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Solid Comment

A simple Solid application meant to read and write comments into users’ pods. This application is only the gateway to Solid and still needs a storing mechanism in a parent application – meaning your application will import this library, which will allow the communication with Solid, but your application still needs to hold a reference where to find the actual comment.


  • The app needs control access, there needs to be in the trust applications section with full access.


  1. Install Solid Comment
npm i solid-comment
  1. Import the library into your project
// const SolidComment = require("solid-comment")
import SolidComment from "solid-comment"
  1. Configuration
  • solidCommentId: is the unique identifier for the specific instance this module is loaded. This will always have to be unique, otherwise it will override/write to other existing directories.
  • eventVisibility: decides if the comments can be discovered without the direct link.
  • serverStorageEndpointUrl: is the endpoint where the application implementing this module will persist references to the comments that have been posted. This endpoint will receive a JSON object with a url key and its value the URL to the comment. No more information is needed nor should be stored.
const solidComment = new SolidComment({
    solidCommentId: "sc-development-private-event-1",
    eventVisibility: "private",
    serverStorageEndpointUrl: "https://server-where-comment-urls-are-persisted"
  1. Initialize application

This will render all the components as soon as the DOM is completely ready. This is important as the components need elements from the DOM to attach to. The application will also check for a session, this is needed for the authentication with a Solid identity provider.

  1. Pass comment URLs to application

If the comments cannot be retrieved immediately on page render, they can be asynchronously fetched and passed to the application. SolidComment expects a list of strings with the URL to a single comment.

// these should be ["url-to-comment-1", "url-to-comment-2", …]


  1. Install solid-comment in Indico
npm i solid-comment
  1. Import library in the JavaScript files where it is needed
// indico/modules/events/client/js/display.js

import { SolidComment } from 'solid-comment'
  1. Make sure axiosIndico is bound to window.indicoAxios
import {indicoAxios} from 'indico/utils/axios';
// …
function bindIndicoAxiosToWindow() {
  window.indicoAxios = indicoAxios;
// …
  1. Add HTML and JavaScript to initialize solid-comment
<!-- indico/modules/events/templates/display/indico/meeting.html -->
<main class="solid-comment">
    <!-- paste content of src/index.html -->

  function pythonBooleanToJS(str) {
      return str === 'True'

  window.onload = () => {
      const isEventProtected = pythonBooleanToJS('{{ event.is_protected }}');
      const eventVisibility = isEventProtected ? "private" : "public";
      const eventId = '{{ }}'
      const solidCommentId = `sc-indico-meeting-${eventVisibility}-${eventId}`;
      const serverUrl = `${eventId}/solid-comments`
      const solidComment = new SolidComment({
          solidCommentId: solidCommentId,
          eventVisibility: eventVisibility,
          serverStorageEndpointUrl: serverUrl,
          appUrl: window.location.href.split('?')[0]

      async function main() {
          await solidComment.initApp()
          await fetch(serverUrl)
              .then(response => response.json())
              .then(data => solidComment.setComments(data))

Extra HTTP Client

If your application holding the references to the comments requires extra configuration to enable communication with the storage endpoint, the setAppClient method in the SolidComment class sets a passed in client, which will then be used to GET and POST to the provided storage endpoint.

// const solidComment = new SolidComment({ … })
// Indico example:
// solidComment.setAppClient(window.indicoAxios)


  1. Clone the repository
$ git clone
$ cd solid-comment
  1. Install dependencies
$ npm ci
  1. Run webpack development server
$ npm start
  1. Copy index.html into dist/ directory
$ cp src/index.html dist/index.html
  1. Start the JSON server
$ npm run json-server # $ json-server db.json -p 3001

Design Choices

  • This library stores each comment in a single file. Also, will the parent application implementing this library hold the reference URL to each comment. This enables the easiest possibility to add a pagination feature and thus improve performance by only loading the necessary comments.
  • If a comment fails to be fetch from the by the server (Indico) persisted list of references to the comment, it will simply show a “Comment is unavailable.” notice in the interface.