Package org.apache.catalina.filters

Class CorsFilter

java.lang.Object
javax.servlet.GenericFilter
org.apache.catalina.filters.CorsFilter
All Implemented Interfaces:
Serializable, Filter, FilterConfig
public class CorsFilter extends GenericFilter

A Filter that enable client-side cross-origin requests by implementing W3C's CORS (Cross-Origin Resource Sharing) specification for resources. Each HttpServletRequest request is inspected as per specification, and appropriate response headers are added to 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 doFilter(ServletRequest, ServletResponse, FilterChain) and add appropriate locking so that the doFilter() method executes with a consistent configuration.
See Also:

  • Field Details

    • RESPONSE_HEADER_ACCESS_CONTROL_ALLOW_ORIGIN

      public static final String RESPONSE_HEADER_ACCESS_CONTROL_ALLOW_ORIGIN
      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.
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    • RESPONSE_HEADER_ACCESS_CONTROL_ALLOW_CREDENTIALS

      public static final String RESPONSE_HEADER_ACCESS_CONTROL_ALLOW_CREDENTIALS
      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.
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    • RESPONSE_HEADER_ACCESS_CONTROL_EXPOSE_HEADERS

      public static final String RESPONSE_HEADER_ACCESS_CONTROL_EXPOSE_HEADERS
      The Access-Control-Expose-Headers header indicates which headers are safe to expose to the API of a CORS API specification
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    • RESPONSE_HEADER_ACCESS_CONTROL_MAX_AGE

      public static final String RESPONSE_HEADER_ACCESS_CONTROL_MAX_AGE
      The Access-Control-Max-Age header indicates how long the results of a preflight request can be cached in a preflight result cache.
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    • RESPONSE_HEADER_ACCESS_CONTROL_ALLOW_METHODS

      public static final String RESPONSE_HEADER_ACCESS_CONTROL_ALLOW_METHODS
      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.
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    • RESPONSE_HEADER_ACCESS_CONTROL_ALLOW_HEADERS

      public static final String RESPONSE_HEADER_ACCESS_CONTROL_ALLOW_HEADERS
      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.
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    • REQUEST_HEADER_VARY

      @Deprecated public static final String REQUEST_HEADER_VARY
      Deprecated.
      Unused. Will be removed in Tomcat 10
      The Vary header indicates allows disabling proxy caching by indicating the the response depends on the origin.
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    • REQUEST_HEADER_ORIGIN

      public static final String REQUEST_HEADER_ORIGIN
      The Origin header indicates where the cross-origin request or preflight request originates from.
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    • REQUEST_HEADER_ACCESS_CONTROL_REQUEST_METHOD

      public static final String REQUEST_HEADER_ACCESS_CONTROL_REQUEST_METHOD
      The Access-Control-Request-Method header indicates which method will be used in the actual request as part of the preflight request.
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    • REQUEST_HEADER_ACCESS_CONTROL_REQUEST_HEADERS

      public static final String REQUEST_HEADER_ACCESS_CONTROL_REQUEST_HEADERS
      The Access-Control-Request-Headers header indicates which headers will be used in the actual request as part of the preflight request.
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    • HTTP_REQUEST_ATTRIBUTE_PREFIX

      public static final String HTTP_REQUEST_ATTRIBUTE_PREFIX
      The prefix to a CORS request attribute.
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    • HTTP_REQUEST_ATTRIBUTE_ORIGIN

      public static final String HTTP_REQUEST_ATTRIBUTE_ORIGIN
      Attribute that contains the origin of the request.
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    • HTTP_REQUEST_ATTRIBUTE_IS_CORS_REQUEST

      public static final String HTTP_REQUEST_ATTRIBUTE_IS_CORS_REQUEST
      Boolean value, suggesting if the request is a CORS request or not.
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    • HTTP_REQUEST_ATTRIBUTE_REQUEST_TYPE

      public static final String HTTP_REQUEST_ATTRIBUTE_REQUEST_TYPE
      Type of CORS request, of type CorsFilter.CORSRequestType.
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    • HTTP_REQUEST_ATTRIBUTE_REQUEST_HEADERS

