Rename Metadata URL to Context

We've been adding a lot of information into the metadata URL: the metadata base URL, the entity set, the derived type, the selected properties, ...

This requires clients to parse this string, taking away some of the simplicity of using transport formats for structured data (JSON, XML).

We could represent the metadata URL in parsed syntax:

JSON

• rename the odata.metadata annotation to odata.context
• make it an object with properties
  • url: string
  • set: string
  • type: string (qualified name, (relative) url, "$ref")
  • projection: array of selected properties as strings or objects, the latter having name-value pairs name, recursive, projection

Atom

• replace the metadata:metadata attribute with a metadata:context element
• structure is
  • url: xs:anyUri
  • set: SimpleIdentifier
  • type: string
  • projection: ...

No change to the odata.metadata=none | full | minimal in the json format parameter.

In the docs refer to the "odata context".

Example

metadata URL:
"odata.metadata":"http://host/service/$metadata#Employees/Sales.Manager(DirectReports+(FirstName,LastName))"

context object:
"odata.context":{
"url":"http://host/service/$metadata",
"set":"Employees",
"type":"Sales.Manager",
"projection":[
"*",

]
}