FeignClient 抛出而不是返回具有错误 http 状态的 ResponseEntity
FeignClient throws instead of returning ResponseEntity with error http status
因为我使用 ResponseEntity<T> 作为我的 FeignClient 方法的 return 值，我期望它 return 一个状态为 400 的 ResponseEntity 如果它是服务器 return秒。但它会抛出 FeignException.
如何获得正确的 ResponseEntity 而不是来自 FeignClient 的异常？
这是我的 FeignClient：
@FeignClient(value = "uaa", configuration = OauthFeignClient.Conf.class)
public interface OauthFeignClient {
@RequestMapping(
value = "/oauth/token",
method = RequestMethod.POST,
consumes = MULTIPART_FORM_DATA_VALUE,
produces = APPLICATION_JSON_VALUE)
ResponseEntity<OauthTokenResponse> token(Map<String, ?> formParams);
class Conf {
@Value("${oauth.client.password}")
String oauthClientPassword;
@Bean
public Encoder feignFormEncoder() {
return new SpringFormEncoder();
}
@Bean
public Contract feignContract() {
return new SpringMvcContract();
}
@Bean
public BasicAuthRequestInterceptor basicAuthRequestInterceptor() {
return new BasicAuthRequestInterceptor("web-client", oauthClientPassword);
}
}
}
下面是我的使用方法：
@PostMapping("/login")
public ResponseEntity<LoginTokenPair> getTokens(@RequestBody @Valid LoginRequest userCredentials) {
Map<String, String> formData = new HashMap<>();
ResponseEntity<OauthTokenResponse> response = oauthFeignClient.token(formData);
//code never reached if contacted service returns a 400
...
}
因此，查看源代码，似乎唯一的解决方案实际上是使用 feign.Response 作为 FeignClient 方法的 return 类型，并用 [=13] 之类的东西手动解码 body =]（当然要注意 2xx 状态，因为对于错误状态，body 很可能是错误描述而不是有效负载 ;）。
这使得提取和转发状态成为可能，header、body 等，即使状态不在 2xx 范围内也是如此。
编辑：
这是一种转发状态的方法，headers 和映射 JSON body（如果可能）：
public static class JsonFeignResponseHelper {
private final ObjectMapper json = new ObjectMapper();
public <T> Optional<T> decode(Response response, Class<T> clazz) {
if(response.status() >= 200 && response.status() < 300) {
try {
return Optional.of(json.readValue(response.body().asReader(), clazz));
} catch(IOException e) {
return Optional.empty();
}
} else {
return Optional.empty();
}
}
public <T, U> ResponseEntity<U> toResponseEntity(Response response, Class<T> clazz, Function<? super T, ? extends U> mapper) {
Optional<U> payload = decode(response, clazz).map(mapper);
return new ResponseEntity(
payload.orElse(null),//didn't find a way to feed body with original content if payload is empty
convertHeaders(response.headers()),
HttpStatus.valueOf(response.status()));
}
public MultiValueMap<String, String> convertHeaders(Map<String, Collection<String>> responseHeaders) {
MultiValueMap<String, String> responseEntityHeaders = new LinkedMultiValueMap<>();
responseHeaders.entrySet().stream().forEach(e ->
responseEntityHeaders.put(e.getKey(), new ArrayList<>(e.getValue())));
return responseEntityHeaders;
}
}
可以如下使用：
@PostMapping("/login")
public ResponseEntity<LoginTokenPair> getTokens(@RequestBody @Valid LoginRequest userCredentials) throws IOException {
Response response = oauthFeignClient.token();
return feignHelper.toResponseEntity(
response,
OauthTokenResponse.class,
oauthTokenResponse -> new LoginTokenPair(
new BearerToken(oauthTokenResponse.access_token, oauthTokenResponse.expires_in),
new BearerToken(oauthTokenResponse.refresh_token, refreshTokenValidity)));
}
这会保存 headers 和状态代码，但错误消息会丢失：/
顺便说一句，我之前给出的解决方案有效，但我的初衷是个坏主意：错误就是错误，不应该 在标称流量上处理。像 Feign 一样抛出异常，并用 @ExceptionHandler 处理它是进入 Spring MVC 世界的更好方法。
所以两个解决方案：
- 为
FeignException 添加一个 @ExceptionHandler
- 使用
ErrorDecoder 配置 FeignClient 以转换您的业务层知道的异常中的错误（并且已经为 @ExceptionHandler 提供）
