org.apache.camel.language.datasonnet.DatasonnetExpression Maven / Gradle / Ivy
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* 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.camel.language.datasonnet;
import java.io.File;
import java.io.IOException;
import java.nio.charset.Charset;
import java.nio.file.FileVisitResult;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.SimpleFileVisitor;
import java.nio.file.attribute.BasicFileAttributes;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import com.datasonnet.Mapper;
import com.datasonnet.MapperBuilder;
import com.datasonnet.document.DefaultDocument;
import com.datasonnet.document.Document;
import com.datasonnet.document.MediaType;
import com.datasonnet.document.MediaTypes;
import com.datasonnet.header.Header;
import com.datasonnet.spi.Library;
import org.apache.camel.CamelContext;
import org.apache.camel.Exchange;
import org.apache.camel.RuntimeExpressionException;
import org.apache.camel.spi.ExpressionResultTypeAware;
import org.apache.camel.support.ExchangeHelper;
import org.apache.camel.support.ExpressionAdapter;
import org.apache.camel.support.MessageHelper;
import org.apache.commons.io.IOUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class DatasonnetExpression extends ExpressionAdapter implements ExpressionResultTypeAware {
private static final Logger LOG = LoggerFactory.getLogger(DatasonnetExpression.class);
private final String expression;
private MediaType bodyMediaType;
private MediaType outputMediaType;
private Class resultType;
private Collection libraryPaths;
private transient DatasonnetLanguage language;
public DatasonnetExpression(String expression) {
this.expression = expression;
}
public static DatasonnetExpression builder(String expression) {
DatasonnetExpression answer = new DatasonnetExpression(expression);
return answer;
}
public static DatasonnetExpression builder(String expression, Class resultType) {
DatasonnetExpression answer = new DatasonnetExpression(expression);
answer.setResultType(resultType);
return answer;
}
@Override
public boolean matches(Exchange exchange) {
this.outputMediaType = MediaTypes.APPLICATION_JAVA;
return evaluate(exchange, Boolean.class);
}
@SuppressWarnings("unchecked")
@Override
public T evaluate(Exchange exchange, Class type) {
try {
// pass exchange to CML lib using thread as context
CML.getInstance().getExchange().set(exchange);
Document result = doEvaluate(exchange);
if (!type.equals(Object.class)) {
return ExchangeHelper.convertToType(exchange, type, result.getContent());
} else if (resultType == null || resultType.equals(Document.class)) {
return (T) result;
} else {
return (T) result.getContent();
}
} catch (Exception e) {
throw new RuntimeExpressionException("Unable to evaluate DataSonnet expression: " + expression, e);
} finally {
CML.getInstance().getExchange().remove();
}
}
private Document doEvaluate(Exchange exchange) {
MediaType bodyMT = bodyMediaType;
if (bodyMT == null && !expression.startsWith(Header.DATASONNET_HEADER)) {
//Try to auto-detect input mime type if it was not explicitly set
String typeHeader = exchange.getProperty(DatasonnetConstants.BODY_MEDIATYPE,
exchange.getIn().getHeader(Exchange.CONTENT_TYPE), String.class);
if (typeHeader != null) {
bodyMT = MediaType.valueOf(typeHeader);
}
}
Document body;
String bodyAsString = MessageHelper.extractBodyAsString(exchange.getMessage());
if (exchange.getMessage().getBody() instanceof Document) {
body = (Document) exchange.getMessage().getBody();
} else if (exchange.getMessage().getBody() == null || "".equals(bodyAsString)) {
//Empty body, force type to be application/java
body = new DefaultDocument<>("", MediaTypes.APPLICATION_JAVA);
} else if (MediaTypes.APPLICATION_JAVA.equalsTypeAndSubtype(bodyMT) || bodyMT == null) {
body = new DefaultDocument<>(exchange.getMessage().getBody());
} else {
body = new DefaultDocument<>(bodyAsString, bodyMT);
