Struts example source code file (FileUploadInterceptor.java)

This example Struts source code file (FileUploadInterceptor.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Struts tags/keywords

default_message, file, http, httpservletrequest, io, list, locale, multipartrequestwrapper, multipartrequestwrapper, object, object, request, response, servlet, set, string, string, util, validationaware, validationaware

The Struts FileUploadInterceptor.java source code

/*
 * $Id: FileUploadInterceptor.java 1065764 2011-01-31 20:43:25Z jafl $
 *
 * 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.struts2.interceptor;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.ActionProxy;
import com.opensymphony.xwork2.ValidationAware;
import com.opensymphony.xwork2.inject.Inject;
import com.opensymphony.xwork2.interceptor.AbstractInterceptor;
import com.opensymphony.xwork2.util.LocalizedTextUtil;
import com.opensymphony.xwork2.util.PatternMatcher;
import com.opensymphony.xwork2.util.TextParseUtil;
import com.opensymphony.xwork2.util.logging.Logger;
import com.opensymphony.xwork2.util.logging.LoggerFactory;
import org.apache.struts2.ServletActionContext;
import org.apache.struts2.dispatcher.multipart.MultiPartRequestWrapper;

import javax.servlet.http.HttpServletRequest;
import java.io.File;
import java.util.*;

/**
 * <!-- START SNIPPET: description -->
 * <p/>
 * Interceptor that is based off of {@link MultiPartRequestWrapper}, which is automatically applied for any request that
 * includes a file. It adds the following parameters, where [File Name] is the name given to the file uploaded by the
 * HTML form:
 * <p/>
 * <ul>
 * <p/>
 * <li>[File Name] : File - the actual File
 * <p/>
 * <li>[File Name]ContentType : String - the content type of the file
 * <p/>
 * <li>[File Name]FileName : String - the actual name of the file uploaded (not the HTML name)
 * <p/>
 * </ul>
 * <p/>
 * <p/> You can get access to these files by merely providing setters in your action that correspond to any of the three
 * patterns above, such as setDocument(File document), setDocumentContentType(String contentType), etc.
 * <br/>See the example code section.
 * <p/>
 * <p/> This interceptor will add several field errors, assuming that the action implements {@link ValidationAware}.
 * These error messages are based on several i18n values stored in struts-messages.properties, a default i18n file
 * processed for all i18n requests. You can override the text of these messages by providing text for the following
 * keys:
 * <p/>
 * <ul>
 * <p/>
 * <li>struts.messages.error.uploading - a general error that occurs when the file could not be uploaded
 * <p/>
 * <li>struts.messages.error.file.too.large - occurs when the uploaded file is too large
 * <p/>
 * <li>struts.messages.error.content.type.not.allowed - occurs when the uploaded file does not match the expected
 * content types specified</li>
 * <p/>
 * <li>struts.messages.error.file.extension.not.allowed - occurs when the uploaded file does not match the expected
 * file extensions specified</li>
 * <p/>
 * </ul>
 * <p/>
 * <!-- END SNIPPET: description -->
