org.apache.catalina.filters.CorsFilter Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.apache.catalina.filters;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Locale;
import java.util.Set;
import jakarta.servlet.FilterChain;
import jakarta.servlet.GenericFilter;
import jakarta.servlet.ServletException;
import jakarta.servlet.ServletRequest;
import jakarta.servlet.ServletResponse;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;
import org.apache.tomcat.util.http.RequestUtil;
import org.apache.tomcat.util.http.ResponseUtil;
import org.apache.tomcat.util.res.StringManager;
/**
*
* A {@link jakarta.servlet.Filter} that enable client-side cross-origin requests by implementing W3C's CORS
* (Cross-Origin Resource Sharing) specification for resources. Each
* {@link HttpServletRequest} request is inspected as per specification, and appropriate response headers are added to
* {@link HttpServletResponse}.
*
*
* By default, it also sets following request attributes, that help to determine the nature of the request downstream.
*
*
* - cors.isCorsRequest: Flag to determine if the request is a CORS request. Set to
true if a CORS
* request; false otherwise.
* - cors.request.origin: The Origin URL, i.e. the URL of the page from where the request is originated.
* - cors.request.type: Type of request. Possible values:
*
* - SIMPLE: A request which is not preceded by a pre-flight request.
* - ACTUAL: A request which is preceded by a pre-flight request.
* - PRE_FLIGHT: A pre-flight request.
* - NOT_CORS: A normal same-origin request.
* - INVALID_CORS: A cross-origin request which is invalid.
*
*
* - cors.request.headers: Request headers sent as 'Access-Control-Request-Headers' header, for pre-flight
* request.
*
* If you extend this class and override one or more of the getXxx() methods, consider whether you also need to override
* {@link CorsFilter#doFilter(ServletRequest, ServletResponse, FilterChain)} and add appropriate locking so that the
* {@code doFilter()} method executes with a consistent configuration.
*
* @see CORS specification
*/
public class CorsFilter extends GenericFilter {
private static final long serialVersionUID = 1L;
private static final StringManager sm = StringManager.getManager(CorsFilter.class);
private transient Log log = LogFactory.getLog(CorsFilter.class); // must not be static
/**
* A {@link Collection} of origins consisting of zero or more origins that are allowed access to the resource.
*/
private final Collection allowedOrigins = new HashSet<>();
/**
* 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 allowedHttpMethods = new HashSet<>();
/**
* A {@link Collection} of headers consisting of zero or more header field names that are supported by the resource.
*/
private final Collection allowedHttpHeaders = new HashSet<>();
/**
* 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 exposedHeaders = new HashSet<>();
/**
* 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;
/**
* Determines if the request should be decorated or not.
*/
private boolean decorateRequest;
@Override
public void doFilter(final ServletRequest servletRequest, final ServletResponse servletResponse,
final FilterChain filterChain) throws IOException, ServletException {
if (!(servletRequest instanceof HttpServletRequest) || !(servletResponse instanceof HttpServletResponse)) {
throw new ServletException(sm.getString("corsFilter.onlyHttp"));
}
// 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 (isDecorateRequest()) {
decorateCORSProperties(request, requestType);
}
switch (requestType) {
case SIMPLE:
// Handles a Simple CORS request.
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() throws ServletException {
parseAndStore(getInitParameter(PARAM_CORS_ALLOWED_ORIGINS, DEFAULT_ALLOWED_ORIGINS),
getInitParameter(PARAM_CORS_ALLOWED_METHODS, DEFAULT_ALLOWED_HTTP_METHODS),
getInitParameter(PARAM_CORS_ALLOWED_HEADERS, DEFAULT_ALLOWED_HTTP_HEADERS),
getInitParameter(PARAM_CORS_EXPOSED_HEADERS, DEFAULT_EXPOSED_HEADERS),
getInitParameter(PARAM_CORS_SUPPORT_CREDENTIALS, DEFAULT_SUPPORTS_CREDENTIALS),
getInitParameter(PARAM_CORS_PREFLIGHT_MAXAGE, DEFAULT_PREFLIGHT_MAXAGE),
getInitParameter(PARAM_CORS_REQUEST_DECORATE, DEFAULT_DECORATE_REQUEST));
}
/**
* This method returns the parameter's value if it exists, or defaultValue if not.
