/*
* 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.nifi.web;
import com.ibm.icu.text.CharsetDetector;
import com.ibm.icu.text.CharsetMatch;
import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.codec.binary.Base64;
import org.apache.commons.io.IOUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.nifi.authorization.AccessDeniedException;
import org.apache.nifi.stream.io.StreamUtils;
import org.apache.nifi.web.ViewableContent.DisplayMode;
import org.apache.tika.detect.DefaultDetector;
import org.apache.tika.io.TikaInputStream;
import org.apache.tika.metadata.Metadata;
import org.apache.tika.mime.MediaType;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Controller servlet for viewing content. This is responsible for generating
* the markup for the header and footer of the page. Included in that is the
* combo that allows the user to choose how they wait to view the data
* (original, formatted, hex). If a data viewer is registered for the detected
* content type, it will include the markup it generates in the response.
*/
public class ContentViewerController extends HttpServlet {
private static final Logger logger = LoggerFactory.getLogger(ContentViewerController.class);
// 1.5kb - multiple of 12 (3 bytes = 4 base 64 encoded chars)
private final static int BUFFER_LENGTH = 1536;
/**
* Gets the content and defers to registered viewers to generate the markup.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
@Override
protected void doGet(final HttpServletRequest request, final HttpServletResponse response) throws ServletException, IOException {
// specify the charset in a response header
response.addHeader("Content-Type", "text/html; charset=UTF-8");
// get the content
final ServletContext servletContext = request.getServletContext();
final ContentAccess contentAccess = (ContentAccess) servletContext.getAttribute("nifi-content-access");
final ContentRequestContext contentRequest;
try {
contentRequest = getContentRequest(request);
} catch (final Exception e) {
request.setAttribute("title", "Error");
request.setAttribute("messages", "Unable to interpret content request.");
// forward to the error page
final ServletContext viewerContext = servletContext.getContext("/nifi");
viewerContext.getRequestDispatcher("/message").forward(request, response);
return;
}
if (contentRequest.getDataUri() == null) {
request.setAttribute("title", "Error");
request.setAttribute("messages", "The data reference must be specified.");
// forward to the error page
final ServletContext viewerContext = servletContext.getContext("/nifi");
viewerContext.getRequestDispatcher("/message").forward(request, response);
return;
}
// get the content
final DownloadableContent downloadableContent;
try {
downloadableContent = contentAccess.getContent(contentRequest);
} catch (final ResourceNotFoundException rnfe) {
request.setAttribute("title", "Error");
request.setAttribute("messages", "Unable to find the specified content");
// forward to the error page
final ServletContext viewerContext = servletContext.getContext("/nifi");
viewerContext.getRequestDispatcher("/message").forward(request, response);
return;
} catch (final AccessDeniedException ade) {
request.setAttribute("title", "Access Denied");
request.setAttribute("messages", "Unable to approve access to the specified content: " + ade.getMessage());
// forward to the error page
final ServletContext viewerContext = servletContext.getContext("/nifi");
viewerContext.getRequestDispatcher("/message").forward(request, response);
return;
} catch (final Exception e) {
request.setAttribute("title", "Error");
request.setAttribute("messages", "An unexpected error has occurred: " + e.getMessage());
// forward to the error page
final ServletContext viewerContext = servletContext.getContext("/nifi");
viewerContext.getRequestDispatcher("/message").forward(request, response);
return;
}
// determine how we want to view the data
String mode = request.getParameter("mode");
// if the name isn't set, use original
if (mode == null) {
mode = DisplayMode.Original.name();
}
// determine the display mode
final DisplayMode displayMode;
try {
displayMode = DisplayMode.valueOf(mode);
} catch (final IllegalArgumentException iae) {
request.setAttribute("title", "Error");
request.setAttribute("messages", "Invalid display mode: " + mode);
// forward to the error page
final ServletContext viewerContext = servletContext.getContext("/nifi");
viewerContext.getRequestDispatcher("/message").forward(request, response);
return;
}
// buffer the content to support resetting in case we need to detect the content type or char encoding
try (final BufferedInputStream bis = new BufferedInputStream(downloadableContent.getContent());) {
final String mimeType;
final String normalizedMimeType;
// when standalone and we don't know the type is null as we were able to directly access the content bypassing the rest endpoint,
// when clustered and we don't know the type set to octet stream since the content was retrieved from the node's rest endpoint
if (downloadableContent.getType() == null || StringUtils.startsWithIgnoreCase(downloadableContent.getType(), MediaType.OCTET_STREAM.toString())) {
