/*
* Copyright 2006-2007 Graeme Rocher
*
* 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 grails.converters;
import grails.io.IOUtils;
import grails.util.GrailsWebUtil;
import groovy.lang.Closure;
import groovy.util.BuilderSupport;
import java.io.IOException;
import java.io.InputStream;
import java.io.PushbackInputStream;
import java.io.Reader;
import java.io.Writer;
import java.util.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.codehaus.groovy.grails.web.json.JSONArray;
import org.codehaus.groovy.grails.web.json.JSONElement;
import org.codehaus.groovy.grails.web.json.JSONException;
import org.codehaus.groovy.grails.web.json.JSONObject;
import org.codehaus.groovy.grails.web.json.JSONTokener;
import org.codehaus.groovy.grails.web.json.JSONWriter;
import org.codehaus.groovy.grails.web.json.PathCapturingJSONWriterWrapper;
import org.codehaus.groovy.grails.web.json.PrettyPrintJSONWriter;
import org.grails.web.converters.AbstractConverter;
import org.grails.web.converters.Converter;
import org.grails.web.converters.ConverterUtil;
import org.grails.web.converters.IncludeExcludeConverter;
import org.grails.web.converters.configuration.ConverterConfiguration;
import org.grails.web.converters.configuration.ConvertersConfigurationHolder;
import org.grails.web.converters.configuration.DefaultConverterConfiguration;
import org.grails.web.converters.exceptions.ConverterException;
import org.grails.web.converters.marshaller.ClosureObjectMarshaller;
import org.grails.web.converters.marshaller.ObjectMarshaller;
import grails.web.mime.MimeType;
/**
* A converter that converts domain classes, Maps, Lists, Arrays, POJOs and POGOs to JSON.
*
* @author Siegfried Puchbauer
* @author Graeme Rocher
*/
public class JSON extends AbstractConverter<JSONWriter> implements IncludeExcludeConverter<JSONWriter> {
private final static Log log = LogFactory.getLog(JSON.class);
private static final String CACHED_JSON = "org.codehaus.groovy.grails.CACHED_JSON_REQUEST_CONTENT";
protected Object target;
protected final ConverterConfiguration<JSON> config;
protected final CircularReferenceBehaviour circularReferenceBehaviour;
protected boolean prettyPrint;
protected JSONWriter writer;
protected Stack<Object> referenceStack;
protected ConverterConfiguration<JSON> initConfig() {
return ConvertersConfigurationHolder.getConverterConfiguration(JSON.class);
}
/**
* Default Constructor for a JSON Converter
*/
public JSON() {
config = initConfig();
encoding = config != null ? config.getEncoding() : "UTF-8";
contentType = MimeType.JSON.getName();
circularReferenceBehaviour = config != null ? config.getCircularReferenceBehaviour() : CircularReferenceBehaviour.DEFAULT;
prettyPrint = config != null && config.isPrettyPrint();
}
/**
* Creates a new JSON Converter for the given Object
*
* @param target the Object to convert
*/
public JSON(Object target) {
this();
setTarget(target);
}
public void setPrettyPrint(boolean prettyPrint) {
this.prettyPrint = prettyPrint;
}
private void prepareRender(Writer out) {
writer = prettyPrint ? new PrettyPrintJSONWriter(out) : new JSONWriter(out);
if (circularReferenceBehaviour == CircularReferenceBehaviour.PATH) {
if (log.isInfoEnabled()) {
log.info(String.format("Using experimental CircularReferenceBehaviour.PATH for %s", getClass().getName()));
}
writer = new PathCapturingJSONWriterWrapper(writer);
}
referenceStack = new Stack<Object>();
}
private void finalizeRender(Writer out) {
try {
out.flush();
out.close();
}
catch (Exception e) {
log.warn("Unexpected exception while closing a writer: " + e.getMessage());
}
}
/**
* Directs the JSON Writer to the given Writer
*
* @param out the Writer
* @throws org.grails.web.converters.exceptions.ConverterException
*
*/
public void render(Writer out) throws ConverterException {
prepareRender(out);
try {
value(target);
}
finally {
finalizeRender(out);
}
}
/**
* Directs the JSON Writer to the Outputstream of the HttpServletResponse and sets the Content-Type to application/json
*
* @param response a HttpServletResponse
* @throws ConverterException
*/
public void render(HttpServletResponse response) throws ConverterException {
response.setContentType(GrailsWebUtil.getContentType(contentType, encoding));
try {
render(response.getWriter());
}
catch (IOException e) {
throw new ConverterException(e);
}
}
public JSONWriter getWriter() throws ConverterException {