      public static final String HTTP_REQUEST_ATTRIBUTE_REQUEST_HEADERS
      Request headers sent as 'Access-Control-Request-Headers' header, for pre-flight request.
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    • SIMPLE_HTTP_REQUEST_CONTENT_TYPE_VALUES

      public static final Collection<String> SIMPLE_HTTP_REQUEST_CONTENT_TYPE_VALUES
      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.
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    • DEFAULT_ALLOWED_ORIGINS

      public static final String DEFAULT_ALLOWED_ORIGINS
      By default, no origins are allowed to make requests.
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    • DEFAULT_ALLOWED_HTTP_METHODS

      public static final String DEFAULT_ALLOWED_HTTP_METHODS
      By default, following methods are supported: GET, POST, HEAD and OPTIONS.
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    • DEFAULT_PREFLIGHT_MAXAGE

      public static final String DEFAULT_PREFLIGHT_MAXAGE
      By default, time duration to cache pre-flight response is 30 mins.
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    • DEFAULT_SUPPORTS_CREDENTIALS

      public static final String DEFAULT_SUPPORTS_CREDENTIALS
      By default, support credentials is disabled.
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    • DEFAULT_ALLOWED_HTTP_HEADERS

      public static final String DEFAULT_ALLOWED_HTTP_HEADERS
      By default, following headers are supported: Origin,Accept,X-Requested-With, Content-Type, Access-Control-Request-Method, and Access-Control-Request-Headers.
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    • DEFAULT_EXPOSED_HEADERS

      public static final String DEFAULT_EXPOSED_HEADERS
      By default, none of the headers are exposed in response.
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    • DEFAULT_DECORATE_REQUEST

      public static final String DEFAULT_DECORATE_REQUEST
      By default, request is decorated with CORS attributes.
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    • PARAM_CORS_ALLOWED_ORIGINS

      public static final String PARAM_CORS_ALLOWED_ORIGINS
      Key to retrieve allowed origins from FilterConfig.
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    • PARAM_CORS_SUPPORT_CREDENTIALS

      public static final String PARAM_CORS_SUPPORT_CREDENTIALS
      Key to retrieve support credentials from FilterConfig.
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    • PARAM_CORS_EXPOSED_HEADERS

      public static final String PARAM_CORS_EXPOSED_HEADERS
      Key to retrieve exposed headers from FilterConfig.
      See Also:

    • PARAM_CORS_ALLOWED_HEADERS

      public static final String PARAM_CORS_ALLOWED_HEADERS
      Key to retrieve allowed headers from FilterConfig.
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    • PARAM_CORS_ALLOWED_METHODS

      public static final String PARAM_CORS_ALLOWED_METHODS
      Key to retrieve allowed methods from FilterConfig.
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    • PARAM_CORS_PREFLIGHT_MAXAGE

      public static final String PARAM_CORS_PREFLIGHT_MAXAGE
      Key to retrieve preflight max age from FilterConfig.
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    • PARAM_CORS_REQUEST_DECORATE

      public static final String PARAM_CORS_REQUEST_DECORATE
      Key to determine if request should be decorated.
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  • Constructor Details

    • CorsFilter

      public CorsFilter()

  • Method Details

    • doFilter

      public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException
      Description copied from interface: javax.servlet.Filter
      The doFilter method of the Filter is called by the container each time a request/response pair is passed through the chain due to a client request for a resource at the end of the chain. The FilterChain passed in to this method allows the Filter to pass on the request and response to the next entity in the chain.

      A typical implementation of this method would follow the following pattern:-
      1. Examine the request
      2. Optionally wrap the request object with a custom implementation to filter content or headers for input filtering
      3. Optionally wrap the response object with a custom implementation to filter content or headers for output filtering
      4. a) Either invoke the next entity in the chain using the FilterChain object (chain.doFilter()),
      4. b) or not pass on the request/response pair to the next entity in the filter chain to block the request processing
      5. Directly set headers on the response after invocation of the next entity in the filter chain.