// attempt to detect the content stream if we don't know what it is ()
final DefaultDetector detector = new DefaultDetector();
// create the stream for tika to process, buffered to support reseting
final TikaInputStream tikaStream = TikaInputStream.get(bis);
// provide a hint based on the filename
final Metadata metadata = new Metadata();
metadata.set(Metadata.RESOURCE_NAME_KEY, downloadableContent.getFilename());
// Get mime type
final MediaType mediatype = detector.detect(tikaStream, metadata);
mimeType = mediatype.toString();
} else {
mimeType = downloadableContent.getType();
}
// Extract only mime type and subtype from content type (anything after the first ; are parameters)
// Lowercase so subsequent code does not need to implement case insensitivity
normalizedMimeType = mimeType.split(";",2)[0].toLowerCase();
// add attributes needed for the header
request.setAttribute("filename", downloadableContent.getFilename());
request.setAttribute("contentType", mimeType);
// generate the header
request.getRequestDispatcher("/WEB-INF/jsp/header.jsp").include(request, response);
// remove the attributes needed for the header
request.removeAttribute("filename");
request.removeAttribute("contentType");
// generate the markup for the content based on the display mode
if (DisplayMode.Hex.equals(displayMode)) {
final byte[] buffer = new byte[BUFFER_LENGTH];
final int read = StreamUtils.fillBuffer(bis, buffer, false);
// trim the byte array if necessary
byte[] bytes = buffer;
if (read != buffer.length) {
bytes = new byte[read];
System.arraycopy(buffer, 0, bytes, 0, read);
}
// convert bytes into the base 64 bytes
final String base64 = Base64.encodeBase64String(bytes);
// defer to the jsp
request.setAttribute("content", base64);
request.getRequestDispatcher("/WEB-INF/jsp/hexview.jsp").include(request, response);
} else {
// lookup a viewer for the content
final String contentViewerUri = servletContext.getInitParameter(normalizedMimeType);
// handle no viewer for content type
if (contentViewerUri == null) {
request.getRequestDispatcher("/WEB-INF/jsp/no-viewer.jsp").include(request, response);
} else {
// create a request attribute for accessing the content
request.setAttribute(ViewableContent.CONTENT_REQUEST_ATTRIBUTE, new ViewableContent() {
@Override
public InputStream getContentStream() {
return bis;
}
@Override
public String getContent() throws IOException {
// detect the charset
final CharsetDetector detector = new CharsetDetector();
detector.setText(bis);
detector.enableInputFilter(true);
final CharsetMatch match = detector.detect();
// ensure we were able to detect the charset
if (match == null) {
throw new IOException("Unable to detect character encoding.");
}
// convert the stream using the detected charset
return IOUtils.toString(bis, match.getName());
}
@Override
public ViewableContent.DisplayMode getDisplayMode() {
return displayMode;
}
@Override
public String getFileName() {
return downloadableContent.getFilename();
}
@Override
public String getContentType() {
return normalizedMimeType;
}
@Override
public String getRawContentType() {
return mimeType;
}
});
try {
// generate the content
final ServletContext viewerContext = servletContext.getContext(contentViewerUri);
viewerContext.getRequestDispatcher("/view-content").include(request, response);
} catch (final Exception e) {
String message = e.getMessage() != null ? e.getMessage() : e.toString();
message = "Unable to generate view of data: " + message;
// log the error
logger.error(message);
if (logger.isDebugEnabled()) {
logger.error(StringUtils.EMPTY, e);
}
// populate the request attributes
request.setAttribute("title", "Error");
request.setAttribute("messages", message);
// forward to the error page
final ServletContext viewerContext = servletContext.getContext("/nifi");
viewerContext.getRequestDispatcher("/message").forward(request, response);
return;
}
// remove the request attribute
request.removeAttribute(ViewableContent.CONTENT_REQUEST_ATTRIBUTE);
}
}
// generate footer
request.getRequestDispatcher("/WEB-INF/jsp/footer.jsp").include(request, response);
}
}
/**
* @param request request
* @return Get the content request context based on the specified request
*/
private ContentRequestContext getContentRequest(final HttpServletRequest request) {
final String ref = request.getParameter("ref");
final String clientId = request.getParameter("clientId");
final URI refUri = URI.create(ref);
final String query = refUri.getQuery();
String rawClusterNodeId = null;
if (query != null) {
final String[] queryParameters = query.split("&");
for (int i = 0; i < queryParameters.length; i++) {
if (queryParameters[0].startsWith("clusterNodeId=")) {
rawClusterNodeId = StringUtils.substringAfterLast(queryParameters[0], "clusterNodeId=");
}
}
}
final String clusterNodeId = rawClusterNodeId;
return new ContentRequestContext() {
@Override
public String getDataUri() {
return ref;
}
@Override
public String getClusterNodeId() {
return clusterNodeId;
}
@Override
public String getClientId() {
return clientId;
}
@Override
public String getProxiedEntitiesChain() {
return null;
}
};
}
}