}
// the mapper is pre initialized
Mapper mapper = language.lookup(expression)
.orElseThrow(() -> new IllegalStateException("Datasonnet expression not initialized"));
MediaType outMT = outputMediaType;
if (outMT == null) {
//Try to auto-detect output mime type if it was not explicitly set
String typeHeader = exchange.getProperty(DatasonnetConstants.OUTPUT_MEDIATYPE,
exchange.getIn().getHeader(DatasonnetConstants.OUTPUT_MEDIATYPE), String.class);
if (typeHeader != null) {
outMT = MediaType.valueOf(typeHeader);
} else {
outMT = MediaTypes.ANY;
}
}
Map> inputs = Collections.singletonMap("body", body);
if (resultType == null || resultType.equals(Document.class)) {
return mapper.transform(body, inputs, outMT, Object.class);
} else {
return mapper.transform(body, inputs, outMT, resultType);
}
}
private Map resolveImports(DatasonnetLanguage language) {
if (libraryPaths == null) {
return language.getClasspathImports();
}
Map answer = new HashMap<>();
LOG.debug("Explicit library path is: {}", libraryPaths);
for (String nextPath : libraryPaths) {
final File nextLibDir = new File(nextPath);
if (nextLibDir.isDirectory()) {
try {
Files.walkFileTree(nextLibDir.toPath(), new SimpleFileVisitor() {
@Override
public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
File f = file.toFile();
if (!f.isDirectory() && f.getName().toLowerCase().endsWith(".libsonnet")) {
String content = IOUtils.toString(file.toUri(), Charset.defaultCharset());
Path relative = nextLibDir.toPath().relativize(file);
LOG.debug("Loading DataSonnet library: {}", relative);
answer.put(relative.toString(), content);
}
return FileVisitResult.CONTINUE;
}
});
} catch (IOException e) {
LOG.warn("Unable to load DataSonnet library from: " + nextPath, e);
}
}
}
return answer;
}
@Override
public void init(CamelContext context) {
super.init(context);
language = (DatasonnetLanguage) context.resolveLanguage("datasonnet");
// initialize mapper eager
language.computeIfMiss(expression, () -> {
MapperBuilder builder = new MapperBuilder(expression)
.withInputNames("body")
.withImports(resolveImports(language))
.withLibrary(CML.getInstance())
.withDefaultOutput(MediaTypes.APPLICATION_JAVA);
Set additionalLibraries = context.getRegistry().findByType(com.datasonnet.spi.Library.class);
for (Library lib : additionalLibraries) {
builder = builder.withLibrary(lib);
}
return builder.build();
});
}
// Getter/Setter methods
// -------------------------------------------------------------------------
public MediaType getBodyMediaType() {
return bodyMediaType;
}
/**
* The message's body MediaType
*/
public void setBodyMediaType(MediaType inputMimeType) {
this.bodyMediaType = inputMimeType;
}
public MediaType getOutputMediaType() {
return outputMediaType;
}
/**
* The MediaType to output
*/
public void setOutputMediaType(MediaType outputMimeType) {
this.outputMediaType = outputMimeType;
}
public Collection getLibraryPaths() {
return libraryPaths;
}
/**
* The paths to search for .libsonnet files
*/
public void setLibraryPaths(Collection libraryPaths) {
this.libraryPaths = libraryPaths;
}
@Override
public String getExpressionText() {
return this.expression;
}
@Override
public Class getResultType() {
return this.resultType;
}
/**
* Sets the class of the result type (type from output).
*
* The default result type is com.datasonnet.document.Document
*/
public void setResultType(Class targetType) {
this.resultType = targetType;
}
// Fluent builder methods
// -------------------------------------------------------------------------
public DatasonnetExpression bodyMediaType(MediaType bodyMediaType) {
setBodyMediaType(bodyMediaType);
return this;
}
public DatasonnetExpression outputMediaType(MediaType outputMediaType) {
setOutputMediaType(outputMediaType);
return this;
}
@Override
public String toString() {
return "datasonnet: " + expression;
}
}
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