2 * Copyright (c) 2020 PANTHEON.tech, s.r.o. and others. All rights reserved.
4 * This program and the accompanying materials are made available under the
5 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
6 * and is available at http://www.eclipse.org/legal/epl-v10.html
8 package org.opendaylight.restconf.server.spi;
10 import static java.util.Objects.requireNonNull;
12 import com.google.common.annotations.VisibleForTesting;
13 import java.io.IOException;
14 import java.io.Writer;
15 import java.time.Instant;
16 import java.time.OffsetDateTime;
17 import java.time.ZoneId;
18 import java.time.format.DateTimeFormatter;
19 import javax.xml.XMLConstants;
20 import javax.xml.parsers.DocumentBuilderFactory;
21 import javax.xml.parsers.ParserConfigurationException;
22 import javax.xml.stream.XMLOutputFactory;
23 import javax.xml.stream.XMLStreamException;
24 import javax.xml.stream.XMLStreamWriter;
25 import javax.xml.xpath.XPath;
26 import javax.xml.xpath.XPathConstants;
27 import javax.xml.xpath.XPathExpression;
28 import javax.xml.xpath.XPathExpressionException;
29 import javax.xml.xpath.XPathFactory;
30 import org.eclipse.jdt.annotation.NonNull;
31 import org.eclipse.jdt.annotation.Nullable;
32 import org.opendaylight.netconf.api.NamespaceURN;
33 import org.opendaylight.yangtools.concepts.Immutable;
34 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
35 import org.opendaylight.yangtools.yang.data.api.schema.stream.NormalizedNodeStreamWriter;
36 import org.opendaylight.yangtools.yang.data.api.schema.stream.NormalizedNodeWriter;
37 import org.opendaylight.yangtools.yang.model.api.EffectiveModelContext;
38 import org.w3c.dom.Document;
39 import org.w3c.dom.Element;
41 public abstract class EventFormatter<T> implements Immutable {
42 private static final XPathFactory XPF = XPathFactory.newInstance();
44 // FIXME: NETCONF-369: XPath operates without namespace context, therefore we need an namespace-unaware builder.
45 // Once it is fixed we can use UntrustedXML instead.
46 private static final @NonNull DocumentBuilderFactory DBF;
49 final DocumentBuilderFactory f = DocumentBuilderFactory.newInstance();
50 f.setCoalescing(true);
51 f.setExpandEntityReferences(false);
52 f.setIgnoringElementContentWhitespace(true);
53 f.setIgnoringComments(true);
54 f.setXIncludeAware(false);
56 f.setFeature(XMLConstants.FEATURE_SECURE_PROCESSING, true);
57 f.setFeature("http://apache.org/xml/features/disallow-doctype-decl", true);
58 f.setFeature("http://apache.org/xml/features/nonvalidating/load-external-dtd", false);
59 f.setFeature("http://xml.org/sax/features/external-general-entities", false);
60 f.setFeature("http://xml.org/sax/features/external-parameter-entities", false);
61 } catch (final ParserConfigurationException e) {
62 throw new ExceptionInInitializerError(e);
67 protected static final XMLOutputFactory XML_OUTPUT_FACTORY = XMLOutputFactory.newFactory();
69 private final TextParameters textParams;
70 private final XPathExpression filter;
72 protected EventFormatter(final TextParameters textParams) {
73 this.textParams = requireNonNull(textParams);
77 protected EventFormatter(final TextParameters params, final String xpathFilter) throws XPathExpressionException {
78 textParams = requireNonNull(params);
82 xpath = XPF.newXPath();
84 // FIXME: NETCONF-369: we need to bind the namespace context here and for that we need the SchemaContext
85 filter = xpath.compile(xpathFilter);
89 public final @Nullable String eventData(final EffectiveModelContext schemaContext, final T input,
90 final Instant now) throws Exception {
91 return filterMatches(schemaContext, input, now) ? createText(textParams, schemaContext, input, now) : null;
95 * Export the provided input into the provided document so we can verify whether a filter matches the content.
97 * @param doc the document to fill
98 * @param schemaContext context to use for the export
99 * @param input data to export
100 * @throws IOException if any IOException occurs during export to the document
102 protected abstract void fillDocument(Document doc, EffectiveModelContext schemaContext, T input) throws IOException;
105 * Format the input data into string representation of the data provided.
107 * @param params output text parameters
108 * @param schemaContext context to use for the export
109 * @param input input data
110 * @param now time the event happened
111 * @return String representation of the formatted data
112 * @throws Exception if the underlying formatters fail to export the data to the requested format
114 protected abstract String createText(TextParameters params, EffectiveModelContext schemaContext, T input,
115 Instant now) throws Exception;
117 private boolean filterMatches(final EffectiveModelContext schemaContext, final T input, final Instant now)
119 if (filter == null) {
125 doc = DBF.newDocumentBuilder().newDocument();
126 } catch (final ParserConfigurationException e) {
127 throw new IOException("Failed to create a new document", e);
129 fillDocument(doc, schemaContext, input);
133 eval = (Boolean) filter.evaluate(doc, XPathConstants.BOOLEAN);
134 } catch (final XPathExpressionException e) {
135 throw new IllegalStateException("Failed to evaluate expression " + filter, e);
142 * Formats data specified by RFC3339.
144 * @param now time stamp
145 * @return Data specified by RFC3339.
147 protected static final String toRFC3339(final Instant now) {
148 return DateTimeFormatter.ISO_OFFSET_DATE_TIME.format(OffsetDateTime.ofInstant(now, ZoneId.systemDefault()));
151 protected static final @NonNull Element createNotificationElement(final Document doc, final Instant now) {
152 final var notificationElement = doc.createElementNS(NamespaceURN.NOTIFICATION, "notification");
153 final var eventTimeElement = doc.createElement("eventTime");
154 eventTimeElement.setTextContent(toRFC3339(now));
155 notificationElement.appendChild(eventTimeElement);
156 return notificationElement;
159 protected static final @NonNull XMLStreamWriter createStreamWriterWithNotification(final Writer writer,
160 final Instant now) throws XMLStreamException {
161 final var xmlStreamWriter = XML_OUTPUT_FACTORY.createXMLStreamWriter(writer);
162 xmlStreamWriter.setDefaultNamespace(NamespaceURN.NOTIFICATION);
164 xmlStreamWriter.writeStartElement(NamespaceURN.NOTIFICATION, "notification");
165 xmlStreamWriter.writeDefaultNamespace(NamespaceURN.NOTIFICATION);
167 xmlStreamWriter.writeStartElement("eventTime");
168 xmlStreamWriter.writeCharacters(toRFC3339(now));
169 xmlStreamWriter.writeEndElement();
170 return xmlStreamWriter;
173 protected static final void writeBody(final NormalizedNodeStreamWriter writer, final NormalizedNode body)
175 try (var nodeWriter = NormalizedNodeWriter.forStreamWriter(writer)) {
176 nodeWriter.write(body);