com.frameworkset.common.filter

Class HeaderFilter

java.lang.Object

com.frameworkset.common.filter.HeaderFilter

All Implemented Interfaces:

javax.servlet.Filter

public class HeaderFilter
extends java.lang.Object
implements javax.servlet.Filter

Description:

Copyright (c) 2018

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	HeaderFilter.CORSRequestType Enumerates varies types of CORS requests.

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.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.
static java.lang.String	DEFAULT_ALLOWED_HTTP_METHODS By default, following methods are supported: GET, POST, HEAD and OPTIONS.
static java.lang.String	DEFAULT_ALLOWED_ORIGINS By default, all origins are allowed to make requests.
static java.lang.String	DEFAULT_DECORATE_REQUEST By default, request is decorated with CORS attributes.
static java.lang.String	DEFAULT_EXPOSED_HEADERS By default, none of the headers are exposed in response.
static java.lang.String	DEFAULT_PREFLIGHT_MAXAGE By default, time duration to cache pre-flight response is 30 mins.
static java.lang.String	DEFAULT_SUPPORTS_CREDENTIALS By default, support credentials is turned on.
static java.lang.String	HTTP_REQUEST_ATTRIBUTE_IS_CORS_REQUEST Boolean value, suggesting if the request is a CORS request or not.
static java.lang.String	HTTP_REQUEST_ATTRIBUTE_ORIGIN Attribute that contains the origin of the request.
static java.lang.String	HTTP_REQUEST_ATTRIBUTE_PREFIX The prefix to a CORS request attribute.
static java.lang.String	HTTP_REQUEST_ATTRIBUTE_REQUEST_HEADERS Request headers sent as 'Access-Control-Request-Headers' header, for pre-flight request.
static java.lang.String	HTTP_REQUEST_ATTRIBUTE_REQUEST_TYPE Type of CORS request, of type HeaderFilter.CORSRequestType.
static java.lang.String	PARAM_CORS_ALLOWED_HEADERS Key to retrieve allowed headers from javax.servlet.FilterConfig.
static java.lang.String	PARAM_CORS_ALLOWED_METHODS Key to retrieve allowed methods from javax.servlet.FilterConfig.
static java.lang.String	PARAM_CORS_ALLOWED_ORIGINS Key to retrieve allowed origins from javax.servlet.FilterConfig.
static java.lang.String	PARAM_CORS_EXPOSED_HEADERS Key to retrieve exposed headers from javax.servlet.FilterConfig.
static java.lang.String	PARAM_CORS_PREFLIGHT_MAXAGE Key to retrieve preflight max age from javax.servlet.FilterConfig.
static java.lang.String	PARAM_CORS_REQUEST_DECORATE Key to determine if request should be decorated.
static java.lang.String	PARAM_CORS_SUPPORT_CREDENTIALS Key to retrieve support credentials from
static java.lang.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.
static java.lang.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.
static java.lang.String	REQUEST_HEADER_ORIGIN The Origin header indicates where the cross-origin request or preflight request originates from.
static java.lang.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.
static java.lang.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.
static java.lang.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.
static java.lang.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.
static java.lang.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
static java.lang.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.
static java.util.Collection<java.lang.String>	SIMPLE_HTTP_REQUEST_CONTENT_TYPE_VALUES Collection of media type values for the Content-Type header that will be treated as 'simple'.

Constructor Summary

Constructors

Constructor and Description
HeaderFilter()

Method Summary

Modifier and Type	Method and Description
protected HeaderFilter.CORSRequestType	checkRequestType(javax.servlet.http.HttpServletRequest request) Determines the request type.
protected static void	decorateCORSProperties(javax.servlet.http.HttpServletRequest request, HeaderFilter.CORSRequestType corsRequestType) Decorates the HttpServletRequest, with CORS attributes.
void	destroy()
void	doFilter(javax.servlet.ServletRequest servletRequest, javax.servlet.ServletResponse servletResponse, javax.servlet.FilterChain filterChain)
java.util.Collection<java.lang.String>	getAllowedHttpHeaders() Returns a Set of headers support by resource.
java.util.Collection<java.lang.String>	getAllowedHttpMethods() Returns a Set of HTTP methods that are allowed to make requests.
java.util.Collection<java.lang.String>	getAllowedOrigins() Returns the Set of allowed origins that are allowed to make requests.
java.util.Collection<java.lang.String>	getExposedHeaders() Obtain the headers to expose.
long	getPreflightMaxAge() Returns the preflight response cache time in seconds.
protected void	handlePreflightCORS(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response, javax.servlet.FilterChain filterChain) Handles CORS pre-flight request.
protected void	handleSimpleCORS(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response, javax.servlet.FilterChain filterChain) Handles a CORS request of type HeaderFilter.CORSRequestType.SIMPLE.
void	init(javax.servlet.FilterConfig filterConfig)
boolean	isAnyOriginAllowed() Determines if any origin is allowed to make CORS request.
boolean	isSupportsCredentials() Determines is supports credentials is enabled.
protected static boolean	isValidOrigin(java.lang.String origin) Checks if a given origin is valid or not.
protected static java.lang.String	join(java.util.Collection<java.lang.String> elements, java.lang.String joinSeparator) Joins elements of Set into a string, where each element is separated by the provided separator.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

RESPONSE_HEADER_ACCESS_CONTROL_ALLOW_ORIGIN

public static final java.lang.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.

