/
jsonrpc.js
114 lines (99 loc) · 3.11 KB
/
jsonrpc.js
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class JSONRPC {
constructor () {
this._requestID = 0;
this._openRequests = {};
}
/**
* Make an RPC request and retrieve the result.
* @param {string} method - the remote method to call.
* @param {object} params - the parameters to pass to the remote method.
* @returns {Promise} - a promise for the result of the call.
*/
sendRemoteRequest (method, params) {
const requestID = this._requestID++;
const promise = new Promise((resolve, reject) => {
this._openRequests[requestID] = {resolve, reject};
});
this._sendRequest(method, params, requestID);
return promise;
}
/**
* Make an RPC notification with no expectation of a result or callback.
* @param {string} method - the remote method to call.
* @param {object} params - the parameters to pass to the remote method.
*/
sendRemoteNotification (method, params) {
this._sendRequest(method, params);
}
/**
* Handle an RPC request from remote, should return a result or Promise for result, if appropriate.
* @param {string} method - the method requested by the remote caller.
* @param {object} params - the parameters sent with the remote caller's request.
*/
didReceiveCall (/* method , params */) {
throw new Error('Must override didReceiveCall');
}
_sendMessage (/* jsonMessageObject */) {
throw new Error('Must override _sendMessage');
}
_sendRequest (method, params, id) {
const request = {
jsonrpc: '2.0',
method,
params
};
if (id !== null) {
request.id = id;
}
this._sendMessage(request);
}
_handleMessage (json) {
if (json.jsonrpc !== '2.0') {
throw new Error(`Bad or missing JSON-RPC version in message: ${json}`);
}
if (json.hasOwnProperty('method')) {
this._handleRequest(json);
} else {
this._handleResponse(json);
}
}
_sendResponse (id, result, error) {
const response = {
jsonrpc: '2.0',
id
};
if (error) {
response.error = error;
} else {
response.result = result || null;
}
this._sendMessage(response);
}
_handleResponse (json) {
const {result, error, id} = json;
const openRequest = this._openRequests[id];
delete this._openRequests[id];
if (openRequest) {
if (error) {
openRequest.reject(error);
} else {
openRequest.resolve(result);
}
}
}
_handleRequest (json) {
const {method, params, id} = json;
const rawResult = this.didReceiveCall(method, params);
if (id) {
Promise.resolve(rawResult).then(
result => {
this._sendResponse(id, result);
},
error => {
this._sendResponse(id, null, error);
}
);
}
}
}
module.exports = JSONRPC;