PathTemplate.java
/*
* JBoss, Home of Professional Open Source.
* Copyright 2014 Red Hat, Inc., and individual contributors
* as indicated by the @author tags.
*
* 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
*
* 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.
*/
package io.undertow.util;
import io.undertow.UndertowMessages;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
/**
* Represents a parsed web socket path template.
* <p>
* This class can be compared to other path templates, with templates that are considered
* lower have a higher priority, and should be checked first.
* <p>
* This comparison can also be used to check for semantically equal paths, if
* a.compareTo(b) == 0 then the two paths are equivalent, which will generally
* result in a deployment exception.
*
* @author Stuart Douglas
*/
public class PathTemplate implements Comparable<PathTemplate> {
private final String templateString;
private final boolean template;
private final String base;
final List<Part> parts;
private final Set<String> parameterNames;
private final boolean trailingSlash;
private PathTemplate(String templateString, final boolean template, final String base, final List<Part> parts, Set<String> parameterNames, boolean trailingSlash) {
this.templateString = templateString;
this.template = template;
this.base = base;
this.parts = parts;
this.parameterNames = Collections.unmodifiableSet(parameterNames);
this.trailingSlash = trailingSlash;
}
public static PathTemplate create(final String inputPath) {
// a path is required
if(inputPath == null) {
throw UndertowMessages.MESSAGES.pathMustBeSpecified();
}
// prepend a "/" if none is present
if(!inputPath.startsWith("/")) {
return PathTemplate.create("/" + inputPath);
}
// create string from modified string
final String path = inputPath;
int state = 0;
String base = "";
List<Part> parts = new ArrayList<>();
int stringStart = 0;
//0 parsing base
//1 parsing base, last char was /
//2 in template part
//3 just after template part, expecting /
//4 expecting either template or segment
//5 in segment
for (int i = 0; i < path.length(); ++i) {
final int c = path.charAt(i);
switch (state) {
case 0: {
if (c == '/') {
state = 1;
} else if (c == '*') {
base = path.substring(0, i + 1);
stringStart = i;
state = 5;
} else {
state = 0;
}
break;
}
case 1: {
if (c == '{') {
base = path.substring(0, i);
stringStart = i + 1;
state = 2;
} else if (c == '*') {
base = path.substring(0, i + 1);
stringStart = i;
state = 5;
} else if (c != '/') {
state = 0;
}
break;
}
case 2: {
if (c == '}') {
Part part = new Part(true, path.substring(stringStart, i));
parts.add(part);
stringStart = i;
state = 3;
}
break;
}
case 3: {
if (c == '/') {
state = 4;
} else {
throw UndertowMessages.MESSAGES.couldNotParseUriTemplate(path, i);
}
break;
}
case 4: {
if (c == '{') {
stringStart = i + 1;
state = 2;
} else if (c != '/') {
stringStart = i;
state = 5;
}
break;
}
case 5: {
if (c == '/') {
Part part = new Part(false, path.substring(stringStart, i));
parts.add(part);
stringStart = i + 1;
state = 4;
}
break;
}
}
}
boolean trailingSlash = false;
switch (state) {
case 1:
trailingSlash = true;
//fall through
case 0: {
base = path;
break;
}
case 2: {
throw UndertowMessages.MESSAGES.couldNotParseUriTemplate(path, path.length());
}
case 4: {
trailingSlash = true;
break;
}
case 5: {
Part part = new Part(false, path.substring(stringStart));
parts.add(part);
break;
}
}
final Set<String> templates = new HashSet<>();
for(Part part : parts) {
if(part.template) {
templates.add(part.part);
}
}
return new PathTemplate(path, state > 1 && !base.contains("*"), base, parts, templates, trailingSlash);
}
/**
* Check if the given uri matches the template. If so then it will return true and
* place the value of any path parameters into the given map.
