/**
* Copyright 2012-2013 eBay Software Foundation, All Rights Reserved.
*
* 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 edu.stanford.nlp.naturalli.demo;
import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* <p>
* A {@link Filter} that enable client-side cross-origin requests by
* implementing W3C's CORS (<b>C</b>ross-<b>O</b>rigin <b>R</b>esource
* <b>S</b>haring) specification for resources. Each {@link HttpServletRequest}
* request is inspected as per specification, and appropriate response headers
* are added to {@link HttpServletResponse}.
* </p>
*
* <p>
* By default, it also sets following request attributes, that helps to
* determine nature of request downstream.
* <ul>
* <li><b>cors.isCorsRequest:</b> Flag to determine if request is a CORS
* request. Set to <code>true</code> if CORS request; <code>false</code>
* otherwise.</li>
* <li><b>cors.request.origin:</b> The Origin URL.</li>
* <li><b>cors.request.type:</b> Type of request. Values: <code>simple</code> or
* <code>preflight</code> or <code>not_cors</code> or <code>invalid_cors</code></li>
* <li><b>cors.request.headers:</b> Request headers sent as
* 'Access-Control-Request-Headers' header, for pre-flight request.</li>
* </ul>
* </p>
*
* @author Mohit Soni
* @see <a href="http://www.w3.org/TR/cors/">CORS specification</a>
*
* note[Gabor]: STOLEN SHAMELESSLY FROM https://github.com/eBay/cors-filter/blob/master/LICENSE
* DO NOT DISTRIBUTE WITH CORENLP!!!!
*
*/
public final class CORSFilter implements Filter {
// ----------------------------------------------------- Instance variables
/**
* Holds filter configuration.
*/
private FilterConfig filterConfig;
/**
* A {@link Collection} of origins consisting of zero or more origins that
* are allowed access to the resource.
*/
private final Collection<String> allowedOrigins;
/**
* Determines if any origin is allowed to make request.
*/
private boolean anyOriginAllowed;
/**
* A {@link Collection} of methods consisting of zero or more methods that
* are supported by the resource.
*/
private final Collection<String> allowedHttpMethods;
/**
* A {@link Collection} of headers consisting of zero or more header field
* names that are supported by the resource.
*/
private final Collection<String> allowedHttpHeaders;
/**
* A {@link Collection} of exposed headers consisting of zero or more header
* field names of headers other than the simple response headers that the
* resource might use and can be exposed.
*/
private final Collection<String> exposedHeaders;
/**
* A supports credentials flag that indicates whether the resource supports
* user credentials in the request. It is true when the resource does and
* false otherwise.
*/
private boolean supportsCredentials;
/**
* Indicates (in seconds) how long the results of a pre-flight request can
* be cached in a pre-flight result cache.
*/
private long preflightMaxAge;
/**
* Controls access log logging.
*/
private boolean loggingEnabled;
/**
* Determines if the request should be decorated or not.
*/
private boolean decorateRequest;
// --------------------------------------------------------- Constructor(s)
public CORSFilter() {
this.allowedOrigins = new HashSet<>();
this.allowedHttpMethods = new HashSet<>();
this.allowedHttpHeaders = new HashSet<>();
this.exposedHeaders = new HashSet<>();
}
// --------------------------------------------------------- Public methods
@Override
public void doFilter(final ServletRequest servletRequest,
final ServletResponse servletResponse,
final FilterChain filterChain) throws IOException,
ServletException {
if (!(servletRequest instanceof HttpServletRequest)
|| !(servletResponse instanceof HttpServletResponse)) {
String message =
"CORS doesn't support non-HTTP request or response.";
throw new ServletException(message);
}
// Safe to downcast at this point.
HttpServletRequest request = (HttpServletRequest) servletRequest;
HttpServletResponse response = (HttpServletResponse) servletResponse;
// Determines the CORS request type.
CORSFilter.CORSRequestType requestType = checkRequestType(request);
// Adds CORS specific attributes to request.
if (decorateRequest) {
CORSFilter.decorateCORSProperties(request, requestType);
}
switch (requestType) {
case SIMPLE:
// Handles a Simple CORS request.
this.handleSimpleCORS(request, response, filterChain);
break;
case ACTUAL:
// Handles an Actual CORS request.
this.handleSimpleCORS(request, response, filterChain);
break;
case PRE_FLIGHT:
// Handles a Pre-flight CORS request.
this.handlePreflightCORS(request, response, filterChain);
break;
case NOT_CORS:
// Handles a Normal request that is not a cross-origin request.
this.handleNonCORS(request, response, filterChain);
break;
default:
// Handles a CORS request that violates specification.
