Social Graph API's "lookup" method

Contents

1. Introduction
2. URL format
3. Request Parameters
   1. Pretty Printing
   2. JSONP Callback
   3. Querying Node(s)
   4. Following me links
   5. Requesting Edges
4. Response Structure

Introduction

The lookup method gives you low-level access to the Social Graph API's underlying directed graph. It lets you list all the edges out of or into a given node.

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URL format

The lookup method is accessible with URLs like:

http://socialgraph.apis.google.com/lookup?<parameter 1>&<parameter 2>&<parameter n>

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Parameters

The follow is a summary of the available parameters:

Pretty-printing the output

To get started, the boolean pretty parameter enables pretty-printing of the JSON response. It will keep you sane while you're experimenting with the API.

Try opening this URL:

http://socialgraph.apis.google.com/lookup?pretty=1

What you'll see is the basic structure of all responses:

{
 "canonical_mapping": {
 },
 "nodes": {
 }
}

The first dictionary, canonical_mapping is a mapping of the things you asked for (in this case, nothing) to their canonical versions. The canonical version is important, as it's the key into the second dictionary, nodes. The nodes dictionary contains objects (dictionaries) for each node that was loaded. In this case, however, no data was requested so it is empty.

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Specifying a callback function

If you intend to use this API from JavaScript inside a browser, you'll need to use the callback parameter, specifying a callback function to run with the response object.

Example:

http://socialgraph.apis.google.com/lookup?pretty=1&callback=foo

Which results in:

foo({
 "canonical_mapping": {
 },
 "nodes": {
 }
});

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Querying Node(s)

The q parameter is a comma-separated list of nodes you'd like to load.

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Following me links

If you set the boolean fme parameter to 1 (or true), you signal that you're interested in loading not just the nodes represented in your q parameter, but also any nodes declared as "me" from the nodes you did request, recursively.

For example, imagine the following graph:

A ---> B ---> C
   me    me

... and your q parameter were A, and you set fme to true, all of A, B, and C will be returned.

Note, however, that nodes B and C will not show up in the response's canonical_mapping structure, as that's only for your q parameters. To find the keys in the response structure for B and C, you need to look at the value of A's claimed_nodes, which is an array of all nodes which are reachable by following only the directed me edges. In this case, you would see a response of:

{
 "canonical_mapping": {
  "A": "a"
 },
 "nodes": {
  "a": {
   "attributes": {},
   "claimed_nodes": [ "b", "c" ]
  },
  "b": {
   "attributes": {},
   "claimed_nodes": [ "c" ]
  },
  "c": {
   "attributes": {},
   "claimed_nodes": []
  }
 }
}

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Requesting Edges

The boolean edo parameter requests directed edges "out" (or originating) from each returned node and causes the nodes_referenced dictionary to be returned. For instance, for edges of type friend, these would be all the people who the node(s) declares as a public friend.

The boolean edi parameter requests directed edges "in" (arriving at) each returned node, and causes the nodes_referenced_by dictionary to be returned. For instance, for edges of type friend, these would be all the people who declare the node(s) as a public friend (often called "followers" or "fans").

Of course, all edges aren't of type friend. See the documentation on edge types for more information.

To demonstrate the edo and edi parameters, imagine the following graph:

A --------> B ---------> C
   friend     sibling 
              co-resident

If you did a query of q=A,B,C&edo=1&edi=1&pretty=1, you'd receive the following response:

{
 "canonical_mapping": {
  "A": "a"
  "B": "b"
  "C": "c"
 },
 "nodes": {
  "a": {
   "attributes": {},
   "nodes_referenced": {
    "b": {
     "types": [ "friend" ]
    }
   },
   "nodes_referenced_by": {
   },
  },
  "b": {
   "attributes": {},
   "nodes_referenced": {
    "c": {
     "types": [ "co-resident", "sibling" ]
    }
   },
   "nodes_referenced_by": {
    "a": {
     "types": [ "friend" ]
    }
   },
  },
  "c": {
   "attributes": {},
   "nodes_referenced": {
   },
   "nodes_referenced_by": {
    "b": {
     "types": [ "co-resident", "sibling" ]
    }
   },
  }
 }
}

Notice how the b node has populated dictionaries for both outgoing and incoming edges. From this response, you can learn the following:

• A declares B as a friend, but it's not reciprocal. You could say A is a "fan" of B, or A "follows" B, but not "A and B are friends"
• Likewise, B declares that C is his/her sibling and co-resident, but it's not reciprocal.

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Response Structure

The JSON response format, ignoring the optional callback, is structurally as follows:

• JSON Response dictionary, containing properties:
  • canonical_mapping: an dictionary (Object) mapping explicitly requested nodes (from the q parameter) to canonicalized URLs which also serve as the necessary lookup key into the response's nodes dictionary.
  • nodes: a dictionary from canonical URL to node objects. Note that this dictionary will contain both nodes requested explicitly with the query parameter, as well as nodes loaded implicitly as a result of following me edges when requested with the fme parameter. The implicitly loaded nodes are also keyed by their canonical URL, but you won't know their canonical URLs until you look at the explicitly requested nodes. Each returned node may have the following properties:
    • attributes: a dictionary of node attributes.
    • claimed_nodes: an array of URLs that this node claims to own, recursively. This is the set of nodes reachable via me edges, starting with this node. See the description of the fme parameter above. Note that this list of claimed URLs does not represent a strongly connected graph. If you need to compute the strongly connected subset, you need to look at all the claimed nodes' claimed_nodes properties as well. This property is only returned when fme is set.
    • unverified_claiming_nodes: an array of URLs that claim this node, but which are not in claimed_nodes. That is, it's the set of URLs with an inbound me edge, minus the set of URLs in claimed_nodes. You should lend no confidence to the information in this field. These people may be spammers, imposters, etc. This field is only returned as a convenience in hopes that a human might recognize one of their own accounts which they just haven't linked into their real graph. This field is only returned when all three of edo, edi, and fme are set.
    • nodes_referenced: when edo is set, this returns the nodes which node links to. The value is another object, keyed on canonicalized URL:
      • types: an array of edge types for this outbound edge
    • nodes_referenced_by: when edi is set, this returns the nodes which links to this node. The value is another object, keyed on canonicalized URL:
      • types: an array of edge types for this inbound edge

You might find it helpful to explore the example apps at left, especially the Parameter Playground to help you see the responses in action.

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