Java tutorial
/** * Copyright (C) 2012-2015 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 ninja.diagnostics; import java.io.IOException; import java.io.PrintWriter; import java.io.StringWriter; import java.io.Writer; import java.net.URI; import java.net.URL; import java.util.List; import java.util.Map; import ninja.Context; import ninja.Cookie; import ninja.Result; import ninja.Route; import ninja.exceptions.InternalServerErrorException; import ninja.utils.ResponseStreams; import org.apache.commons.io.IOUtils; import org.apache.commons.lang3.StringEscapeUtils; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * Utility class for rendering <code>DiagnosticError</code> instances as * a Result. Does not rely on any 3rd party rendering library to permit * rendering exceptions in the case where a template engine fails! * * @author Joe Lauer (https://twitter.com/jjlauer) * @author Fizzed, Inc. (http://fizzed.com) */ public class DiagnosticErrorRenderer { private static final Logger logger = LoggerFactory.getLogger(DiagnosticErrorRenderer.class); private final StringBuilder s; private DiagnosticErrorRenderer() { s = new StringBuilder(); } public String render() { return s.toString(); } static public void tryToRender(Context context, Result result, DiagnosticError diagnosticError, boolean throwInternalServerExceptionOnError) { try { DiagnosticErrorRenderer errorRenderer = build(context, result, diagnosticError); errorRenderer.renderResult(context, result); } catch (IOException e) { // fallback to ninja system-wide error handler? if (throwInternalServerExceptionOnError) { throw new InternalServerErrorException(e); } else { logger.error("Something is really fishy. Unable to render diagnostic error", e); } } } public void renderResult(Context context, Result result) throws IOException { String out = render(); // set context response content type result.contentType("text/html"); result.charset("utf-8"); ResponseStreams responseStreams = context.finalizeHeaders(result); try (Writer w = responseStreams.getWriter()) { w.write(out); w.flush(); w.close(); } } static public DiagnosticErrorRenderer build(Context context, Result result, DiagnosticError diagnosticError) throws IOException { Result underlyingResult = diagnosticError.getUnderlyingResult(); return new DiagnosticErrorRenderer().appendHeader(context, result, diagnosticError.getTitle()) .appendTabsBegin(new String[] { "Exception", "Context", "Request", "Response" }) .appendTabBegin(0) .appendSourceSnippet(diagnosticError.getSourceLocation(), diagnosticError.getSourceLines(), diagnosticError.getLineNumberOfSourceLines(), diagnosticError.getLineNumberOfError()) .appendThrowable(diagnosticError.getThrowable()).appendTabEnd() .appendTabBegin(1).appendContext(context).appendTabEnd() .appendTabBegin(2).appendRequest(context).appendTabEnd() .appendTabBegin(3).appendResponse(underlyingResult).appendTabEnd() .appendTabsEnd().appendFooter(); } private DiagnosticErrorRenderer appendHeader(Context context, Result result, String title) throws IOException { String headerTemplate = getResource("diagnostic_header.html"); String styleTemplate = getResource("diagnostic.css"); // simple token replacement headerTemplate = headerTemplate.replace("${TITLE}", escape(title)); headerTemplate = headerTemplate.replace("${STYLE}", escape(styleTemplate)); s.append(headerTemplate); if (result != null) { s.append(" <p id=\"detail\">\n"); if (result.getStatusCode() != 200) { s.append("Status code ").append(result.getStatusCode()); } s.append(" for request '").append(context.getMethod()).append(" ").append(context.getRequestPath()) .append("'\n"); // append info about the route itself if (context.getRoute() != null) { Route route = context.getRoute(); s.append("<br />In controller method '").append(route.getControllerClass().getCanonicalName()) .append(".").append(route.getControllerMethod().getName()).append("'\n"); } s.append(" </p>\n"); } return this; } private DiagnosticErrorRenderer appendTabsBegin(String[] names) throws IOException { s.append("<div class='tabs standard'>\n"); s.append(" <ul class=\"tab-links\">\n"); for (int i = 0; i < names.length; i++) { s.append(" <li"); if (i == 0) { s.append(" class=\"active\""); } s.append("><a href=\"#tab").append(i).append("\">").append(escape(names[i])).append("</a></li>\n"); } s.append(" </ul>\n"); s.append(" <div class=\"tab-content\">\n"); return this; } private DiagnosticErrorRenderer appendTabsEnd() throws