return writer;
}
public void convertAnother(Object o) throws ConverterException {
value(o);
}
public void build(@SuppressWarnings("rawtypes") Closure c) throws ConverterException {
new Builder(this).execute(c);
}
/**
* @param o
* @throws ConverterException
*/
public void value(Object o) throws ConverterException {
o = config.getProxyHandler().unwrapIfProxy(o);
try {
if (o == null || o.equals(JSONObject.NULL)) {
writer.valueNull();
}
else if (o instanceof CharSequence) {
writer.value(o);
}
else if (o instanceof Class<?>) {
writer.value(((Class<?>)o).getName());
}
else if (o instanceof Number) {
writer.value((Number)o);
} else if (o instanceof Boolean) {
writer.value((Boolean)o);
} else if (o.getClass().isPrimitive() && !o.getClass().equals(byte[].class)) {
writer.value(o);
}
else {
if (referenceStack.contains(o)) {
handleCircularRelationship(o);
}
else {
referenceStack.push(o);
ObjectMarshaller<JSON> marshaller = config.getMarshaller(o);
if (marshaller == null) {
throw new ConverterException("Unconvertable Object of class: " + o.getClass().getName());
}
marshaller.marshalObject(o, this);
referenceStack.pop();
}
}
}
catch (ConverterException ce) {
throw ce;
}
catch (JSONException e) {
throw new ConverterException(e);
}
}
public ObjectMarshaller<JSON> lookupObjectMarshaller(Object target) {
return config.getMarshaller(target);
}
public int getDepth() {
return referenceStack.size();
}
public void property(String key, Object value) throws JSONException, ConverterException {
writer.key(key);
value(value);
}
/**
* Performs the conversion and returns the resulting JSON as String
*
* @param prettyPrint true, if the output should be indented, otherwise false
* @return a JSON String
* @throws JSONException
*/
public String toString(boolean prettyPrint) throws JSONException {
String json = super.toString();
if (prettyPrint) {
Object jsonObject = new JSONTokener(json).nextValue();
if (jsonObject instanceof JSONObject) {
return ((JSONObject) jsonObject).toString(3);
}
if (jsonObject instanceof JSONArray) {
return ((JSONArray) jsonObject).toString(3);
}
}
return json;
}
/**
* Parses the given JSON String and returns either a JSONObject or a JSONArray
*
* @param reader JSON source
* @return either a JSONObject or a JSONArray - depending on the given JSON
* @throws ConverterException when the JSON content is not valid
*/
public static JSONElement parse(Reader reader) throws ConverterException {
return parse(IOUtils.toString(reader));
}
/**
* Parses the given JSON String and returns either a JSONObject or a JSONArray
*
* @param source A string containing some JSON
* @return either a JSONObject or a JSONArray - depending on the given JSON
* @throws ConverterException when the JSON content is not valid
*/
public static JSONElement parse(String source) throws ConverterException {
try {
final Object value = new JSONTokener(source).nextValue();
if (value instanceof JSONElement) {
return (JSONElement) value;
}
// return empty object
return new JSONObject();
}
catch (JSONException e) {
throw new ConverterException("Error parsing JSON", e);
}
}
/**
* Parses the given JSON and returns either a JSONObject or a JSONArray
*
* @param is An InputStream which delivers some JSON
* @param encoding the Character Encoding to use
* @return either a JSONObject or a JSONArray - depending on the given JSON
* @throws ConverterException when the JSON content is not valid
*/
public static JSONElement parse(InputStream is, String encoding) throws ConverterException {
return parse(IOUtils.toString(is, encoding));
}
/**
* Parses the given request's InputStream and returns either a JSONObject or a JSONArray
*
* @param request the JSON Request
* @return either a JSONObject or a JSONArray - depending on the given JSON
* @throws ConverterException when the JSON content is not valid
*/
public static Object parse(HttpServletRequest request) throws ConverterException {
Object json = request.getAttribute(CACHED_JSON);
if (json != null) {
return json;
}
String encoding = request.getCharacterEncoding();
if (encoding == null) {
encoding = Converter.DEFAULT_REQUEST_ENCODING;
}
try {
PushbackInputStream pushbackInputStream = null;
int firstByte = -1;
try {
pushbackInputStream = new PushbackInputStream(request.getInputStream());
firstByte = pushbackInputStream.read();
} catch (IOException ioe) {}
if (firstByte == -1) {
return new JSONObject();