我更喜欢第二种解决方案，因为接收到的错误消息结构可能会从一个客户端更改为另一个客户端，因此您可以使用每个客户端的错误解码从这些错误中提取更细粒度的数据。
FeignClient with conf（很抱歉 feign-form 引入的噪音）
@FeignClient(value = "uaa", configuration = OauthFeignClient.Config.class)
public interface OauthFeignClient {
@RequestMapping(
value = "/oauth/token",
method = RequestMethod.POST,
consumes = MULTIPART_FORM_DATA_VALUE,
produces = APPLICATION_JSON_VALUE)
DefaultOAuth2AccessToken token(Map<String, ?> formParams);
@Configuration
class Config {
@Value("${oauth.client.password}")
String oauthClientPassword;
@Autowired
private ObjectFactory<HttpMessageConverters> messageConverters;
@Bean
public Encoder feignFormEncoder() {
return new SpringFormEncoder(new SpringEncoder(messageConverters));
}
@Bean
public Decoder springDecoder() {
return new ResponseEntityDecoder(new SpringDecoder(messageConverters));
}
@Bean
public Contract feignContract() {
return new SpringMvcContract();
}
@Bean
public BasicAuthRequestInterceptor basicAuthRequestInterceptor() {
return new BasicAuthRequestInterceptor("web-client", oauthClientPassword);
}
@Bean
public ErrorDecoder uaaErrorDecoder(Decoder decoder) {
return (methodKey, response) -> {
try {
OAuth2Exception uaaException = (OAuth2Exception) decoder.decode(response, OAuth2Exception.class);
return new SroException(
uaaException.getHttpErrorCode(),
uaaException.getOAuth2ErrorCode(),
Arrays.asList(uaaException.getSummary()));
} catch (Exception e) {
return new SroException(
response.status(),
"Authorization server responded with " + response.status() + " but failed to parse error payload",
Arrays.asList(e.getMessage()));
}
};
}
}
}
常见业务异常
public class SroException extends RuntimeException implements Serializable {
public final int status;
public final List<String> errors;
public SroException(final int status, final String message, final Collection<String> errors) {
super(message);
this.status = status;
this.errors = Collections.unmodifiableList(new ArrayList<>(errors));
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (!(o instanceof SroException)) return false;
SroException sroException = (SroException) o;
return status == sroException.status &&
Objects.equals(super.getMessage(), sroException.getMessage()) &&
Objects.equals(errors, sroException.errors);
}
@Override
public int hashCode() {
return Objects.hash(status, super.getMessage(), errors);
}
}
错误处理程序（从 ResponseEntityExceptionHandler 扩展中提取）
@ExceptionHandler({SroException.class})
public ResponseEntity<Object> handleSroException(SroException ex) {
return new SroError(ex).toResponse();
}
错误响应DTO
@XmlRootElement
public class SroError implements Serializable {
public final int status;
public final String message;
public final List<String> errors;
public SroError(final int status, final String message, final Collection<String> errors) {
this.status = status;
this.message = message;
this.errors = Collections.unmodifiableList(new ArrayList<>(errors));
}
public SroError(final SroException e) {
this.status = e.status;
this.message = e.getMessage();
this.errors = Collections.unmodifiableList(e.errors);
}
protected SroError() {
this.status = -1;
this.message = null;
this.errors = null;
}
public ResponseEntity<Object> toResponse() {
return new ResponseEntity(this, HttpStatus.valueOf(this.status));
}
public ResponseEntity<Object> toResponse(HttpHeaders headers) {
return new ResponseEntity(this, headers, HttpStatus.valueOf(this.status));
