discord4j.rest.response

Interface ResponseFunction

All Known Implementing Classes:

CompositeTransformer, EmptyResponseTransformer, ResumingTransformer, RetryingTransformer

@Experimental
public interface ResponseFunction

A transformation function used while processing DiscordWebRequest objects.

Using ResponseFunction objects is targeted to supporting Router implementations that allow enrichment of a response Mono pipeline, allowing cross-cutting behavior for specialized error handling or retrying under specific conditions like an HTTP status code or a given API request route. Usage beyond this concern is not supported and could interfere with downstream operations.

Typical ResponseFunction usage is through RouterOptions, where it can be applied using one of the static helper methods defined in this class.

Method Summary

Modifier and Type	Method and Description
static EmptyResponseTransformer	emptyIfNotFound() Transform every HTTP 404 status code into an empty response into an empty sequence, effectively suppressing the ClientException that would be forwarded otherwise.
static EmptyResponseTransformer	emptyIfNotFound(RouteMatcher routeMatcher) Transforms HTTP 404 status codes caused by requests matching the given RouteMatcher into an empty sequence, effectively suppressing the ClientException that would be forwarded otherwise.
static EmptyResponseTransformer	emptyOnErrorStatus(RouteMatcher routeMatcher, Integer... codes) Transforms the given error status codes caused by requests matching the given RouteMatcher, effectively suppressing the ClientException that would be forwarded otherwise.
static RetryingTransformer	retryOnceOnErrorStatus(Integer... codes) Applies a retry strategy to retry once with a fixed backoff of 1 second to the given error status codes caused by any request, effectively suppressing the ClientException that would be forwarded otherwise.
static RetryingTransformer	retryOnceOnErrorStatus(RouteMatcher routeMatcher, Integer... codes) Applies a retry strategy to retry once with a fixed backoff of 1 second to the given error status codes caused by requests matching the given RouteMatcher, effectively suppressing the ClientException that would be forwarded otherwise.
static RetryingTransformer	retryWhen(RouteMatcher routeMatcher, Retry<?> retry) Applies a custom retry strategy to the requests matching the given RouteMatcher, effectively suppressing the ClientException that would be forwarded otherwise.
Function<Mono<ClientResponse>,Mono<ClientResponse>>	transform(DiscordWebRequest request) Transform a Mono pipeline using the given DiscordWebRequest as hint for parameterization of the resulting transformation.

Method Detail

transform

Function<Mono<ClientResponse>,Mono<ClientResponse>> transform(DiscordWebRequest request)

Transform a Mono pipeline using the given DiscordWebRequest as hint for parameterization of the resulting transformation.

Parameters:

request - the DiscordRequest used for the targeted Mono sequence

Returns:

a Function that allows immediately mapping this Mono into a target Mono instance

emptyIfNotFound

static EmptyResponseTransformer emptyIfNotFound()

Transform every HTTP 404 status code into an empty response into an empty sequence, effectively suppressing the ClientException that would be forwarded otherwise. See emptyIfNotFound(RouteMatcher) for an override that supports applying the transformation to a subset of requests.

Returns:

a ResponseFunction that transforms any HTTP 404 error into an empty sequence

emptyIfNotFound

static EmptyResponseTransformer emptyIfNotFound(RouteMatcher routeMatcher)

Transforms HTTP 404 status codes caused by requests matching the given RouteMatcher into an empty sequence, effectively suppressing the ClientException that would be forwarded otherwise. See emptyIfNotFound() to apply this transformation across all Router requests.

Parameters:

routeMatcher - the RouteMatcher determining whether to match a particular request

Returns:

a ResponseFunction that transforms matching HTTP 404 errors into an empty sequence

emptyOnErrorStatus

static EmptyResponseTransformer emptyOnErrorStatus(RouteMatcher routeMatcher,
                                                   Integer... codes)

Transforms the given error status codes caused by requests matching the given RouteMatcher, effectively suppressing the ClientException that would be forwarded otherwise.

Only a subset of HTTP status codes is supported, like all the ones from 400 and 500 series, except for the 429 (Too Many Requests) error that is handled upstream.

Parameters:

routeMatcher - the RouteMatcher determining whether to match a particular request

codes - the list of HTTP status codes to match when applying this transformation

Returns:

a ResponseFunction that transforms matching requests and response statuses into an empty sequence

retryOnceOnErrorStatus

static RetryingTransformer retryOnceOnErrorStatus(Integer... codes)

Applies a retry strategy to retry once with a fixed backoff of 1 second to the given error status codes caused by any request, effectively suppressing the ClientException that would be forwarded otherwise.

Only a subset of HTTP status codes is supported, like all the ones from 400 and 500 series, except for the 429 (Too Many Requests) error that is handled upstream.

Please note that if you specify error codes 502, 503 or 504 you will replace a built-in retry factory that handles Discord service errors using an exponential backoff with jitter strategy.

Parameters:

codes - the list of HTTP status codes to match when applying this transformation

Returns:

a ResponseFunction that transforms matching response statuses into sequence that retries the request once after waiting 1 second.

retryOnceOnErrorStatus

static RetryingTransformer retryOnceOnErrorStatus(RouteMatcher routeMatcher,
                                                  Integer... codes)

Applies a retry strategy to retry once with a fixed backoff of 1 second to the given error status codes caused by requests matching the given RouteMatcher, effectively suppressing the ClientException that would be forwarded otherwise.

Only a subset of HTTP status codes is supported, like all the ones from 400 and 500 series, except for the 429 (Too Many Requests) error that is handled upstream.

Please note that if you specify error codes 502, 503 or 504 you will replace a built-in retry factory that handles Discord service errors using an exponential backoff with jitter strategy.

Parameters:

routeMatcher - the RouteMatcher determining whether to match a particular request

codes - the list of HTTP status codes to match when applying this transformation

Returns:

a ResponseFunction that transforms matching response statuses into sequence that retries the request once after waiting 1 second.

retryWhen

static RetryingTransformer retryWhen(RouteMatcher routeMatcher,
                                     Retry<?> retry)

Applies a custom retry strategy to the requests matching the given RouteMatcher, effectively suppressing the ClientException that would be forwarded otherwise.

Care must be taken when applying this transformation while using a long running retry factory, as it may effectively block further requests on the same rate limiting bucket.

Parameters:

routeMatcher - the RouteMatcher determining whether to match a particular request

retry - the Retry factory to install while applying this transformation

Returns:

a ResponseFunction that transforms matching response statuses into sequence that retries the request once after waiting 1 second.