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
No content to map due to end-of-input when decoding empty returns using JacksonDecoder.
Added UnitTests to show JacksonDecoder error. Added unit test to GsonDecoder to verify behavior is as expected.
Added a check for available inputStream data before trying to read into an Object.
closes#247
Files had various formatting differences, as did pull requests. Rather than
create our own style, this inherits and requires the well documented Google
Java Style.
Feign has `MethodMetadata.bodyType()`, but never passed it to encoders.
Encoders that register type adapters need to do so based on the
interface desired as opposed to the implementation class. This change
breaks api compatibility for < 8.x, by requiring an additional arg
on `Encoder.encode`.
see https://github.com/square/retrofit/issues/713
Dagger 1.x and 2.x are incompatible. Rather than choose one over the
other, this change removes Dagger completely. Users can now choose any
injector, constructing Feign via its Builder.
This change also drops support for javax.inject.Named, which has
been replaced by feign.Param.
see #120
Feign 8.x will no longer support Dagger, nor interfaces annotated with `javax.inject.@Named`. Users must migrate from `javax.inject.@Named` to `feign.@Param` via Feign v7.1+ before attempting to update to Feign 8.0.
For example, the following uses `@Param` as opposed to `@Named` to annotate template parameters.
```java
interface GitHub {
@RequestLine("GET /repos/{owner}/{repo}/contributors")
List<Contributor> contributors(@Param("owner") String owner, @Param("repo") String repo);
}
```
AssertJ has more powerful test assertions and does not run the risk of
interfering with the classpath of main code, such as guava does. This
removes guava from test and example code and adjusts using AssertJ in
some cases.
JUnit Rules, such as MockWebServerRule, reduce boilerplate setup present
in our tests. By migrating off TestNG, and onto rules, our tests become
more maintainable as JUnit is well understood.
Request/Response/RequestTemplate are now fundamentally based on a byte[] body field.
For Request/RequestTemplate, if a charset is provided, it can be treated as text.
For many users of the library, the change should barely be noticeable, as the methods that
were changed were mostly used internally.
There were some non-backwards-compatible signature changes that require a
major version bump, however.
The logic in GsonCodec was split into GsonEncoder and GsonDecoder, each of which can
now be used separately. GsonCodec was deprecated, and can be removed in the next major
version. To facilitate use outside of Dagger, the double-to-int map type adapter was broken into
its own class, and is included by default when using the default constructors of either the
encoder or decoder. The examples have been updated to use the new encoder/decoder instead
of the codec.
This is intended as a step towards simplifying Feign.
This changeset removes the generics from both interfaces, and changes their
Dagger bindings from SET to UNIQUE.
Additionally, in changing the signatures for Encoder/Decoder, it focuses on use
of the RequestTemplate and Response objects, allowing us to extend them
in the future to support binary data without needing to change the
Encoder/Decoder signatures again.
adriancole
Adrian Cole
Adrian Cole
bcrow
Rob Spieldenner
David M. Carr