IOException { s.append(" </div>\n"); s.append("</div>\n"); return this; } private DiagnosticErrorRenderer appendTabBegin(int index) throws IOException { s.append(" <div id=\"tab").append(index).append("\" class=\"tab"); if (index == 0) { s.append(" active"); } s.append("\">\n"); return this; } private DiagnosticErrorRenderer appendTabEnd() throws IOException { s.append(" </div>\n"); return this; } private DiagnosticErrorRenderer appendFooter() throws IOException { // embed jquery s.append("<script type='text/javascript'>").append(getResource("jquery-1.11.1.min.js")).append("</script>"); // diagnostic javascript s.append("<script type='text/javascript'>").append(getResource("diagnostic.js")).append("</script>"); // footer body -> html tags s.append(getResource("diagnostic_footer.html")); return this; } private DiagnosticErrorRenderer appendContext(Context context) throws IOException { s.append("<div class=\"context\">\n"); s.append("<h2>Route</h2>\n"); if (context.getRoute() != null) { Route route = context.getRoute(); appendNameValue(s, "Http method", route.getHttpMethod()); appendNameValue(s, "Controller method", route.getControllerClass().getCanonicalName() + "." + route.getControllerMethod().getName() + "()"); StringBuilder params = new StringBuilder(); for (Class type : route.getControllerMethod().getParameterTypes()) { if (params.length() > 0) { params.append(", "); } params.append(type.getCanonicalName()); } appendNameValue(s, "Controller parameters", params.toString()); } else { appendNoValues(s); } s.append("<h2>Session</h2>\n"); if (context.getSession() != null && !context.getSession().getData().isEmpty()) { for (Map.Entry<String, String> sessionEntry : context.getSession().getData().entrySet()) { appendNameValue(s, sessionEntry.getKey(), sessionEntry.getValue()); } } else { appendNoValues(s); } s.append("<h2>Flash</h2>\n"); if (context.getFlashScope() != null && !context.getFlashScope().getCurrentFlashCookieData().isEmpty()) { for (Map.Entry<String, String> sessionEntry : context.getFlashScope().getCurrentFlashCookieData() .entrySet()) { appendNameValue(s, sessionEntry.getKey(), sessionEntry.getValue()); } } else { appendNoValues(s); } s.append("<h2>Attributes</h2>\n"); Map<String, Object> attributes = context.getAttributes(); if (attributes != null && !attributes.isEmpty()) { for (Map.Entry<String, Object> entry : attributes.entrySet()) { appendNameValue(s, entry.getKey(), (entry.getValue() != null ? entry.getValue().toString() : "null")); } } else { appendNoValues(s); } List<Cookie> cookies = context.getCookies(); if (cookies == null || cookies.isEmpty()) { s.append("<h2>Cookies</h2>\n"); appendNoValues(s); } else { for (Cookie cookie : context.getCookies()) { s.append("<h2>Cookie: ").append(cookie.getName()).append("</h2>\n"); appendNameValue(s, "Value", cookie.getValue()); appendNameValue(s, "Path", cookie.getPath()); appendNameValue(s, "Domain", cookie.getDomain()); appendNameValue(s, "HTTP only", cookie.isHttpOnly() + ""); appendNameValue(s, "Secure", cookie.isSecure() + ""); appendNameValue(s, "Max age", cookie.getMaxAge() + ""); appendNameValue(s, "Comment", cookie.getComment()); } } s.append("</div>\n"); return this; } private DiagnosticErrorRenderer appendRequest(Context context) throws IOException { s.append("<div class=\"context\">\n"); s.append("<h2>Request</h2>\n"); appendNameValue(s, "Context path", context.getContextPath()); appendNameValue(s, "Hostname", context.getHostname()); appendNameValue(s, "Method", context.getMethod()); appendNameValue(s, "Remote address", context.getRemoteAddr()); appendNameValue(s, "Content type", context.getRequestContentType()); appendNameValue(s, "Path", context.getRequestPath()); appendNameValue(s, "Scheme", context.getScheme()); s.append("<h2>Parameters</h2>\n"); Map<String, String[]> parameters = context.getParameters(); if (parameters != null && !parameters.isEmpty()) { for (Map.Entry<String, String[]> entry : parameters.entrySet()) { for (String value : entry.getValue()) { appendNameValue(s, entry.getKey(), value); } } } else { appendNoValues(s); } s.append("<h2>Headers</h2>\n"); Map<String, List<String>> headers = context.getHeaders(); if (headers != null && !headers.isEmpty()) { for (Map.Entry<String, List<String>> entry : headers.entrySet()) { for (String value : entry.getValue()) { appendNameValue(s, entry.getKey(), value); } } } else { appendNoValues(s); } s.append("</div>\n"); return this; } private