DwebTransports
General transport library for Decentralized Web handles multiple underlying transports.
Background
This library is part of a general project at the Internet Archive (archive.org) to support the decentralized web.
Goals
- to allow a single API that can be used for most basic interactions with decentralized transports.
- to support multiple URLs, on different transports, so that the (current) underlying unreliability is hidden.
- to allow Internet Archive content to be made available decentralized.
Installation for developers in node / yarn
In your app's package.json file, add
"@internetarchive/dweb-transports": "latest",
then
yarn install
Installation for developers on browsers.
- Install node and npm or yarn
- Clone this repo and cd to it.
-
webpack --mode productonwill create dist/dweb_transports_bundle.js - Add
<SCRIPT type="text/javascript" src="dweb_transports_bundle.js"></SCRIPT>to your<HEAD>
Then code like this should work.
async function main(url) {
try {
// and if not found will use the defaulttransports specified here.
await DwebTransports.p_connect({
defaulttransports: ["HTTP","IPFS"], // Default transports if not specified
transports: searchparams.getAll("transport") // Allow override default from URL parameters
});
// Any code you want to run after connected to transports goes here.
} catch(err) {
console.log("App Error:", err);
alert(err.message);
}
}
var searchparams = new URL(window.location.href).searchParams;
To develop on dweb-transports
Clone this repo from github.
yarn install
Should pick up the dependencies.
- See WRITINGSHIMS.md to add your transport to the library.
- Or ARCHIVEINTEGRATION.md for allowing your transport to support Internet Archive content
Notes on implemntation
Implementation on HTTP (TransportHTTP.js)
The HTTP interface is pretty simple.
fetch or streams are straightforward HTTP GETs to a URL
Lists and Tables are implemented via append-only files on the HTTP server using URLs that contain hashes. “Add” appends to this file, “list” retrieves the file.
Listmonitor isn’t supported, and can’t really be as there is no open channel to the client.
Implementation on IPFS (TransportIPFS.js)
This section will only make sense if you understand something about IPFS.
See TransportIPFS.js in the repository for details for code.
IPFS has two Javascript versions, both of which currently implement only a subset of IPFS (JS-IPFS is missing IPNS, and JS-IPFS-API is missing pubsub). We are mostly using JS-IPFS because JS-IPFS-API creates a centralisation point of failure at a known HTTP host, and because JS-IPFS-API has issues connecting to a local IPFS peer because of some odd security choices by IPFS.
IPFS is initialized via creating a IPFS object with a configuration. We use the Websockets connctor since the alternative, but its got a single point of failure. WebRTC is an alternative but is seriously broken (crashes both chrome and firefox)
Blocks are stored and retrieved via ipfs.files.get and ipfs.files.add.
For lists and tables - see YJS which uses IPFS.
Issues with IPFS
Error feedback is a little fuzzy, generally you'll get a success code and then no data. So fallback to http fails.
There are issues with IPFS swarms that we haven’t been able to figure out about how to ensure that “put”ting to IPFS creates an object that can be read at all other browsers, and persists. See DT issue#2
Naming hasn’t been implemented in IPFS yet, partly because IPNS is not available in the JS-IPFS, and partly because IPNS has serious problems: (requirement to rebroadcast every 24 hours so not persistent; merkle tree so change at leaf changes top level; doesnt work in JS-IPFS;) We implemented naming outside of IPFS (in dweb-archivecontoller.Routing.js) to get it to work.
To install IPFS for Node (and this needs testing)
yarn add ipfs ipfs-http-client
This will get overridden by an update of dweb-mirror, so its probably you will want this as a dependency of whatever is using dweb-transports instead.
To use IPFS pass "IPFS" in during the "connect" step
Implementation on WebTorrent
WebTorrent implements the BitTorrent protocol in the browser. It will work for retrieval of objects and currently has the fastest/most-reliable stream interface.
We also have a modified Seeder/Tracker which are currently (Sept2018) in testing on our gateway.
To install WebTorrent for Node (and this needs testing)
yarn add webtorrent
This will get overridden by an update of dweb-mirror, so its probably you will want this as a dependency of whatever is using dweb-transports instead.
To use WebTorrent pass "WEBTORRENT" in during the "connect" step
Implementation on YJS (TransportYJS.js)
YJS implements a decentralized database over a number of transports including IPFS. It supports several modes of which we only use “Arrays” to implement append-only logs and "Map" to implement key-value tables.
There is no authentication built into YJS but If using via the higher level CommonList (CL) object, the authentication isnt required since the CL will validate anything sent.
To install YJS for Node (and this needs testing)
yarn add yjs
This will get overridden by an update of dweb-mirror, so its probably you will want this as a dependency of whatever is using dweb-transports instead.
To use YJS pass "YJS" in during the "connect" step
Implementation on GUN
GUN implements a decentralized database and we have mostly migrated to it (from YJS) because there is some support and an active team.
Our tables and Lists are mapped as JSON objects inside GUN nodes due to some limitations in GUN's architecture for multi-level objects.
Still (as of Sept2018) working on Authentiction, and some reliability/bug issues.
To install GUN for Node (and this needs testing)
yarn add gun
This will get overridden by an update of dweb-mirror, so its probably you will want this as a dependency of whatever is using dweb-transports instead.
To use GUN pass "GUN" in during the "connect" step
Implementation on WOLK
WOLK has implemented and maintain there own shim which is part of dweb-transports
To install WOLK for Node (and this needs testing)
yarn add "git://github.com/wolkdb/wolkjs.git#master"
This will get overridden by an update of dweb-mirror, so its probably you will want this as a dependency of whatever is using dweb-transports instead.
To use WOLK pass "WOLK" in during the "connect" step
Implementation on FLUENCE
FLUENCE has implemented and maintain there own shim which is part of dweb-transports
To install FLUENCE for Node (and this needs testing)
yarn add fluence
This will get overridden by an update of dweb-mirror, so its probably you will want this as a dependency of whatever is using dweb-transports instead.
To use FLUENCE pass "FLUENCE" in during the "connect" step
Implementation of ContentHash
We have a simple Contenthash store/fetch that supports lists and key-value databases, and knows about retrieving content by sha1 hash from the Archive
No installation is required - it builds on the HTTP transport
To use, pass "HASH" in during the "connect" step
See also
See example_block.html for an example of connecting, storing and retrieving.
See API.md for the detailed API.
See Dweb document index for a list of the repos that make up the Internet Archive's Dweb project, and an index of other documents.
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