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (!(o instanceof SroError)) return false;
SroError sroException = (SroError) o;
return status == sroException.status &&
Objects.equals(message, sroException.message) &&
Objects.equals(errors, sroException.errors);
}
@Override
public int hashCode() {
return Objects.hash(status, message, errors);
}
}
Feign client usage 注意错误是如何透明处理的（没有 try / catch）感谢 @ControllerAdvice & @ExceptionHandler({SroException.class})
@RestController
@RequestMapping("/uaa")
public class AuthenticationController {
private static final BearerToken REVOCATION_TOKEN = new BearerToken("", 0L);
private final OauthFeignClient oauthFeignClient;
private final int refreshTokenValidity;
@Autowired
public AuthenticationController(
OauthFeignClient oauthFeignClient,
@Value("${oauth.ttl.refresh-token}") int refreshTokenValidity) {
this.oauthFeignClient = oauthFeignClient;
this.refreshTokenValidity = refreshTokenValidity;
}
@PostMapping("/login")
public ResponseEntity<LoginTokenPair> getTokens(@RequestBody @Valid LoginRequest userCredentials) {
Map<String, String> formData = new HashMap<>();
formData.put("grant_type", "password");
formData.put("client_id", "web-client");
formData.put("username", userCredentials.username);
formData.put("password", userCredentials.password);
formData.put("scope", "openid");
DefaultOAuth2AccessToken response = oauthFeignClient.token(formData);
return ResponseEntity.ok(new LoginTokenPair(
new BearerToken(response.getValue(), response.getExpiresIn()),
new BearerToken(response.getRefreshToken().getValue(), refreshTokenValidity)));
}
@PostMapping("/logout")
public ResponseEntity<LoginTokenPair> revokeTokens() {
return ResponseEntity
.ok(new LoginTokenPair(REVOCATION_TOKEN, REVOCATION_TOKEN));
}
@PostMapping("/refresh")
public ResponseEntity<BearerToken> refreshToken(@RequestHeader("refresh_token") String refresh_token) {
Map<String, String> formData = new HashMap<>();
formData.put("grant_type", "refresh_token");
formData.put("client_id", "web-client");
formData.put("refresh_token", refresh_token);
formData.put("scope", "openid");
DefaultOAuth2AccessToken response = oauthFeignClient.token(formData);
return ResponseEntity.ok(new BearerToken(response.getValue(), response.getExpiresIn()));
}
}
因为我使用 ResponseEntity<T> 作为我的 FeignClient 方法的 return 值，我期望它 return 一个状态为 400 的 ResponseEntity 如果它是服务器 return秒。但它会抛出 FeignException.
如何获得正确的 ResponseEntity 而不是来自 FeignClient 的异常？
这是我的 FeignClient：
@FeignClient(value = "uaa", configuration = OauthFeignClient.Conf.class)
public interface OauthFeignClient {
@RequestMapping(
value = "/oauth/token",
method = RequestMethod.POST,
consumes = MULTIPART_FORM_DATA_VALUE,
produces = APPLICATION_JSON_VALUE)
ResponseEntity<OauthTokenResponse> token(Map<String, ?> formParams);
class Conf {
@Value("${oauth.client.password}")
String oauthClientPassword;
@Bean
public Encoder feignFormEncoder() {
return new SpringFormEncoder();
}
@Bean
public Contract feignContract() {
return new SpringMvcContract();
}
@Bean
public BasicAuthRequestInterceptor basicAuthRequestInterceptor() {
return new BasicAuthRequestInterceptor("web-client", oauthClientPassword);
}
}
}
下面是我的使用方法：
@PostMapping("/login")
public ResponseEntity<LoginTokenPair> getTokens(@RequestBody @Valid LoginRequest userCredentials) {
Map<String, String> formData = new HashMap<>();
ResponseEntity<OauthTokenResponse> response = oauthFeignClient.token(formData);
//code never reached if contacted service returns a 400
...
