org.eclipse.jetty.servlets.CrossOriginFilter Maven / Gradle / Ivy
/*
* Copyright (c) 2009-2009 Mort Bay Consulting Pty. Ltd.
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* and Apache License v2.0 which accompanies this distribution.
* The Eclipse Public License is available at
* http://www.eclipse.org/legal/epl-v10.html
* The Apache License v2.0 is available at
* http://www.opensource.org/licenses/apache2.0.php
*
* You may elect to redistribute this code under either of these licenses.
*/
package org.eclipse.jetty.servlets;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
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;
import org.eclipse.jetty.util.log.Log;
import org.eclipse.jetty.util.log.Logger;
/**
* Implementation of the
* cross-origin resource sharing.
* A typical example is to use this filter to allow cross-domain
* cometd communication using the standard
* long polling transport instead of the JSONP transport (that is less
* efficient and less reactive to failures).
* This filter allows the following configuration parameters:
*
* - allowedOrigins, a comma separated list of origins that are
* allowed to access the resources. Default value is *, meaning all
* origins
* - allowedMethods, a comma separated list of HTTP methods that
* are allowed to be used when accessing the resources. Default value is
* GET,POST
* - allowedHeaders, a comma separated list of HTTP headers that
* are allowed to be specified when accessing the resources. Default value
* is X-Requested-With
* - preflightMaxAge, the number of seconds that preflight requests
* can be cached by the client. Default value is 1800 seconds, or 30
* minutes
* - allowCredentials, a boolean indicating if the resource allows
* requests with credentials. Default value is false
*
* A typical configuration could be:
*
* <web-app ...>
* ...
* <filter>
* <filter-name>cross-origin</filter-name>
* <filter-class>org.eclipse.jetty.servlets.CrossOriginFilter</filter-class>
* </filter>
* <filter-mapping>
* <filter-name>cross-origin</filter-name>
* <url-pattern>/cometd/*</url-pattern>
* </filter-mapping>
* ...
* </web-app>
*
*
* @version $Revision$ $Date$
*/
public class CrossOriginFilter implements Filter
{
private static final Logger LOG = Log.getLogger(CrossOriginFilter.class);
// Request headers
private static final String ORIGIN_HEADER = "Origin";
public static final String ACCESS_CONTROL_REQUEST_METHOD_HEADER = "Access-Control-Request-Method";
public static final String ACCESS_CONTROL_REQUEST_HEADERS_HEADER = "Access-Control-Request-Headers";
// Response headers
public static final String ACCESS_CONTROL_ALLOW_ORIGIN_HEADER = "Access-Control-Allow-Origin";
public static final String ACCESS_CONTROL_ALLOW_METHODS_HEADER = "Access-Control-Allow-Methods";
public static final String ACCESS_CONTROL_ALLOW_HEADERS_HEADER = "Access-Control-Allow-Headers";
public static final String ACCESS_CONTROL_MAX_AGE_HEADER = "Access-Control-Max-Age";
public static final String ACCESS_CONTROL_ALLOW_CREDENTIALS_HEADER = "Access-Control-Allow-Credentials";
// Implementation constants
public static final String ALLOWED_ORIGINS_PARAM = "allowedOrigins";
public static final String ALLOWED_METHODS_PARAM = "allowedMethods";
public static final String ALLOWED_HEADERS_PARAM = "allowedHeaders";
public static final String PREFLIGHT_MAX_AGE_PARAM = "preflightMaxAge";
public static final String ALLOW_CREDENTIALS_PARAM = "allowCredentials";
private static final String ANY_ORIGIN = "*";
private static final List SIMPLE_HTTP_METHODS = Arrays.asList("GET", "POST", "HEAD");
private boolean anyOriginAllowed;
private List allowedOrigins = new ArrayList();
private List allowedMethods = new ArrayList();
private List allowedHeaders = new ArrayList();
private int preflightMaxAge = 0;
private boolean allowCredentials;
public void init(FilterConfig config) throws ServletException
{
String allowedOriginsConfig = config.getInitParameter(ALLOWED_ORIGINS_PARAM);
if (allowedOriginsConfig == null)
allowedOriginsConfig = "*";
String[] allowedOrigins = allowedOriginsConfig.split(",");
