package com.almende.eve.rpc.jsonrpc;
import java.io.IOException;
import java.lang.annotation.Annotation;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;
import java.util.TreeSet;
import java.util.UUID;
import java.util.logging.Level;
import java.util.logging.Logger;
import com.almende.eve.agent.annotation.Namespace;
import com.almende.eve.rpc.RequestParams;
import com.almende.eve.rpc.annotation.Access;
import com.almende.eve.rpc.annotation.AccessType;
import com.almende.eve.rpc.annotation.Name;
import com.almende.eve.rpc.annotation.Required;
import com.almende.eve.rpc.annotation.Sender;
import com.almende.eve.rpc.jsonrpc.jackson.JOM;
import com.almende.util.AnnotationUtil;
import com.almende.util.AnnotationUtil.AnnotatedClass;
import com.almende.util.AnnotationUtil.AnnotatedMethod;
import com.almende.util.AnnotationUtil.AnnotatedParam;
import com.almende.util.NamespaceUtil;
import com.almende.util.NamespaceUtil.CallTuple;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.ObjectNode;
public final class JSONRPC {
private JSONRPC() {
}
private static Logger logger = Logger.getLogger(JSONRPC.class.getName());
// TODO: implement JSONRPC 2.0 Batch
/**
* Invoke a method on an object
*
* @param obj
* Request will be invoked on the given object
* @param request
* A request in JSON-RPC format
* @return
* @throws IOException
* @throws JsonMappingException
* @throws JsonGenerationException
*/
public static String invoke(Object destination, String request,
JSONAuthorizor auth) throws IOException {
return invoke(destination, request, null, auth);
}
/**
* Invoke a method on an object
*
* @param obj
* Request will be invoked on the given object
* @param request
* A request in JSON-RPC format
* @param requestParams
* Optional request parameters
* @return
* @throws IOException
* @throws JsonMappingException
* @throws JsonGenerationException
*/
public static String invoke(Object destination, String request,
RequestParams requestParams, JSONAuthorizor auth)
throws IOException {
JSONRequest jsonRequest = null;
JSONResponse jsonResponse = null;
try {
jsonRequest = new JSONRequest(request);
jsonResponse = invoke(destination, jsonRequest, requestParams, auth);
} catch (JSONRPCException err) {
jsonResponse = new JSONResponse(err);
}
return jsonResponse.toString();
}
/**
* Invoke a method on an object
*
* @param destination
* destination url
* @param obj
* will be invoked on the given object
* @return
*/
public static JSONResponse invoke(Object destination, JSONRequest request,
JSONAuthorizor auth) {
return invoke(destination, request, null, auth);
}
/**
* Invoke a method on an object
*
* @param obj
* Request will be invoked on the given object
* @param request
* A request in JSON-RPC format
* @param requestParams
* Optional request parameters
* @return
*/
public static JSONResponse invoke(Object destination, JSONRequest request,
RequestParams requestParams, JSONAuthorizor auth) {
JSONResponse resp = new JSONResponse();
resp.setId(request.getId());
try {
CallTuple tuple = NamespaceUtil.get(destination,
request.getMethod());
Object realDest = tuple.getDestination();
String realMethod = tuple.getMethodName();
AnnotatedMethod annotatedMethod = getMethod(realDest, realMethod,
requestParams, auth);
if (annotatedMethod == null) {
throw new JSONRPCException(
JSONRPCException.CODE.METHOD_NOT_FOUND,
"Method '"
+ request.getMethod()
+ "' not found. The method does not exist or you are not authorized.");
}
Method method = annotatedMethod.getActualMethod();
Object[] params = castParams(request.getParams(),
annotatedMethod.getParams(), requestParams);
Object result = method.invoke(realDest, params);
if (result == null) {
result = JOM.createNullNode();
}
resp.setResult(result);
} catch (JSONRPCException err) {
resp.setError((JSONRPCException) err);
} catch (Exception err) {
if (err.getCause() != null
&& err.getCause() instanceof JSONRPCException) {
resp.setError((JSONRPCException) err.getCause());
} else {
if (err instanceof InvocationTargetException
&& err.getCause() != null) {
err = (Exception) err.getCause();
}
logger.log(Level.WARNING,
"Exception raised, returning it as JSONRPCException.",
err);
