org.apache.camel.support.ScriptHelper Maven / Gradle / Ivy
/*
* 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.support;
import java.io.IOException;
import java.io.InputStream;
import org.apache.camel.CamelContext;
import org.apache.camel.Exchange;
import org.apache.camel.RuntimeCamelException;
import org.apache.camel.spi.Language;
import org.apache.camel.util.IOHelper;
import org.apache.camel.util.StringHelper;
public final class ScriptHelper {
private ScriptHelper() {
}
/**
* Resolves the expression/predicate whether it refers to an external script on the file/classpath etc.
* This requires to use the prefix resource: such as resource:classpath:com/foo/myscript.groovy,
* resource:file:/var/myscript.groovy.
*
* If not then the returned value is returned as-is.
*/
public static String resolveOptionalExternalScript(CamelContext camelContext, String expression) {
return resolveOptionalExternalScript(camelContext, null, expression);
}
/**
* Resolves the expression/predicate whether it refers to an external script on the file/classpath etc.
* This requires to use the prefix resource: such as resource:classpath:com/foo/myscript.groovy,
* resource:file:/var/myscript.groovy.
*
* If not then the returned value is returned as-is.
*
* If the exchange is provided (not null), then the external script can be referred via simple language for dynamic values, etc.
* resource:classpath:${header.myFileName}
*/
public static String resolveOptionalExternalScript(CamelContext camelContext, Exchange exchange, String expression) {
if (expression == null) {
return null;
}
String external = expression;
// must be one line only
int newLines = StringHelper.countChar(expression, '\n');
if (newLines > 1) {
// okay then just use as-is
return expression;
}
// must start with resource: to denote an external resource
if (external.startsWith("resource:")) {
external = external.substring(9);
if (ResourceHelper.hasScheme(external)) {
if (exchange != null && LanguageSupport.hasSimpleFunction(external)) {
Language simple = exchange.getContext().resolveLanguage("simple");
external = simple.createExpression(external).evaluate(exchange, String.class);
}
InputStream is = null;
try {
is = ResourceHelper.resolveMandatoryResourceAsInputStream(camelContext, external);
expression = camelContext.getTypeConverter().convertTo(String.class, is);
} catch (IOException e) {
throw new RuntimeCamelException("Cannot load resource " + external, e);
} finally {
IOHelper.close(is);
}
}
}
return expression;
}
}