this.handleInvalidCORS(request, response, filterChain);
break;
}
}
@Override
public void init(final FilterConfig filterConfig) throws ServletException {
// Initialize defaults
parseAndStore(DEFAULT_ALLOWED_ORIGINS, DEFAULT_ALLOWED_HTTP_METHODS,
DEFAULT_ALLOWED_HTTP_HEADERS, DEFAULT_EXPOSED_HEADERS,
DEFAULT_SUPPORTS_CREDENTIALS, DEFAULT_PREFLIGHT_MAXAGE,
DEFAULT_LOGGING_ENABLED, DEFAULT_DECORATE_REQUEST);
this.filterConfig = filterConfig;
this.loggingEnabled = false;
if (filterConfig != null) {
String configAllowedOrigins =
filterConfig.getInitParameter(PARAM_CORS_ALLOWED_ORIGINS);
String configAllowedHttpMethods =
filterConfig.getInitParameter(PARAM_CORS_ALLOWED_METHODS);
String configAllowedHttpHeaders =
filterConfig.getInitParameter(PARAM_CORS_ALLOWED_HEADERS);
String configExposedHeaders =
filterConfig.getInitParameter(PARAM_CORS_EXPOSED_HEADERS);
String configSupportsCredentials =
filterConfig
.getInitParameter(PARAM_CORS_SUPPORT_CREDENTIALS);
String configPreflightMaxAge =
filterConfig.getInitParameter(PARAM_CORS_PREFLIGHT_MAXAGE);
String configLoggingEnabled =
filterConfig.getInitParameter(PARAM_CORS_LOGGING_ENABLED);
String configDecorateRequest =
filterConfig.getInitParameter(PARAM_CORS_REQUEST_DECORATE);
parseAndStore(configAllowedOrigins, configAllowedHttpMethods,
configAllowedHttpHeaders,
configExposedHeaders, configSupportsCredentials,
configPreflightMaxAge,
configLoggingEnabled, configDecorateRequest);
}
}
// --------------------------------------------------------------- Handlers
/**
* Handles a CORS request of type {@link CORSRequestType}.SIMPLE.
*
* @param request
* The {@link HttpServletRequest} object.
* @param response
* The {@link HttpServletResponse} object.
* @param filterChain
* The {@link FilterChain} object.
* @throws IOException
* @throws ServletException
* @see <a href="http://www.w3.org/TR/cors/#resource-requests">Simple
* Cross-Origin Request, Actual Request, and Redirects</a>
*/
public void handleSimpleCORS(final HttpServletRequest request,
final HttpServletResponse response, final FilterChain filterChain)
throws IOException, ServletException {
CORSFilter.CORSRequestType requestType =
checkRequestType(request);
if (!(requestType == CORSFilter.CORSRequestType.SIMPLE
|| requestType == CORSFilter.CORSRequestType.ACTUAL)) {
String message =
"Expects a HttpServletRequest object of type "
+ CORSFilter.CORSRequestType.SIMPLE
+ " or "
+ CORSFilter.CORSRequestType.ACTUAL;
throw new IllegalArgumentException(message);
}
final String origin =
request.getHeader(CORSFilter.REQUEST_HEADER_ORIGIN);
final String method = request.getMethod();
// Section 6.1.2
if (!isOriginAllowed(origin)) {
handleInvalidCORS(request, response, filterChain);
return;
}
if (!allowedHttpMethods.contains(method)) {
handleInvalidCORS(request, response, filterChain);
return;
}
// Section 6.1.3
// Add a single Access-Control-Allow-Origin header.
if (anyOriginAllowed && !supportsCredentials) {
// If resource doesn't support credentials and if any origin is
// allowed
// to make CORS request, return header with '*'.
response.addHeader(
CORSFilter.RESPONSE_HEADER_ACCESS_CONTROL_ALLOW_ORIGIN, "*");
} else {
// If the resource supports credentials add a single
// Access-Control-Allow-Origin header, with the value of the Origin
// header as value.
response.addHeader(
CORSFilter.RESPONSE_HEADER_ACCESS_CONTROL_ALLOW_ORIGIN,
origin);
}
// Section 6.1.3
// If the resource supports credentials, add a single
// Access-Control-Allow-Credentials header with the case-sensitive
// string "true" as value.
if (supportsCredentials) {
response.addHeader(
CORSFilter.RESPONSE_HEADER_ACCESS_CONTROL_ALLOW_CREDENTIALS,
"true");
}
// Section 6.1.4
// If the list of exposed headers is not empty add one or more
// Access-Control-Expose-Headers headers, with as values the header
// field names given in the list of exposed headers.
if ((exposedHeaders != null) && (exposedHeaders.size() > 0)) {
String exposedHeadersString = join(exposedHeaders, ",");
response.addHeader(
CORSFilter.RESPONSE_HEADER_ACCESS_CONTROL_EXPOSE_HEADERS,
exposedHeadersString);
}
// Forward the request down the filter chain.
filterChain.doFilter(request, response);
}
/**
* Handles CORS pre-flight request.