}
因此，查看源代码，似乎唯一的解决方案实际上是使用 feign.Response 作为 FeignClient 方法的 return 类型，并用 [=13] 之类的东西手动解码 body =]（当然要注意 2xx 状态，因为对于错误状态，body 很可能是错误描述而不是有效负载 ;）。
这使得提取和转发状态成为可能，header、body 等，即使状态不在 2xx 范围内也是如此。
编辑： 这是一种转发状态的方法，headers 和映射 JSON body（如果可能）：
public static class JsonFeignResponseHelper {
private final ObjectMapper json = new ObjectMapper();
public <T> Optional<T> decode(Response response, Class<T> clazz) {
if(response.status() >= 200 && response.status() < 300) {
try {
return Optional.of(json.readValue(response.body().asReader(), clazz));
} catch(IOException e) {
return Optional.empty();
}
} else {
return Optional.empty();
}
}
public <T, U> ResponseEntity<U> toResponseEntity(Response response, Class<T> clazz, Function<? super T, ? extends U> mapper) {
Optional<U> payload = decode(response, clazz).map(mapper);
return new ResponseEntity(
payload.orElse(null),//didn't find a way to feed body with original content if payload is empty
convertHeaders(response.headers()),
HttpStatus.valueOf(response.status()));
}
public MultiValueMap<String, String> convertHeaders(Map<String, Collection<String>> responseHeaders) {
MultiValueMap<String, String> responseEntityHeaders = new LinkedMultiValueMap<>();
responseHeaders.entrySet().stream().forEach(e ->
responseEntityHeaders.put(e.getKey(), new ArrayList<>(e.getValue())));
return responseEntityHeaders;
}
}
可以如下使用：
@PostMapping("/login")
public ResponseEntity<LoginTokenPair> getTokens(@RequestBody @Valid LoginRequest userCredentials) throws IOException {
Response response = oauthFeignClient.token();
return feignHelper.toResponseEntity(
response,
OauthTokenResponse.class,
oauthTokenResponse -> new LoginTokenPair(
new BearerToken(oauthTokenResponse.access_token, oauthTokenResponse.expires_in),
new BearerToken(oauthTokenResponse.refresh_token, refreshTokenValidity)));
}
这会保存 headers 和状态代码，但错误消息会丢失：/
顺便说一句，我之前给出的解决方案有效，但我的初衷是个坏主意：错误就是错误，不应该 在标称流量上处理。像 Feign 一样抛出异常，并用 @ExceptionHandler 处理它是进入 Spring MVC 世界的更好方法。
所以两个解决方案：
- 为
FeignException 添加一个 - 使用
ErrorDecoder配置FeignClient以转换您的业务层知道的异常中的错误（并且已经为@ExceptionHandler提供）
@ExceptionHandler
我更喜欢第二种解决方案，因为接收到的错误消息结构可能会从一个客户端更改为另一个客户端，因此您可以使用每个客户端的错误解码从这些错误中提取更细粒度的数据。
FeignClient with conf（很抱歉 feign-form 引入的噪音）
@FeignClient(value = "uaa", configuration = OauthFeignClient.Config.class)
public interface OauthFeignClient {
@RequestMapping(
value = "/oauth/token",
method = RequestMethod.POST,
consumes = MULTIPART_FORM_DATA_VALUE,
produces = APPLICATION_JSON_VALUE)
DefaultOAuth2AccessToken token(Map<String, ?> formParams);
@Configuration
class Config {
@Value("${oauth.client.password}")
String oauthClientPassword;
@Autowired
private ObjectFactory<HttpMessageConverters> messageConverters;
@Bean
public Encoder feignFormEncoder() {
return new SpringFormEncoder(new SpringEncoder(messageConverters));
}
@Bean
public Decoder springDecoder() {
return new ResponseEntityDecoder(new SpringDecoder(messageConverters));
}
@Bean
public Contract feignContract() {
return new SpringMvcContract();
}
@Bean
public BasicAuthRequestInterceptor basicAuthRequestInterceptor() {
return new BasicAuthRequestInterceptor("web-client", oauthClientPassword);
}
@Bean
public ErrorDecoder uaaErrorDecoder(Decoder decoder) {
return (methodKey, response) -> {
try {
OAuth2Exception uaaException = (OAuth2Exception) decoder.decode(response, OAuth2Exception.class);
return new SroException(
uaaException.getHttpErrorCode(),
uaaException.getOAuth2ErrorCode(),
Arrays.asList(uaaException.getSummary()));
} catch (Exception e) {
return new SroException(
response.status(),
"Authorization server responded with " + response.status() + " but failed to parse error payload",
Arrays.asList(e.getMessage()));
}
};
}
}
}
常见业务异常
public class SroException extends RuntimeException implements Serializable {
public final int status;
public final List<String> errors;
