Subsumption

subsumption : The act of subsuming.

subsuming : to include or place within something larger or more comprehensive : encompass as a subordinate or component element (red, green, and yellow are subsumed under the term “color”).

Metadata in URIs

URIs can contain metadata: http://www.mesonet.info/data/q/5/n/768/2014-11-04T06:00:00Z

• 5 is the degree size of the quadrangle
• 768 is the sequence number of the quadrangle
• 2014-11-04T06:00:00Z is the start of the time period.

Subsumption in URI Resolution

These URIs subsume and maintain information via relative resolution:

• Subset: n/768/2014-11-04T06:00:00Z
  base http://www.mesonet.info/data/q/5/2014-11-04T06:00:00Z
• Next period: 2014-11-04T06:30:00Z
  base http://www.mesonet.info/data/q/5/n/768/2014-11-04T06:00:00Z
• Nearby: ../769/2014-11-04T06:00:00Z
  base http://www.mesonet.info/data/q/5/n/768/2014-11-04T06:00:00Z

JavaScript Activity: Use the URL class to resolve these URIs.

Query Parameters

Query parameters can contain:

• metadata data
• essential input (the username/id)
• format and control options
• actual queries!

They are equally valid alternatives to path segments?

How do you choose?

• Does the information object need to be a resource?
• Do you need to perform operations on a resource or its subresources?
• Is linking and URI resolution important (i.e., maybe subsumption is important)?
• Is the scale of data such that individual resources might become unwise?

Activity: Service design with a Node.js and MongoDB.