Dapps¶

In galacteek, dapps (also called icapsules) are written in QML, and can also take advantage of traditional web interfaces thanks to the QML integration with QtWebEngine (meaning you can write hybrid applications).

Capsules are deployed to IPFS and are referenced in the capsules registry. The capsules and the registry are defined as YAML-LD, and they are then turned into RDF.

Hello world example¶

This is an Hello world app, but we display the Content ID of the text, and not the text itself. Here we import the gforce capsule.

This small example stores the content Hello world in IPFS and shows the IPFS hash (CID) in a text field. The full program lets you type in some text and see what the corresponding CID for the text is.

import QtQuick 2.2
import GForce 1.0
import GForce.ipfs 1.0
import GForce.forms 1.0

GEmbeddedDapp {
  IpfsOperator {
    id: ipfsop
  }

  IText {
    id: helloCid
    color: 'red'
    font.pixelSize: 20
  }

  Connections {
    target: ipfsop

    function onOpDone(opid, result) {
      helloCid.text = result.Hash
    }
  }

  Component.onCompleted: {
    let rid = ipfsop.addStr('Hello world')
  }
}

The IpfsOperator object performs operations in IPFS in an asynchronous manner, so that the QML UI is not blocked.

Write the manifest¶

You'll need to write a manifest for the application. The manifest should be named manifest.yaml and is written as YAML-LD.

The manifest must have the following properties:

id: This is the uri of the capsule manifest and it must be unique. The URN namespace (the first part after urn:) can be anything you want (doesn't need to be glk)
capsuleType: the type of capsule. Possible values are: dapp-qml, lib-qml
iconIpfsPath: the IPFS CID/path of the dapp's icon
description
latest: uri of the latest release

The releases section of the manifest should list the capsule releases. The id of your release must contain a valid version at the end of the urn::

urn:glk:dapps:examples:helloworld:1.0.1

The dependencies list can include version numbers or use the latest query::

depends:
  - urn:glk:libs:qml:somelib:1.0.0
  - urn:glk:libs:qml:gforce?=version=latest

A capsule contains one or more components. The definition of each component should contain:

id: This is the uri of the component
icapsule: This is the uri of the capsule it's bound to
sourceType: Where to load the capsule from: local or ipfs
fsPath: If you're developing your dapp locally, put the path of the component here (and use a local sourceType)
cid: The CID of the tar-gzipped component
qmlEntryPoint: If your capsule is a dapp, this is the filename of the QML code that will be executed when your dapp is run.

Here's the generated manifest.

'@type': ICapsuleManifest

name: helloworld
id: urn:glk:dapps:examples:helloworld
uri: urn:glk:dapps:examples:helloworld
capsuleType: dapp-qml
iconIpfsPath: bafkreigkcazy7umh3dv7c2arwrbs5ni5t4qqfm6c5ybpbiekyjmzsiqsuq
description: Hello world dapp example

latest: urn:glk:dapps:examples:helloworld:1.0.4
stable: urn:glk:dapps:examples:helloworld:1.0.4

releases:
- '@type': ICapsule
  id: urn:glk:dapps:examples:helloworld:1.0.4
  manifest: urn:glk:dapps:examples:helloworld

  depends:
  - urn:glk:libs:qml:gforce?=version=latest

  usesComponent:
  - '@type': ICapsuleComponent
    id: urn:glk:dapps:examples:helloworld:1.0.4#core
    icapsule: urn:glk:dapps:examples:helloworld:1.0.4
    sourceType: ipfs
    cid: bafkreidkt36o655ru5nuiunubtnfntjlxka7nxukj2blxlxpnxnb2nuuxm
    qmlEntryPoint: HelloWorld.qml

You can checkout the git repository here for the complete dapp.

Test your dapp¶

You will need to store the manifest in a local registry. In your home directory, create a file called icapsule-registry-dev-purple.yaml (purple is the default registry branch) and store your manifest:

'@context':
  '@vocab': 'ips://galacteek.ld/'

'@type': 'ICapsulesRegistry'

id: urn:glk:icapregs:local:myregistry
revision: 1

manifests:
  - '@type': ICapsuleManifest
    your manifest here ...

Restart galacteek and you should see all your capsules in the dapps workspace.

Web example¶

This example shows how to embed a webengine widget to interact with the dweb. DWebView can access the same protocols as the browser tabs in galacteek.

import QtQuick 2.2
import GForce 1.0
import GForce.ipfs 1.0

GEmbeddedDapp {
  id: dapp

  DWebView {
    id: dwebView

    url: 'ipfs://ipfs.io'
  }
}