sample.ContextFilter.java Source code

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Here is the source code for sample.ContextFilter.java

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/*
 * Copyright 2002-2016 the original author or authors.
 *
 * Licensed 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 sample;

import java.io.IOException;
import java.util.StringTokenizer;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import javax.servlet.http.HttpServletResponse;

import org.springframework.core.Ordered;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;
import org.springframework.web.filter.OncePerRequestFilter;

/**
 * @author Rob Winch
 */
@Component
@Order(Ordered.HIGHEST_PRECEDENCE)
public class ContextFilter extends OncePerRequestFilter {

    @Override
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response,
            FilterChain filterChain) throws ServletException, IOException {
        String tenantId = getTenantId(request);
        if (tenantId == null) {
            filterChain.doFilter(request, response);
            return;
        }
        filterChain.doFilter(new TenantAwareHttpServletRequest(request, tenantId), response);
    }

    private String getTenantId(HttpServletRequest request) {
        String requestUrl = currentUrl(request);

        if ("".equals(requestUrl) || "/".equals(requestUrl)) {
            return null;
        }
        StringTokenizer tokens = new StringTokenizer(requestUrl, "/");
        if (tokens.hasMoreTokens()) {
            String result = tokens.nextToken();
            if (tokens.hasMoreTokens() || requestUrl.endsWith("/")) {
                return result;
            }
        }
        return null;
    }

    private String currentUrl(HttpServletRequest request) {
        StringBuilder url = new StringBuilder();
        url.append(request.getServletPath());

        String pathInfo = request.getPathInfo();
        if (pathInfo != null) {
            url.append(pathInfo);
        }
        return url.toString();
    }

    /**
     * A wrapper for the HttpServletRequest that includes the tenant id in the
     * context path. Note that we do not cache the servletPath or the
     * contextPath as this can lead to problem with forwarding requests.
     *
     * @author Rob Winch
     *
     */
    private static class TenantAwareHttpServletRequest extends HttpServletRequestWrapper {
        private final String tenantId;

        public TenantAwareHttpServletRequest(HttpServletRequest request, String tenantId) {
            super(request);
            this.tenantId = tenantId;
        }

        @Override
        public String getServletPath() {
            String servletPath = super.getServletPath();
            int start = servletPath.indexOf(tenantId);
            if (start < 0) {
                return servletPath;
            }
            int end = start + tenantId.length();
            return servletPath.substring(end);
        }

        @Override
        public String getContextPath() {
            return super.getContextPath() + "/" + tenantId;
        }
    }
}