Reading responsesedit
The Response object, either returned by the synchronous performRequest methods or
received as an argument in ResponseListener#onSuccess(Response), wraps the
response object returned by the http client and exposes the following information:
-
getRequestLine - information about the performed request
-
getHost - the host that returned the response
-
getStatusLine - the response status line
-
getHeaders -
the response headers, which can also be retrieved by name
though
getHeader(String) -
getEntity -
the response body enclosed in an
org.apache.http.HttpEntityobject
When performing a request, an exception is thrown (or received as an argument
in ResponseListener#onFailure(Exception) in the following scenarios:
-
IOException - communication problem (e.g. SocketTimeoutException etc.)
-
ResponseException -
a response was returned, but its status code indicated
an error (not
2xx). AResponseExceptionoriginates from a valid http response, hence it exposes its correspondingResponseobject which gives access to the returned response.
A ResponseException is not thrown for HEAD requests that return
a 404 status code because it is an expected HEAD response that simply
denotes that the resource is not found. All other HTTP methods (e.g., GET)
throw a ResponseException for 404 responses unless the ignore parameter
contains 404. ignore is a special client parameter that doesn’t get sent
to Elasticsearch and contains a comma separated list of error status codes.
It allows to control whether some error status code should be treated as an
expected response rather than as an exception. This is useful for instance
with the get api as it can return 404 when the document is missing, in which
case the response body will not contain an error but rather the usual get api
response, just without the document as it was not found.