Java tutorial
/********************************************************************************** * $URL$ * $Id$ ********************************************************************************** * * Copyright (c) 2003, 2004, 2005, 2006, 2007, 2008 The Sakai Foundation * * Licensed under the Educational Community 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.opensource.org/licenses/ECL-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.sakaiproject.jsf.renderer; import java.io.File; import java.io.IOException; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import javax.faces.FacesException; import javax.faces.application.FacesMessage; import javax.faces.component.UIComponent; import javax.faces.component.UIForm; import javax.faces.component.UIInput; import javax.faces.context.ExternalContext; import javax.faces.context.FacesContext; import javax.faces.context.ResponseWriter; import javax.faces.render.Renderer; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletRequestWrapper; import org.apache.commons.fileupload.FileItem; import org.sakaiproject.jsf.util.RendererUtil; public class InputFileUploadRenderer extends Renderer { private static final String ID_INPUT_ELEMENT = ".uploadId"; private static final String ID_HIDDEN_ELEMENT = ".hiddenId"; private static final String ATTR_REQUEST_DECODED = ".decoded"; private static final String[] PASSTHROUGH_ATTRIBUTES = { "accept", "accesskey", "align", "disabled", "maxlength", "readonly", "size", "style", "tabindex" }; public static final String ATTR_UPLOADS_DONE = "sakai.uploads.done"; public void encodeBegin(FacesContext context, UIComponent component) throws IOException { if (!component.isRendered()) return; ResponseWriter writer = context.getResponseWriter(); String clientId = component.getClientId(context); //HttpServletRequest request = (HttpServletRequest) context.getExternalContext().getRequest(); // check that the structure of the form is valid boolean atDecodeTime = false; String errorMessage = checkForErrors(context, component, clientId, atDecodeTime); if (errorMessage != null) { addFacesMessage(context, clientId, errorMessage); } // output field that allows user to upload a file writer.startElement("input", null); writer.writeAttribute("type", "file", null); writer.writeAttribute("name", clientId + ID_INPUT_ELEMENT, null); String styleClass = (String) RendererUtil.getAttribute(context, component, "styleClass"); if (styleClass != null) writer.writeAttribute("class", styleClass, null); boolean writeNullPassthroughAttributes = false; RendererUtil.writePassthroughAttributes(PASSTHROUGH_ATTRIBUTES, writeNullPassthroughAttributes, context, component); writer.endElement("input"); // another comment // output hidden field that helps test that the filter is working right writer.startElement("input", null); writer.writeAttribute("type", "hidden", null); writer.writeAttribute("name", clientId + ID_HIDDEN_ELEMENT, null); writer.writeAttribute("value", "filter_is_functioning_properly", null); writer.endElement("input"); } public void decode(FacesContext context, UIComponent comp) { UIInput component = (UIInput) comp; if (!component.isRendered()) return; ExternalContext external = context.getExternalContext(); HttpServletRequest request = (HttpServletRequest) external.getRequest(); String clientId = component.getClientId(context); String directory = (String) RendererUtil.getAttribute(context, component, "directory"); // mark that this component has had decode() called during request // processing request.setAttribute(clientId + ATTR_REQUEST_DECODED, "true"); // check for user errors and developer errors boolean atDecodeTime = true; String errorMessage = checkForErrors(context, component, clientId, atDecodeTime); if (errorMessage != null) { addFacesMessage(context, clientId, errorMessage); return; } // get the file item FileItem item = getFileItem(context, component); if (item.getName() == null || item.getName().length() == 0) { if (component.isRequired()) { addFacesMessage(context, clientId, "Please specify a file."); component.setValid(false); } return; } if (directory == null || directory.length() == 0) { // just passing on the FileItem as the value of the component, without persisting it. component.setSubmittedValue(item); } else { // persisting to a permenent file in a directory. // pass on the server-side filename as the value of the component. File dir = new File(directory); String filename = item.getName(); filename = filename.replace('\\', '/'); // replaces Windows path seperator character "\" with "/" filename = filename.substring(filename.lastIndexOf("/") + 1); File persistentFile = new File(dir, filename); try { item.write(persistentFile); component.setSubmittedValue(persistentFile.getPath()); } catch (Exception ex) { throw new FacesException(ex); } } } /** * Check for errors (both developer errors and user errors) - return a * user-friendly error message describing the error, or null if there are no * errors. */ private static String checkForErrors(FacesContext context, UIComponent component, String clientId, boolean atDecodeTime) { ExternalContext external = context.getExternalContext(); HttpServletRequest request = (HttpServletRequest) external.getRequest(); UIForm form = null; try { form = getForm(component); } catch (IllegalArgumentException e) { // there are more than one nested form - thats not OK! return "DEVELOPER ERROR: The <inputFileUpload> tag must be enclosed in just ONE form. Nested forms confuse the browser."; } if (form == null || !"multipart/form-data".equals(RendererUtil.getAttribute(context, form, "enctype"))) { return "DEVELOPER ERROR: The <inputFileUpload> tag must be enclosed in a <h:form enctype=\"multipart/form-data\"> tag."; } // check tag attributes String directory = (String) RendererUtil.getAttribute(context, component, "directory"); if (directory != null && directory.length() != 0) { // the tag is configured to persist the uploaded files to a directory. // check that the specified directory exists, and is writeable File dir = new File(directory); if (!dir.isDirectory() || !dir.exists()) { return "DEVELOPER ERROR: The directory specified on the <inputFileUpload> tag does not exist or is not writable.