/**
* Copyright 2005-2014 Restlet
*
* The contents of this file are subject to the terms of one of the following
* open source licenses: Apache 2.0 or or EPL 1.0 (the "Licenses"). You can
* select the license that you prefer but you may not use this file except in
* compliance with one of these Licenses.
*
* You can obtain a copy of the Apache 2.0 license at
* http://www.opensource.org/licenses/apache-2.0
*
* You can obtain a copy of the EPL 1.0 license at
* http://www.opensource.org/licenses/eclipse-1.0
*
* See the Licenses for the specific language governing permissions and
* limitations under the Licenses.
*
* Alternatively, you can obtain a royalty free commercial license with less
* limitations, transferable or non-transferable, directly at
* http://restlet.com/products/restlet-framework
*
* Restlet is a registered trademark of Restlet S.A.S.
*/
package org.restlet.routing;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.logging.Logger;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.restlet.Context;
import org.restlet.Request;
import org.restlet.Response;
import org.restlet.data.Reference;
import org.restlet.util.Resolver;
/**
* String template with a pluggable model. Supports both formatting and parsing.
* The template variables can be inserted using the "{name}" syntax and
* described using the modifiable map of variable descriptors. When no
* descriptor is found for a given variable, the template logic uses its default
* variable property initialized using the default {@link Variable} constructor.<br>
* <br>
* Note that the variable descriptors can be changed before the first parsing or
* matching call. After that point, changes won't be taken into account.<br>
* <br>
* Format and parsing methods are specially available to deal with requests and
* response. See {@link #format(Request, Response)} and
* {@link #parse(String, Request)}.
*
* @see Resolver
* @see <a href="http://code.google.com/p/uri-templates/">URI Template
* specification</a>
* @author Jerome Louvel
*/
public class Template {
/** Mode where all characters must match the template and size be identical. */
public static final int MODE_EQUALS = 2;
/** Mode where characters at the beginning must match the template. */
public static final int MODE_STARTS_WITH = 1;
/**
* Appends to a pattern a repeating group of a given content based on a
* class of characters.
*
* @param pattern
* The pattern to append to.
* @param content
* The content of the group.
* @param required
* Indicates if the group is required.
*/
private static void appendClass(StringBuilder pattern, String content,
boolean required) {
pattern.append("(");
if (content.equals(".")) {
// Special case for the TYPE_ALL variable type because the
// dot looses its meaning inside a character class
pattern.append(content);
} else {
pattern.append("[").append(content).append(']');
}
if (required) {
pattern.append("+");
} else {
pattern.append("*");
}
pattern.append(")");
}
/**
* Appends to a pattern a repeating group of a given content based on a
* non-capturing group.
*
* @param pattern
* The pattern to append to.
* @param content
* The content of the group.
* @param required
* Indicates if the group is required.
*/
private static void appendGroup(StringBuilder pattern, String content,
boolean required) {
pattern.append("((?:").append(content).append(')');
if (required) {
pattern.append("+");
} else {
pattern.append("*");
}
pattern.append(")");
}
/**
* Returns the Regex pattern string corresponding to a variable.
*
* @param variable
* The variable.
* @return The Regex pattern string corresponding to a variable.
*/
private static String getVariableRegex(Variable variable) {
String result = null;
if (variable.isFixed()) {
result = "(" + Pattern.quote(variable.getDefaultValue()) + ")";
} else {
// Expressions to create character classes
final String ALL = ".";
final String ALPHA = "a-zA-Z";
final String DIGIT = "\\d";
final String ALPHA_DIGIT = ALPHA + DIGIT;
final String HEXA = DIGIT + "ABCDEFabcdef";
final String URI_UNRESERVED = ALPHA_DIGIT + "\\-\\.\\_\\~";
final String URI_GEN_DELIMS = "\\:\\/\\?\\#\\[\\]\\@";
final String URI_SUB_DELIMS = "\\!\\$\\&\\'\\(\\)\\*\\+\\,\\;\\=";
final String URI_RESERVED = URI_GEN_DELIMS + URI_SUB_DELIMS;
final String WORD = "\\w";
// Basic rules expressed by the HTTP rfc.
