Understanding pump.io

What is it?

pump.io is an activity stream server

that models a social network

with a simple REST API.

Activities

• Record what happened
• Real things we do
• Digital things we do
  
• Subject-verb-object structure
  
• Extensible structure
  

Subject Verb Object

• Evan posted a photo.
• Karen liked Evan's photo.
• John created a project.
• Bill joined John's project.
• Bill added a task to John's project.
• Maria followed Bill.
• Maria added Bill to her "Friends" list.
• John updated his profile.
  

Custom activities

• Edward planted strawberries.
  
• Janet did a 15 minute workout on the elliptical machine.
• Bill ate a breakfast burrito at Celia's.
• Jennifer killed the Dragon King for 18,000 gold.
• Server 075 had a disk error.
  

Audience

• Who is the activity for?
• Determined by the program and the author
• Some "default"
• Only the audience can see the activity
  

Audience examples

• All Laura's followers
• John, Alison, and Frank
  
• People on Dennis's "Family" list
  
• Members of the "New Auditorium" project
• Everyone in the world
  

Streams

• Group activities together
• Organized around a theme
  
• In reverse chronological order (newest first)
  

Example streams

• The activities Bill did.
• The activities by people Bill follows.
• The activities shared with a group.
• The activities about an image.
• The activities sent directly to Josephine.
• The major activities that Jane did.
• The minor activities by people Karen follows.
  

Major? Minor?

• Separates "important" from "background" activities
  
• Major activities generally create new objects.
• Minor activities modify or respond to existing objects.
• Minor activities change the social graph.
  

REST API

• Consistent JSON representation
  
• Endpoints for each stream
• All streams are readable
• Some streams are writable
• Streams are filtered by audience
  

Representing objects

• Unique ID
• Object type
• Other information varies by type
  

{
     "id": "tag:social.example,2013:user:1481",
     "objectType": "person",
     "displayName": "Evan Prodromou",
     "url": "http://social.example/evanp",
     "image": {
          "url": "http://avatar.social.example/evanp.jpg"
     }
}

Representing activities

• Actor (is an object)
  
• Verb
• Object (is an object)
  
• Summary
  

{
   "id": "urn:uuid:85e80e20-cd1b-11e2-82f1-c8f73398600c",
   "actor": {     "id": "tag:social.example,2013:user:1481",
     "objectType": "person"   },
   "verb": "create",
   "object": {
        "id": "http://social.example/note/13",
        "objectType": "note",
        "content": "Hello, World"
   },
   "summary": "Evan created a note."
}

REST endpoints

• Inbox: stream of activities by people Alice follows (read-only)
  
• Outbox: stream of activities with Alice as the subject (read-write)
  
• Direct inbox: stream of activities with Alice as the audience (read-only)

Activity distribution

• Bill sends a new activity to his outbox endpoint
• pump.io distributes the activity to the right inbox streams based on the audience and the social graph
• Other users get the new activity in their inboxes
  

Social graph

• Who follows whom
• Who is on a contact list
• Who is a member of a group
• Determined by past activities
  

Social graph

• Dave follows Helen +
  
• Helen posts a photo =
  

• the post-photo activity is in Dave's inbox.

Accessing the social graph

• REST API endpoints
• Streams of objects (not activities)

Social graph examples

• All Deirdre's followers.
• Members of Stan's "Coworkers" list.
• Members of the "Softball Team" group.
  

What can I use it for?

• Web-based social network
• mobile social network
  
• activity streams for apps
• embedded activity
  

Learning more

• http://pump.io/
• http://activitystrea.ms/
• https://e14n.com/evan