package com.almende.eve.rpc.jsonrpc;
import java.io.IOException;
import java.lang.annotation.Annotation;
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.List;
import java.util.Map;
import java.util.Set;
import java.util.HashSet;
import java.util.TreeMap;
import java.util.TreeSet;
import com.almende.eve.agent.annotation.AccessType;
import com.almende.eve.agent.annotation.Name;
import com.almende.eve.agent.annotation.Required;
import com.almende.eve.rpc.RequestParams;
import com.almende.eve.rpc.jsonrpc.jackson.JOM;
import com.almende.eve.agent.annotation.Access;
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.fasterxml.jackson.core.JsonGenerationException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.ObjectNode;
public class JSONRPC {
//static private Logger logger = Logger.getLogger(JSONRPC.class.getName());
// TODO: the integration with requestParams is quite a mess.
// 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
*/
static public String invoke (Object object, String request)
throws JsonGenerationException, JsonMappingException, IOException {
return invoke(object, request, null);
}
/**
* 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
*/
static public String invoke (Object object, String request,
RequestParams requestParams)
throws JsonGenerationException, JsonMappingException, IOException {
JSONRequest jsonRequest = null;
JSONResponse jsonResponse = null;
try {
jsonRequest = new JSONRequest(request);
jsonResponse = invoke(object, jsonRequest, requestParams);
}
catch (JSONRPCException err) {
jsonResponse = new JSONResponse(err);
}
return jsonResponse.toString();
}
/**
* Invoke a method on an object
* @param sender Sender url
* @param obj will be invoked on the given object
* @return
*/
static public JSONResponse invoke (Object object, JSONRequest request) {
return invoke(object, request, null);
}
/**
* 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
*/
static public JSONResponse invoke (Object object, JSONRequest request,
RequestParams requestParams) {
JSONResponse resp = new JSONResponse();
resp.setId(request.getId());
try {
AnnotatedMethod annotatedMethod = getMethod(object.getClass(),
request.getMethod(), requestParams);
if (annotatedMethod == null) {
throw new JSONRPCException(
JSONRPCException.CODE.METHOD_NOT_FOUND,
"Method '" + request.getMethod() + "' not found");
}
Method method = annotatedMethod.getActualMethod();
Object[] params = castParams(request.getParams(),
annotatedMethod.getParams(), requestParams);
Object result = method.invoke(object, params);
if (result == null) {
result = JOM.createNullNode();
}
resp.setResult(result);
}
catch (Exception err) {
if (err instanceof JSONRPCException) {
resp.setError((JSONRPCException) err);
}
else if (err.getCause() != null &&
err.getCause() instanceof JSONRPCException) {
resp.setError((JSONRPCException) err.getCause());
}
else {
JSONRPCException jsonError = new JSONRPCException(
JSONRPCException.CODE.INTERNAL_ERROR, getMessage(err));
// TODO: return useful, readable stacktrace
jsonError.setData(err);
resp.setError(jsonError);
err.printStackTrace(); // TODO: cleanup printing stacktrace
}
}
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
*/
static public List<String> validate (Class<?> c, RequestParams requestParams) {
List<String> errors = new ArrayList<String>();
Set<String> methodNames = new HashSet<String>();
AnnotatedClass ac = AnnotationUtil.get(c);
for (AnnotatedMethod method : ac.getMethods()) {
boolean available = isAvailable(method, requestParams);
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);
// each of the method parameters must have the @Name annotation
List<AnnotatedParam> params = method.getParams();
for(int i = 0; i < params.size(); i++){
List<Annotation> matches = new ArrayList<Annotation>();
for (Annotation a : params.get(i).getAnnotations()) {
if (requestParams != null && requestParams.has(a)) {
matches.add(a);
}
else if (a instanceof Name) {
matches.add(a);
}
}
if (matches.size() == 0) {
errors.add("Parameter " + i + " in public method '" + name +
"' is missing the @Name annotation, which is" +
" required for JSON-RPC.");
}
else if (matches.size() > 1) {
String str = "";
for (Annotation a : matches) {
str += a + " ";
}
errors.add("Parameter " + i + " in public method '" + name +
"' contains " + matches.size() + " annotations " +
"(" + str + "), but only one is allowed.");
}
}
}
}
return errors;
}
/**
* Describe all JSON-RPC methods of given class
* @param c The class to be described
* @param requestParams Optional request parameters.