*
* @param name The parameter's name
* @param defaultValue The default value to return if the parameter does not exist
*
* @return The parameter's value or the default value if the parameter does not exist
*/
private String getInitParameter(String name, String defaultValue) {
String value = getInitParameter(name);
if (value != null) {
return value;
}
return defaultValue;
}
/**
* 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 an IO error occurred
* @throws ServletException Servlet error propagation
*
* @see Simple Cross-Origin Request, Actual Request, and
* Redirects
*/
protected 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)) {
throw new IllegalArgumentException(sm.getString("corsFilter.wrongType2", CorsFilter.CORSRequestType.SIMPLE,
CorsFilter.CORSRequestType.ACTUAL));
}
final String origin = request.getHeader(REQUEST_HEADER_ORIGIN);
final String method = request.getMethod();
// Section 6.1.2
if (!isOriginAllowed(origin)) {
handleInvalidCORS(request, response, filterChain);
return;
}
if (!getAllowedHttpMethods().contains(method)) {
handleInvalidCORS(request, response, filterChain);
return;
}
addStandardHeaders(request, response);
// 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 an IO error occurred
* @throws ServletException Servlet error propagation
*/
protected 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(sm.getString("corsFilter.wrongType1",
CORSRequestType.PRE_FLIGHT.name().toLowerCase(Locale.ENGLISH)));
}
final String origin = request.getHeader(REQUEST_HEADER_ORIGIN);
// Section 6.2.2
if (!isOriginAllowed(origin)) {
handleInvalidCORS(request, response, filterChain);
return;
}
// Section 6.2.3
String accessControlRequestMethod = request.getHeader(REQUEST_HEADER_ACCESS_CONTROL_REQUEST_METHOD);
if (accessControlRequestMethod == null) {
handleInvalidCORS(request, response, filterChain);
return;
} else {
accessControlRequestMethod = accessControlRequestMethod.trim();
}
// Section 6.2.4
String accessControlRequestHeadersHeader = request.getHeader(REQUEST_HEADER_ACCESS_CONTROL_REQUEST_HEADERS);
List accessControlRequestHeaders = new ArrayList<>();
if (accessControlRequestHeadersHeader != null && !accessControlRequestHeadersHeader.trim().isEmpty()) {
String[] headers = accessControlRequestHeadersHeader.trim().split(",");
for (String header : headers) {
accessControlRequestHeaders.add(header.trim().toLowerCase(Locale.ENGLISH));
}
}
// Section 6.2.5
if (!getAllowedHttpMethods().contains(accessControlRequestMethod)) {
handleInvalidCORS(request, response, filterChain);
return;
}
// Section 6.2.6
if (!accessControlRequestHeaders.isEmpty()) {
for (String header : accessControlRequestHeaders) {
if (!getAllowedHttpHeaders().contains(header)) {
handleInvalidCORS(request, response, filterChain);
return;
}
}
}
addStandardHeaders(request, response);
// 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 an IO error occurred
* @throws ServletException Servlet error propagation
*/
private void handleNonCORS(final HttpServletRequest request, final HttpServletResponse response,
final FilterChain filterChain) throws IOException, ServletException {
if (!isAnyOriginAllowed()) {
// If only specific origins are allowed, the response will vary by
// origin
ResponseUtil.addVaryFieldName(response, REQUEST_HEADER_ORIGIN);
}
// 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.
*/
private void handleInvalidCORS(final HttpServletRequest request, final HttpServletResponse response,
final FilterChain filterChain) {
String origin = request.getHeader(REQUEST_HEADER_ORIGIN);
String method = request.getMethod();
String accessControlRequestHeaders = request.getHeader(REQUEST_HEADER_ACCESS_CONTROL_REQUEST_HEADERS);
response.setContentType("text/plain");
response.setStatus(HttpServletResponse.SC_FORBIDDEN);
response.resetBuffer();
if (log.isDebugEnabled()) {
sm.getString("corsFilter.invalidRequest", origin, method, accessControlRequestHeaders);
}
}
/*
* Sets a standard set of headers to reduce response variation which in turn is intended to aid caching.
*/
private void addStandardHeaders(final HttpServletRequest request, final HttpServletResponse response) {
final String method = request.getMethod();
final String origin = request.getHeader(REQUEST_HEADER_ORIGIN);
// Local copy to avoid concurrency issues if isAnyOriginAllowed()
// is overridden.
boolean anyOriginAllowed = isAnyOriginAllowed();
if (!anyOriginAllowed) {
// If only specific origins are allowed, the response will vary by
// origin
ResponseUtil.addVaryFieldName(response, REQUEST_HEADER_ORIGIN);
}
// CORS requests (SIMPLE, ACTUAL, PRE_FLIGHT) set the following headers
// although non-CORS requests do not need to. The headers are always set
// as a) they do no harm in the non-CORS case and b) it allows the same
// response to be cached for CORS and non-CORS requests.