* <p>
* Note the map may be modified even if the match in unsuccessful, however in this case
* it will be emptied before the method returns
*
* @param path The request path, relative to the context root
* @param pathParameters The path parameters map to fill out
* @return true if the URI is a match
*/
public boolean matches(final String path, final Map<String, String> pathParameters) {
if (!template && base.contains("*")) {
final int indexOf = base.indexOf("*");
final String startBase = base.substring(0, indexOf);
if (!path.startsWith(startBase)) {
return false;
}
pathParameters.put("*", path.substring(indexOf,path.length()));
return true;
}
if (!path.startsWith(base)) {
return false;
}
int baseLength = base.length();
if (!template) {
return path.length() == baseLength;
}
if(trailingSlash) {
//the template has a trailing slash
//we verify this first as it is cheap
//and it simplifies the matching algorithm below
if(path.charAt(path.length() -1 ) != '/') {
return false;
}
}
int currentPartPosition = 0;
PathTemplate.Part current = parts.get(currentPartPosition);
int stringStart = baseLength;
int i;
for (i = baseLength; i < path.length(); ++i) {
final char currentChar = path.charAt(i);
if (currentChar == '?' || current.part.equals("*")) {
break;
} else if (currentChar == '/') {
String result = path.substring(stringStart, i);
if (current.template) {
pathParameters.put(current.part, result);
} else if (!result.equals(current.part)) {
pathParameters.clear();
return false;
}
++currentPartPosition;
if (currentPartPosition == parts.size()) {
//this is a match if this is the last character
return i == (path.length() - 1);
}
current = parts.get(currentPartPosition);
stringStart = i + 1;
}
}
if (currentPartPosition + 1 != parts.size()) {
pathParameters.clear();
return false;
}
String result = path.substring(stringStart, i);
if (current.part.equals("*")) {
pathParameters.put(current.part, path.substring(stringStart,path.length()));
return true;
}
if (current.template) {
pathParameters.put(current.part, result);
} else if (!result.equals(current.part)) {
pathParameters.clear();
return false;
}
return true;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (!(o instanceof PathTemplate)) return false;
PathTemplate that = (PathTemplate) o;
return this.compareTo(that) == 0;
}
@Override
public int hashCode() {
int result = getTemplateString() != null ? getTemplateString().hashCode() : 0;
result = 31 * result + (template ? 1 : 0);
result = 31 * result + (getBase() != null ? getBase().hashCode() : 0);
result = 31 * result + (parts != null ? parts.hashCode() : 0);
result = 31 * result + (getParameterNames() != null ? getParameterNames().hashCode() : 0);
return result;
}
@Override
public int compareTo(final PathTemplate o) {
//we want templates with the highest priority to sort first
//so we sort in reverse priority order
//templates have lower priority
if (template && !o.template) {
return 1;
} else if (o.template && !template) {
return -1;
}
int res = base.compareTo(o.base);
if (res > 0) {
//our base is longer
return -1;
} else if (res < 0) {
return 1;
} else if (!template) {
//they are the same path
return 0;
}
//the first path with a non-template element
int i = 0;
for (; ; ) {
if (parts.size() == i) {
if (o.parts.size() == i) {
return base.compareTo(o.base);
}
return 1;
} else if (o.parts.size() == i) {
//we have more parts, so should be checked first
return -1;
}
Part thisPath = parts.get(i);
Part otherPart = o.parts.get(i);
if (thisPath.template && !otherPart.template) {
//non template part sorts first
return 1;
} else if (!thisPath.template && otherPart.template) {
return -1;
} else if (!thisPath.template) {
int r = thisPath.part.compareTo(otherPart.part);
if (r != 0) {
return r;
}
}
++i;
}
}
public String getBase() {
return base;
}
public String getTemplateString() {
return templateString;
}
public Set<String> getParameterNames() {
return parameterNames;
}
private static class Part {
final boolean template;
final String part;
private Part(final boolean template, final String part) {
this.template = template;
this.part = part;
}
@Override
public String toString() {
return "Part{" +
"template=" + template +
", part='" + part + '\'' +
'}';
}
}
@Override
public String toString() {
return "PathTemplate{" +
"template=" + template +
", base='" + base + '\'' +
", parts=" + parts +
'}';
}
}