for (String allowedOrigin : allowedOrigins)
{
allowedOrigin = allowedOrigin.trim();
if (allowedOrigin.length() > 0)
{
if (ANY_ORIGIN.equals(allowedOrigin))
{
anyOriginAllowed = true;
this.allowedOrigins.clear();
break;
}
else
{
this.allowedOrigins.add(allowedOrigin);
}
}
}
String allowedMethodsConfig = config.getInitParameter(ALLOWED_METHODS_PARAM);
if (allowedMethodsConfig == null)
allowedMethodsConfig = "GET,POST,HEAD";
allowedMethods.addAll(Arrays.asList(allowedMethodsConfig.split(",")));
String allowedHeadersConfig = config.getInitParameter(ALLOWED_HEADERS_PARAM);
if (allowedHeadersConfig == null)
allowedHeadersConfig = "X-Requested-With,Content-Type,Accept,Origin";
allowedHeaders.addAll(Arrays.asList(allowedHeadersConfig.split(",")));
String preflightMaxAgeConfig = config.getInitParameter(PREFLIGHT_MAX_AGE_PARAM);
if (preflightMaxAgeConfig == null)
preflightMaxAgeConfig = "1800"; // Default is 30 minutes
try
{
preflightMaxAge = Integer.parseInt(preflightMaxAgeConfig);
}
catch (NumberFormatException x)
{
LOG.info("Cross-origin filter, could not parse '{}' parameter as integer: {}", PREFLIGHT_MAX_AGE_PARAM, preflightMaxAgeConfig);
}
String allowedCredentialsConfig = config.getInitParameter(ALLOW_CREDENTIALS_PARAM);
if (allowedCredentialsConfig == null)
allowedCredentialsConfig = "true";
allowCredentials = Boolean.parseBoolean(allowedCredentialsConfig);
if (LOG.isDebugEnabled())
{
LOG.debug("Cross-origin filter configuration: " +
ALLOWED_ORIGINS_PARAM + " = " + allowedOriginsConfig + ", " +
ALLOWED_METHODS_PARAM + " = " + allowedMethodsConfig + ", " +
ALLOWED_HEADERS_PARAM + " = " + allowedHeadersConfig + ", " +
PREFLIGHT_MAX_AGE_PARAM + " = " + preflightMaxAgeConfig + ", " +
ALLOW_CREDENTIALS_PARAM + " = " + allowedCredentialsConfig);
}
}
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException
{
handle((HttpServletRequest)request, (HttpServletResponse)response, chain);
}
private void handle(HttpServletRequest request, HttpServletResponse response, FilterChain chain) throws IOException, ServletException
{
String origin = request.getHeader(ORIGIN_HEADER);
// Is it a cross origin request ?
if (origin != null && isEnabled(request))
{
if (originMatches(origin))
{
if (isSimpleRequest(request))
{
LOG.debug("Cross-origin request to {} is a simple cross-origin request", request.getRequestURI());
handleSimpleResponse(request, response, origin);
}
else if (isPreflightRequest(request))
{
LOG.debug("Cross-origin request to {} is a preflight cross-origin request", request.getRequestURI());
handlePreflightResponse(request, response, origin);
}
else
{
LOG.debug("Cross-origin request to {} is a non-simple cross-origin request", request.getRequestURI());
handleSimpleResponse(request, response, origin);
}
}
else
{
LOG.debug("Cross-origin request to " + request.getRequestURI() + " with origin " + origin + " does not match allowed origins " + allowedOrigins);
}
}
chain.doFilter(request, response);
}
protected boolean isEnabled(HttpServletRequest request)
{
// WebSocket clients such as Chrome 5 implement a version of the WebSocket
// protocol that does not accept extra response headers on the upgrade response
if ("Upgrade".equalsIgnoreCase(request.getHeader("Connection")) &&
"WebSocket".equalsIgnoreCase(request.getHeader("Upgrade")))
{
return false;
}
return true;
}
private boolean originMatches(String originList)
{
if (anyOriginAllowed)
return true;
if (originList.trim().length() == 0)
return false;
String[] origins = originList.split(" ");
for (String origin : origins)
{
if (origin.trim().length() == 0)
continue;
boolean allowed = false;
for (String allowedOrigin : allowedOrigins)
{
if (allowedOrigin.equals(origin))
{
allowed = true;
break;
}
}
if (!allowed)
return false;
}
return true;
}
private boolean isSimpleRequest(HttpServletRequest request)
{
String method = request.getMethod();
if (SIMPLE_HTTP_METHODS.contains(method))
{
// TODO: implement better detection of simple headers
// The specification says that for a request to be simple, custom request headers must be simple.
