Notes on graph navigation

[tpetricek]

Assuming we have

• Yoda : hero
• Luke : hero
• Obi Wan : hero
• Darth Wader : enemy
• Tatooine : planet
• Dagobath : planet

And relations:

• Luke -(fights)-> Darth Wader
• Luke -(lives on)-> Tatooine

We are creating tree like this one:

starwars
  - hero
      - Luke
      - Yoda
  - planet
      - Tatooine
      - Dagobath

And if you select starwars.hero.Luke then you get sub-tree:

  - fights
      - Darth Wader
  - lives on
      - Tatooine

Different requests

/starwars -- list all types of nodes

[ { "name":"hero",
    "returns":{"kind":"nested","endpoint":"/nodes_of_type/hero"} },
  { "name":"planet",
    "returns":{"kind":"nested","endpoint":"/nodes_of_type/planet"} } ]

/starwars/nodes_of_type/ -- list all nodes of type

[ { "name":"Luke",
    "returns":{"kind":"nested","endpoint":"/links_from_node/1"} },
  { "name":"Yoda",
    "returns":{"kind":"nested","endpoint":"/links_from_node/2"} } ]

/starwars/links_from_node/
-- list all relations linking node with with something

[ { "name":"fights",
    "returns":{"kind":"nested","endpoint":"/linked_from_node/1/figthts" } },
  { "name":"lives on",
    "returns":{"kind":"nested","endpoint":"/linked_from_node/2/lives on"} } ]

/starwars/linked_from_node//
-- list all nodes connected to by relation

[ { "name":"Darth Wader",
    "returns":{"kind":"nested","endpoint":"/links_from_node/3" } }]

Eventually, we get to something like:

{ "name":"get properties",
  "returns":
    { "kind":"primitive",
      "type": {"name":"seq","params":[{"name":"tuple","params":["string","float"]}]},
      "endpoint":"/data" } }

We need to handle the following requests (here :thing is a variable):

• /starwars -- list all types of nodes
• /starwars/nodes_of_type/:type -- list all nodes of type
• /starwars/links_from_node/:node-id -- list all relations linking node with with something
• /starwars/linked_from_node/:node-id/:relation -- list all nodes connected to by relation