\n" + "Check the permissions on directory:\n" + dir; } } FileItem item = getFileItem(context, component); boolean isMultipartRequest = request.getContentType() != null && request.getContentType().startsWith("multipart/form-data"); boolean wasMultipartRequestFullyParsed = request.getParameter(clientId + ID_HIDDEN_ELEMENT) != null; String requestFilterStatus = (String) request.getAttribute("upload.status"); Object requestFilterUploadLimit = request.getAttribute("upload.limit"); Exception requestFilterException = (Exception) request.getAttribute("upload.exception"); boolean wasDecodeAlreadyCalledOnTheRequest = "true" .equals(request.getAttribute(clientId + ATTR_REQUEST_DECODED)); if (wasDecodeAlreadyCalledOnTheRequest && !atDecodeTime) { // decode() was already called on the request, and we're now at encode() time - so don't do further error checking // as the FileItem may no longer be valid. return null; } // at this point, if its not a multipart request, it doesn't have a file and there isn't an error. if (!isMultipartRequest) return null; // check for user errors if ("exception".equals(requestFilterStatus)) { return "An error occured while processing the uploaded file. The error was:\n" + requestFilterException; } else if ("size_limit_exceeded".equals(requestFilterStatus)) { // the user tried to upload too large a file return "The upload size limit of " + requestFilterUploadLimit + "MB has been exceeded."; } else if (item == null || item.getName() == null || item.getName().length() == 0) { // The file item will be null if the component was previously not rendered. return null; } else if (item.getSize() == 0) { return "The filename '" + item.getName() + "' is invalid. Please select a valid file."; } if (!wasMultipartRequestFullyParsed) { return "An error occured while processing the uploaded file. The error was:\n" + "DEVELOPER ERROR: The <inputFileUpload> tag requires a <filter> in web.xml to parse the uploaded file.\n" + "Check that the Sakai RequestFilter is properly configured in web.xml."; } if (item.getName().indexOf("..") >= 0) { return "The filename '" + item.getName() + "' is invalid. Please select a valid file."; } // everything checks out fine! The upload was parsed, and a FileItem // exists with a filename and non-zero length return null; } /** * Return the FileItem (if present) for the given component. Subclasses * of this Renderer could get the FileItem in a different way. * First, try getting it from the request attributes (Sakai style). Then * try getting it from a method called getFileItem() on the HttpServletRequest * (unwrapping the request if necessary). */ private static FileItem getFileItem(FacesContext context, UIComponent component) { String clientId = component.getClientId(context); HttpServletRequest request = (HttpServletRequest) context.getExternalContext().getRequest(); FileItem item = null; String fieldName = clientId + ID_INPUT_ELEMENT; // first try just getting it from the request attributes, // where the Sakai RequestFilter puts it. item = (FileItem) request.getAttribute(fieldName); if (item != null) return item; // For custom filter compatibility (MyFaces for example), // walk up the HttpServletRequestWrapper chain looking for a getFileItem() method. while (request != null) { // call the getFileItem() method by reflection, so as to not introduce a dependency // on MyFaces, and so the wrapper class that has getFileItem() doesn't have to // implement an interface (as long as it has the right method signature it'll work). try { Class reqClass = request.getClass(); Method getFileItemMethod = reqClass.getMethod("getFileItem", new Class[] { String.class }); Object returned = getFileItemMethod.invoke(request, new Object[] { fieldName }); if (returned instanceof FileItem) return (FileItem) returned; } catch (NoSuchMethodException nsme) { } catch (InvocationTargetException ite) { } catch (IllegalArgumentException iae) { } catch (IllegalAccessException iaxe) { } // trace up the request wrapper classes, looking for a getFileItem() method if (request instanceof HttpServletRequestWrapper) { request = (HttpServletRequest) ((HttpServletRequestWrapper) request).getRequest(); } else { request = null; } } return null; } private static void addFacesMessage(FacesContext context, String clientId, String message) { context.addMessage(clientId, new FacesMessage(FacesMessage.SEVERITY_ERROR, message, message)); } /** * get containing UIForm from component hierarchy. * @throws IllegalArgumentException If there is more than one enclosing form - only one form is allowed! */ private static UIForm getForm(UIComponent component) throws IllegalArgumentException { UIForm ret = null; while (component != null) { if (component instanceof UIForm) { if (ret != null) { // Cannot have a doubly-nested form! throw new IllegalArgumentException(); } ret = (UIForm) component; } component = component.getParent(); } return ret; } }