A JSON-RPC server with object synchronization based on JSON-Patch
npm install push-model
It is called a Push Model because it is intended to be used as part of a server-side MVC Model layer or MVVM ViewModel layer that requires the ability to push changes to clients.
The Model/ViewModel layer can handle JSON-RPC requests and return data directly to the requester, or it may choose to place data in a _model object_ that is published to interested clients. Harmony Proxy is used to detect subsequent changes to the data, which are published incrementally as JSON Patches.
javascript
const pm = require("push-model");
const server = require("http").createServer();
const model = {
//properties that client can subscribe to
prop1: ...,
prop2: ..., //RPC methods
method1: function(...args) {
...
return result; //or promise
},
method2: ...
};
pm.mount(server, "/path", model, acceptOrigins);
`
This creates an HTTP server and mounts on the specified route. Clients can send RPC requests to this route over either HTTP or WebSocket, which invoke the corresponding methods on the model. Return values are automatically sent back as JSON-RPC responses.
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The PUB/SUB mechanism is only available to WebSocket clients.##### SUB/UNSUB
Clients call SUB/UNSUB to start/stop observing changes to the model object. The
pointer parameter, a JSON Pointer, indicates which part of the model to observe.
`
SUB(pointer)
UNSUB(pointer)
##### PUB
Server calls PUB to notify clients of changes to the model. The
parameter holds an array of JSON Patches describing a series of changes that were made to the model.
`
SUB(patches)
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##### ErrorResponse
A return value of type ErrorResponse will be translated into a JSON-RPC error message.
return new pm.ErrorResponse(code, message, data);
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An MVC chat server that uses object synchronization to push chat messages to clients.
javascript
pm.mount(server, "/chat", {
//data
chatLog: [], //actions
sendChat: function(name, message) {
this.chatLog.push(name + ": " + message);
}
});
`
Examples
##### Running the Chat Example
Open a command prompt in the push-model directory and run:
npm install
node examples/chat/model.js
That will start the chat model on localhost:8080. Then open the file examples/chat/chat.html in two browser windows and start chatting!##### Running the Shared TodoList Example
Open a command prompt in the push-model directory and run:
npm install
node examples/sharedtodolist/model.js
Then open the file examples/sharedtodolist/todo.html in two or more browser windows. If you use Chrome, you must run a local web server because Chrome does not allow AJAX over file:// URL.##### Running the Messenger Example
npm install
node examples/messenger/model.js