/**
* Copyright Alex Objelean
*/
package ro.isdc.wro.extensions.script;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import org.apache.commons.io.IOUtils;
import org.apache.commons.lang3.Validate;
import org.mozilla.javascript.Context;
import org.mozilla.javascript.RhinoException;
import org.mozilla.javascript.ScriptableObject;
import org.mozilla.javascript.tools.ToolErrorReporter;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import ro.isdc.wro.WroRuntimeException;
import ro.isdc.wro.extensions.locator.WebjarUriLocator;
/**
* Used to evaluate javascript on the serverside using rhino javascript engine. Encapsulate and hides all implementation
* details used by rhino to evaluate javascript on the serverside.
*
* @author Alex Objelean
*/
public final class RhinoScriptBuilder {
private static final Logger LOG = LoggerFactory.getLogger(RhinoScriptBuilder.class);
private static final String SCRIPT_ENV = "env.rhino.min.js";
private static final String SCRIPT_JSON = "json2.min.js";
private static final String SCRIPT_CYCLE = "cycle.js";
private final ScriptableObject scope;
private RhinoScriptBuilder() {
this(null);
}
private RhinoScriptBuilder(final ScriptableObject scope) {
this.scope = createContext(scope);
}
private Context getContext() {
initContext();
return Context.getCurrentContext();
}
/**
* @return the context
*/
public ScriptableObject getScope() {
return this.scope;
}
/**
* Initialize the context.
*/
private ScriptableObject createContext(final ScriptableObject initialScope) {
final Context context = getContext();
context.setOptimizationLevel(-1);
// TODO redirect errors from System.err to LOG.error()
context.setErrorReporter(new ToolErrorReporter(false));
context.setLanguageVersion(Context.VERSION_1_8);
InputStream script = null;
final ScriptableObject scriptCommon = (ScriptableObject) context.initStandardObjects(initialScope);
try {
script = getClass().getResourceAsStream("commons.js");
context.evaluateReader(scriptCommon, new InputStreamReader(script), "commons.js", 1, null);
} catch (final IOException e) {
throw new RuntimeException("Problem while evaluationg commons script.", e);
} finally {
IOUtils.closeQuietly(script);
}
return scriptCommon;
}
/**
* Add a client side environment to the script context (client-side aware).
*
* @return {@link RhinoScriptBuilder} used to chain evaluation of the scripts.
* @throws IOException
*/
public RhinoScriptBuilder addClientSideEnvironment() {
try {
final InputStream scriptEnv = getClass().getResourceAsStream(SCRIPT_ENV);
evaluateChain(scriptEnv, SCRIPT_ENV);
return this;
} catch (final IOException e) {
throw new RuntimeException("Couldn't initialize env.rhino script", e);
}
}
/**
* This method will load JSON utility and aslo a Douglas Crockford's <a
* href="https://github.com/douglascrockford/JSON-js/blob/master/cycle.js">utility</a> required for decycling objects
* which would fail otherwise when using JSON.stringify.
*/
public RhinoScriptBuilder addJSON() {
try {
final InputStream script = new WebjarUriLocator().locate(WebjarUriLocator.createUri("20110223/json2.js"));
final InputStream scriptCycle = getClass().getResourceAsStream(SCRIPT_CYCLE);
evaluateChain(script, SCRIPT_JSON);
evaluateChain(scriptCycle, SCRIPT_CYCLE);
return this;
} catch (final IOException e) {
throw new RuntimeException("Couldn't initialize json2.min.js script", e);
}
}
/**
* Evaluates a script and return {@link RhinoScriptBuilder} for a chained script evaluation.
*
* @param stream {@link InputStream} of the script to evaluate.
* @param sourceName the name of the evaluated script.
* @return {@link RhinoScriptBuilder} chain with required script evaluated.
* @throws IOException if the script couldn't be retrieved.
*/
public RhinoScriptBuilder evaluateChain(final InputStream stream, final String sourceName)
throws IOException {
Validate.notNull(stream);
try {
getContext().evaluateReader(scope, new InputStreamReader(stream), sourceName, 1, null);
return this;
} catch(final RhinoException e) {
if (e instanceof RhinoException) {
LOG.error("RhinoException: {}", RhinoUtils.createExceptionMessage(e));
}
throw e;
} catch (final RuntimeException e) {
LOG.error("Exception caught", e);
throw e;
} finally {
stream.close();
}
}
/**
* Makes sure the context is properly initialized.
*/
private void initContext() {
if (Context.getCurrentContext() == null) {
Context.enter();
}
}
/**
* Evaluates a script and return {@link RhinoScriptBuilder} for a chained script evaluation.
*
* @param script the string representation of the script to evaluate.
* @param sourceName the name of the evaluated script.
* @return evaluated object.
* @throws IOException if the script couldn't be retrieved.
*/
public RhinoScriptBuilder evaluateChain(final String script, final String sourceName) {
Validate.notNull(script);
getContext().evaluateString(scope, script, sourceName, 1, null);
return this;
}
/**
* Evaluates a script from a reader.
*
* @param reader {@link Reader} of the script to evaluate.
* @param sourceName the name of the evaluated script.
* @return evaluated object.
* @throws IOException if the script couldn't be retrieved.
*/
public Object evaluate(final Reader reader, final String sourceName)
throws IOException {
Validate.notNull(reader);
try {
return evaluate(IOUtils.toString(reader), sourceName);
} finally {
reader.close();
}
}
/**
* Evaluates a script.
*
* @param script string representation of the script to evaluate.
* @param sourceName the name of the evaluated script.
* @return evaluated object.
* @throws IOException if the script couldn't be retrieved.
*/
public Object evaluate(final String script, final String sourceName) {
Validate.notNull(script);
// make sure we have a context associated with current thread
try {
return getContext().evaluateString(scope, script, sourceName, 1, null);
} catch (final RhinoException e) {
final String message = RhinoUtils.createExceptionMessage(e);
LOG.error("JavaScriptException occured: {}", message);
throw new WroRuntimeException(message);
} finally {
// Rhino throws an exception when trying to exit twice. Make sure we don't get any exception
if (Context.getCurrentContext() != null) {
Context.exit();
}
}
}
/**
* @return default {@link RhinoScriptBuilder} for script evaluation chaining.
*/
public static RhinoScriptBuilder newChain() {
return new RhinoScriptBuilder();
}
public static RhinoScriptBuilder newChain(final ScriptableObject scope) {
return new RhinoScriptBuilder(scope);
}
/**
* @return default {@link RhinoScriptBuilder} for script evaluation chaining.
*/
public static RhinoScriptBuilder newClientSideAwareChain() {
return new RhinoScriptBuilder().addClientSideEnvironment();
}
}