 * <p/>
 * <p/> Interceptor parameters:
 * <p/>
 * <!-- START SNIPPET: parameters -->
 * <p/>
 * <ul>
 * <p/>
 * <li>maximumSize (optional) - the maximum size (in bytes) that the interceptor will allow a file reference to be set
 * on the action. Note, this is <b>not related to the various properties found in struts.properties.
 * Default to approximately 2MB.</li>
 * <p/>
 * <li>allowedTypes (optional) - a comma separated list of content types (ie: text/html) that the interceptor will allow
 * a file reference to be set on the action. If none is specified allow all types to be uploaded.</li>
 * <p/>
 * <li>allowedExtensions (optional) - a comma separated list of file extensions (ie: .html) that the interceptor will allow
 * a file reference to be set on the action. If none is specified allow all extensions to be uploaded.</li>
 * </ul>
 * <p/>
 * <p/>
 * <!-- END SNIPPET: parameters -->
 * <p/>
 * <p/> Extending the interceptor:
 * <p/>
 * <p/>
 * <p/>
 * <!-- START SNIPPET: extending -->
 * <p/>
 * You can extend this interceptor and override the acceptFile method to provide more control over which files
 * are supported and which are not.
 * <p/>
 * <!-- END SNIPPET: extending -->
 * <p/>
 * <p/> Example code:
 * <p/>
 * <pre>
 * <!-- START SNIPPET: example-configuration -->
 * <action name="doUpload" class="com.example.UploadAction">
 *     <interceptor-ref name="fileUpload"/>
 *     <interceptor-ref name="basicStack"/>
 *     <result name="success">good_result.jsp</result>
 * </action>
 * <!-- END SNIPPET: example-configuration -->
 * </pre>
 * <p/>
 * <!-- START SNIPPET: multipart-note -->
 * <p/>
 * You must set the encoding to <code>multipart/form-data in the form where the user selects the file to upload.
 * <p/>
 * <!-- END SNIPPET: multipart-note -->
 * <p/>
 * <pre>
 * <!-- START SNIPPET: example-form -->
 *   <s:form action="doUpload" method="post" enctype="multipart/form-data">
 *       <s:file name="upload" label="File"/>
 *       <s:submit/>
 *   </s:form>
 * <!-- END SNIPPET: example-form -->
 * </pre>
 * <p/>
 * And then in your action code you'll have access to the File object if you provide setters according to the
 * naming convention documented in the start.
 * <p/>
 * <pre>
 * <!-- START SNIPPET: example-action -->
 *    package com.example;
 * <p/>
 *    import java.io.File;
 *    import com.opensymphony.xwork2.ActionSupport;
 * <p/>
 *    public UploadAction extends ActionSupport {
 *       private File file;
 *       private String contentType;
 *       private String filename;
 * <p/>
 *       public void setUpload(File file) {
 *          this.file = file;
 *       }
 * <p/>
 *       public void setUploadContentType(String contentType) {
 *          this.contentType = contentType;
 *       }
 * <p/>
 *       public void setUploadFileName(String filename) {
 *          this.filename = filename;
 *       }
 * <p/>
 *       public String execute() {
 *          //...
 *          return SUCCESS;
 *       }
 *  }
 * <!-- END SNIPPET: example-action -->
 * </pre>
 */
public class FileUploadInterceptor extends AbstractInterceptor {