See Also:

Constant Field Values

RESPONSE_HEADER_ACCESS_CONTROL_ALLOW_CREDENTIALS

public static final java.lang.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.

See Also:

Constant Field Values

RESPONSE_HEADER_ACCESS_CONTROL_EXPOSE_HEADERS

public static final java.lang.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

See Also:

Constant Field Values

RESPONSE_HEADER_ACCESS_CONTROL_MAX_AGE

public static final java.lang.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.

See Also:

Constant Field Values

RESPONSE_HEADER_ACCESS_CONTROL_ALLOW_METHODS

public static final java.lang.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.

See Also:

Constant Field Values

RESPONSE_HEADER_ACCESS_CONTROL_ALLOW_HEADERS

public static final java.lang.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.

See Also:

Constant Field Values

REQUEST_HEADER_ORIGIN

public static final java.lang.String REQUEST_HEADER_ORIGIN

The Origin header indicates where the cross-origin request or preflight request originates from.

See Also:

Constant Field Values

REQUEST_HEADER_ACCESS_CONTROL_REQUEST_METHOD

public static final java.lang.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.

See Also:

Constant Field Values

REQUEST_HEADER_ACCESS_CONTROL_REQUEST_HEADERS

public static final java.lang.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.

See Also:

Constant Field Values

HTTP_REQUEST_ATTRIBUTE_PREFIX

public static final java.lang.String HTTP_REQUEST_ATTRIBUTE_PREFIX

The prefix to a CORS request attribute.

See Also:

Constant Field Values

HTTP_REQUEST_ATTRIBUTE_ORIGIN

public static final java.lang.String HTTP_REQUEST_ATTRIBUTE_ORIGIN

Attribute that contains the origin of the request.

See Also:

Constant Field Values

HTTP_REQUEST_ATTRIBUTE_IS_CORS_REQUEST

public static final java.lang.String HTTP_REQUEST_ATTRIBUTE_IS_CORS_REQUEST

Boolean value, suggesting if the request is a CORS request or not.

See Also:

Constant Field Values

HTTP_REQUEST_ATTRIBUTE_REQUEST_TYPE

public static final java.lang.String HTTP_REQUEST_ATTRIBUTE_REQUEST_TYPE

Type of CORS request, of type HeaderFilter.CORSRequestType.

See Also:

Constant Field Values

HTTP_REQUEST_ATTRIBUTE_REQUEST_HEADERS

public static final java.lang.String HTTP_REQUEST_ATTRIBUTE_REQUEST_HEADERS

Request headers sent as 'Access-Control-Request-Headers' header, for pre-flight request.

See Also:

Constant Field Values

SIMPLE_HTTP_REQUEST_CONTENT_TYPE_VALUES

public static final java.util.Collection<java.lang.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.

See Also:

http://www.w3.org/TR/cors/#terminology

DEFAULT_ALLOWED_ORIGINS

public static final java.lang.String DEFAULT_ALLOWED_ORIGINS

By default, all origins are allowed to make requests.

See Also:

Constant Field Values

DEFAULT_ALLOWED_HTTP_METHODS

public static final java.lang.String DEFAULT_ALLOWED_HTTP_METHODS

By default, following methods are supported: GET, POST, HEAD and OPTIONS.

See Also:

Constant Field Values

DEFAULT_PREFLIGHT_MAXAGE

public static final java.lang.String DEFAULT_PREFLIGHT_MAXAGE

By default, time duration to cache pre-flight response is 30 mins.

See Also:

Constant Field Values

DEFAULT_SUPPORTS_CREDENTIALS

public static final java.lang.String DEFAULT_SUPPORTS_CREDENTIALS

By default, support credentials is turned on.

See Also:

Constant Field Values

DEFAULT_ALLOWED_HTTP_HEADERS

public static final java.lang.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.

See Also:

Constant Field Values

DEFAULT_EXPOSED_HEADERS

public static final java.lang.String DEFAULT_EXPOSED_HEADERS

By default, none of the headers are exposed in response.

See Also:

Constant Field Values

DEFAULT_DECORATE_REQUEST

public static final java.lang.String DEFAULT_DECORATE_REQUEST

By default, request is decorated with CORS attributes.