// Add a single Access-Control-Allow-Origin header.
if (anyOriginAllowed) {
// If any origin is allowed, return header with '*'.
response.addHeader(RESPONSE_HEADER_ACCESS_CONTROL_ALLOW_ORIGIN, "*");
} else {
// Add a single Access-Control-Allow-Origin header, with the value
// of the Origin header as value.
response.addHeader(RESPONSE_HEADER_ACCESS_CONTROL_ALLOW_ORIGIN, origin);
}
// If the resource supports credentials, add a single
// Access-Control-Allow-Credentials header with the case-sensitive
// string "true" as value.
if (isSupportsCredentials()) {
response.addHeader(RESPONSE_HEADER_ACCESS_CONTROL_ALLOW_CREDENTIALS, "true");
}
// 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.
// Local copy to avoid concurrency issues if getExposedHeaders()
// is overridden.
Collection exposedHeaders = getExposedHeaders();
if (exposedHeaders != null && exposedHeaders.size() > 0) {
String exposedHeadersString = join(exposedHeaders, ",");
response.addHeader(RESPONSE_HEADER_ACCESS_CONTROL_EXPOSE_HEADERS, exposedHeadersString);
}
if ("OPTIONS".equals(method)) {
// For an OPTIONS request, the response will vary based on the
// value or absence of the following headers. Hence they need be be
// included in the Vary header.
ResponseUtil.addVaryFieldName(response, REQUEST_HEADER_ACCESS_CONTROL_REQUEST_METHOD);
ResponseUtil.addVaryFieldName(response, REQUEST_HEADER_ACCESS_CONTROL_REQUEST_HEADERS);
// CORS PRE_FLIGHT (OPTIONS) requests set the following headers although
// non-CORS OPTIONS requests do not need to. The headers are always set
// as a) they do no harm in the non-CORS case and b) it allows the same
// response to be cached for CORS and non-CORS requests.
// Local copy to avoid concurrency issues if getPreflightMaxAge()
// is overridden.
long preflightMaxAge = getPreflightMaxAge();
if (preflightMaxAge > 0) {
response.addHeader(RESPONSE_HEADER_ACCESS_CONTROL_MAX_AGE, String.valueOf(preflightMaxAge));
}
// Local copy to avoid concurrency issues if getAllowedHttpMethods()
// is overridden.
Collection allowedHttpMethods = getAllowedHttpMethods();
if (allowedHttpMethods != null && !allowedHttpMethods.isEmpty()) {
response.addHeader(RESPONSE_HEADER_ACCESS_CONTROL_ALLOW_METHODS, join(allowedHttpMethods, ","));
}
// Local copy to avoid concurrency issues if getAllowedHttpHeaders()
// is overridden.
Collection allowedHttpHeaders = getAllowedHttpHeaders();
if (allowedHttpHeaders != null && !allowedHttpHeaders.isEmpty()) {
response.addHeader(RESPONSE_HEADER_ACCESS_CONTROL_ALLOW_HEADERS, join(allowedHttpHeaders, ","));
}
}
}
/**
* Decorates the {@link HttpServletRequest}, with CORS attributes.
*
* - cors.isCorsRequest: Flag to determine if request is a CORS request. Set to
true if CORS
* request; false otherwise.
* - cors.request.origin: The Origin URL.
* - cors.request.type: Type of request. Values:
simple or preflight or
* not_cors or invalid_cors
* - cors.request.headers: Request headers sent as 'Access-Control-Request-Headers' header, for pre-flight
* request.
*
*
* @param request The {@link HttpServletRequest} object.
* @param corsRequestType The {@link CORSRequestType} object.