JSONRPCException jsonError = new JSONRPCException(
JSONRPCException.CODE.INTERNAL_ERROR, getMessage(err),
err);
jsonError.setData(err);
resp.setError(jsonError);
}
}
return resp;
}
/**
* Validate whether the given class contains valid JSON-RPC methods. A class
* if valid when:<br>
* - There are no public methods with equal names<br>
* - The parameters of all public methods have the @Name annotation<br>
* If the class is not valid, an Exception is thrown
*
* @param c
* The class to be verified
* @param requestParams
* optional request parameters
* @return errors A list with validation errors. When no problems are found,
* an empty list is returned
*/
public static List<String> validate(Class<?> c, RequestParams requestParams) {
List<String> errors = new ArrayList<String>();
Set<String> methodNames = new HashSet<String>();
AnnotatedClass ac = null;
try {
ac = AnnotationUtil.get(c);
if (ac != null) {
for (AnnotatedMethod method : ac.getMethods()) {
boolean available = isAvailable(method, null,
requestParams, null);
if (available) {
// The method name may only occur once
String name = method.getName();
if (methodNames.contains(name)) {
errors.add("Public method '"
+ name
+ "' is defined more than once, which is not"
+ " allowed for JSON-RPC.");
}
methodNames.add(name);
// TODO: I removed duplicate @Name check. If you reach
// this point the function at least has named
// parameters, due to the isAvailable() call. Should we
// add a duplicates check to isAvailable()?
}
}
}
} catch (Exception e) {
logger.log(Level.WARNING, "Problems wrapping class for annotation",
e);
errors.add("Class can't be wrapped for annotation, exception raised:"
+ e.getLocalizedMessage());
}
return errors;
}
private static Map<String, Object> _describe(Object c,
RequestParams requestParams, String namespace) {
Map<String, Object> methods = new TreeMap<String, Object>();
try {
AnnotatedClass annotatedClass = AnnotationUtil.get(c.getClass());
for (AnnotatedMethod method : annotatedClass.getMethods()) {
if (isAvailable(method, null, requestParams, null)) {
// format as JSON
List<Object> descParams = new ArrayList<Object>();
for (AnnotatedParam param : method.getParams()) {
if (getRequestAnnotation(param, requestParams) == null) {
String name = getName(param);
Map<String, Object> paramData = new HashMap<String, Object>();
paramData.put("name", name);
paramData.put("type",
typeToString(param.getGenericType()));
paramData.put("required", isRequired(param));
descParams.add(paramData);
}
}
Map<String, Object> result = new HashMap<String, Object>();
result.put("type",
typeToString(method.getGenericReturnType()));
Map<String, Object> desc = new HashMap<String, Object>();
String methodName = namespace.equals("") ? method.getName()
: namespace + "." + method.getName();
desc.put("method", methodName);
desc.put("params", descParams);
desc.put("result", result);
methods.put(methodName, desc);
}
}
for (AnnotatedMethod method : annotatedClass
.getAnnotatedMethods(Namespace.class)) {
String innerNamespace = method.getAnnotation(Namespace.class)
.value();
methods.putAll(_describe(
method.getActualMethod().invoke(c, (Object[]) null),
requestParams, innerNamespace));
}
} catch (Exception e) {
logger.log(Level.WARNING, "Failed to describe class", e);
return null;
}
return methods;
}
/**
* Describe all JSON-RPC methods of given class
*
* @param c
* The class to be described
* @param requestParams
* Optional request parameters.
* @param asString
* If false (default), the returned description is a JSON
* structure. If true, the described methods will be in an easy
* to read string.
* @return
*/
public static List<Object> describe(Object c, RequestParams requestParams) {
try {
Map<String, Object> methods = _describe(c, requestParams, "");
// create a sorted array
List<Object> sortedMethods = new ArrayList<Object>();
TreeSet<String> methodNames = new TreeSet<String>(methods.keySet());
for (String methodName : methodNames) {
sortedMethods.add(methods.get(methodName));
}
return sortedMethods;
} catch (Exception e) {
logger.log(Level.WARNING, "Failed to describe class", e);
return null;
}
}
/**
* Get type description from a class. Returns for example "String" or
* "List<String>".