// Here for simplicity I just check if there is a Access-Control-Request-Method header,
// which is required for preflight requests
return request.getHeader(ACCESS_CONTROL_REQUEST_METHOD_HEADER) == null;
}
return false;
}
private boolean isPreflightRequest(HttpServletRequest request)
{
String method = request.getMethod();
if (!"OPTIONS".equalsIgnoreCase(method))
return false;
if (request.getHeader(ACCESS_CONTROL_REQUEST_METHOD_HEADER) == null)
return false;
return true;
}
private void handleSimpleResponse(HttpServletRequest request, HttpServletResponse response, String origin)
{
response.setHeader(ACCESS_CONTROL_ALLOW_ORIGIN_HEADER, origin);
if (allowCredentials)
response.setHeader(ACCESS_CONTROL_ALLOW_CREDENTIALS_HEADER, "true");
}
private void handlePreflightResponse(HttpServletRequest request, HttpServletResponse response, String origin)
{
boolean methodAllowed = isMethodAllowed(request);
if (!methodAllowed)
return;
boolean headersAllowed = areHeadersAllowed(request);
if (!headersAllowed)
return;
response.setHeader(ACCESS_CONTROL_ALLOW_ORIGIN_HEADER, origin);
if (allowCredentials)
response.setHeader(ACCESS_CONTROL_ALLOW_CREDENTIALS_HEADER, "true");
if (preflightMaxAge > 0)
response.setHeader(ACCESS_CONTROL_MAX_AGE_HEADER, String.valueOf(preflightMaxAge));
response.setHeader(ACCESS_CONTROL_ALLOW_METHODS_HEADER, commify(allowedMethods));
response.setHeader(ACCESS_CONTROL_ALLOW_HEADERS_HEADER, commify(allowedHeaders));
}
private boolean isMethodAllowed(HttpServletRequest request)
{
String accessControlRequestMethod = request.getHeader(ACCESS_CONTROL_REQUEST_METHOD_HEADER);
LOG.debug("{} is {}", ACCESS_CONTROL_REQUEST_METHOD_HEADER, accessControlRequestMethod);
boolean result = false;
if (accessControlRequestMethod != null)
result = allowedMethods.contains(accessControlRequestMethod);
LOG.debug("Method {} is" + (result ? "" : " not") + " among allowed methods {}", accessControlRequestMethod, allowedMethods);
return result;
}
private boolean areHeadersAllowed(HttpServletRequest request)
{
String accessControlRequestHeaders = request.getHeader(ACCESS_CONTROL_REQUEST_HEADERS_HEADER);
LOG.debug("{} is {}", ACCESS_CONTROL_REQUEST_HEADERS_HEADER, accessControlRequestHeaders);
boolean result = true;
if (accessControlRequestHeaders != null)
{
String[] headers = accessControlRequestHeaders.split(",");
for (String header : headers)
{
boolean headerAllowed = false;
for (String allowedHeader : allowedHeaders)
{
if (header.trim().equalsIgnoreCase(allowedHeader.trim()))
{
headerAllowed = true;
break;
}
}
if (!headerAllowed)
{
result = false;
break;
}
}
}
LOG.debug("Headers [{}] are" + (result ? "" : " not") + " among allowed headers {}", accessControlRequestHeaders, allowedHeaders);
return result;
}
private String commify(List strings)
{
StringBuilder builder = new StringBuilder();
for (int i = 0; i < strings.size(); ++i)
{
if (i > 0) builder.append(",");
String string = strings.get(i);
builder.append(string);
}
return builder.toString();
}
public void destroy()
{
anyOriginAllowed = false;
allowedOrigins.clear();
allowedMethods.clear();
allowedHeaders.clear();
preflightMaxAge = 0;
allowCredentials = false;
}
}