*/
protected static void decorateCORSProperties(final HttpServletRequest request,
final CORSRequestType corsRequestType) {
if (request == null) {
throw new IllegalArgumentException(sm.getString("corsFilter.nullRequest"));
}
if (corsRequestType == null) {
throw new IllegalArgumentException(sm.getString("corsFilter.nullRequestType"));
}
switch (corsRequestType) {
case SIMPLE:
case ACTUAL:
request.setAttribute(HTTP_REQUEST_ATTRIBUTE_IS_CORS_REQUEST, Boolean.TRUE);
request.setAttribute(HTTP_REQUEST_ATTRIBUTE_ORIGIN, request.getHeader(REQUEST_HEADER_ORIGIN));
request.setAttribute(HTTP_REQUEST_ATTRIBUTE_REQUEST_TYPE,
corsRequestType.name().toLowerCase(Locale.ENGLISH));
break;
case PRE_FLIGHT:
request.setAttribute(HTTP_REQUEST_ATTRIBUTE_IS_CORS_REQUEST, Boolean.TRUE);
request.setAttribute(HTTP_REQUEST_ATTRIBUTE_ORIGIN, request.getHeader(REQUEST_HEADER_ORIGIN));
request.setAttribute(HTTP_REQUEST_ATTRIBUTE_REQUEST_TYPE,
corsRequestType.name().toLowerCase(Locale.ENGLISH));
String headers = request.getHeader(REQUEST_HEADER_ACCESS_CONTROL_REQUEST_HEADERS);
if (headers == null) {
headers = "";
}
request.setAttribute(HTTP_REQUEST_ATTRIBUTE_REQUEST_HEADERS, headers);
break;
case NOT_CORS:
request.setAttribute(HTTP_REQUEST_ATTRIBUTE_IS_CORS_REQUEST, Boolean.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}; null if elements {@link Set} is null.
*/
protected static String join(final Collection 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 The HTTP Servlet request
*
* @return the CORS type
*/
protected CORSRequestType checkRequestType(final HttpServletRequest request) {
CORSRequestType requestType = CORSRequestType.INVALID_CORS;
if (request == null) {
throw new IllegalArgumentException(sm.getString("corsFilter.nullRequest"));
}
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 (!RequestUtil.isValidOrigin(originHeader)) {
requestType = CORSRequestType.INVALID_CORS;
} else if (RequestUtil.isSameOrigin(request, originHeader)) {
return CORSRequestType.NOT_CORS;
} else {
String method = request.getMethod();
if (method != null) {
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 mediaType = getMediaType(request.getContentType());
if (mediaType != null) {
if (SIMPLE_HTTP_REQUEST_CONTENT_TYPE_VALUES.contains(mediaType)) {
requestType = CORSRequestType.SIMPLE;
} else {
requestType = CORSRequestType.ACTUAL;
}
}
} else {
requestType = CORSRequestType.ACTUAL;
}
}
}
} else {
requestType = CORSRequestType.NOT_CORS;
}
return requestType;
}
/**
* Return the lower case, trimmed value of the media type from the content type.
*/
private String getMediaType(String contentType) {
if (contentType == null) {
return null;
}
String result = contentType.toLowerCase(Locale.ENGLISH);
int firstSemiColonIndex = result.indexOf(';');
if (firstSemiColonIndex > -1) {
result = result.substring(0, firstSemiColonIndex);
}
result = result.trim();
return result;
}
/**
* Checks if the Origin is allowed to make a CORS request.
*
* @param origin The Origin.
*
* @return true if origin is allowed; false otherwise.
*/
private boolean isOriginAllowed(final String origin) {
if (isAnyOriginAllowed()) {
return true;
}
// If 'Origin' header is a case-sensitive match of any of allowed
// origins, then return true, else return false.
return getAllowedOrigins().contains(origin);
}
/**
* 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.
*
* @throws ServletException If the configuration is invalid
*/
private void parseAndStore(final String allowedOrigins, final String allowedHttpMethods,
final String allowedHttpHeaders, final String exposedHeaders, final String supportsCredentials,
final String preflightMaxAge, final String decorateRequest) throws ServletException {
if (allowedOrigins.trim().equals("*")) {
this.anyOriginAllowed = true;
} else {
this.anyOriginAllowed = false;
Set setAllowedOrigins = parseStringToSet(allowedOrigins);
this.allowedOrigins.clear();
this.allowedOrigins.addAll(setAllowedOrigins);
}
Set setAllowedHttpMethods = parseStringToSet(allowedHttpMethods);
this.allowedHttpMethods.clear();
this.allowedHttpMethods.addAll(setAllowedHttpMethods);
Set setAllowedHttpHeaders = parseStringToSet(allowedHttpHeaders);
Set lowerCaseHeaders = new HashSet<>();
for (String header : setAllowedHttpHeaders) {
String lowerCase = header.toLowerCase(Locale.ENGLISH);
lowerCaseHeaders.add(lowerCase);
}
this.allowedHttpHeaders.clear();
this.allowedHttpHeaders.addAll(lowerCaseHeaders);
Set setExposedHeaders = parseStringToSet(exposedHeaders);
this.exposedHeaders.clear();
this.exposedHeaders.addAll(setExposedHeaders);
// For any value other than 'true' this will be false.
