io.pivotal.poc.gateway.filters.pre.XPathHeaderEnrichingFilter.java Source code

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Here is the source code for io.pivotal.poc.gateway.filters.pre.XPathHeaderEnrichingFilter.java

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/*
 * Copyright 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 io.pivotal.poc.gateway.filters.pre;

import java.util.Map;

import org.w3c.dom.Node;

import org.springframework.integration.xml.DefaultXmlPayloadConverter;
import org.springframework.integration.xml.XmlPayloadConverter;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.multipart.support.StandardMultipartHttpServletRequest;
import org.springframework.xml.xpath.XPathExpression;
import org.springframework.xml.xpath.XPathExpressionFactory;

import com.netflix.zuul.context.RequestContext;

/**
 * @author Mark Fisher
 */
public class XPathHeaderEnrichingFilter extends AbstractPreFilter {

    private final String key;

    private final XPathExpression expression;

    private final XmlPayloadConverter converter = new DefaultXmlPayloadConverter();

    public XPathHeaderEnrichingFilter(String key, String xpathExpression) {
        super(1);
        this.key = key;
        this.expression = XPathExpressionFactory.createXPathExpression(xpathExpression);
    }

    @Override
    protected boolean shouldFilter(RequestContext requestContext) {
        return null != this.extractMultipartRequest(requestContext.getRequest());
    }

    @Override
    protected void filter(RequestContext requestContext) {
        StandardMultipartHttpServletRequest multipartRequest = this
                .extractMultipartRequest(requestContext.getRequest());
        try {
            for (Map.Entry<String, MultipartFile> entry : multipartRequest.getFileMap().entrySet()) {
                String value = this.evaluateExpression(entry.getValue().getInputStream());
                if (value != null) {
                    String headerName = String.format("%s.%s", entry.getKey(), key);
                    log.info("adding header from xpath evaluation: {}={}", headerName, value);
                    requestContext.getZuulRequestHeaders().put(headerName, value);
                }
            }
        } catch (Exception e) {
            log.error("xpath header enrichment failed", e);
        }
    }

    private String evaluateExpression(Object source) throws Exception {
        Node node = converter.convertToNode(source);
        return this.expression.evaluateAsString(node);
    }
}