src-openfeign

Feign makes writing java http clients easier

java http-client interface jax-rs okhttp3 slf4j

History

Adrian Cole 79f32ce035 Adds Feign.Builder.decode404() to reduce boilerplate for empty semantics This adds the `Feign.Builder.decode404()` flag which indicates decoders should process responses with 404 status. It also changes all first-party decoders (like gson) to return well-known empty values by default. Further customization is possible by wrapping or creating a custom decoder. Prior to this change, we used custom invocation handlers as the way to add fallback values based on exception or return status. `feign-hystrix` uses this to return `HystrixCommand<X>`, but the general pattern applies to anything that has a type representing both success and failure, such as `Try<X>` or `Observable<X>`. As we define it here, 404 status is not a retry or fallback policy, it is just empty semantics. By limiting Feign's special processing to 404, we gain a lot with very little supporting code. If instead we opened all codes, Feign could easily turn bad request, redirect, or server errors silently to null. This sort of configuration issue is hard to troubleshoot. 404 -> empty is a very safe policy vs all codes. Moreover, we don't create a cliff, where folks seeking fallback policy eventually realize they can't if only given a response code. Fallback systems like Hystrix address exceptions that occur before or in lieu of a response. By special-casing 404, we avoid a slippery slope of half- implementing Hystrix. Finally, 404 handling has been commonly requested: it has a clear use- case, and through that value. This design supports that without breaking compatibility, or impacting existing integrations such as Hystrix or Ribbon. See #238 #287	9 years ago
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main/java/feign/gson	Adds Feign.Builder.decode404() to reduce boilerplate for empty semantics	9 years ago
test/java/feign/gson	Adds Feign.Builder.decode404() to reduce boilerplate for empty semantics	9 years ago

Adrian Cole 79f32ce035 Adds Feign.Builder.decode404() to reduce boilerplate for empty semantics

This adds the `Feign.Builder.decode404()` flag which indicates decoders
should process responses with 404 status. It also changes all
first-party decoders (like gson) to return well-known empty values by
default. Further customization is possible by wrapping or creating a
custom decoder.

Prior to this change, we used custom invocation handlers as the way to
add fallback values based on exception or return status. `feign-hystrix`
uses this to return `HystrixCommand<X>`, but the general pattern applies
to anything that has a type representing both success and failure, such
as `Try<X>` or `Observable<X>`.

As we define it here, 404 status is not a retry or fallback policy, it
is just empty semantics. By limiting Feign's special processing to 404,
we gain a lot with very little supporting code.

If instead we opened all codes, Feign could easily turn bad request,
redirect, or server errors silently to null. This sort of configuration
issue is hard to troubleshoot. 404 -> empty is a very safe policy vs
all codes.

Moreover, we don't create a cliff, where folks seeking fallback policy
eventually realize they can't if only given a response code. Fallback
systems like Hystrix address exceptions that occur before or in lieu of
a response. By special-casing 404, we avoid a slippery slope of half-
implementing Hystrix.

Finally, 404 handling has been commonly requested: it has a clear use-
case, and through that value. This design supports that without breaking
compatibility, or impacting existing integrations such as Hystrix or
Ribbon.

See #238 #287

9 years ago

main/java/feign/gson

Adds Feign.Builder.decode404() to reduce boilerplate for empty semantics

9 years ago

test/java/feign/gson

Adds Feign.Builder.decode404() to reduce boilerplate for empty semantics

9 years ago