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Core Concepts

Before building with SolidOS, understand these foundational concepts.

Solid Pods​

A pod (Personal Online Datastore) is where your data lives.

https://alice.solidcommunity.net/
├── profile/
│   └── card#me          ← WebID (identity)
├── public/              ← Anyone can read
├── private/             ← Only you can access
├── contacts/
│   ├── alice.ttl
│   └── bob.ttl
└── settings/
    └── prefs.ttl

Key properties:

  • You own it — your data, your control
  • ACL protected — fine-grained access control
  • Linked Data — everything connects via URIs
  • Protocol-based — any compliant server works

RDF & Linked Data​

Solid uses RDF (Resource Description Framework) — data as triples:

# Subject → Predicate → Object

<#me> a foaf:Person ;
    foaf:name "Alice" ;
    foaf:knows <https://bob.example.com/profile/card#me> .

Why RDF?

  • Universal identifiers — URIs for everything
  • Vocabularies — shared meaning (foaf:Person, vcard:email)
  • Linking — connect data across pods
  • Queryable — SPARQL for complex queries

Common Vocabularies​

PrefixVocabularyUsed For
foaf:Friend of a FriendPeople, social
vcard:vCardContacts
schema:Schema.orgGeneral
solid:SolidSolid-specific
acl:Web Access ControlPermissions

WebID​

Your WebID is your identity on the decentralized web:

https://alice.solidcommunity.net/profile/card#me

It's a URI that:

  • Identifies you uniquely
  • Points to your profile document
  • Can be dereferenced (fetched) to learn about you
  • Uses the #me fragment convention

The Pane System​

SolidOS renders data through panes — specialized UI components.

How Panes Work​

// Each pane declares what it can handle
const contactPane = {
  name: 'contact',

  // "Can you render this resource?"
  label: (subject, context) => {
    if (subject.hasType(vcard('Individual'))) {
      return "Contact"  // Yes! Return a label
    }
    return null  // No, pass to next pane
  },

  // "Render it!"
  render: (subject, dom, context) => {
    const div = dom.createElement('div')
    // Build the UI...
    return div
  }
}

Pane Selection​

When rendering a resource, SolidOS:

  1. Queries all registered panes
  2. Each pane returns a label (or null)
  3. Most specific pane wins
  4. Falls back to generic pane if none match
Resource: /contacts/alice.ttl (type: vcard:Individual)

Panes consulted:
  ✓ contacts-pane    → "Contact"     (specific, wins!)
  ✓ generic-pane     → "Data"        (fallback)
  ✗ chat-pane        → null          (can't handle)
  ✗ meeting-pane     → null          (can't handle)

The Store​

SolidOS uses rdflib.js to manage RDF data in memory:

import { store } from 'solid-logic'

// Fetch data into the store
await store.fetcher.load('https://alice.example/profile/card')

// Query the store
const name = store.any(
  namedNode('https://alice.example/profile/card#me'),
  foaf('name'),
  null
)

// Update the store
store.add(
  namedNode('https://alice.example/profile/card#me'),
  foaf('nick'),
  literal('Ali')
)

// Write back to pod
await store.updater.update([], [/* statements */])

Authentication​

SolidOS handles authentication via Solid-OIDC:

import { authn } from 'solid-logic'

// Check current user
const webId = authn.currentUser()

// Login
await authn.login()

// Logout
await authn.logout()

Access Control​

Solid uses Web Access Control (WAC) for permissions:

# .acl file
<#authorization>
    a acl:Authorization ;
    acl:agent <https://alice.example/profile/card#me> ;
    acl:accessTo <./document.ttl> ;
    acl:mode acl:Read, acl:Write .

Modes:

  • acl:Read — view the resource
  • acl:Write — modify the resource
  • acl:Append — add to (but not modify)
  • acl:Control — manage permissions

Next Steps​