DiagnosticErrorRenderer appendResponse(Result result) throws IOException { s.append("<div class=\"context\">\n"); s.append("<h2>Application Result</h2>\n"); if (result == null) { // request did not get far enough along in processing to actually // have a response for us to debug appendNoValues(s, "Application failure before a result was created"); return this; } appendNameValue(s, "Template", result.getTemplate()); appendNameValue(s, "Charset", result.getCharset()); appendNameValue(s, "Content type", result.getContentType()); appendNameValue(s, "Status code", result.getStatusCode() + ""); List<String> supportedContentTypes = result.supportedContentTypes(); if (supportedContentTypes == null || supportedContentTypes.isEmpty()) { appendNameValue(s, "Supported content types", "None set"); } else { for (int i = 0; i < supportedContentTypes.size(); i++) { appendNameValue(s, "Supported content type #" + i, supportedContentTypes.get(i)); } } appendNameValue(s, "Fallback content type", result.fallbackContentType().or("None set")); appendNameValue(s, "Json View", (result.getJsonView() != null ? result.getJsonView().getClass().getCanonicalName() : "None")); s.append("<h2>Renderable</h2>\n"); Object renderable = result.getRenderable(); // only rendering exceptions would have the renderable actually set // to something other than a DiagnosticError if (renderable == null || renderable instanceof DiagnosticError) { appendNoValues(s); } else if (renderable instanceof Map) { Map<String, Object> map = (Map<String, Object>) renderable; for (Map.Entry<String, Object> entry : map.entrySet()) { appendNameValue(s, entry.getKey(), (entry.getValue() != null ? entry.getValue().toString() : "null")); } } else { appendNameValue(s, "Class of", renderable.getClass().getCanonicalName()); } s.append("<h2>Headers</h2>\n"); Map<String, String> headers = result.getHeaders(); if (headers != null && !headers.isEmpty()) { for (Map.Entry<String, String> entry : headers.entrySet()) { appendNameValue(s, entry.getKey(), entry.getValue()); } } else { appendNoValues(s); } s.append("</div>\n"); return this; } private void appendNameValue(StringBuilder sb, String name, String value) throws IOException { sb.append("<pre><span class=\"line\" style=\"width: 200px;\">"); sb.append(escape(name)); sb.append("</span><span class=\"route\" style=\"left: 210px\">"); sb.append(escape(value)); sb.append("</span></pre>"); } private void appendNoValues(StringBuilder sb) throws IOException { appendNoValues(sb, "No values"); } private void appendNoValues(StringBuilder sb, String title) throws IOException { sb.append("<pre style=\"border-bottom: 0px;\"><span style=\"position: absolute; left: 45px;\">") .append(escape(title)).append("</span></pre><br/>"); } private DiagnosticErrorRenderer appendSourceSnippet(URI sourceLocation, List<String> sourceLines, int lineNumberOfSourceLines, int lineNumberOfError) { if (sourceLocation != null) { s.append(" <h2>").append(escape(sourceLocation.toString())).append("</h2>\n"); } if (sourceLines != null) { s.append(" <div>\n"); for (int i = 0; i < sourceLines.size(); i++) { s.append("<pre>"); int lineNumber = lineNumberOfSourceLines + i; // line of error? String cssClass = (lineNumber == lineNumberOfError ? "line error" : "line info"); s.append("<span class=\"").append(cssClass).append("\">").append(lineNumber).append("</span>"); s.append("<span class=\"").append("route").append("\">").append(escape(sourceLines.get(i))) .append("</span>"); s.append("</pre>"); } s.append(" </div>\n"); } return this; } private DiagnosticErrorRenderer appendThrowable(Throwable throwable) throws IOException { s.append("<h2>Stack Trace</h2>"); if (throwable != null) { s.append("<pre><span class=\"stacktrace\">").append(escape(throwableStackTraceToString(throwable))) .append("</span></pre>\n"); } else { appendNoValues(s, "Result was not triggered by an exception"); } return this; } private String throwableStackTraceToString(Throwable throwable) { StringWriter sw = new StringWriter(); try (PrintWriter pw = new PrintWriter(sw)) { throwable.printStackTrace(pw); } return sw.toString(); } private String escape(String value) { return StringEscapeUtils.escapeHtml4(value); } private String getResource(String resourceName) throws IOException { URL url = getClass().getResource(resourceName); if (url == null) { throw new IOException("Unable to find diagnostic resource: " + resourceName); } return IOUtils.toString(url); } }