this.supportsCredentials = Boolean.parseBoolean(supportsCredentials);
if (this.supportsCredentials && this.anyOriginAllowed) {
throw new ServletException(sm.getString("corsFilter.invalidSupportsCredentials"));
}
try {
if (!preflightMaxAge.isEmpty()) {
this.preflightMaxAge = Long.parseLong(preflightMaxAge);
} else {
this.preflightMaxAge = 0L;
}
} catch (NumberFormatException e) {
throw new ServletException(sm.getString("corsFilter.invalidPreflightMaxAge"), e);
}
// For any value other than '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$lt;String>
*/
private Set parseStringToSet(final String data) {
String[] splits;
if (data != null && data.length() > 0) {
splits = data.split(",");
} else {
splits = new String[] {};
}
Set set = new HashSet<>();
if (splits.length > 0) {
for (String split : splits) {
set.add(split.trim());
}
}
return set;
}
/**
* Determines if any origin is allowed to make CORS request.
*
* @return true if it's enabled; false otherwise.
*/
public boolean isAnyOriginAllowed() {
return anyOriginAllowed;
}
/**
* Obtain the headers to expose.
*
* @return the headers that should be exposed by browser.
*/
public Collection getExposedHeaders() {
return exposedHeaders;
}
/**
* Determines is supports credentials is enabled.
*
* @return true if the use of credentials is supported otherwise false
*/
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 getAllowedOrigins() {
return allowedOrigins;
}
/**
* Returns a {@link Set} of HTTP methods that are allowed to make requests.
*
* @return {@link Set}
*/
public Collection getAllowedHttpMethods() {
return allowedHttpMethods;
}
/**
* Returns a {@link Set} of headers support by resource.
*
* @return {@link Set}
*/
public Collection getAllowedHttpHeaders() {
return allowedHttpHeaders;
}
/**
* Should CORS specific attributes be added to the request.
*
* @return {@code true} if the request should be decorated, otherwise {@code false}
*/
public boolean isDecorateRequest() {
return decorateRequest;
}
/*
* Log objects are not Serializable but this Filter is because it extends GenericFilter. Tomcat won't serialize a
* Filter but in case something else does...
*/
private void readObject(ObjectInputStream ois) throws ClassNotFoundException, IOException {
ois.defaultReadObject();
log = LogFactory.getLog(CorsFilter.class);
}
// -------------------------------------------------- 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.
*/
protected enum CORSRequestType {
/**
* A simple HTTP request, i.e. it shouldn't be pre-flighted.
*/
SIMPLE,
/**
* An 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 media type values for the Content-Type header that will be treated as 'simple'. Note
* media-type values are compared ignoring parameters and in a case-insensitive manner.
*
* @see http://www.w3.org/TR/cors/#terminology
*/
public static final Collection SIMPLE_HTTP_REQUEST_CONTENT_TYPE_VALUES = Collections.unmodifiableSet(
new HashSet<>(Arrays.asList("application/x-www-form-urlencoded", "multipart/form-data", "text/plain")));
// ------------------------------------------------ Configuration Defaults
/**
* By default, no 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 disabled.
*/
public static final String DEFAULT_SUPPORTS_CREDENTIALS = "false";
/**
* 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, 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 jakarta.servlet.FilterConfig}.
*/
public static final String PARAM_CORS_ALLOWED_ORIGINS = "cors.allowed.origins";
/**
* Key to retrieve support credentials from {@link jakarta.servlet.FilterConfig}.
*/
public static final String PARAM_CORS_SUPPORT_CREDENTIALS = "cors.support.credentials";
/**
* Key to retrieve exposed headers from {@link jakarta.servlet.FilterConfig}.
*/
public static final String PARAM_CORS_EXPOSED_HEADERS = "cors.exposed.headers";
/**
* Key to retrieve allowed headers from {@link jakarta.servlet.FilterConfig}.
*/
public static final String PARAM_CORS_ALLOWED_HEADERS = "cors.allowed.headers";
/**
* Key to retrieve allowed methods from {@link jakarta.servlet.FilterConfig}.
*/
public static final String PARAM_CORS_ALLOWED_METHODS = "cors.allowed.methods";
/**
* Key to retrieve preflight max age from {@link jakarta.servlet.FilterConfig}.
*/
public static final String PARAM_CORS_PREFLIGHT_MAXAGE = "cors.preflight.maxage";
/**
* Key to determine if request should be decorated.
*/
public static final String PARAM_CORS_REQUEST_DECORATE = "cors.request.decorate";
}