final String CRLF = "\\r\\n";
final String CTL = "\\p{Cntrl}";
final String LWS = CRLF + "\\ \\t";
final String SEPARATOR = "\\(\\)\\<\\>\\@\\,\\;\\:\\[\\]\"\\/\\\\?\\=\\{\\}\\ \\t";
final String TOKEN = "[^" + SEPARATOR + "]";
final String COMMENT = "[^" + CTL + "]" + "[^\\(\\)]" + LWS;
final String COMMENT_ATTRIBUTE = "[^\\;\\(\\)]";
// Expressions to create non-capturing groups
final String PCT_ENCODED = "\\%[" + HEXA + "][" + HEXA + "]";
// final String PCHAR = "[" + URI_UNRESERVED + "]|(?:" + PCT_ENCODED
// + ")|[" + URI_SUB_DELIMS + "]|\\:|\\@";
final String PCHAR = "[" + URI_UNRESERVED + URI_SUB_DELIMS
+ "\\:\\@]|(?:" + PCT_ENCODED + ")";
final String QUERY = PCHAR + "|\\/|\\?";
final String FRAGMENT = QUERY;
final String URI_PATH = PCHAR + "|\\/";
final String URI_ALL = "[" + URI_RESERVED + URI_UNRESERVED
+ "]|(?:" + PCT_ENCODED + ")";
// Special case of query parameter characters
final String QUERY_PARAM_DELIMS = "\\!\\$\\'\\(\\)\\*\\+\\,\\;";
final String QUERY_PARAM_CHAR = "[" + URI_UNRESERVED
+ QUERY_PARAM_DELIMS + "\\:\\@]|(?:" + PCT_ENCODED + ")";
final String QUERY_PARAM = QUERY_PARAM_CHAR + "|\\/|\\?";
final StringBuilder coreRegex = new StringBuilder();
switch (variable.getType()) {
case Variable.TYPE_ALL:
appendClass(coreRegex, ALL, variable.isRequired());
break;
case Variable.TYPE_ALPHA:
appendClass(coreRegex, ALPHA, variable.isRequired());
break;
case Variable.TYPE_DIGIT:
appendClass(coreRegex, DIGIT, variable.isRequired());
break;
case Variable.TYPE_ALPHA_DIGIT:
appendClass(coreRegex, ALPHA_DIGIT, variable.isRequired());
break;
case Variable.TYPE_URI_ALL:
appendGroup(coreRegex, URI_ALL, variable.isRequired());
break;
case Variable.TYPE_URI_UNRESERVED:
appendClass(coreRegex, URI_UNRESERVED, variable.isRequired());
break;
case Variable.TYPE_WORD:
appendClass(coreRegex, WORD, variable.isRequired());
break;
case Variable.TYPE_URI_FRAGMENT:
appendGroup(coreRegex, FRAGMENT, variable.isRequired());
break;
case Variable.TYPE_URI_PATH:
appendGroup(coreRegex, URI_PATH, variable.isRequired());
break;
case Variable.TYPE_URI_QUERY:
appendGroup(coreRegex, QUERY, variable.isRequired());
break;
case Variable.TYPE_URI_QUERY_PARAM:
appendGroup(coreRegex, QUERY_PARAM, variable.isRequired());
break;
case Variable.TYPE_URI_SEGMENT:
appendGroup(coreRegex, PCHAR, variable.isRequired());
break;
case Variable.TYPE_TOKEN:
appendClass(coreRegex, TOKEN, variable.isRequired());
break;
case Variable.TYPE_COMMENT:
appendClass(coreRegex, COMMENT, variable.isRequired());
break;
case Variable.TYPE_COMMENT_ATTRIBUTE:
appendClass(coreRegex, COMMENT_ATTRIBUTE, variable.isRequired());
break;
}
result = coreRegex.toString();
}
return result;
}
/** The default variable to use when no matching variable descriptor exists. */
private volatile Variable defaultVariable;
/** True if the variables must be encoded when formatting the template. */
private volatile boolean encodingVariables;
/** The logger to use. */
private volatile Logger logger;
/** The matching mode to use when parsing a formatted reference. */
private volatile int matchingMode;
/** The pattern to use for formatting or parsing. */
private volatile String pattern;
/** The internal Regex pattern. */
private volatile Pattern regexPattern;
/** The sequence of Regex variable names as found in the pattern string. */
private volatile List<String> regexVariables;
/** The map of variables associated to the route's template. */
private final Map<String, Variable> variables;
/**
* Default constructor. Each variable matches any sequence of characters by
* default. When parsing, the template will attempt to match the whole
* template. When formatting, the variable are replaced by an empty string
* if they don't exist in the model.
