatchAllowExtraPath() {
this.determineRemainingPath = true;
}
public boolean isMatchOptionalTrailingSeparator() {
return matchOptionalTrailingSeparator;
}
public void set(String key, String value, MultiValueMap parameters) {
if (this.extractedUriVariables == null) {
this.extractedUriVariables = new HashMap<>();
}
this.extractedUriVariables.put(key, value);
if (!parameters.isEmpty()) {
if (this.extractedMatrixVariables == null) {
this.extractedMatrixVariables = new HashMap<>();
}
this.extractedMatrixVariables.put(key, CollectionUtils.unmodifiableMultiValueMap(parameters));
}
}
public PathMatchInfo getPathMatchResult() {
if (this.extractedUriVariables == null) {
return PathMatchInfo.EMPTY;
}
else {
return new PathMatchInfo(this.extractedUriVariables, this.extractedMatrixVariables);
}
}
/**
* Return if element at specified index is a separator.
* @param pathIndex possible index of a separator
* @return {@code true} if element is a separator
*/
boolean isSeparator(int pathIndex) {
return this.pathElements.get(pathIndex) instanceof Separator;
}
/**
* Return the decoded value of the specified element.
* @param pathIndex path element index
* @return the decoded value
*/
String pathElementValue(int pathIndex) {
Element element = (pathIndex < this.pathLength) ? this.pathElements.get(pathIndex) : null;
if (element instanceof PathContainer.PathSegment) {
return ((PathContainer.PathSegment)element).valueToMatch();
}
return "";
}
}
}
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