angular-odata documentation

Resources

A resource describes a URL of the OData service: its path segments and its query options. You build resources with ODataClient (or with a service) and then call methods that send requests. Every request method returns an Observable.

The examples in this chapter use the TripPin sample service, as the demo application does.

Entity sets

Example :
import { firstValueFrom } from 'rxjs';

const airports = client.entitySet<Airport>('Airports');

// GET Airports
const { entities } = await firstValueFrom(airports.fetch());

// GET Airports?$count=true
const { annots } = await firstValueFrom(airports.fetch({ withCount: true }));
console.log(annots.count);

// GET Airports/$count
const count = await firstValueFrom(airports.count().fetch());

// GET Airports?$top=1
const { entity: first } = await firstValueFrom(airports.fetchOne());

// Fetch pages until there are at least 4 airports
const { entities: four } = await firstValueFrom(airports.fetchMany(4));

// Follow every next link and return all the airports
const { entities: all } = await firstValueFrom(airports.fetchAll());

fetch() emits { entities, annots }. annots holds the annotations of the response: count, skip and skiptoken (from the next link), etag, and so on.

Changing and copying resources

query() changes the resource it is called on. Call clone() first to keep the original:

Example :
const unitedStates = airports
  .clone()
  .query((q) => q.filter(({ e, t }) => e().eq(t.Location.City.CountryRegion, 'United States')));

airports.query((q) => q.filter(({ e, t }) => e().eq(t.Location.City.Region, 'California')));
airports.query((q) => q.filter().clear());

Entities

Pass the key to entity(). Use an object for compound keys, or to name the key property:

Example :
const cyyz = client.entitySet<Airport>('Airports').entity('CYYZ');
const russell = client.entitySet<Person>('People').entity({ UserName: 'russellwhyte' });

cyyz.fetch().subscribe(({ entity, annots }) => console.log(entity, annots.etag));
cyyz.fetchEntity().subscribe((airport) => {});

russell.update(person); // PUT
russell.modify({ FirstName: 'Russell' }); // PATCH
russell.destroy(); // DELETE

Send the entity ETag with the etag option to use optimistic concurrency: russell.modify(changes, { etag: annots.etag }).

Navigation properties and properties

Example :
const trips = russell.navigationProperty<Trip>('Trips');
trips.fetch().subscribe(({ entities }) => {});
trips
  .entity(0)
  .fetch()
  .subscribe(({ entity }) => {});

// $ref
russell.navigationProperty<Person>('Friends').reference();

// Single property value
russell
  .property<string>('FirstName')
  .fetchProperty()
  .subscribe((value) => {});

Media

Media entities, such as TripPin photos, expose their content with media():

Example :
client
  .entitySet<Photo>('Photos')
  .entity(person.Photo)
  .media()
  .fetchBlob()
  .subscribe((blob) => (image.src = URL.createObjectURL(blob)));

Functions and actions

Unbound callables are built from the client. Bound callables are built from the resource they are bound to.

Example :
// Unbound function
client
  .function<{ lat: number; lon: number }, Airport>('GetNearestAirport')
  .callEntity({ lat: 33, lon: -118 })
  .subscribe((airport) => {});

// Function bound to an entity
russell
  .function<{ userName: string }, Trip[]>(
    'Microsoft.OData.SampleService.Models.TripPin.GetFriendsTrips',
  )
  .callEntities({ userName: 'ronaldmundy' })
  .subscribe((trips) => {});

// Unbound action
client.action<null, null>('ResetDataSource').call(null).subscribe();

The call* helpers choose how the response is read: callProperty, callEntity, callEntities, callModel, callCollection, callArraybuffer and callBlob. Generated services include typed methods for every callable. See Code generation.

Singletons

Example :
client
  .singleton<Person>('Me')
  .fetch()
  .subscribe(({ entity }) => {});

Batch requests

batch().exec() collects every request created inside its callback and sends them all in a single $batch request. Each inner observable still emits its own response.

Example :
import { combineLatest } from 'rxjs';

const people = client.entitySet<Person>('People');
client
  .batch()
  .exec(() =>
    combineLatest({
      russell: people.entity('russellwhyte').fetch(),
      scott: people.entity('scottketchum').fetch(),
    }),
  )
  .subscribe(([result$, response]) => result$.subscribe(({ russell, scott }) => {}));

Several APIs

When you register several APIs, use apiFor() to build resources for one of them:

Example :
const northwind = client.apiFor('Northwind');
const orders = await firstValueFrom(northwind.entitySet<Order>('Orders').fetchEntities());

Saving and restoring resources

A resource can be converted to JSON, for example to keep the current query of a page, and rebuilt later:

Example :
const json = airports.toJson();
const restored = client.fromJson(json) as ODataEntitySetResource<Airport>;
restored.fetch().subscribe(({ entities }) => {});

Metadata

Example :
// GET $metadata, parsed into an ODataMetadata object
client
  .metadata()
  .fetch()
  .subscribe((metadata) => console.log(metadata.toConfig()));

Low-level HTTP

ODataClient also has get, post, put, patch, delete and request methods that take a resource or a URL, for cases the resource API does not cover.

Query options

Every resource has a query() method that edits its query options. See Query builder.

Example :
airports.query((q) => q.top(5));
console.log(airports.toString()); // Airports?$top=5

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