    private static final long serialVersionUID = -4764627478894962478L;

    protected static final Logger LOG = LoggerFactory.getLogger(FileUploadInterceptor.class);
    private static final String DEFAULT_MESSAGE = "no.message.found";

    protected boolean useActionMessageBundle;

    protected Long maximumSize;
    protected Set<String> allowedTypesSet = Collections.emptySet();
    protected Set<String> allowedExtensionsSet = Collections.emptySet();

    private PatternMatcher matcher;

    @Inject
    public void setMatcher(PatternMatcher matcher) {
        this.matcher = matcher;
    }

    public void setUseActionMessageBundle(String value) {
        this.useActionMessageBundle = Boolean.valueOf(value);
    }

    /**
     * Sets the allowed extensions
     *
     * @param allowedExtensions A comma-delimited list of extensions
     */
    public void setAllowedExtensions(String allowedExtensions) {
        allowedExtensionsSet = TextParseUtil.commaDelimitedStringToSet(allowedExtensions);
    }

    /**
     * Sets the allowed mimetypes
     *
     * @param allowedTypes A comma-delimited list of types
     */
    public void setAllowedTypes(String allowedTypes) {
        allowedTypesSet = TextParseUtil.commaDelimitedStringToSet(allowedTypes);
    }

    /**
     * Sets the maximum size of an uploaded file
     *
     * @param maximumSize The maximum size in bytes
     */
    public void setMaximumSize(Long maximumSize) {
        this.maximumSize = maximumSize;
    }

    /* (non-Javadoc)
     * @see com.opensymphony.xwork2.interceptor.Interceptor#intercept(com.opensymphony.xwork2.ActionInvocation)
     */

    public String intercept(ActionInvocation invocation) throws Exception {
        ActionContext ac = invocation.getInvocationContext();

        HttpServletRequest request = (HttpServletRequest) ac.get(ServletActionContext.HTTP_REQUEST);

        if (!(request instanceof MultiPartRequestWrapper)) {
            if (LOG.isDebugEnabled()) {
                ActionProxy proxy = invocation.getProxy();
                LOG.debug(getTextMessage("struts.messages.bypass.request", new Object[]{proxy.getNamespace(), proxy.getActionName()}, ac.getLocale()));
            }

            return invocation.invoke();
        }

        ValidationAware validation = null;

        Object action = invocation.getAction();

        if (action instanceof ValidationAware) {
            validation = (ValidationAware) action;
        }

        MultiPartRequestWrapper multiWrapper = (MultiPartRequestWrapper) request;

        if (multiWrapper.hasErrors()) {
            for (String error : multiWrapper.getErrors()) {
                if (validation != null) {
                    validation.addActionError(error);
                }

                LOG.warn(error);
            }
        }

        // bind allowed Files
        Enumeration fileParameterNames = multiWrapper.getFileParameterNames();
        while (fileParameterNames != null && fileParameterNames.hasMoreElements()) {
            // get the value of this input tag
            String inputName = (String) fileParameterNames.nextElement();

            // get the content type
            String[] contentType = multiWrapper.getContentTypes(inputName);

            if (isNonEmpty(contentType)) {
                // get the name of the file from the input tag
                String[] fileName = multiWrapper.getFileNames(inputName);

                if (isNonEmpty(fileName)) {
                    // get a File object for the uploaded File
                    File[] files = multiWrapper.getFiles(inputName);
                    if (files != null && files.length > 0) {
                        List<File> acceptedFiles = new ArrayList(files.length);
                        List<String> acceptedContentTypes = new ArrayList(files.length);
                        List<String> acceptedFileNames = new ArrayList(files.length);
                        String contentTypeName = inputName + "ContentType";
                        String fileNameName = inputName + "FileName";

                        for (int index = 0; index < files.length; index++) {
                            if (acceptFile(action, files[index], fileName[index], contentType[index], inputName, validation, ac.getLocale())) {
                                acceptedFiles.add(files[index]);
                                acceptedContentTypes.add(contentType[index]);
                                acceptedFileNames.add(fileName[index]);
                            }
                        }

                        if (!acceptedFiles.isEmpty()) {
                            Map<String, Object> params = ac.getParameters();

                            params.put(inputName, acceptedFiles.toArray(new File[acceptedFiles.size()]));
                            params.put(contentTypeName, acceptedContentTypes.toArray(new String[acceptedContentTypes.size()]));
                            params.put(fileNameName, acceptedFileNames.toArray(new String[acceptedFileNames.size()]));
                        }
                    }
                } else {
                    LOG.warn(getTextMessage(action, "struts.messages.invalid.file", new Object[]{inputName}, ac.getLocale()));
                }
            } else {
                LOG.warn(getTextMessage(action, "struts.messages.invalid.content.type", new Object[]{inputName}, ac.getLocale()));
            }
        }

        // invoke action
        return invocation.invoke();
    }

    /**
     * Override for added functionality. Checks if the proposed file is acceptable based on contentType and size.
     *
     * @param action      - uploading action for message retrieval.
     * @param file        - proposed upload file.
     * @param contentType - contentType of the file.
     * @param inputName   - inputName of the file.
     * @param validation  - Non-null ValidationAware if the action implements ValidationAware, allowing for better
     *                    logging.
     * @param locale
     * @return true if the proposed file is acceptable by contentType and size.
     */
    protected boolean acceptFile(Object action, File file, String filename, String contentType, String inputName, ValidationAware validation, Locale locale) {
        boolean fileIsAcceptable = false;

