RestClient

Implements: IConfigurable, IReferenceable, IOpenable

Description

The RestClient class allows you to create clients that call remote endpoints using the HTTP/REST protocol.

Configuration parameters

• base_route: base route for a remote URI
• connection(s):
  • discovery_key: (optional) key to retrieve the connection from IDiscovery
  • protocol: connection protocol (http or https)
  • host: host name or IP address
  • port: port number
  • uri: resource URI or connection string with all parameters in it
• options:
  • retries: number of retries (default: 3)
  • connect_timeout: connection timeout in milliseconds (default: 10 sec)
  • timeout: invocation timeout in milliseconds (default: 10 sec)
  • correlationId: place for adding correalationId, query - in query string, headers - in headers, both - in query and headers (default: query)

References

• *:logger:*:*:1.0 - (optional) ILogger components to pass log messages
• *:counters:*:*:1.0 - (optional) ICounters components to pass collected measurements
• *:traces:*:*:1.0 - (optional) ITracer components to record traces
• *:discovery:*:*:1.0 - (optional) IDiscovery services to resolve a connection

Fields

Instance methods

addCorrelationId

Adds a correlation id (correlationId) to the invocation parameter map.

protected addCorrelationId(params: any, correlationId: string): any

• params: any - invocation parameters.
• correlationId: string - (optional) transaction id used to trace execution through the call chain.
• returns: any - invocation parameters with added correlation id.

addFilterParams

Adds filter parameters (with the same name as they defined) to the invocation parameter map.

protected addFilterParams(params: any, filters: any): any

• params: any - invocation parameters.
• filters: any - (optional) filter parameters
• returns: any - invocation parameters with added filter parameters.

addPagingParams

Adds paging parameters (skip, take, total) to invocation parameter map.

protected addPagingParams(params: any, paging: any): any

• params: any - invocation parameters.
• paging: any - (optional) paging parameters
• returns: any - invocation parameters with added paging parameters.

call

Calls a remote method via HTTP/REST protocol.

protected call<T>(method: string, route: string, correlationId?: string, params: any = {}, data?: any): Promise<T>

• method: string - HTTP method: “get”, “head”, “post”, “put”, “delete”
• route: string - a command route. Base route will be added to this route
• correlationId: string - (optional) transaction id used to trace execution through a call chain.
• params: any - (optional) query parameters.
• data: any - (optional) body object.
• returns: Promise<T> - result object

close

Closes a component and frees used resources.

public close(correlationId: string): Promise<void>

• correlationId: string - (optional) transaction id used to trace execution through a call chain.

configure

Configures a component by passing configuration parameters.

public configure(config: ConfigParams): void

• config: ConfigParams - configuration parameters to be set.

instrument

Adds instrumentation to log calls and measures call time. It returns a Timing object that is used to end the time measurement.

protected instrument(correlationId: string, name: string): InstrumentTiming

• correlationId: string - (optional) transaction id used to trace execution through a call chain.
• name: string - method name.
• returns: InstrumentTiming - InstrumentTiming object used to end the time measurement.

isOpen

Checks if the component is open.

public isOpen(): boolean

• returns: boolean - True if the component is open and False otherwise.

open

Opens the component.

public open(correlationId: string): Promise<void>

• correlationId: string - (optional) transaction id used to trace execution through a call chain.

setReferences

Sets references to dependent components.

public setReferences(references: IReferences): void

• references: IReferences - references used to locate the component dependencies.

Examples

class MyRestClient extends RestClient implements IMyClient {
   ...
   public async getData(correlationId: string, id: string): Promise<MyData> {
        let timing = this.instrument(correlationId, 'myclient.get_data');
        try {
            return await this.call("get", "/get_data" correlationId, { id: id }, null);
        } catch (ex) {
            timing.endFailure(ex);
        } finally {
            timing.endTiming();
        }
   }
   ...
}

let client = new MyRestClient();
client.configure(ConfigParams.fromTuples(
    "connection.protocol", "http",
    "connection.host", "localhost",
    "connection.port", 8080
));

let result = await client.getData("123", "1");

See also

• RestService

• CommandableHttpService