OpenIDM 5.5 external/rest call throws No content to map due to end-of-input

[JavierKainos]

When using openidm.action(“external/rest”, “call”, params) inside a groovy script and also using the REST API as follows an error is thrown.

curl http://localhost:9080/openidm/external/rest?_action=call -X POST \
-H “Content-Type: application/json” \
-H “X-OpenIDM-Username: USERNAME” \
-H “X-OpenIDM-Password: PASSWORD” \
–data ‘{ “url”: “http://192.168.35.6:8080/accounts/USER_ID/deregister”, “method”: “POST”,”headers”: { “Content-Type”: “application/json” }}’

The call returns a 204 and we can verify that it is executed successfully but when handling the response by OpenIDM it throws the following exception:

Apr 12, 2018 1:44:07 PM org.forgerock.openidm.servlet.internal.ServletConnectionFactory$3 lambda$handleRequestWithLogging$8
WARNING: Resource exception: 500 Internal Server Error: “No content to map due to end-of-input
at [Source: [email protected]; line: 1, column: 0]”
org.forgerock.json.resource.InternalServerErrorException: No content to map due to end-of-input
at [Source: [email protected]; line: 1, column: 0]
at org.forgerock.openidm.external.rest.RestService$1.apply(RestService.java:369)
at org.forgerock.openidm.external.rest.RestService$1.apply(RestService.java:331)
at org.forgerock.util.promise.PromiseImpl.lambda$then$6(PromiseImpl.java:369)
at org.forgerock.util.promise.PromiseImpl.handleCompletion(PromiseImpl.java:531)
at org.forgerock.util.promise.PromiseImpl.setState(PromiseImpl.java:572)
at org.forgerock.util.promise.PromiseImpl.tryHandleResult(PromiseImpl.java:258)
at org.forgerock.util.promise.PromiseImpl.handleResult(PromiseImpl.java:208)
at org.forgerock.util.promise.PromiseImpl.lambda$then$6(PromiseImpl.java:369)
at org.forgerock.util.promise.PromiseImpl.handleCompletion(PromiseImpl.java:531)
at org.forgerock.util.promise.PromiseImpl.setState(PromiseImpl.java:572)
at org.forgerock.util.promise.PromiseImpl.tryHandleResult(PromiseImpl.java:258)
at org.forgerock.util.promise.PromiseImpl.handleResult(PromiseImpl.java:208)
at org.forgerock.util.promise.PromiseImpl.lambda$then$6(PromiseImpl.java:369)
at org.forgerock.util.promise.PromiseImpl.handleCompletion(PromiseImpl.java:531)
at org.forgerock.util.promise.PromiseImpl.setState(PromiseImpl.java:572)
at org.forgerock.util.promise.PromiseImpl.tryHandleResult(PromiseImpl.java:258)
at org.forgerock.util.promise.PromiseImpl.handleResult(PromiseImpl.java:208)
at org.forgerock.http.apache.async.AsyncHttpClient$PromiseHttpAsyncResponseConsumer.responseCompleted(AsyncHttpClient.java:143)
at org.apache.http.impl.nio.client.MainClientExec.responseCompleted(MainClientExec.java:383)
at org.apache.http.impl.nio.client.DefaultClientExchangeHandlerImpl.responseCompleted(DefaultClientExchangeHandlerImpl.java:168)
at org.apache.http.nio.protocol.HttpAsyncRequestExecutor.processResponse(HttpAsyncRequestExecutor.java:436)
at org.apache.http.nio.protocol.HttpAsyncRequestExecutor.responseReceived(HttpAsyncRequestExecutor.java:309)
at org.apache.http.impl.nio.DefaultNHttpClientConnection.consumeInput(DefaultNHttpClientConnection.java:255)
at org.apache.http.impl.nio.client.InternalIODispatch.onInputReady(InternalIODispatch.java:81)
at org.apache.http.impl.nio.client.InternalIODispatch.onInputReady(InternalIODispatch.java:39)
at org.apache.http.impl.nio.reactor.AbstractIODispatch.inputReady(AbstractIODispatch.java:114)
at org.apache.http.impl.nio.reactor.BaseIOReactor.readable(BaseIOReactor.java:162)
at org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvent(AbstractIOReactor.java:337)
at org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvents(AbstractIOReactor.java:315)
at org.apache.http.impl.nio.reactor.AbstractIOReactor.execute(AbstractIOReactor.java:276)
at org.apache.http.impl.nio.reactor.BaseIOReactor.execute(BaseIOReactor.java:104)
at org.apache.http.impl.nio.reactor.AbstractMultiworkerIOReactor$Worker.run(AbstractMultiworkerIOReactor.java:588)
at java.lang.Thread.run(Thread.java:748)
Caused by: com.fasterxml.jackson.databind.JsonMappingException: No content to map due to end-of-input
at [Source: [email protected]; line: 1, column: 0]
at com.fasterxml.jackson.databind.JsonMappingException.from(JsonMappingException.java:270)
at com.fasterxml.jackson.databind.ObjectMapper._initForReading(ObjectMapper.java:3854)
at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:3799)
at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2903)
at org.forgerock.http.util.Json.parse(Json.java:253)
at org.forgerock.http.util.Json.readJson(Json.java:211)
at org.forgerock.http.protocol.Entity.getJson(Entity.java:230)
at org.forgerock.openidm.external.rest.RestService$1.apply(RestService.java:349)
… 32 more

[[email protected]]

Your endpoint does not seem to return (valid) json. Try detectResultFormat=false.

[JavierKainos]

Tried detectResultFormat: false but the error is still happening.

The problem was in the external API. A POST request is sent to the endpoint and it returns 204(No content) but the client expects a response body as the HTTP method was a POST.

[Javilete]

After further investigation, it seems that 204 No Content is not a valid response from a external service when using “external/rest” API. In the case of a DELETE 204 No Content is a valid response and it throws the same error. I guess it is the internal client used by OpenIDM to send HTTP requests

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