*
* @param c
* @return
*/
private static String typeToString(Type c) {
String s = c.toString();
// replace full namespaces to short names
int point = s.lastIndexOf('.');
while (point >= 0) {
int angle = s.lastIndexOf('<', point);
int space = s.lastIndexOf(' ', point);
int start = Math.max(angle, space);
s = s.substring(0, start + 1) + s.substring(point + 1);
point = s.lastIndexOf('.');
}
// remove modifiers like "class blabla" or "interface blabla"
int space = s.indexOf(' ');
int angle = s.indexOf('<', point);
if (space >= 0 && (angle < 0 || angle > space)) {
s = s.substring(space + 1);
}
return s;
}
/**
* Retrieve a description of an error
*
* @param error
* @return message String with the error description of the cause
*/
private static String getMessage(Throwable error) {
Throwable cause = error;
while (cause.getCause() != null) {
cause = cause.getCause();
}
return cause.toString();
}
/**
* Find a method by name, which is available for JSON-RPC, and has named
* parameters
*
* @param destination
* @param method
* @param requestParams
* @return methodType meta information on the method, or null if not found
*/
private static AnnotatedMethod getMethod(Object destination, String method,
RequestParams requestParams, JSONAuthorizor auth) {
AnnotatedClass annotatedClass;
try {
annotatedClass = AnnotationUtil.get(destination.getClass());
List<AnnotatedMethod> methods = annotatedClass.getMethods(method);
for (AnnotatedMethod m : methods) {
if (isAvailable(m, destination, requestParams, auth)) {
return m;
}
}
} catch (Exception e) {
logger.log(Level.WARNING, "GetMethod failed:", e);
}
return null;
}
/**
* Cast a JSONArray or JSONObject params to the desired paramTypes
*
* @param params
* @param paramTypes
* @param requestParams
* @return
* @throws Exception
*/
private static Object[] castParams(Object params,
List<AnnotatedParam> annotatedParams, RequestParams requestParams) {
ObjectMapper mapper = JOM.getInstance();
if (annotatedParams.size() == 0) {
return new Object[0];
}
if (params instanceof ObjectNode) {
// JSON-RPC 2.0 with named parameters in a JSONObject
if (annotatedParams.size() == 1
&& annotatedParams.get(0).getType()
.equals(ObjectNode.class)
&& annotatedParams.get(0).getAnnotations().size() == 0) {
// the method expects one parameter of type JSONObject
// feed the params object itself to it.
Object[] objects = new Object[1];
objects[0] = params;
return objects;
} else {
ObjectNode paramsObject = (ObjectNode) params;
Object[] objects = new Object[annotatedParams.size()];
for (int i = 0; i < annotatedParams.size(); i++) {
AnnotatedParam p = annotatedParams.get(i);
Annotation a = getRequestAnnotation(p, requestParams);
if (a != null) {
// this is a systems parameter
objects[i] = requestParams.get(a);
} else {
String name = getName(p);
if (name != null) {
// this is a named parameter
if (paramsObject.has(name)) {
objects[i] = mapper.convertValue(
paramsObject.get(name), p.getType());
} else {
if (isRequired(p)) {
throw new ClassCastException(
"Required parameter '" + name
+ "' missing");
} else if (p.getType().isPrimitive()) {
// TODO: should this test be moved to
// isAvailable()?