*
* @param pattern
* The pattern to use for formatting or parsing.
*/
public Template(String pattern) {
this(pattern, MODE_EQUALS, Variable.TYPE_ALL, "", true, false);
}
/**
* Constructor.
*
* @param pattern
* The pattern to use for formatting or parsing.
* @param matchingMode
* The matching mode to use when parsing a formatted reference.
*/
public Template(String pattern, int matchingMode) {
this(pattern, matchingMode, Variable.TYPE_ALL, "", true, false);
}
/**
* Constructor.
*
* @param pattern
* The pattern to use for formatting or parsing.
* @param matchingMode
* The matching mode to use when parsing a formatted reference.
* @param defaultType
* The default type of variables with no descriptor.
* @param defaultDefaultValue
* The default value for null variables with no descriptor.
* @param defaultRequired
* The default required flag for variables with no descriptor.
* @param defaultFixed
* The default fixed value for variables with no descriptor.
*/
public Template(String pattern, int matchingMode, int defaultType,
String defaultDefaultValue, boolean defaultRequired,
boolean defaultFixed) {
this(pattern, matchingMode, defaultType, defaultDefaultValue,
defaultRequired, defaultFixed, false);
}
/**
* Constructor.
*
* @param pattern
* The pattern to use for formatting or parsing.
* @param matchingMode
* The matching mode to use when parsing a formatted reference.
* @param defaultType
* The default type of variables with no descriptor.
* @param defaultDefaultValue
* The default value for null variables with no descriptor.
* @param defaultRequired
* The default required flag for variables with no descriptor.
* @param defaultFixed
* The default fixed value for variables with no descriptor.
* @param encodingVariables
* True if the variables must be encoded when formatting the
* template.
*/
public Template(String pattern, int matchingMode, int defaultType,
String defaultDefaultValue, boolean defaultRequired,
boolean defaultFixed, boolean encodingVariables) {
this.logger = (logger == null) ? Context.getCurrentLogger() : logger;
this.pattern = pattern;
this.defaultVariable = new Variable(defaultType, defaultDefaultValue,
defaultRequired, defaultFixed);
this.matchingMode = matchingMode;
this.variables = new ConcurrentHashMap<String, Variable>();
this.regexPattern = null;
this.encodingVariables = encodingVariables;
}
/**
* Creates a formatted string based on the given map of values.
*
* @param values
* The values to use when formatting.
* @return The formatted string.
* @see Resolver#createResolver(Map)
*/
public String format(Map<String, ?> values) {
return format(Resolver.createResolver(values));
}
/**
* Creates a formatted string based on the given request and response.
*
* @param request
* The request to use as a model.
* @param response
* The response to use as a model.
* @return The formatted string.
* @see Resolver#createResolver(Request, Response)
*/
public String format(Request request, Response response) {
return format(Resolver.createResolver(request, response));
}
/**
* Creates a formatted string based on the given variable resolver.
*
* @param resolver
* The variable resolver to use.
* @return The formatted string.
