A standalone universal viewer & verifier for blockcerts credentials
The component is developed with Polymer 3. To use the component in your project, install it via:
npm i @blockcerts/blockcerts-verifier
If your project does not require support for IE11, you can use the following build:
<script src="node_modules/@blockcerts/blockcerts-verifier/dist/main.js"></script>
<blockcerts-verifier></blockcerts-verifier>
Chrome will support natively the code, but for Firefox, Safari, MS Edge (Opera and Brave), you will need to add the webcomponent loader before:
<script src="node_modules/@webcomponents/webcomponentsjs/webcomponents-loader.js"></script>
If your project requires support for IE11, you will need to use the ie11 build:
<script src="node_modules/@webcomponents/webcomponentsjs/custom-elements-es5-adapter.js"></script>
<script src="node_modules/@webcomponents/webcomponentsjs/webcomponents-loader.js"></script>
<script src="node_modules/@blockcerts/blockcerts-verifier/dist/ie11.js"></script>
Please note that because this is transpiled to ES5, the custom-elements-es5-adapter code is required for it to work properly in more modern browsers.
Have a look at the Demo Pages to see examples of the usage
By the default, the component will:
- Display a Blockcerts record in
card
mode (concise information) - Will allow verification of a Blockcerts Record
- Enables auto-verification (verification as the record is loaded)
The component will understand the following options:
-
allow-download
: (Boolean. default:false
). Enables the download of the record. At this moment only records provided by Learning Machine are downloadable.Example:
<blockcerts-verifier allow-download></blockcerts-verifier>
-
allow-social-share
: (Boolean. default:false
). Allows sharing the record on the social networks (LinkedIn, Facebook and Twitter).Example:
<blockcerts-verifier allow-social-share></blockcerts-verifier>
-
disable-auto-verify
: (Boolean. default:false
). Disables starting automatically the verification sequence as the record is loaded.Example:
<blockcerts-verifier disable-auto-verify></blockcerts-verifier>
-
disable-verify
: (Boolean. default:false
). Disables verification of the record altogether.Example:
<blockcerts-verifier disable-verify></blockcerts-verifier>
-
display-mode
: (String, oneOf('card', 'full', 'fullscreen'). default:card
). Changes the display of a record.card
will be a concise summary of the record with a link to the full record.full
will show the actual record as designed by the emitter.fullscreen
will display a two-column overlay (in desktop) that takes the window dimensions. The certificate displays similar asfull
. NOTA: only works for certificates that have adisplayHTML
property.
Example:
<blockcerts-verifier display-mode="full"></blockcerts-verifier>
-
show-metadata
: (Boolean. default:false
). Enables showing the metadata of a record.Example:
<blockcerts-verifier show-metadata></blockcerts-verifier>
-
src
: (String. default:''
). Allows loading an initial record with no further actions required.src
can be either an absolute URL, or a relative path.Example:
<blockcerts-verifier src='../fixtures/valid-certificate-example.json'></blockcerts-verifier>
-
theme
: (String. default:'bright'
). Adapts to the background of the page that hosts the component. If the component is displayed on a dark background, you should use thedark
option. If it's bright, then use thebright
option.Example:
<blockcerts-verifier theme='dark'></blockcerts-verifier>
-
locale: (String. defaults to:
'auto'
, if language code not recognized will default to English (en
)). Viewsrc/i18n/lang
to see the list of supported languages. Contributions welcome.Example:
<blockcerts-verifier locale='fr'></blockcerts-verifier>
The component will emit events on different moment of the certificate life cycle.
To subscribe and track these events you should add on your consumer page event listeners on the window
object.
See the event demo page for a working example.
The information is communicated via the detail
key of the event.
Supported Events:
-
certificate-load
Triggered when a certificate has been loaded into the component. Returns:
- the
certificateDefinition
(object) on which the action was called.
- the
-
certificate-verify
Triggered when the verification process of a certificate is started. Returns:
- the
certificateDefinition
(object) on which the action was called.
- the
-
certificate-share
Triggered when a social network link is clicked. Returns:
- the
certificateDefinition
(object) on which the action was called. - the
socialNetwork
(string) to which the record was shared.
- the
npm run start
Will make the demo page available on http://localhost:8081/demo/.
The sanitizer
is used in order to protect against malicious certificates that could hold XSS attacks.
It is an overlay of the xss library, since at times, you might want to be able to configure or adapt the whitelist to your own needs.
To modify it, you should edit the sanitizer/index.js
file.
More specifically if you wish to whitelist some CSS properties, add them to the object whiteListedCssProperties
.
npm run build:sanitizer
This will generate the sanitizer.js
file, which is then used by the application and the tests.
If you want to work on the sanitizer in watch mode (and auto-generate your changes), use the following command:
npm run build:sanitizer -- -w
npm run test:application
NOTE: application must be started to run the tests, or at the very least the mock-server via the npm run start:mock-server
(automatically included in the npm run start
command).
watch mode
npm run test:application:watch
npm run test:components
"watch" mode
npm run test:components:persist
Will allow refreshing the test page: http://localhost:8000/components/blockcerts-verifier/generated-index.html?cli_browser_id=0
The npm run start
command will also start a SASS compiler watcher, which means that any stylesheet within the components
folder will be transpiled to a polymer component that can be reused within another component. ie:
import CSS from './_components.button-css';
[...]
_render () {
return html`${CSS}[...]`
}
To reduce the amount of code duplication, and following the ITCSS philosophy, you may need to import some of the shared-styles in your component. To do so, in your component's SASS file, add the following instruction:
/* in _components.my-component.sass */
@import '../../../shared-styles/objects.text';
[...component styles]
@import '../../../shared-styles/utils.a11y';
Please note that the SASS watcher does not observe changes in the shared styles folder, and will not automatically recompile any consumer stylesheet. You will have to recompile them yourselves (TODO: improve DevX here).
Please have a look through the ADR documentation to get more context around the architecture and the ways of developing a component.