throw new ClassCastException("Parameter '"
+ name
+ "' cannot be both optional and "
+ "a primitive type ("
+ p.getType().getSimpleName() + ")");
} else {
objects[i] = null;
}
}
} else {
// this is a problem
throw new ClassCastException("Name of parameter "
+ i + " not defined");
}
}
}
return objects;
}
} else {
throw new ClassCastException("params must be a JSONObject");
}
}
/**
* Create a JSONRequest from a java method and arguments
*
* @param method
* @param args
* @return
*/
public static JSONRequest createRequest(Method method, Object[] args) {
AnnotatedMethod annotatedMethod = null;
try {
annotatedMethod = new AnnotationUtil.AnnotatedMethod(method);
} catch (Exception e) {
logger.log(Level.WARNING,
"Method can't be used as annotated method", e);
throw new IllegalArgumentException("Method '" + method.getName()
+ "' can't be used as annotated method.", e);
}
List<AnnotatedParam> annotatedParams = annotatedMethod.getParams();
ObjectNode params = JOM.createObjectNode();
for (int i = 0; i < annotatedParams.size(); i++) {
AnnotatedParam annotatedParam = annotatedParams.get(i);
if (i < args.length && args[i] != null) {
String name = getName(annotatedParam);
if (name != null) {
JsonNode paramValue = JOM.getInstance().convertValue(
args[i], JsonNode.class);
params.put(name, paramValue);
} else {
throw new IllegalArgumentException("Parameter " + i
+ " in method '" + method.getName()
+ "' is missing the @Name annotation.");
}
} else if (isRequired(annotatedParam)) {
throw new IllegalArgumentException("Required parameter " + i
+ " in method '" + method.getName() + "' is null.");
}
}
String id = UUID.randomUUID().toString();
return new JSONRequest(id, method.getName(), params);
}
public static boolean hasPrivate(Class<?> clazz) {
AnnotatedClass annotated = AnnotationUtil.get(clazz);
for (Annotation anno : annotated.getAnnotations()) {
if (anno.annotationType().equals(Access.class)
&& ((Access) anno).value() == AccessType.PRIVATE) {
return true;
}
if (anno.annotationType().equals(Sender.class)) {
return true;
}
}
return false;
}
/**
* Check whether a method is available for JSON-RPC calls. This is the case
* when it is public, has named parameters, and has a public or private @Access
* annotation
*
* @param annotatedMethod
* @param requestParams
* @return available
*/
private static boolean isAvailable(AnnotatedMethod method,
Object destination, RequestParams requestParams, JSONAuthorizor auth) {
int mod = method.getActualMethod().getModifiers();
Access methodAccess = method.getAnnotation(Access.class);
if (destination != null
&& !method.getActualMethod().getDeclaringClass()
.isAssignableFrom(destination.getClass())) {
return false;
}
if (!(Modifier.isPublic(mod) && hasNamedParams(method, requestParams))) {
return false;
}
Access classAccess = AnnotationUtil.get(
destination != null ? destination.getClass() : method
.getActualMethod().getDeclaringClass()).getAnnotation(
Access.class);
if (methodAccess == null) {
methodAccess = classAccess;
}
if (methodAccess == null) {
// New default: UNAVAILABLE!
return false;
}
if (methodAccess.value() == AccessType.UNAVAILABLE) {
return false;
}
if (methodAccess.value() == AccessType.PRIVATE) {
return auth != null ? auth.onAccess(
(String) requestParams.get(Sender.class),
methodAccess.tag()) : false;
}
if (methodAccess.value() == AccessType.SELF) {
return auth != null ? auth.isSelf(
(String) requestParams.get(Sender.class)) : false;
}
return true;
}
/**
* Test whether a method has named parameters
*
* @param annotatedMethod
* @param requestParams
* @return hasNamedParams
*/
private static boolean hasNamedParams(AnnotatedMethod method,
RequestParams requestParams) {
for (AnnotatedParam param : method.getParams()) {
boolean found = false;
for (Annotation a : param.getAnnotations()) {
if (requestParams != null && requestParams.has(a)) {
found = true;
break;
} else if (a instanceof Name) {
found = true;
break;
}
}
if (!found) {
return false;
}
}
return true;
}
/**
* Test if a parameter is required Reads the parameter annotation @Required.
* Returns True if the annotation is not provided.
*
* @param param
* @return required
*/
private static boolean isRequired(AnnotatedParam param) {
boolean required = true;
Required requiredAnnotation = param.getAnnotation(Required.class);
if (requiredAnnotation != null) {
required = requiredAnnotation.value();
}
return required;
}
/**
* Get the name of a parameter Reads the parameter annotation @Name. Returns
* null if the annotation is not provided.
*
* @param param
* @return name
*/
private static String getName(AnnotatedParam param) {
String name = null;
Name nameAnnotation = param.getAnnotation(Name.class);
if (nameAnnotation != null) {
name = nameAnnotation.value();
}
return name;
}
/**
* Find a request annotation in the given parameters Returns null if no
* system annotation is not found
*
* @param param
* @param requestParams
* @return annotation
*/
private static Annotation getRequestAnnotation(AnnotatedParam param,
RequestParams requestParams) {
for (Annotation annotation : param.getAnnotations()) {
if (requestParams != null && requestParams.has(annotation)) {
return annotation;
}
}
return null;
}
}