* @param asJSON If true, the described methods will be in an easy
* to parse JSON structure. If false, the returned
* description will be in human readable format.
* @return
*/
public static List<Object> describe(Class<?> c, RequestParams requestParams,
Boolean asJSON) {
try {
Map<String, Object> methods = new TreeMap<String, Object>();
if (asJSON == null) {
asJSON = false;
}
AnnotatedClass annotatedClass = AnnotationUtil.get(c);
for (AnnotatedMethod method : annotatedClass.getMethods()) {
if (isAvailable(method, requestParams)) {
if (asJSON) {
// 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>();
desc.put("method", method.getName());
desc.put("params", descParams);
desc.put("result", result);
methods.put(method.getName(), desc);
}
else {
// format as string
String p = "";
for(AnnotatedParam param : method.getParams()){
if (getRequestAnnotation(param, requestParams) == null) {
String name = getName(param);
String type = typeToString(param.getGenericType());
if (!p.isEmpty()) {
p += ", ";
}
String ps = type + " " + name;
p += isRequired(param) ? ps : ("[" + ps + "]");
}
}
String desc = typeToString(method.getGenericReturnType()) +
" " + method.getName() + "(" + p + ")";
methods.put(method.getName(), desc);
}
}
}
// 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) {
e.printStackTrace();
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;
/*
// TODO: do some more professional reflection...
String s = c.getSimpleName();
// the following seems not to work
TypeVariable<?>[] types = c.getTypeParameters();
if (types.length > 0) {
s += "<";
for (int j = 0; j < types.length; j++) {
TypeVariable<?> jj = types[j];
s += jj.getName();
... not working
//s += types[j].getClass().getSimpleName();
}
s += ">";
}
*/
}
/**
* Retrieve a description of an error
* @param error
* @return message String with the error description of the cause
*/
static private 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 objectClass
* @param method
* @param requestParams
* @return methodType meta information on the method, or null if not found
*/
static private AnnotatedMethod getMethod(Class<?> objectClass, String method,
RequestParams requestParams) {
AnnotatedClass annotatedClass = AnnotationUtil.get(objectClass);
List<AnnotatedMethod> methods = annotatedClass.getMethods(method);
for (AnnotatedMethod m : methods) {
if (isAvailable(m, requestParams)) {
return m;
}
}
return null;
}
/**
* Cast a JSONArray or JSONObject params to the desired paramTypes
* @param params
* @param paramTypes
* @param requestParams
* @return
* @throws Exception
*/
static private Object[] castParams(Object params,
List<AnnotatedParam> annotatedParams,
RequestParams requestParams) throws Exception {
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 Exception(
"Required parameter '" + name + "' missing");
}
//else if (paramType.getSuperclass() == null) {
else if (p.getType().isPrimitive()) {
throw new Exception(
"Parameter '" + name + "' cannot be both optional and " +
"a primitive type (" + p.getType().getSimpleName() + ")");
}
else {
objects[i] = null;
}
}
}
else {
// this is a problem
throw new Exception("Name of parameter " + i + " not defined");
}
}
}
return objects;
}
}
else {
throw new Exception("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 = new AnnotationUtil.AnnotatedMethod(method);
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.");
}
}
return new JSONRequest(method.getName(), params);
}
/**
* Check whether a method is available for JSON-RPC calls. This is the
* case when it is public, has named parameters, and has no
* annotation @Access(UNAVAILABLE)
* @param annotatedMethod
* @param requestParams
* @return available
*/
private static boolean isAvailable(AnnotatedMethod method,
RequestParams requestParams) {
int mod = method.getActualMethod().getModifiers();
Access access = method.getAnnotation(Access.class);
return Modifier.isPublic(mod) &&
hasNamedParams(method, requestParams) &&
(access == null ||
(access.value() != AccessType.UNAVAILABLE &&
access.visible()));
}
/**
* 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;
}
}