      Parameters:
      servletRequest - The request to process
      servletResponse - The response associated with the request
      filterChain - Provides access to the next filter in the chain for this filter to pass the request and response to for further processing
      Throws:
      IOException - if an I/O error occurs during this filter's processing of the request
      ServletException - if the processing fails for any other reason

    • init

      public void init() throws ServletException
      Description copied from class: javax.servlet.GenericFilter
      Convenience method for sub-classes to save them having to call super.init(config). This is a NO-OP by default.
      Overrides:
      init in class GenericFilter
      Throws:
      ServletException - If an exception occurs that interrupts the Filter's normal operation

    • handleSimpleCORS

      protected void handleSimpleCORS(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws IOException, ServletException
      Handles a CORS request of type CorsFilter.CORSRequestType.SIMPLE.
      Parameters:
      request - The HttpServletRequest object.
      response - The HttpServletResponse object.
      filterChain - The FilterChain object.
      Throws:
      IOException - an IO error occurred
      ServletException - Servlet error propagation
      See Also:

    • handlePreflightCORS

      protected void handlePreflightCORS(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws IOException, ServletException
      Handles CORS pre-flight request.
      Parameters:
      request - The HttpServletRequest object.
      response - The HttpServletResponse object.
      filterChain - The FilterChain object.
      Throws:
      IOException - an IO error occurred
      ServletException - Servlet error propagation

    • decorateCORSProperties

      protected static void decorateCORSProperties(HttpServletRequest request, CorsFilter.CORSRequestType corsRequestType)
      Decorates the 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.
      Parameters:
      request - The HttpServletRequest object.
      corsRequestType - The CorsFilter.CORSRequestType object.

    • join

      protected static String join(Collection<String> elements, String joinSeparator)
      Joins elements of Set into a string, where each element is separated by the provided separator.
      Parameters:
      elements - The Set containing elements to join together.
      joinSeparator - The character to be used for separating elements.
      Returns:
      The joined String; null if elements Set is null.

    • checkRequestType

      protected CorsFilter.CORSRequestType checkRequestType(HttpServletRequest request)
      Determines the request type.
      Parameters:
      request - The HTTP Servlet request
      Returns:
      the CORS type

    • isValidOrigin

      @Deprecated protected static boolean isValidOrigin(String origin)
      Deprecated.
      This will be removed in Tomcat 10 Use RequestUtil.isValidOrigin(String)
      Checks if a given origin is valid or not. Criteria:
      • If an encoded character is present in origin, it's not valid.
      • If origin is "null", it's valid.
      • Origin should be a valid URI
      Parameters:
      origin - The origin URI
      Returns:
      true if the origin was valid
      See Also:

    • isAnyOriginAllowed

      public boolean isAnyOriginAllowed()
      Determines if any origin is allowed to make CORS request.
      Returns:
      true if it's enabled; false otherwise.

    • getExposedHeaders

      public Collection<String> getExposedHeaders()
      Obtain the headers to expose.
      Returns:
      the headers that should be exposed by browser.

    • isSupportsCredentials

      public boolean isSupportsCredentials()
      Determines is supports credentials is enabled.
      Returns:
      true if the use of credentials is supported otherwise false

    • getPreflightMaxAge

      public long getPreflightMaxAge()
      Returns the preflight response cache time in seconds.
      Returns:
      Time to cache in seconds.

    • getAllowedOrigins

      public Collection<String> getAllowedOrigins()
      Returns the Set of allowed origins that are allowed to make requests.
      Returns:
      Set

    • getAllowedHttpMethods

      public Collection<String> getAllowedHttpMethods()
      Returns a Set of HTTP methods that are allowed to make requests.
      Returns:
      Set

    • getAllowedHttpHeaders

      public Collection<String> getAllowedHttpHeaders()
      Returns a Set of headers support by resource.
      Returns:
      Set

    • isDecorateRequest

      public boolean isDecorateRequest()
      Should CORS specific attributes be added to the request.
      Returns:
      true if the request should be decorated, otherwise false