*
* @param request
* The {@link HttpServletRequest} object.
* @param response
* The {@link HttpServletResponse} object.
* @param filterChain
* The {@link FilterChain} object.
* @throws IOException
* @throws ServletException
*/
public void handlePreflightCORS(final HttpServletRequest request,
final HttpServletResponse response, final FilterChain filterChain)
throws IOException, ServletException {
CORSRequestType requestType = checkRequestType(request);
if (requestType != CORSRequestType.PRE_FLIGHT) {
throw new IllegalArgumentException(
"Expects a HttpServletRequest object of type "
+ CORSRequestType.PRE_FLIGHT.name().toLowerCase());
}
final String origin =
request.getHeader(CORSFilter.REQUEST_HEADER_ORIGIN);
// Section 6.2.2
if (!isOriginAllowed(origin)) {
handleInvalidCORS(request, response, filterChain);
return;
}
// Section 6.2.3
String accessControlRequestMethod =
request.getHeader(CORSFilter.REQUEST_HEADER_ACCESS_CONTROL_REQUEST_METHOD);
if (accessControlRequestMethod == null
|| (!HTTP_METHODS
.contains(accessControlRequestMethod.trim()))) {
handleInvalidCORS(request, response, filterChain);
return;
} else {
accessControlRequestMethod = accessControlRequestMethod.trim();
}
// Section 6.2.4
String accessControlRequestHeadersHeader =
request.getHeader(CORSFilter.REQUEST_HEADER_ACCESS_CONTROL_REQUEST_HEADERS);
List<String> accessControlRequestHeaders = new LinkedList<>();
if (accessControlRequestHeadersHeader != null
&& !accessControlRequestHeadersHeader.trim().isEmpty()) {
String[] headers =
accessControlRequestHeadersHeader.trim().split(",");
for (String header : headers) {
accessControlRequestHeaders.add(header.trim().toLowerCase());
}
}
// Section 6.2.5
if (!allowedHttpMethods.contains(accessControlRequestMethod)) {
handleInvalidCORS(request, response, filterChain);
return;
}
// Section 6.2.6
if (!accessControlRequestHeaders.isEmpty()) {
for (String header : accessControlRequestHeaders) {
if (!allowedHttpHeaders.contains(header)) {
handleInvalidCORS(request, response, filterChain);
return;
}
}
}
// Section 6.2.7
if (supportsCredentials) {
response.addHeader(
CORSFilter.RESPONSE_HEADER_ACCESS_CONTROL_ALLOW_ORIGIN,
origin);
response.addHeader(
CORSFilter.RESPONSE_HEADER_ACCESS_CONTROL_ALLOW_CREDENTIALS,
"true");
} else {
if (anyOriginAllowed) {
response.addHeader(
CORSFilter.RESPONSE_HEADER_ACCESS_CONTROL_ALLOW_ORIGIN,
"*");
} else {
response.addHeader(
CORSFilter.RESPONSE_HEADER_ACCESS_CONTROL_ALLOW_ORIGIN,
origin);
}
}
// Section 6.2.8
if (preflightMaxAge > 0) {
response.addHeader(
CORSFilter.RESPONSE_HEADER_ACCESS_CONTROL_MAX_AGE,
String.valueOf(preflightMaxAge));
}
// Section 6.2.9
response.addHeader(
CORSFilter.RESPONSE_HEADER_ACCESS_CONTROL_ALLOW_METHODS,
accessControlRequestMethod);
// Section 6.2.10
if ((allowedHttpHeaders != null) && (!allowedHttpHeaders.isEmpty())) {
response.addHeader(
CORSFilter.RESPONSE_HEADER_ACCESS_CONTROL_ALLOW_HEADERS,
join(allowedHttpHeaders, ","));
}
// Do not forward the request down the filter chain.
}
/**
* Handles a request, that's not a CORS request, but is a valid request i.e.
* it is not a cross-origin request. This implementation, just forwards the
* request down the filter chain.
*
* @param request
* The {@link HttpServletRequest} object.
* @param response
* The {@link HttpServletResponse} object.
* @param filterChain
* The {@link FilterChain} object.
