## [PPWA](https://via.hypothes.is/https://gozala.hashbase.io/posts/Native%20talk.html)

### Setup

Application needs to to host a [static html file](https://github.com/Gozala/peerdium/blob/master/docs/index.html) to bootstrap itself off of IPFS network that embeds [lunet client][] implementation (or equivalent) and contain `meta` tag providing [IPFS][] path to an actual application resources.

<meta
  name="mount"
  content="/ipfs/QmYjtd61SyXU4aVSKWBrtDiXjHtpJVFCbvR7RgJ57BPZro/"
/>

<script
  type="module" async
  src="https://lunet.link/lunet/client.js">
</script>

Application also needs to host another [`lunet.js`] file that will be used by a [lunet client][] to setup a [service worker][] that will serve app resources from under the mounted IPFS path. In practice [`lunet.js`][] file just needs to import [lunet proxy][].

importScripts("https://lunet.link/lunet/proxy.js")

> That is necessary because [service worker][] can not be registered only from the URL that it will be serving.

### Data Flow

When application is loaded [lunet client][] will bootstrap things and then fetch resources from IPFS corresponding to the location (resolves path relative to mounting path). Then update document accordingly.

Below diagram illustrates flow through which browser fetches each resource.

App -> Proxy ServiceWorker:fetch
Note left of Proxy ServiceWorker:Realy thorugh client
Proxy ServiceWorker -> App:
App -> iframe:
iframe -> lunet: relay request
lunet -> SharedWorker: serve request
SharedWorker -> Daemon: /api/v0/cat
Daemon -> SharedWorker:
SharedWorker -> lunet:
lunet -> iframe:
iframe -> App:
App -> Proxy ServiceWorker:
Proxy ServiceWorker -> App:

Additonally proxy service worker also will relay request towards IPFS [Daemon REST API](https://docs.ipfs.io/reference/api/http/) that are targeted at `https://lunet.link/` host. That is also exactly how [peerdium example][] [publishes](https://github.com/Gozala/peerdium/blob/960422670399a76d5bbb9aff4f2c1cf704ebf0a9/static/js/editor.js#L97-L108) and [loads](https://github.com/Gozala/peerdium/blob/960422670399a76d5bbb9aff4f2c1cf704ebf0a9/static/js/editor.js#L110-L119) documents out of IPFS network.

> **Warning**: At the moment lunet will allow any embedder to read / write data into IPFS. In a future lunet (embedded in iframe) will obtain user consent before doing so.

[lunet client]:https://github.com/Gozala/lunet/blob/master/docs/lunet/client.js
[IPFS]:http://ipfs.io/
[service worker]:https://developer.mozilla.org/en-US/docs/Web/API/Service_Worker_API/Using_Service_Workers#Updating_your_service_worker
[`lunet.js`]:https://github.com/Gozala/peerdium/blob/master/docs/lunet.js
[lunet proxy]:https://github.com/Gozala/lunet/blob/master/docs/lunet/proxy.js
[peerdium example]:https://gozala.io/peerdium/