See Also:

Constant Field Values

PARAM_CORS_ALLOWED_ORIGINS

public static final java.lang.String PARAM_CORS_ALLOWED_ORIGINS

Key to retrieve allowed origins from javax.servlet.FilterConfig.

See Also:

Constant Field Values

PARAM_CORS_SUPPORT_CREDENTIALS

public static final java.lang.String PARAM_CORS_SUPPORT_CREDENTIALS

Key to retrieve support credentials from

See Also:

Constant Field Values

PARAM_CORS_EXPOSED_HEADERS

public static final java.lang.String PARAM_CORS_EXPOSED_HEADERS

Key to retrieve exposed headers from javax.servlet.FilterConfig.

See Also:

Constant Field Values

PARAM_CORS_ALLOWED_HEADERS

public static final java.lang.String PARAM_CORS_ALLOWED_HEADERS

Key to retrieve allowed headers from javax.servlet.FilterConfig.

See Also:

Constant Field Values

PARAM_CORS_ALLOWED_METHODS

public static final java.lang.String PARAM_CORS_ALLOWED_METHODS

Key to retrieve allowed methods from javax.servlet.FilterConfig.

See Also:

Constant Field Values

PARAM_CORS_PREFLIGHT_MAXAGE

public static final java.lang.String PARAM_CORS_PREFLIGHT_MAXAGE

Key to retrieve preflight max age from javax.servlet.FilterConfig.

See Also:

Constant Field Values

PARAM_CORS_REQUEST_DECORATE

public static final java.lang.String PARAM_CORS_REQUEST_DECORATE

Key to determine if request should be decorated.

See Also:

Constant Field Values

Constructor Detail

HeaderFilter

public HeaderFilter()

Method Detail

doFilter

public void doFilter(javax.servlet.ServletRequest servletRequest,
                     javax.servlet.ServletResponse servletResponse,
                     javax.servlet.FilterChain filterChain)
              throws java.io.IOException,
                     javax.servlet.ServletException

Specified by:

doFilter in interface javax.servlet.Filter

Throws:

java.io.IOException

javax.servlet.ServletException

init

public void init(javax.servlet.FilterConfig filterConfig)
          throws javax.servlet.ServletException

Specified by:

init in interface javax.servlet.Filter

Throws:

javax.servlet.ServletException

handleSimpleCORS

protected void handleSimpleCORS(javax.servlet.http.HttpServletRequest request,
                                javax.servlet.http.HttpServletResponse response,
                                javax.servlet.FilterChain filterChain)
                         throws java.io.IOException,
                                javax.servlet.ServletException

Handles a CORS request of type HeaderFilter.CORSRequestType.SIMPLE.

Parameters:

request - The HttpServletRequest object.

response - The HttpServletResponse object.

filterChain - The object.

Throws:

java.io.IOException - an IO error occurred

javax.servlet.ServletException

See Also:

Simple Cross-Origin Request, Actual Request, and Redirects

handlePreflightCORS

protected void handlePreflightCORS(javax.servlet.http.HttpServletRequest request,
                                   javax.servlet.http.HttpServletResponse response,
                                   javax.servlet.FilterChain filterChain)
                            throws java.io.IOException,
                                   javax.servlet.ServletException

Handles CORS pre-flight request.

Parameters:

request - The HttpServletRequest object.

response - The HttpServletResponse object.

filterChain - The object.

Throws:

java.io.IOException - an IO error occurred

javax.servlet.ServletException

destroy

public void destroy()

Specified by:

destroy in interface javax.servlet.Filter

decorateCORSProperties

protected static void decorateCORSProperties(javax.servlet.http.HttpServletRequest request,
                                             HeaderFilter.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 HeaderFilter.CORSRequestType object.

join

protected static java.lang.String join(java.util.Collection<java.lang.String> elements,
                                       java.lang.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 HeaderFilter.CORSRequestType checkRequestType(javax.servlet.http.HttpServletRequest request)

Determines the request type.

Parameters:

request - The HTTP Servlet request

Returns:

the CORS type

isValidOrigin

protected static boolean isValidOrigin(java.lang.String origin)

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:

RFC952

isAnyOriginAllowed

public boolean isAnyOriginAllowed()

Determines if any origin is allowed to make CORS request.

Returns:

true if it's enabled; false otherwise.

getExposedHeaders

public java.util.Collection<java.lang.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 java.util.Collection<java.lang.String> getAllowedOrigins()

Returns the Set of allowed origins that are allowed to make requests.

Returns:

Set

getAllowedHttpMethods

public java.util.Collection<java.lang.String> getAllowedHttpMethods()

Returns a Set of HTTP methods that are allowed to make requests.

Returns:

Set

getAllowedHttpHeaders

public java.util.Collection<java.lang.String> getAllowedHttpHeaders()

Returns a Set of headers support by resource.

Returns:

Set