* @throws IOException
* @throws ServletException
*/
public void handleNonCORS(final HttpServletRequest request,
final HttpServletResponse response, final FilterChain filterChain)
throws IOException, ServletException {
// Let request pass.
filterChain.doFilter(request, response);
}
/**
* Handles a CORS request that violates specification.
*
* @param request
* The {@link HttpServletRequest} object.
* @param response
* The {@link HttpServletResponse} object.
* @param filterChain
* The {@link FilterChain} object.
* @throws IOException
* @throws ServletException
*/
public void handleInvalidCORS(final HttpServletRequest request,
final HttpServletResponse response, final FilterChain filterChain) {
String origin = request.getHeader(CORSFilter.REQUEST_HEADER_ORIGIN);
String method = request.getMethod();
String accessControlRequestHeaders =
request.getHeader(REQUEST_HEADER_ACCESS_CONTROL_REQUEST_HEADERS);
String message =
"Invalid CORS request; Origin=" + origin + ";Method=" + method;
if (accessControlRequestHeaders != null) {
message =
message + ";Access-Control-Request-Headers="
+ accessControlRequestHeaders;
}
response.setContentType("text/plain");
response.setStatus(HttpServletResponse.SC_FORBIDDEN);
response.resetBuffer();
log(message);
}
@Override
public void destroy() {
// NOOP
}
// -------------------------------------------------------- Utility methods
/**
* Decorates the {@link HttpServletRequest}, with CORS attributes.
* <ul>
* <li><b>cors.isCorsRequest:</b> Flag to determine if request is a CORS
* request. Set to <code>true</code> if CORS request; <code>false</code>
* otherwise.</li>
* <li><b>cors.request.origin:</b> The Origin URL.</li>
* <li><b>cors.request.type:</b> Type of request. Values:
* <code>simple</code> or <code>preflight</code> or <code>not_cors</code> or
* <code>invalid_cors</code></li>
* <li><b>cors.request.headers:</b> Request headers sent as
* 'Access-Control-Request-Headers' header, for pre-flight request.</li>
* </ul>
*
* @param request
* The {@link HttpServletRequest} object.
* @param corsRequestType
* The {@link CORSRequestType} object.
*/
public static void decorateCORSProperties(final HttpServletRequest request,
final CORSRequestType corsRequestType) {
if (request == null) {
throw new IllegalArgumentException(
"HttpServletRequest object is null");
}
if (corsRequestType == null) {
throw new IllegalArgumentException("CORSRequestType object is null");
}
switch (corsRequestType) {
case SIMPLE:
request.setAttribute(
CORSFilter.HTTP_REQUEST_ATTRIBUTE_IS_CORS_REQUEST, true);
request.setAttribute(CORSFilter.HTTP_REQUEST_ATTRIBUTE_ORIGIN,
request.getHeader(CORSFilter.REQUEST_HEADER_ORIGIN));
request.setAttribute(
CORSFilter.HTTP_REQUEST_ATTRIBUTE_REQUEST_TYPE,
corsRequestType.name().toLowerCase());
break;
case ACTUAL:
request.setAttribute(
CORSFilter.HTTP_REQUEST_ATTRIBUTE_IS_CORS_REQUEST, true);
request.setAttribute(CORSFilter.HTTP_REQUEST_ATTRIBUTE_ORIGIN,
request.getHeader(CORSFilter.REQUEST_HEADER_ORIGIN));
request.setAttribute(
CORSFilter.HTTP_REQUEST_ATTRIBUTE_REQUEST_TYPE,
corsRequestType.name().toLowerCase());
break;
case PRE_FLIGHT:
request.setAttribute(
CORSFilter.HTTP_REQUEST_ATTRIBUTE_IS_CORS_REQUEST, true);
request.setAttribute(CORSFilter.HTTP_REQUEST_ATTRIBUTE_ORIGIN,
request.getHeader(CORSFilter.REQUEST_HEADER_ORIGIN));
request.setAttribute(
CORSFilter.HTTP_REQUEST_ATTRIBUTE_REQUEST_TYPE,
corsRequestType.name().toLowerCase());
String headers =
request.getHeader(REQUEST_HEADER_ACCESS_CONTROL_REQUEST_HEADERS);
if (headers == null) {
headers = "";
}
request.setAttribute(
CORSFilter.HTTP_REQUEST_ATTRIBUTE_REQUEST_HEADERS,
headers
);
break;
case NOT_CORS:
request.setAttribute(
CORSFilter.HTTP_REQUEST_ATTRIBUTE_IS_CORS_REQUEST, false);
break;
default:
// Don't set any attributes
break;
}
}
/**
* Joins elements of {@link Set} into a string, where each element is
* separated by the provided separator.
