RestClient

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

Constructors

NewRestClient

NewRestClient creates new instance of RestClient

NewRestClient() *RestClient

Fields

Methods

AddCorrelationId

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

(c *RestClient) AddCorrelationId(params *StringValueMap, correlationId string) *StringValueMap

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

AddFilterParams

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

(c *RestClient) AddFilterParams(params *cdata.StringValueMap, filter *cdata.FilterParams) *cdata.StringValueMap

• params: *cdata.StringValueMap - invocation parameters.
• filter: *cdata.FilterParams - (optional) filter parameters
• returns: *cdata.StringValueMap - invocation parameters with added filter parameters.

AddPagingParams

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

(c *RestClient) AddPagingParams(params *cdata.StringValueMap, paging *cdata.PagingParams) *cdata.StringValueMap

• params: *cdata.StringValueMap - invocation parameters.
• paging: *cdata.PagingParams - (optional) paging parameters
• returns: *cdata.StringValueMap - invocation parameters with added paging parameters.

Call

Calls a remote method via HTTP/REST protocol.

(c *RestClient) Call(ctx context.Context, method string, route string, correlationId string, params *cdata.StringValueMap, data interface{}) (result interface{}, err error)

• ctx: context.Context - operation context.
• 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: *cdata.StringValueMap - (optional) query parameters.
• data: interface{} - (optional) body object.
• returns: (result interface{}, err error) - result object

Close

Closes a component and frees used resources.

(c *RestClient) ctx context.Context, correlationId string) error

• ctx: context.Context - operation context.
• correlationId: string - (optional) transaction id used to trace execution through a call chain.
• returns: error - returns error if not closed

Configure

Configures a component by passing configuration parameters.

(c *RestClient) Configure(ctx context.Context, config *cconf.ConfigParams)

• ctx: context.Context - operation context.
• 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.

(c *RestClient) Instrument(ctx context.Context, correlationId string, name string) *service.InstrumentTiming

• ctx: context.Context - operation context.
• correlationId: string - (optional) transaction id used to trace execution through a call chain.
• name: string - method name.
• returns: *service.InstrumentTiming - Instrument Timing object used to end the time measurement.

IsOpen

Checks if the component is open.

(c *RestClient) IsOpen() bool

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

Open

Opens the component.

(c *RestClient) Open(ctx context.Context, correlationId string) error

• ctx: context.Context - operation context.
• correlationId: string - (optional) transaction id used to trace execution through a call chain.
• returns: error - returns error if not opened

SetReferences

Sets references to dependent components.

(c *RestClient) SetReferences(ctx context.Context, references crefer.IReferences)

• ctx: context.Context - operations context.
• references: IReferences - references used to locate the component dependencies.

Examples

type MyRestClient struct {
	*RestClient
}
...
func (c *MyRestClient) GetData(ctx context.Context, correlationId string, id string) (result *tdata.MyDataPage[MyData], err error) {
	timind := c.Instrument(ctx, correlationId, "myData.get_page_by_filter")
	defer timing.EndTiming(ctx)

	params := cdata.NewEmptyStringValueMap()
	params.Set("id", id)
	response, calErr := c.Call(MyDataPageType, "get", "/data", correlationId, params, nil)
	if calErr != nil {
		return nil, calErr
	}

	return return clients.HandleHttpResponse[*tdata.MyDataPage[MyData]](response, correlationId)
}

client := NewMyRestClient()
client.Configure(context.Background(), cconf.NewConfigParamsFromTuples(
	"connection.protocol", "http",
	"connection.host", "localhost",
	"connection.port", 8080,
))

result, err := client.GetData(context.Background(), "123", "1")
...

See also

• RestService

• CommandableHttpService