Read Write Resource Oriented Services

Design of Read/Write Resource-Oriented Services

How read/write resource oriented services are designed ?

The following steps are to be done to design a read/write resource-oriented service.

1. Figure out the dataset.
2. Split the dataset into resources.

3. For each resource.

   • Name the resource with a URI.
     • 3 basic rules to name the resources with URLS:
       • Use path variables to encode hierarchical relationship: parent/child.
       • Use punctuation characters to separate children: parent/child1;child2.
       • Use query variables to imply input to the resource: parent?child=child1.
   • Expose a subset of the uniform interface.
   • Design the representation accepted from the client.
   • Design the representation served to the client.
   • Integrate the resource with other resources using links and forms.
   • Consider the typical course of events: what’s supposed to happen?
   • Consider error conditions: what might go wrong?

4. Build matrix with resource types as rows, and operations as columns

   • Indicate what operations apply to which types
     • provide example URIs and discussion of what will happen
       • especially in the case of POST and PUT
         • POST: create resource
         • PUT: update resources
     • Two questions to help
       • Will clients be creating new resources of this type?
       • Who’s in charge of determining the new resource’s URI? Client or Server?

Issues: Authentication and Authorization

• Now that we are allowing a client to change stuff on our server, we need
  • Authentication: problem of tying a request to a user
  • Authorization: problem of determining which requests to let through for a given user
• HTTP provides mechanisms to enable this (HTTP Basic/Digest) and other web services roll their own (Amazon’s public/private key on subset of request)
• Another Issue: Privacy
  • Can’t transmit “private information” in the clear; need to use HTTPS
• Another Issue: Trust
  • How do you trust your client software to do the right thing?
    • Especially in today’s environment with malware becoming harder and harder to discern.