*/
public String format(Resolver<?> resolver) {
final StringBuilder result = new StringBuilder();
StringBuilder varBuffer = null;
char next;
boolean inVariable = false;
final int patternLength = getPattern().length();
for (int i = 0; i < patternLength; i++) {
next = getPattern().charAt(i);
if (inVariable) {
if (Reference.isUnreserved(next)) {
// Append to the variable name
varBuffer.append(next);
} else if (next == '}') {
// End of variable detected
if (varBuffer.length() == 0) {
getLogger().warning(
"Empty pattern variables are not allowed : "
+ this.regexPattern);
} else {
final String varName = varBuffer.toString();
Object varValue = resolver.resolve(varName);
Variable var = getVariables().get(varName);
// Use the default values instead
if (varValue == null) {
if (var == null) {
var = getDefaultVariable();
}
if (var != null) {
varValue = var.getDefaultValue();
}
}
String varValueString = (varValue == null) ? null
: varValue.toString();
if (this.encodingVariables) {
// In case the values must be encoded.
if (var != null) {
result.append(var.encode(varValueString));
} else {
result.append(Reference.encode(varValueString));
}
} else {
if ((var != null) && var.isEncodingOnFormat()) {
result.append(Reference.encode(varValueString));
} else {
result.append(varValueString);
}
}
// Reset the variable name buffer
varBuffer = new StringBuilder();
}
inVariable = false;
} else {
getLogger().warning(
"An invalid character was detected inside a pattern variable : "
+ this.regexPattern);
}
} else {
if (next == '{') {
inVariable = true;
varBuffer = new StringBuilder();
} else if (next == '}') {
getLogger().warning(
"An invalid character was detected inside a pattern variable : "
+ this.regexPattern);
} else {
result.append(next);
}
}
}
return result.toString();
}
/**
* Returns the default variable.
*
* @return The default variable.
*/
public Variable getDefaultVariable() {
return this.defaultVariable;
}
/**
* Returns the logger to use.
*
* @return The logger to use.
*/
public Logger getLogger() {
return this.logger;
}
/**
* Returns the matching mode to use when parsing a formatted reference.
*
* @return The matching mode to use when parsing a formatted reference.
*/
public int getMatchingMode() {
return this.matchingMode;
}
/**
* Returns the pattern to use for formatting or parsing.
*
* @return The pattern to use for formatting or parsing.
*/
public String getPattern() {
return this.pattern;
}
/**
* Compiles the URI pattern into a Regex pattern.
*
* @return The Regex pattern.
*/
private Pattern getRegexPattern() {
if (this.regexPattern == null) {
synchronized (this) {
if (this.regexPattern == null) {
getRegexVariables().clear();
final StringBuilder patternBuffer = new StringBuilder();
StringBuilder varBuffer = null;
char next;
boolean inVariable = false;
for (int i = 0; i < getPattern().length(); i++) {
next = getPattern().charAt(i);
if (inVariable) {
if (Reference.isUnreserved(next)) {
// Append to the variable name
varBuffer.append(next);
} else if (next == '}') {
// End of variable detected
if (varBuffer.length() == 0) {
getLogger().warning(
"Empty pattern variables are not allowed : "
+ this.regexPattern);
} else {
final String varName = varBuffer.toString();
final int varIndex = getRegexVariables()
.indexOf(varName);
if (varIndex != -1) {
// The variable is used several times in
// the pattern, ensure that this
// constraint is enforced when parsing.
patternBuffer.append("\\"
+ (varIndex + 1));
} else {
// New variable detected. Insert a
// capturing group.
getRegexVariables().add(varName);
Variable var = getVariables().get(
varName);
if (var == null) {
var = getDefaultVariable();
}
patternBuffer
.append(getVariableRegex(var));
}
// Reset the variable name buffer
varBuffer = new StringBuilder();
}
inVariable = false;
} else {
getLogger().warning(
"An invalid character was detected inside a pattern variable : "
+ this.regexPattern);
}
} else {
if (next == '{') {
inVariable = true;
varBuffer = new StringBuilder();
} else if (next == '}') {
getLogger().warning(
"An invalid character was detected inside a pattern variable : "
+ this.regexPattern);
} else {
patternBuffer.append(quote(next));
}
}
}
this.regexPattern = Pattern.compile(patternBuffer
.toString());
}
}
}
return this.regexPattern;
}
/**
* Returns the sequence of Regex variable names as found in the pattern
* string.