*
* @param elements
* The {@link Set} containing elements to join together.
* @param joinSeparator
* The character to be used for separating elements.
* @return The joined {@link String}; <code>null</code> if elements
* {@link Set} is null.
*/
public static String join(final Collection<String> elements,
final String joinSeparator) {
String separator = ",";
if (elements == null) {
return null;
}
if (joinSeparator != null) {
separator = joinSeparator;
}
StringBuilder buffer = new StringBuilder();
boolean isFirst = true;
for (String element : elements) {
if (!isFirst) {
buffer.append(separator);
} else {
isFirst = false;
}
if (element != null) {
buffer.append(element);
}
}
return buffer.toString();
}
/**
* Determines the request type.
*
* @param request
* @return
*/
public CORSRequestType checkRequestType(final HttpServletRequest request) {
CORSRequestType requestType = CORSRequestType.INVALID_CORS;
if (request == null) {
throw new IllegalArgumentException(
"HttpServletRequest object is null");
}
String originHeader = request.getHeader(REQUEST_HEADER_ORIGIN);
// Section 6.1.1 and Section 6.2.1
if (originHeader != null) {
if (originHeader.isEmpty()) {
requestType = CORSRequestType.INVALID_CORS;
} else if (!isValidOrigin(originHeader)) {
requestType = CORSRequestType.INVALID_CORS;
} else {
String method = request.getMethod();
if (method != null && HTTP_METHODS.contains(method)) {
if ("OPTIONS".equals(method)) {
String accessControlRequestMethodHeader =
request.getHeader(REQUEST_HEADER_ACCESS_CONTROL_REQUEST_METHOD);
if (accessControlRequestMethodHeader != null
&& !accessControlRequestMethodHeader.isEmpty()) {
requestType = CORSRequestType.PRE_FLIGHT;
} else if (accessControlRequestMethodHeader != null
&& accessControlRequestMethodHeader.isEmpty()) {
requestType = CORSRequestType.INVALID_CORS;
} else {
requestType = CORSRequestType.ACTUAL;
}
} else if ("GET".equals(method) || "HEAD".equals(method)) {
requestType = CORSRequestType.SIMPLE;
} else if ("POST".equals(method)) {
String contentType = request.getContentType();
if (contentType != null) {
contentType = contentType.toLowerCase().trim();
if (SIMPLE_HTTP_REQUEST_CONTENT_TYPE_VALUES
.contains(contentType)) {
requestType = CORSRequestType.SIMPLE;
} else {
requestType = CORSRequestType.ACTUAL;
}
}
} else if (COMPLEX_HTTP_METHODS.contains(method)) {
requestType = CORSRequestType.ACTUAL;
}
}
}
} else {
requestType = CORSRequestType.NOT_CORS;
}
return requestType;
}
/**
* Checks if the Origin is allowed to make a CORS request.
*
* @param origin
* The Origin.
* @return <code>true</code> if origin is allowed; <code>false</code>
* otherwise.
*/
private boolean isOriginAllowed(final String origin) {
if (anyOriginAllowed) {
return true;
}
// If 'Origin' header is a case-sensitive match of any of allowed
// origins, then return true, else return false.
return allowedOrigins.contains(origin);
}
private void log(String message) {
if (loggingEnabled) {
filterConfig.getServletContext().log(message);
}
}
/**
* Parses each param-value and populates configuration variables. If a param
* is provided, it overrides the default.
*
* @param allowedOrigins
* A {@link String} of comma separated origins.
* @param allowedHttpMethods
* A {@link String} of comma separated HTTP methods.
* @param allowedHttpHeaders
* A {@link String} of comma separated HTTP headers.
* @param exposedHeaders
* A {@link String} of comma separated headers that needs to be
* exposed.
* @param supportsCredentials
* "true" if support credentials needs to be enabled.
* @param preflightMaxAge
* The amount of seconds the user agent is allowed to cache the
* result of the pre-flight request.
* @param loggingEnabled
* Flag to control logging to access log.
