@nmbrco/rimless
v0.2.4
Published
event base communication made easy with a promise-based API wrapping `postMessage`
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rimless
Rimless makes event based communication easy with a promise-based API wrapping postMessage. Works with both iframes and webworkers.
You can use rimless
to call remote procedures, exchange data or expose local functions with iframes/webworkers.
You can see it in action here https://au-re.github.io/rimless.
Installation
Rimless can be installed via npm.
$ npm i -S rimless
or from a CDN
<script src="https://unpkg.com/rimless/lib/rimless.min.js"></script>
Example Usage
in the host website
import { host } from "rimless";
const connection = await host.connect(iframe, {
myVariable: 12,
myFunction: (value) => `hello ${value}`,
});
// access variables on the iframe
console.log(connection.remote.myIframeVariable); // 42
// call remote procedures on the iframe
const result = await connection.remote.myIframeFunction("here");
console.log(result); // hello here
// close the connection
connection.close();
in the iframe
import { guest } from "rimless";
const connection = await guest.connect({
myIframeVariable: 42,
myIframeFunction: (value) => `hello ${value}`,
});
// access variables on the host
console.log(connection.remote.myVariable); // 12
// call remote procedures on host
const res = await connection.remote.myFunction("there");
console.log(res); // hello there
// close the connection
connection.close();
Getting Started
This is how you can connect your website to an iframe or webworker:
import { host } from "rimless";
const iframe = document.getElementById("myIframe");
const worker = new Worker("myWorker");
// connect to the iframe
host.connect(iframe);
// connect to the worker
host.connect(worker);
You also need to connect your iframe/webworker to the host website.
Usage from an iframe:
import { guest } from "rimless";
// connect to the parent website
guest.connect();
Usage from a webworker:
importScripts("https://unpkg.com/rimless/lib/rimless.min.js");
const { guest } = rimless;
// connect to the parent website
guest.connect();
Exposing an API
To do anything meaningful with this connection you need to provide a schema that defines the API of the host/iframe/webworker. Any serializeable values as well as functions are ok to use. In the example below the host website provides a function that will update its background color when invoked.
import { host } from "rimless";
const api = {
setColor: (color) => {
document.body.style.background = color;
},
};
const iframe = document.getElementById("myIframe");
host.connect(iframe, api);
The api schema must be passed on connection, the same applies to the iframe/webworker
.
Calling an RPC
With the host API exposed we can now invoke the remote procedure from the iframe.
import { guest } from "rimless";
// connect returns a promise that resolves in a connection object
// `connection.remote` contains the api you can invoke
guest.connect().then((connection) => {
connection.remote.setColor("#011627");
});
Closing a connection
Closing a connection will remove all event listeners that were registered.
import { guest } from "rimless";
guest.connect().then((connection) => {
connection.close();
});
How it Works
- The guest (iframe/webworker) sends a handshake request to the host with a schema describing its API
- The host confirms the handshake and returns a schema with its own API
Now both can make use of the APIs they have shared with each other, e.g.
- The guest requests
someAction
on the parent. - After verifying the origin, the parent will execute the function mapped to
someAction
and the result is returned to the guest.
Limitations
All parameters passed through postMessage
need to be serializeable. This applies also for all return values of the functions you expose.
// someFunction would return undefined when called in the remote.
const api = {
someFunction: () => () => {},
};
Alternatives
This library is inspired by Postmate and Penpal.
So why does this library exist?
- works with webworkers!
- does not create the iframe (easier to work with libraries like react)
- works with iframes using srcdoc
- works with multiple iframes from the same origin
API
Rimless exports two objects: host
and guest
.
host.connect
Connect your website to a "guest" (iframe/webworker).
host.connect(iframe, {
log: (value) => console.log(value)
});
| Name | Type | Description | Required |
| --- | --- | --- | --- |
| guest
| HTMLIFrameElement
or Worker
| Target of the connection | required |
| schema
| object
| schema of the api you want to expose | - |
| options
| object
| - | - |
guest.connect
Connect a "guest" to your website. The guest connection automatically happens based on the environment it is run.
guest.connect({
log: (value) => console.log(value)
});
| Name | Type | Description | Default |
| --- | --- | --- | --- |
| schema
| object
| schema of the api you want to expose | - |
| options
| object
| - | - |
Contributing
We use the airbnb style guide when writing javascript, with some minor modifications. Make sure eslint is installed and running before making changes, as it will ensure your coding style matches that of the project.
We use commitizen and
angular's conventional changelog
to enforce a consistent commit format. When writing commits, make sure you run npm run commit
instead of git commit
.