*
* @return The sequence of Regex variable names as found in the pattern
* string.
*/
private List<String> getRegexVariables() {
// Lazy initialization with double-check.
List<String> rv = this.regexVariables;
if (rv == null) {
synchronized (this) {
rv = this.regexVariables;
if (rv == null) {
this.regexVariables = rv = new CopyOnWriteArrayList<String>();
}
}
}
return rv;
}
/**
* Returns the list of variable names in the template.
*
* @return The list of variable names.
*/
public List<String> getVariableNames() {
final List<String> result = new ArrayList<String>();
StringBuilder varBuffer = null;
char next;
boolean inVariable = false;
final String pattern = getPattern();
for (int i = 0; i < pattern.length(); i++) {
next = pattern.charAt(i);
if (inVariable) {
if (Reference.isUnreserved(next)) {
// Append to the variable name
varBuffer.append(next);
} else if (next == '}') {
// End of variable detected
if (varBuffer.length() == 0) {
getLogger().warning(
"Empty pattern variables are not allowed : "
+ this.pattern);
} else {
result.add(varBuffer.toString());
// Reset the variable name buffer
varBuffer = new StringBuilder();
}
inVariable = false;
} else {
getLogger().warning(
"An invalid character was detected inside a pattern variable : "
+ this.pattern);
}
} else {
if (next == '{') {
inVariable = true;
varBuffer = new StringBuilder();
} else if (next == '}') {
getLogger().warning(
"An invalid character was detected inside a pattern variable : "
+ this.pattern);
}
}
}
return result;
}
/**
* Returns the modifiable map of variable descriptors. Creates a new
* instance if no one has been set. Note that those variables are only
* descriptors that can influence the way parsing and formatting is done,
* they don't contain the actual value parsed.
*
* @return The modifiable map of variables.
*/
public synchronized Map<String, Variable> getVariables() {
return this.variables;
}
/**
* Indicates if the variables must be encoded when formatting the template.
*
* @return True if the variables must be encoded when formatting the
* template, false otherwise.
*/
public boolean isEncodingVariables() {
return this.encodingVariables;
}
/**
* Indicates if the current pattern matches the given formatted string.
*
* @param formattedString
* The formatted string to match.
* @return The number of matched characters or -1 if the match failed.
*/
public int match(String formattedString) {
int result = -1;
try {
if (formattedString != null) {
final Matcher matcher = getRegexPattern().matcher(
formattedString);
if ((getMatchingMode() == MODE_EQUALS) && matcher.matches()) {
result = matcher.end();
} else if ((getMatchingMode() == MODE_STARTS_WITH)
&& matcher.lookingAt()) {
result = matcher.end();
}
}
} catch (StackOverflowError soe) {
getLogger().warning(
"StackOverflowError exception encountered while matching this string : "
+ formattedString);
}
return result;
}
/**
* Attempts to parse a formatted reference. If the parsing succeeds, the
* given request's attributes are updated.<br>
* Note that the values parsed are directly extracted from the formatted
* reference and are therefore not percent-decoded.
*
* @see Reference#decode(String)
*
* @param formattedString
* The string to parse.
* @param variables
* The map of variables to update.
* @return The number of matched characters or -1 if no character matched.
*/
public int parse(String formattedString, Map<String, Object> variables) {
return parse(formattedString, variables, true);
}
/**
* Attempts to parse a formatted reference. If the parsing succeeds, the
* given request's attributes are updated.<br>
* Note that the values parsed are directly extracted from the formatted
* reference and are therefore not percent-decoded.
*
* @see Reference#decode(String)
*
* @param formattedString
* The string to parse.
