Show generic error messages when server returns no response

[mlambley]

Although I just noticed you might want me to target an earlier branch. 6.x perhaps? Let me know if you wish me to remake this PR.

[elasticmachine]

Since this is a community submitted pull request, a Jenkins build has not been kicked off automatically. Can an Elastic organization member please verify the contents of this patch and then kick off a build manually?

[ezimuel]

I like the idea of using a default unknown message but I would like to refactor a little bit the PR. Please, have a look at the specific comments. Thanks!

[ezimuel]

I think we can move that part into a private function in order to convert $responseBody into a string, using the "Unknown message" as you proposed in case of empty (or null) value. I'm thinking to something like this:

private function convertBodyToString(
    $body, 
    int $statusCode, 
    ElasticsearchException $exception
) : string {
    if (empty($body)) {
        return sprintf(
            "Unknown %d error from Elasticsearch %s",
            $statusCode,
            $exception->getMessage()
        );
    }
    // if body is not string, we convert it so it can be used as Exception message
    if (!is_string($body)) {
        return json_encode($body);
    }
    return $body;
}

We should apply this in process4xxError and process5xxError as well.
@mlambley can you apply this refactor and send the PR against 7.x branch? Thanks!

[mlambley]

I remade the PR for 7.x
Please see #1056

[mlambley]

Closed in favour of #1056