}
pushbackInputStream.unread(firstByte);
json = parse(pushbackInputStream, encoding);
request.setAttribute(CACHED_JSON, json);
return json;
}
catch (IOException e) {
throw new ConverterException("Error parsing JSON", e);
}
}
/**
* Sets the Object which is later converted to JSON
*
* @param target the Object
* @see org.grails.web.converters.Converter
*/
@Override
public void setTarget(Object target) {
this.target = target;
}
protected void handleCircularRelationship(Object o) throws ConverterException {
switch (circularReferenceBehaviour) {
case DEFAULT:
if (!(Map.class.isAssignableFrom(o.getClass()) || Collection.class.isAssignableFrom(o.getClass()))) {
Map<String, Object> props = new HashMap<String, Object>();
props.put("class", o.getClass());
StringBuilder ref = new StringBuilder();
int idx = referenceStack.indexOf(o);
for (int i = referenceStack.size() - 1; i > idx; i--) {
ref.append("../");
}
props.put("_ref", ref.substring(0, ref.length() - 1));
value(props);
}
break;
case EXCEPTION:
throw new ConverterException("Circular Reference detected: class " + o.getClass().getName());
case INSERT_NULL:
value(null);
break;
case PATH:
Map<String, Object> props = new HashMap<String, Object>();
props.put("class", o.getClass());
int idx = referenceStack.indexOf(o);
PathCapturingJSONWriterWrapper pcWriter = (PathCapturingJSONWriterWrapper) writer;
props.put("ref", String.format("root%s", pcWriter.getStackReference(idx)));
value(props);
break;
case IGNORE:
break;
}
}
public static ConverterConfiguration<JSON> getNamedConfig(String configName) throws ConverterException {
ConverterConfiguration<JSON> cfg = ConvertersConfigurationHolder.getNamedConverterConfiguration(configName, JSON.class);
if (cfg == null) {
throw new ConverterException(String.format("Converter Configuration with name '%s' not found!", configName));
}
return cfg;
}
public static Object use(String configName, Closure<?> callable) throws ConverterException {
ConverterConfiguration<JSON> old = ConvertersConfigurationHolder.getThreadLocalConverterConfiguration(JSON.class);
ConverterConfiguration<JSON> cfg = getNamedConfig(configName);
ConvertersConfigurationHolder.setThreadLocalConverterConfiguration(JSON.class, cfg);
try {
return callable.call();
}
finally {
ConvertersConfigurationHolder.setThreadLocalConverterConfiguration(JSON.class, old);
}
}
public static void use(String cfgName) throws ConverterException {
if (cfgName == null || "default".equals(cfgName)) {
ConvertersConfigurationHolder.setThreadLocalConverterConfiguration(JSON.class, null);
}
else {
ConvertersConfigurationHolder.setThreadLocalConverterConfiguration(JSON.class, getNamedConfig(cfgName));
}
}
public static void registerObjectMarshaller(Class<?> clazz, Closure<?> callable) throws ConverterException {
registerObjectMarshaller(new ClosureObjectMarshaller<JSON>(clazz, callable));
}
public static void registerObjectMarshaller(Class<?> clazz, int priority, Closure<?> callable) throws ConverterException {
registerObjectMarshaller(new ClosureObjectMarshaller<JSON>(clazz, callable), priority);
}
public static void registerObjectMarshaller(ObjectMarshaller<JSON> om) throws ConverterException {
ConverterConfiguration<JSON> cfg = ConvertersConfigurationHolder.getConverterConfiguration(JSON.class);
if (cfg == null) {
throw new ConverterException("Default Configuration not found for class " + JSON.class.getName());
}
if (!(cfg instanceof DefaultConverterConfiguration<?>)) {
cfg = new DefaultConverterConfiguration<JSON>(cfg);
ConvertersConfigurationHolder.setDefaultConfiguration(JSON.class, cfg);
}
((DefaultConverterConfiguration<JSON>) cfg).registerObjectMarshaller(om);
}
public static void registerObjectMarshaller(ObjectMarshaller<JSON> om, int priority) throws ConverterException {
ConverterConfiguration<JSON> cfg = ConvertersConfigurationHolder.getConverterConfiguration(JSON.class);
if (cfg == null) {
throw new ConverterException("Default Configuration not found for class " + JSON.class.getName());
}
if (!(cfg instanceof DefaultConverterConfiguration<?>)) {
cfg = new DefaultConverterConfiguration<JSON>(cfg);
ConvertersConfigurationHolder.setDefaultConfiguration(JSON.class, cfg);
}
((DefaultConverterConfiguration<JSON>) cfg).registerObjectMarshaller(om, priority);
}
public static void createNamedConfig(String name, Closure<?> callable) throws ConverterException {