* @param variables
* The map of variables to update.
* @param loggable
* True if the parsing should be logged.
* @return The number of matched characters or -1 if no character matched.
*/
public int parse(String formattedString, Map<String, Object> variables,
boolean loggable) {
int result = -1;
if (formattedString != null) {
try {
Matcher matcher = getRegexPattern().matcher(formattedString);
boolean matched = ((getMatchingMode() == MODE_EQUALS) && matcher
.matches())
|| ((getMatchingMode() == MODE_STARTS_WITH) && matcher
.lookingAt());
if (matched) {
// Update the number of matched characters
result = matcher.end();
// Update the attributes with the variables value
String attributeName = null;
String attributeValue = null;
for (int i = 0; i < getRegexVariables().size(); i++) {
attributeName = getRegexVariables().get(i);
attributeValue = matcher.group(i + 1);
Variable var = getVariables().get(attributeName);
if ((var != null) && var.isDecodingOnParse()) {
attributeValue = Reference.decode(attributeValue);
}
if (loggable) {
getLogger().fine(
"Template variable \"" + attributeName
+ "\" matched with value \""
+ attributeValue + "\"");
}
variables.put(attributeName, attributeValue);
}
}
} catch (StackOverflowError soe) {
getLogger().warning(
"StackOverflowError exception encountered while matching this string : "
+ formattedString);
}
}
return result;
}
/**
* Attempts to parse a formatted reference. If the parsing succeeds, the
* given request's attributes are updated.<br>
* Note that the values parsed are directly extracted from the formatted
* reference and are therefore not percent-decoded.
*
* @see Reference#decode(String)
*
* @param formattedString
* The string to parse.
* @param request
* The request to update.
* @return The number of matched characters or -1 if no character matched.
*/
public int parse(String formattedString, Request request) {
return parse(formattedString, request.getAttributes(),
request.isLoggable());
}
/**
* Quotes special characters that could be taken for special Regex
* characters.
*
* @param character
* The character to quote if necessary.
* @return The quoted character.
*/
private String quote(char character) {
switch (character) {
case '[':
return "\\[";
case ']':
return "\\]";
case '.':
return "\\.";
case '\\':
return "\\\\";
case '$':
return "\\$";
case '^':
return "\\^";
case '?':
return "\\?";
case '*':
return "\\*";
case '|':
return "\\|";
case '(':
return "\\(";
case ')':
return "\\)";
case ':':
return "\\:";
case '-':
return "\\-";
case '!':
return "\\!";
case '<':
return "\\<";
case '>':
return "\\>";
default:
return Character.toString(character);
}
}
/**
* Sets the variable to use, if no variable is given.
*
* @param defaultVariable
*/
public void setDefaultVariable(Variable defaultVariable) {
this.defaultVariable = defaultVariable;
}
/**
* Indicates if the variables must be encoded when formatting the template.
*
* @param encodingVariables
* True if the variables must be encoded when formatting the
* template.
*/
public void setEncodingVariables(boolean encodingVariables) {
this.encodingVariables = encodingVariables;
}
/**
* Sets the logger to use.
*
* @param logger
* The logger to use.
*/
public void setLogger(Logger logger) {
this.logger = logger;
}
/**
* Sets the matching mode to use when parsing a formatted reference.
*
* @param matchingMode
* The matching mode to use when parsing a formatted reference.
*/
public void setMatchingMode(int matchingMode) {
this.matchingMode = matchingMode;
}
/**
* Sets the pattern to use for formatting or parsing.
*
* @param pattern
* The pattern to use for formatting or parsing.
*/
public void setPattern(String pattern) {
this.pattern = pattern;
this.regexPattern = null;
}
/**
* Sets the modifiable map of variables.
*
* @param variables
* The modifiable map of variables.
*/
public void setVariables(Map<String, Variable> variables) {
synchronized (this.variables) {
if (variables != this.variables) {
this.variables.clear();
if (variables != null) {
this.variables.putAll(variables);
}
}
}
}
}