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  /*
   * 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 static org.jboss.web.CatalinaMessages.MESSAGES;
 
 
 
Implementation of a Filter that performs filtering based on comparing the appropriate request property (selected based on which subclass you choose to configure into your Container's pipeline) against a set of regular expressions configured for this Filter.

This filter is configured by setting the allow and/or deny properties to a comma-delimited list of regular expressions (in the syntax supported by the jakarta-regexp library) to which the appropriate request property will be compared. Evaluation proceeds as follows:

  • The subclass extracts the request property to be filtered, and calls the common process() method.
  • If there are any deny expressions configured, the property will be compared to each such expression. If a match is found, this request will be rejected with a "Forbidden" HTTP response.
  • If there are any allow expressions configured, the property will be compared to each such expression. If a match is found, this request will be allowed to pass through to the next filter in the current pipeline.
  • If one or more deny expressions was specified but no allow expressions, allow this request to pass through (because none of the deny expressions matched it).
  • The request will be rejected with a "Forbidden" HTTP response.

This Filter may be attached to any Container, depending on the granularity of the filtering you wish to perform.

Author(s):
Craig R. McClanahan
 
 
 public abstract class RequestFilter
     extends FilterBase implements HttpEventFilter {
 
 
     // ----------------------------------------------------- Instance Variables
 
    
The comma-delimited set of allow expressions.
 
     protected String allow = null;


    
The set of allow regular expressions we will evaluate.
 
     protected Pattern allows[] = new Pattern[0];


    
The set of deny regular expressions we will evaluate.
 
     protected Pattern denies[] = new Pattern[0];


    
The comma-delimited set of deny expressions.
 
    protected String deny = null;
    
    
mime type -- "text/plain"
    private static final String PLAIN_TEXT_MIME_TYPE = "text/plain";
    // ------------------------------------------------------------- Properties


    
Return a comma-delimited set of the allow expressions configured for this Filter, if any; otherwise, return null.
    public String getAllow() {
        return (this.);
    }


    
Set the comma-delimited set of the allow expressions configured for this Filter, if any.

Parameters:
allow The new set of allow expressions
    public void setAllow(String allow) {
        this. = allow;
        this. = precalculate(allow);
        
    }


    
Return a comma-delimited set of the deny expressions configured for this Filter, if any; otherwise, return null.
    public String getDeny() {
        return (this.);
    }


    
Set the comma-delimited set of the deny expressions configured for this Filter, if any.

Parameters:
deny The new set of deny expressions
    public void setDeny(String deny) {
        this. = deny;
        this. = precalculate(deny);
        
    }
    // --------------------------------------------------------- Public Methods


    
Extract the desired request property, and pass it (along with the specified request and response objects) to the protected process() method to perform the actual filtering. This method must be implemented by a concrete subclass.

Parameters:
request The servlet request to be processed
response The servlet response to be created
chain The filter chain
Throws:
java.io.IOException if an input/output error occurs
javax.servlet.ServletException if a servlet error occurs
    public abstract void doFilter(ServletRequest request,
            ServletResponse responseFilterChain chainthrows IOException,
            ServletException;
      
    // ------------------------------------------------------ Protected Methods


    
Return an array of regular expression objects initialized from the specified argument, which must be null or a comma-delimited list of regular expression patterns.

Parameters:
list The comma-separated list of patterns
Throws:
java.lang.IllegalArgumentException if one of the patterns has invalid syntax
    protected Pattern[] precalculate(String list) {
        if (list == null)
            return (new Pattern[0]);
        list = list.trim();
        if (list.length() < 1)
            return (new Pattern[0]);
        list += ",";
        ArrayList<PatternreList = new ArrayList<Pattern>();
        while (list.length() > 0) {
            int comma = list.indexOf(',');
            if (comma < 0)
                break;
            String pattern = list.substring(0, comma).trim();
            try {
                reList.add(Pattern.compile(pattern));
            } catch (PatternSyntaxException e) {
                throw .requestFilterInvalidPattern(patterne);
            }
            list = list.substring(comma + 1);
        }
        Pattern reArray[] = new Pattern[reList.size()];
        return reList.toArray(reArray);
    }


    
Perform the filtering that has been configured for this Filter, matching against the specified request property.

Parameters:
property The request property on which to filter
request The servlet request to be processed
response The servlet response to be processed
Throws:
java.io.IOException if an input/output error occurs
javax.servlet.ServletException if a servlet error occurs
    protected void process(String propertyServletRequest request,
            ServletResponse responseFilterChain chain)
            throws IOExceptionServletException {
        if (isAllowed(property)) {
            chain.doFilter(requestresponse);
        } else {
            if (response instanceof HttpServletResponse) {
                ((HttpServletResponseresponse)
                        .sendError(.);
            } else {
                sendErrorWhenNotHttp(response);
            }
        }
    }

    
Perform the filtering that has been configured for this Filter, matching against the specified request property.

Parameters:
property The property to check against the allow/deny rules
event The comet event to be filtered
chain The comet filter chain
Throws:
java.io.IOException if an input/output error occurs
javax.servlet.ServletException if a servlet error occurs
    protected void processCometEvent(String propertyHttpEvent eventHttpEventFilterChain chain)
            throws IOExceptionServletException {
        HttpServletResponse response = event.getHttpServletResponse();
        
        if (isAllowed(property)) {
            chain.doFilterEvent(event);
        } else {
            response.sendError(.);
            event.close();
        }
    }

    
Process the allow and deny rules for the provided property.

Parameters:
property The property to test against the allow and deny lists
Returns:
true if this request should be allowed, false otherwise
    private boolean isAllowed(String property) {
        for (int i = 0; i < this..lengthi++) {
            if (this.[i].matcher(property).matches()) {
                return false;
            }
        }
     
        // Check the allow patterns, if any
        for (int i = 0; i < this..lengthi++) {
            if (this.[i].matcher(property).matches()) {
                return true;
            }
        }
        // Allow if denies specified but not allows
        if ((this..length > 0) && (this..length == 0)) {
            return true;
        }
        // Deny this request
        return false;
    }
    private void sendErrorWhenNotHttp(ServletResponse response)
            throws IOException {
        response.setContentType();
        response.getWriter().write(.http403());
        response.getWriter().flush();
    }
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