DefaultConverterConfiguration<JSON> cfg = new DefaultConverterConfiguration<JSON>(ConvertersConfigurationHolder.getConverterConfiguration(JSON.class));
try {
callable.call(cfg);
ConvertersConfigurationHolder.setNamedConverterConfiguration(JSON.class, name, cfg);
}
catch (Exception e) {
throw ConverterUtil.resolveConverterException(e);
}
}
public static void withDefaultConfiguration(Closure<?> callable) throws ConverterException {
ConverterConfiguration<JSON> cfg = ConvertersConfigurationHolder.getConverterConfiguration(JSON.class);
if (!(cfg instanceof DefaultConverterConfiguration<?>)) {
cfg = new DefaultConverterConfiguration<JSON>(cfg);
}
try {
callable.call(cfg);
ConvertersConfigurationHolder.setDefaultConfiguration(JSON.class, cfg);
ConvertersConfigurationHolder.setDefaultConfiguration(JSON.class, cfg);
}
catch (Throwable t) {
throw ConverterUtil.resolveConverterException(t);
}
}
@Override
public void setIncludes(List<String> includes) {
setIncludes(target.getClass(), includes);
}
@Override
public void setExcludes(List<String> excludes) {
setExcludes(target.getClass(), excludes);
}
public class Builder extends BuilderSupport {
private JSON json;
public Builder(JSON json) {
this.json = json;
writer = json.writer;
}
public void execute(Closure<?> callable) {
callable.setDelegate(this);
// callable.setDelegate(Closure.DELEGATE_FIRST);
invokeMethod("json", new Object[] { callable });
}
private Stack<BuilderMode> stack = new Stack<BuilderMode>();
private boolean start = true;
private JSONWriter writer;
@Override
protected Object createNode(Object name) {
int retVal = 1;
try {
if (start) {
start = false;
writeObject();
}
else {
if (getCurrent() == null && stack.peek() == BuilderMode.OBJECT) {
throw new IllegalArgumentException("only call to [element { }] is allowed when creating array");
}
if (stack.peek() == BuilderMode.ARRAY) {
writeObject();
retVal = 2;
}
writer.key(String.valueOf(name)).array();
stack.push(BuilderMode.ARRAY);
}
}
catch (JSONException e) {
throw new IllegalArgumentException("invalid element");
}
return retVal;
}
@SuppressWarnings("rawtypes")
@Override
protected Object createNode(Object key, Map valueMap) {
try {
if (stack.peek().equals(BuilderMode.OBJECT)) {
writer.key(String.valueOf(key));
}
writer.object();
for (Object o : valueMap.entrySet()) {
Map.Entry element = (Map.Entry) o;
writer.key(String.valueOf(element.getKey()));//.value(element.getValue());
json.convertAnother(element.getValue());
}
writer.endObject();
return null;
}
catch (JSONException e) {
throw new IllegalArgumentException("invalid element");
}
}
@SuppressWarnings("rawtypes")
@Override
protected Object createNode(Object arg0, Map arg1, Object arg2) {
throw new IllegalArgumentException("not implemented");
}
@SuppressWarnings("rawtypes")
@Override
protected Object createNode(Object key, Object value) {
if (getCurrent() == null && stack.peek()== BuilderMode.OBJECT) {
throw new IllegalArgumentException("only call to [element { }] is allowed when creating array");
}
try {
int retVal = 0;
if (stack.peek().equals(BuilderMode.ARRAY)) {
writeObject();
retVal = 1;
}
if (value instanceof Collection) {
Collection c = (Collection)value;
writer.key(String.valueOf(key));
handleCollectionRecurse(c);
}
else {
writer.key(String.valueOf(key));
json.convertAnother(value); //.value(value);
}
return retVal != 0 ? retVal : null;
}
catch (JSONException e) {
throw new IllegalArgumentException("invalid element");
}
}
@SuppressWarnings("rawtypes")
private void handleCollectionRecurse(Collection c) throws JSONException {
writer.array();
for (Object element : c) {
if (element instanceof Collection) {
handleCollectionRecurse((Collection) element);
}
else {
json.convertAnother(element);
}
}
writer.endArray();
}
@Override
protected void nodeCompleted(Object parent, Object node) {
Object last = null;
if (node == null) {
return;
}
try {
int i = ((Integer)node);
while (i-- > 0) {
last = stack.pop();
if (BuilderMode.ARRAY == last) {
writer.endArray();
}
if (BuilderMode.OBJECT == last) {
writer.endObject();
}
}
}
catch (JSONException e) {
throw new IllegalArgumentException("invalid element on the stack");
}
}
@Override
protected void setParent(Object arg0, Object arg1) {
/* do nothing */
}
private void writeObject() throws JSONException {
writer.object();
stack.push(BuilderMode.OBJECT);
}
}
private enum BuilderMode {
ARRAY,
OBJECT
}
}