public SroException(final int status, final String message, final Collection<String> errors) {
super(message);
this.status = status;
this.errors = Collections.unmodifiableList(new ArrayList<>(errors));
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (!(o instanceof SroException)) return false;
SroException sroException = (SroException) o;
return status == sroException.status &&
Objects.equals(super.getMessage(), sroException.getMessage()) &&
Objects.equals(errors, sroException.errors);
}
@Override
public int hashCode() {
return Objects.hash(status, super.getMessage(), errors);
}
}
错误处理程序（从 ResponseEntityExceptionHandler 扩展中提取）
@ExceptionHandler({SroException.class})
public ResponseEntity<Object> handleSroException(SroException ex) {
return new SroError(ex).toResponse();
}
错误响应DTO
@XmlRootElement
public class SroError implements Serializable {
public final int status;
public final String message;
public final List<String> errors;
public SroError(final int status, final String message, final Collection<String> errors) {
this.status = status;
this.message = message;
this.errors = Collections.unmodifiableList(new ArrayList<>(errors));
}
public SroError(final SroException e) {
this.status = e.status;
this.message = e.getMessage();
this.errors = Collections.unmodifiableList(e.errors);
}
protected SroError() {
this.status = -1;
this.message = null;
this.errors = null;
}
public ResponseEntity<Object> toResponse() {
return new ResponseEntity(this, HttpStatus.valueOf(this.status));
}
public ResponseEntity<Object> toResponse(HttpHeaders headers) {
return new ResponseEntity(this, headers, HttpStatus.valueOf(this.status));
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (!(o instanceof SroError)) return false;
SroError sroException = (SroError) o;
return status == sroException.status &&
Objects.equals(message, sroException.message) &&
Objects.equals(errors, sroException.errors);
}
@Override
public int hashCode() {
return Objects.hash(status, message, errors);
}
}
Feign client usage 注意错误是如何透明处理的（没有 try / catch）感谢 @ControllerAdvice & @ExceptionHandler({SroException.class})
@RestController
@RequestMapping("/uaa")
public class AuthenticationController {
private static final BearerToken REVOCATION_TOKEN = new BearerToken("", 0L);
private final OauthFeignClient oauthFeignClient;
private final int refreshTokenValidity;
@Autowired
public AuthenticationController(
OauthFeignClient oauthFeignClient,
@Value("${oauth.ttl.refresh-token}") int refreshTokenValidity) {
this.oauthFeignClient = oauthFeignClient;
this.refreshTokenValidity = refreshTokenValidity;
}
@PostMapping("/login")
public ResponseEntity<LoginTokenPair> getTokens(@RequestBody @Valid LoginRequest userCredentials) {
Map<String, String> formData = new HashMap<>();
formData.put("grant_type", "password");
formData.put("client_id", "web-client");
formData.put("username", userCredentials.username);
formData.put("password", userCredentials.password);
formData.put("scope", "openid");
DefaultOAuth2AccessToken response = oauthFeignClient.token(formData);
return ResponseEntity.ok(new LoginTokenPair(
new BearerToken(response.getValue(), response.getExpiresIn()),
new BearerToken(response.getRefreshToken().getValue(), refreshTokenValidity)));
}
@PostMapping("/logout")
public ResponseEntity<LoginTokenPair> revokeTokens() {
return ResponseEntity
.ok(new LoginTokenPair(REVOCATION_TOKEN, REVOCATION_TOKEN));
}
@PostMapping("/refresh")
public ResponseEntity<BearerToken> refreshToken(@RequestHeader("refresh_token") String refresh_token) {
Map<String, String> formData = new HashMap<>();
formData.put("grant_type", "refresh_token");
formData.put("client_id", "web-client");
formData.put("refresh_token", refresh_token);
formData.put("scope", "openid");
DefaultOAuth2AccessToken response = oauthFeignClient.token(formData);
return ResponseEntity.ok(new BearerToken(response.getValue(), response.getExpiresIn()));
}
}