        // If it's null the upload failed
        if (file == null) {
            String errMsg = getTextMessage(action, "struts.messages.error.uploading", new Object[]{inputName}, locale);
            if (validation != null) {
                validation.addFieldError(inputName, errMsg);
            }

            LOG.warn(errMsg);
        } else if (maximumSize != null && maximumSize < file.length()) {
            String errMsg = getTextMessage(action, "struts.messages.error.file.too.large", new Object[]{inputName, filename, file.getName(), "" + file.length()}, locale);
            if (validation != null) {
                validation.addFieldError(inputName, errMsg);
            }

            LOG.warn(errMsg);
        } else if ((!allowedTypesSet.isEmpty()) && (!containsItem(allowedTypesSet, contentType))) {
            String errMsg = getTextMessage(action, "struts.messages.error.content.type.not.allowed", new Object[]{inputName, filename, file.getName(), contentType}, locale);
            if (validation != null) {
                validation.addFieldError(inputName, errMsg);
            }

            LOG.warn(errMsg);
        } else if ((!allowedExtensionsSet.isEmpty()) && (!hasAllowedExtension(allowedExtensionsSet, filename))) {
            String errMsg = getTextMessage(action, "struts.messages.error.file.extension.not.allowed", new Object[]{inputName, filename, file.getName(), contentType}, locale);
            if (validation != null) {
                validation.addFieldError(inputName, errMsg);
            }

            LOG.warn(errMsg);
        } else {
            fileIsAcceptable = true;
        }

        return fileIsAcceptable;
    }

    /**
     * @param extensionCollection - Collection of extensions (all lowercase).
     * @param filename            - filename to check.
     * @return true if the filename has an allowed extension, false otherwise.
     */
    private boolean hasAllowedExtension(Collection<String> extensionCollection, String filename) {
        if (filename == null) {
            return false;
        }

        String lowercaseFilename = filename.toLowerCase();
        for (String extension : extensionCollection) {
            if (lowercaseFilename.endsWith(extension)) {
                return true;
            }
        }

        return false;
    }

    /**
     * @param itemCollection - Collection of string items (all lowercase).
     * @param item           - Item to search for.
     * @return true if itemCollection contains the item, false otherwise.
     */
    private boolean containsItem(Collection<String> itemCollection, String item) {
        for (String pattern : itemCollection)
            if (matchesWildcard(pattern, item))
                return true;
        return false;
    }

    private boolean matchesWildcard(String pattern, String text) {
        Object o = matcher.compilePattern(pattern);
        return matcher.match(new HashMap<String, String>(), text, o);
    }

    private boolean isNonEmpty(Object[] objArray) {
        boolean result = false;
        for (int index = 0; index < objArray.length && !result; index++) {
            if (objArray[index] != null) {
                result = true;
            }
        }
        return result;
    }

    private String getTextMessage(String messageKey, Object[] args, Locale locale) {
        return getTextMessage(null, messageKey, args, locale);
    }

    private String getTextMessage(Object action, String messageKey, Object[] args, Locale locale) {
        if (args == null || args.length == 0) {
            if (action != null && useActionMessageBundle) {
                return LocalizedTextUtil.findText(action.getClass(), messageKey, locale);
            }
            return LocalizedTextUtil.findText(this.getClass(), messageKey, locale);
        } else {
            if (action != null && useActionMessageBundle) {
                return LocalizedTextUtil.findText(action.getClass(), messageKey, locale, DEFAULT_MESSAGE, args);
            }
            return LocalizedTextUtil.findText(this.getClass(), messageKey, locale, DEFAULT_MESSAGE, args);
        }
    }
}