OData V4 Service modules - InMemory Connector

Service OData v4 requests from an in memory data store.

Synopsis

The OData V4 InMemory Connector provides functionality to convert the varios types of OData segments into runnable JavaScript functions, that you can execute over an inmemory graph of objects.

In most cases servicing data from memory is not possible - in this case you can use the OData V4 MongoDB Connector

The InMemory connector can be safely used in IoT devices.

Potential usage scenarios

• Server: Create high speed, standard compliant data sharing apis
• Server: Use as a mock or swap-in for acceptance tests in place of the mongodb connector
• Client: use the OData syntax to define data queries or value returning expressions as strings (stored in a configuration) and compile and execute later as JS functions

Usage as server - TypeScript

 import { createFilter } from 'odata-v4-inmemory'

 //example request:  GET /api/products?$filter=category/id eq 5 or color eq 'Red'
 app.get("/api/products", (req: Request, res: Response) => {
   const data = getYourProductArray() //or similar :)
   const filterFn = createFilter(req.query.$filter)
   res.json(data.filter(filterFn))
 })

Usage ES5

 var createFilter = require('odata-v4-inmemory').createFilter

 app.get("/api/products", function(req, res) {
   var data = getYourProductArray() //or similar :)
   var filterFn = createFilter(req.query.$filter)
   res.json(data.filter(filterFn))
 })

Using as expression engine

 import { compileExpression } from 'odata-v4-inmemory'

 const expression = compileExpression("concat((Size add 12) mul 3,Name)")
 const item = {Size:1, Name:'Chai'}
 console.log(expression(item))
 >> 39Chai

Supported OData segments

For now $filter

Support for $select and $expand is next.

Supported $filter expressions

The OData v4 Parser layer supports 100% of the specification. The Connector is about 90% ready on filters. Except for date arithmetic, and geo.* everything is supported.

We are into creating a comprehensive feature availability chart for V1 release

✓ expression 5.1.1.6.3: null
✓ expression 5.1.1.6.1: NullValue eq null
✓ expression 5.1.1.6.1: duration'P12DT23H59M59.999999999999S'
✓ expression 5.1.1.6.1: A eq INF
✓ expression 5.1.1.6.1: A eq 0.31415926535897931e1
✓ expression 5.1.1.6.1: A add B eq hour(07:59:59.999)
✓ expression 5.1.1.6.2: ["a","b"]
✓ expression 5.1.1.1.1: 1 eq 1
✓ expression 5.1.1.1.1: null eq null
✓ expression 5.1.1.1.2: A ne 1
✓ expression 5.1.1.1.3: A gt 2
✓ expression 5.1.1.1.4: A ge 3
✓ expression 5.1.1.1.5: A lt 2
✓ expression 5.1.1.1.6: A le 2
✓ expression 5.1.1.2.3: -A eq 1
✓ expression: A
✓ expression: A/b
✓ expression: A/b eq 1
✓ expression: A/b eq A/b
✓ expression 5.1.1.3: (A/b eq B/a) or (B/c lt 4) and ((E add 2) gt B add A)
✓ expression 5.1.1.1.9: not A ne 1
- expression 5.1.1.1.10: A has enum'b
✓ expression 4.8: A/$count
✓ expression: A/$count eq 3
✓ expression: A le B
✓ expression: A ge B
✓ expression 5.1.1.1.7: A and B
✓ expression 5.1.1.1.8: A or B
✓ expression: (A and B)
✓ expression: A/$count gt 2 and A/$count lt 4
✓ expression: (A/$count gt 2) and A/$count lt 3
✓ expression 5.1.1.2.1: A add B
- expression 5.1.1.2.1: '2016-01-01' add 'P4DT15H'
- expression 5.1.1.2.1: '2016-01-01T12:00:00Z' add 'P4DT15H'
- expression 5.1.1.2.1: duration'P4DT15H' add duration'P4DT15H'
✓ expression 5.1.1.2.1: A sub B
- expression 5.1.1.2.1: '2016-01-01T12:00:00Z' sub 'P4DT15H'
✓ expression: 5 sub 10
✓ expression 5.1.1.2.4: A mul B
✓ expression 5.1.1.2.4: 5 mul 10
✓ expression 5.1.1.2.5: 10 div 3
✓ expression 5.1.1.2.5: (A mul B) div 10
✓ expression 5.1.1.2.6: (A mod B) div 10
✓ expression: A add 'B'
✓ expression: 'A' add 'B'
✓ expression: A/$count add B/$count eq 7
✓ expression: $it eq 5
✓ expression: true eq false
✓ expression: true eq false
✓ expression: A/all(i:i eq 1)
✓ expression: A/all(i:$it eq 1)
✓ expression 5.1.1.5.2: A/all(i: i/a eq 1)
✓ expression 5.1.1.5.1: A/any(i: i/a eq 1)
✓ expression 5.1.1.4.6: substring(A, 2) eq 'BC'
✓ expression: substring('ABC', D) eq 'BC'
✓ expression: substring('ABC', 2) eq 'BC'
✓ expression: A eq 1.5
✓ expression: A eq year(2016-01-01)
✓ expression 5.1.1.4.1: contains(A, 'BC')
✓ expression 5.1.1.4.2: endswith(A, 'CD')
✓ expression 5.1.1.4.3: startswith(A, 'CD')
✓ expression 5.1.1.4.4: length(A) eq 3
✓ expression 5.1.1.4.5: indexof(A, 'DE')
✓ expression 5.1.1.4.7: tolower(A) eq 'abc'
✓ expression 5.1.1.4.8: toupper(A) eq 'ABC'
✓ expression 5.1.1.4.9: trim(A) eq 'abc'
✓ expression 5.1.1.4.10: concat(A,B) eq 'fubar'
✓ expression 5.1.1.4.10: concat(A,concat(B,C)) eq 'fubardoh'
✓ expression 5.1.1.4.11: A eq year(2016-01-01T13:00Z)
✓ expression 5.1.1.4.12: A eq month(2016-01-01T13:00Z)
✓ expression 5.1.1.4.13: A eq day(2016-01-01T13:00Z)
✓ expression 5.1.1.4.14: A eq hour(2016-01-01T13:00Z)
✓ expression 5.1.1.4.15: A eq minute(2016-01-01T13:00Z)
✓ expression 5.1.1.4.16: A eq second(2016-01-01T13:00:02Z)
✓ expression 5.1.1.4.21: year(now())
✓ expression 5.1.1.4.22: year(maxdatetime())
✓ expression 5.1.1.4.23: year(mindatetime())
- expression 5.1.1.4.24: totalseconds(A)
✓ expression 5.1.1.4.25: round(A) eq 42
✓ expression 5.1.1.4.26: floor(A) eq 42
✓ expression 5.1.1.4.27: ceiling(A) eq 42
✓ expression 5.1.1.4.28: isof(Model.Order)
✓ expression 5.1.1.4.28: isof($it, Model.Order)
✓ expression 5.1.1.4.28: Orders/all(item: isof(item, Model.Order))
- expression 5.1.1.4.29: cast(A, Edm.String)
- expression 5.1.1.4.30: geo.distance(A, B)
- expression 5.1.1.4.31: geo.intersects(A, B)
- expression 5.1.1.4.31: geo.length(A)