https://github.com/samdenty/cors-bypass
Bypass the browsers CORS restrictions, without needing to setup a server-side proxy.
https://github.com/samdenty/cors-bypass
Last synced: 6 months ago
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Bypass the browsers CORS restrictions, without needing to setup a server-side proxy.
- Host: GitHub
- URL: https://github.com/samdenty/cors-bypass
- Owner: samdenty
- Created: 2019-01-06T19:20:16.000Z (over 6 years ago)
- Default Branch: master
- Last Pushed: 2019-01-07T18:22:32.000Z (over 6 years ago)
- Last Synced: 2024-11-26T21:15:09.811Z (6 months ago)
- Language: TypeScript
- Homepage: https://cors-bypass.netlify.com
- Size: 144 KB
- Stars: 25
- Watchers: 4
- Forks: 4
- Open Issues: 0
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Metadata Files:
- Readme: README.md
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README
# cors-bypass
Bypass the browsers CORS restrictions, **without needing to setup a server-side proxy**. [Demo](https://cors-bypass.netlify.com/)
- Allows you to make HTTP requests from a HTTPS page
- 100% coverage for the [`WebSocket` API](https://developer.mozilla.org/en-US/docs/Web/API/WebSockets_API) spec
## How does this module work?
It uses [`postMessage`](https://developer.mozilla.org/en-US/docs/Web/API/Window/postMessage) to send cross-domain events, which is used to provide mock HTTP APIs (`fetch`, `WebSocket`, `XMLHTTPRequest` etc.). [Simplified version](https://stackoverflow.com/a/44943661/5269570)
## How do I use it
Theres three components to this module: the `Server`, `Adapter` and `Client`.
### Server
Simply serve a HTML file on a domain from which you want to **make requests from** (HTTP domain for example), with the following (use a bundler like [Webpack](https://webpack.js.org), [Parcel](https://parceljs.org) etc):
```typescript
import { Server } from 'cors-bypass'
const server = new Server()
```
Without a bundler
```html
```
### Adapter
Next you need a HTML file from the domain that **will make requests** (your web app's domain). The adapter is in control of forwarding requests from a client located on _any page of your site_, to the server (using a [`BroadcastChannel`](https://developer.mozilla.org/en-US/docs/Web/API/BroadcastChannel)).
```typescript
import { Adapter } from 'cors-bypass'
const adapter = new Adapter()
```
Without a bundler
```html
```
### Client
As long as the Adapter is running in a different tab (on the same domain as the client), you will be able to make requests.
```typescript
// Located somewhere on https://your-site.com
import * as BypassCors from 'cors-bypass'
const client = new BypassCors.Client()
await client.getServer() // null - no server connected yet
await client.openServerInNewTab({
serverUrl: 'http://random-domain.com/server.html',
adapterUrl: 'https://your-site.com/adapter.html'
})
await client.getServer() // { id: 123, url: 'http://random-domain.com/server.html' }
// Create a WebSocket (websocket is loaded in the server tab, but it's API is available on this page)
const ws = new BypassCors.WebSocket('ws://echo.websocket.org')
ws.onopen = () => ws.send('hello')
ws.onmessage = ({ data }) => console.log('received', data)
```
## Use cases
### HTTP requests for Offline PWAs
As using a Service Worker require HTTPS, it's impossible to connect to local devices which only support HTTP.
Using this module does requires the user to open an extra window, but it lets you bypass cors.