* @throws ServletException
*/
private void parseAndStore(final String allowedOrigins,
final String allowedHttpMethods, final String allowedHttpHeaders,
final String exposedHeaders, final String supportsCredentials,
final String preflightMaxAge, final String loggingEnabled,
final String decorateRequest)
throws ServletException {
if (allowedOrigins != null) {
if (allowedOrigins.trim().equals("*")) {
this.anyOriginAllowed = true;
} else {
this.anyOriginAllowed = false;
Set<String> setAllowedOrigins =
parseStringToSet(allowedOrigins);
this.allowedOrigins.clear();
this.allowedOrigins.addAll(setAllowedOrigins);
}
}
if (allowedHttpMethods != null) {
Set<String> setAllowedHttpMethods =
parseStringToSet(allowedHttpMethods);
this.allowedHttpMethods.clear();
this.allowedHttpMethods.addAll(setAllowedHttpMethods);
}
if (allowedHttpHeaders != null) {
Set<String> setAllowedHttpHeaders =
parseStringToSet(allowedHttpHeaders);
Set<String> lowerCaseHeaders = new HashSet<>();
for (String header : setAllowedHttpHeaders) {
String lowerCase = header.toLowerCase();
lowerCaseHeaders.add(lowerCase);
}
this.allowedHttpHeaders.clear();
this.allowedHttpHeaders.addAll(lowerCaseHeaders);
}
if (exposedHeaders != null) {
Set<String> setExposedHeaders = parseStringToSet(exposedHeaders);
this.exposedHeaders.clear();
this.exposedHeaders.addAll(setExposedHeaders);
}
if (supportsCredentials != null) {
// For any value other then 'true' this will be false.
this.supportsCredentials =
Boolean.parseBoolean(supportsCredentials);
}
if (preflightMaxAge != null) {
try {
if (!preflightMaxAge.isEmpty()) {
this.preflightMaxAge = Long.parseLong(preflightMaxAge);
} else {
this.preflightMaxAge = 0L;
}
} catch (NumberFormatException e) {
throw new ServletException("Unable to parse preflightMaxAge", e);
}
}
if (loggingEnabled != null) {
// For any value other then 'true' this will be false.
this.loggingEnabled = Boolean.parseBoolean(loggingEnabled);
}
if (decorateRequest != null) {
// For any value other then 'true' this will be false.
this.decorateRequest = Boolean.parseBoolean(decorateRequest);
}
}
/**
* Takes a comma separated list and returns a Set<String>.
*
* @param data
* A comma separated list of strings.
* @return Set<String>
*/
private Set<String> parseStringToSet(final String data) {
String[] splits;
if (data != null && data.length() > 0) {
splits = data.split(",");
} else {
splits = new String[] {};
}
Set<String> set = new HashSet<>();
if (splits.length > 0) {
for (String split : splits) {
set.add(split.trim());
}
}
return set;
}
/**
* Checks if a given origin is valid or not. Criteria:
* <ul>
* <li>If an encoded character is present in origin, it's not valid.</li>
* <li>Origin should be a valid {@link URI}</li>
* </ul>
*
* @param origin
* @see <a href="http://tools.ietf.org/html/rfc952">RFC952</a>
* @return
*/
public static boolean isValidOrigin(String origin) {
// Checks for encoded characters. Helps prevent CRLF injection.
if (origin.contains("%")) {
return false;
}
URI originURI;
try {
originURI = new URI(origin);
} catch (URISyntaxException e) {
return false;
}
// If scheme for URI is null, return false. Return true otherwise.
return originURI.getScheme() != null;
}
// -------------------------------------------------------------- Accessors
/**
* Determines if logging is enabled or not.
*
* @return <code>true</code> if it's enabled; false otherwise.
*/
public boolean isLoggingEnabled() {
return loggingEnabled;
}
/**
* Determines if any origin is allowed to make CORS request.
*
* @return <code>true</code> if it's enabled; false otherwise.
*/
public boolean isAnyOriginAllowed() {
return anyOriginAllowed;
}
/**
* Returns a {@link Set} of headers that should be exposed by browser.
*
* @return
*/
public Collection<String> getExposedHeaders() {
return exposedHeaders;
}
/**
* Determines is supports credentials is enabled
*
* @return
*/
public boolean isSupportsCredentials() {
return supportsCredentials;
}
/**
* Returns the preflight response cache time in seconds.
*
* @return Time to cache in seconds.
*/
public long getPreflightMaxAge() {
return preflightMaxAge;
}
/**
* Returns the {@link Set} of allowed origins that are allowed to make
* requests.
*
* @return {@link Set}
*/
public Collection<String> getAllowedOrigins() {
return allowedOrigins;
}
/**
* Returns a {@link Set} of HTTP methods that are allowed to make requests.
*
* @return {@link Set}
*/
public Collection<String> getAllowedHttpMethods() {
return allowedHttpMethods;
}
/**
* Returns a {@link Set} of headers support by resource.
*
* @return {@link Set}
*/
public Collection<String> getAllowedHttpHeaders() {
return allowedHttpHeaders;
}
// -------------------------------------------------- CORS Response Headers
/**
* The Access-Control-Allow-Origin header indicates whether a resource can
* be shared based by returning the value of the Origin request header in
* the response.
*/
public static final String RESPONSE_HEADER_ACCESS_CONTROL_ALLOW_ORIGIN =
"Access-Control-Allow-Origin";
/**
* The Access-Control-Allow-Credentials header indicates whether the
* response to request can be exposed when the omit credentials flag is
* unset. When part of the response to a preflight request it indicates that
* the actual request can include user credentials.
*/
public static final String RESPONSE_HEADER_ACCESS_CONTROL_ALLOW_CREDENTIALS =
"Access-Control-Allow-Credentials";
/**
* The Access-Control-Expose-Headers header indicates which headers are safe
* to expose to the API of a CORS API specification
*/
public static final String RESPONSE_HEADER_ACCESS_CONTROL_EXPOSE_HEADERS =
"Access-Control-Expose-Headers";
/**
* The Access-Control-Max-Age header indicates how long the results of a
* preflight request can be cached in a preflight result cache.
*/
public static final String RESPONSE_HEADER_ACCESS_CONTROL_MAX_AGE =
"Access-Control-Max-Age";
/**
* The Access-Control-Allow-Methods header indicates, as part of the
* response to a preflight request, which methods can be used during the
* actual request.
*/
public static final String RESPONSE_HEADER_ACCESS_CONTROL_ALLOW_METHODS =
"Access-Control-Allow-Methods";
/**
* The Access-Control-Allow-Headers header indicates, as part of the
* response to a preflight request, which header field names can be used
* during the actual request.
*/
public static final String RESPONSE_HEADER_ACCESS_CONTROL_ALLOW_HEADERS =
"Access-Control-Allow-Headers";
// -------------------------------------------------- CORS Request Headers
/**
* The Origin header indicates where the cross-origin request or preflight
* request originates from.
*/
public static final String REQUEST_HEADER_ORIGIN = "Origin";
/**
* The Access-Control-Request-Method header indicates which method will be
* used in the actual request as part of the preflight request.
*/
public static final String REQUEST_HEADER_ACCESS_CONTROL_REQUEST_METHOD =
"Access-Control-Request-Method";
/**
* The Access-Control-Request-Headers header indicates which headers will be
* used in the actual request as part of the preflight request.
*/
public static final String REQUEST_HEADER_ACCESS_CONTROL_REQUEST_HEADERS =
"Access-Control-Request-Headers";
// ----------------------------------------------------- Request attributes
/**
* The prefix to a CORS request attribute.
*/
public static final String HTTP_REQUEST_ATTRIBUTE_PREFIX = "cors.";
/**
* Attribute that contains the origin of the request.
*/
public static final String HTTP_REQUEST_ATTRIBUTE_ORIGIN =
HTTP_REQUEST_ATTRIBUTE_PREFIX + "request.origin";
/**
* Boolean value, suggesting if the request is a CORS request or not.
*/
public static final String HTTP_REQUEST_ATTRIBUTE_IS_CORS_REQUEST =
HTTP_REQUEST_ATTRIBUTE_PREFIX + "isCorsRequest";
/**
* Type of CORS request, of type {@link CORSRequestType}.
*/
public static final String HTTP_REQUEST_ATTRIBUTE_REQUEST_TYPE =
HTTP_REQUEST_ATTRIBUTE_PREFIX + "request.type";
/**
* Request headers sent as 'Access-Control-Request-Headers' header, for
* pre-flight request.
*/
public static final String HTTP_REQUEST_ATTRIBUTE_REQUEST_HEADERS =
HTTP_REQUEST_ATTRIBUTE_PREFIX + "request.headers";
// -------------------------------------------------------------- Constants
/**
* Enumerates varies types of CORS requests. Also, provides utility methods
* to determine the request type.
*/
public static enum CORSRequestType {
/**
* A simple HTTP request, i.e. it shouldn't be pre-flighted.
*/
SIMPLE,
/**
* A HTTP request that needs to be pre-flighted.
*/
ACTUAL,
/**
* A pre-flight CORS request, to get meta information, before a
* non-simple HTTP request is sent.
*/
PRE_FLIGHT,
/**
* Not a CORS request, but a normal request.
*/
NOT_CORS,
/**
* An invalid CORS request, i.e. it qualifies to be a CORS request, but
* fails to be a valid one.
*/
INVALID_CORS
}
/**
* {@link Collection} of HTTP methods. Case sensitive.
*
* @see http://tools.ietf.org/html/rfc2616#section-5.1.1
*/
public static final Collection<String> HTTP_METHODS = new HashSet<>(
Arrays.asList("OPTIONS", "GET", "HEAD", "POST", "PUT", "DELETE",
"TRACE", "CONNECT"));
/**
* {@link Collection} of non-simple HTTP methods. Case sensitive.
*/
public static final Collection<String> COMPLEX_HTTP_METHODS =
new HashSet<>(
Arrays.asList("PUT", "DELETE", "TRACE", "CONNECT"));
/**
* {@link Collection} of Simple HTTP methods. Case sensitive.
*
* @see http://www.w3.org/TR/cors/#terminology
*/
public static final Collection<String> SIMPLE_HTTP_METHODS =
new HashSet<>(
Arrays.asList("GET", "POST", "HEAD"));
/**
* {@link Collection} of Simple HTTP request headers. Case in-sensitive.
*
* @see http://www.w3.org/TR/cors/#terminology
*/
public static final Collection<String> SIMPLE_HTTP_REQUEST_HEADERS =
new HashSet<>(Arrays.asList("Accept", "Accept-Language",
"Content-Language"));
/**
* {@link Collection} of Simple HTTP request headers. Case in-sensitive.
*
* @see http://www.w3.org/TR/cors/#terminology
*/
public static final Collection<String> SIMPLE_HTTP_RESPONSE_HEADERS =
new HashSet<>(Arrays.asList("Cache-Control",
"Content-Language", "Content-Type", "Expires",
"Last-Modified", "Pragma"));
/**
* {@link Collection} of Simple HTTP request headers. Case in-sensitive.
*
* @see http://www.w3.org/TR/cors/#terminology
*/
public static final Collection<String> SIMPLE_HTTP_REQUEST_CONTENT_TYPE_VALUES =
new HashSet<>(Arrays.asList(
"application/x-www-form-urlencoded", "multipart/form-data",
"text/plain"));
// ------------------------------------------------ Configuration Defaults
/**
* By default, all origins are allowed to make requests.
*/
public static final String DEFAULT_ALLOWED_ORIGINS = "*";
/**
* By default, following methods are supported: GET, POST, HEAD and OPTIONS.
*/
public static final String DEFAULT_ALLOWED_HTTP_METHODS =
"GET,POST,HEAD,OPTIONS";
/**
* By default, time duration to cache pre-flight response is 30 mins.
*/
public static final String DEFAULT_PREFLIGHT_MAXAGE = "1800";
/**
* By default, support credentials is turned on.
*/
public static final String DEFAULT_SUPPORTS_CREDENTIALS = "true";
/**
* By default, following headers are supported:
* Origin,Accept,X-Requested-With, Content-Type,
* Access-Control-Request-Method, and Access-Control-Request-Headers.
*/
public static final String DEFAULT_ALLOWED_HTTP_HEADERS =
"Origin,Accept,X-Requested-With,Content-Type,"
+
"Access-Control-Request-Method,Access-Control-Request-Headers";
/**
* By default, none of the headers are exposed in response.
*/
public static final String DEFAULT_EXPOSED_HEADERS = "";
/**
* By default, access log logging is turned off
*/
public static final String DEFAULT_LOGGING_ENABLED = "false";
/**
* By default, request is decorated with CORS attributes.
*/
public static final String DEFAULT_DECORATE_REQUEST = "true";
// ----------------------------------------Filter Config Init param-name(s)
/**
* Key to retrieve allowed origins from {@link FilterConfig}.
*/
public static final String PARAM_CORS_ALLOWED_ORIGINS =
"cors.allowed.origins";
/**
* Key to retrieve support credentials from {@link FilterConfig}.
*/
public static final String PARAM_CORS_SUPPORT_CREDENTIALS =
"cors.support.credentials";
/**
* Key to retrieve exposed headers from {@link FilterConfig}.
*/
public static final String PARAM_CORS_EXPOSED_HEADERS =
"cors.exposed.headers";
/**
* Key to retrieve allowed headers from {@link FilterConfig}.
*/
public static final String PARAM_CORS_ALLOWED_HEADERS =
"cors.allowed.headers";
/**
* Key to retrieve allowed methods from {@link FilterConfig}.
*/
public static final String PARAM_CORS_ALLOWED_METHODS =
"cors.allowed.methods";
/**
* Key to retrieve preflight max age from {@link FilterConfig}.
*/
public static final String PARAM_CORS_PREFLIGHT_MAXAGE =
"cors.preflight.maxage";
/**
* Key to retrieve access log logging flag.
*/
public static final String PARAM_CORS_LOGGING_ENABLED =
"cors.logging.enabled";
/**
* Key to determine if request should be decorated.
*/
public static final String PARAM_CORS_REQUEST_DECORATE =
"cors.request.decorate";
}