Empty media type in HTTP 200 responses

[dmandalidis]

Hi all,

RESTEASY-3178 introduced an exception whenever an HTTP 200 response is received without a Content-Type response header.

However, based on my understanding, this sort of handling is stricter than the HTTP specification which does not mandate such a header. Although weird, an HTTP 200 response without a Content-Type is valid.

I haven't checked the implications, but I think RESTeasy is safe to assume application/octet-stream if Content-Type header is not present in HTTP 200 responses.

Quoting RFC9110:

A sender that generates a message containing content SHOULD generate a Content-Type header field in that message unless the intended media type of the enclosed representation is unknown to the sender. If a Content-Type header field is not present, the recipient MAY either assume a media type of "application/octet-stream" ([[RFC2046](https://datatracker.ietf.org/doc/html/rfc2046)], [Section 4.5.1](https://www.rfc-editor.org/rfc/rfc2046#section-4.5.1)) or examine the data to determine its type.

also RFC7231 states that the response can be empty (philosophically, what's the content-type of an empty response? :) ).

Thanks for reading,
Dimitris

cc @jamezp

[dmandalidis]

Hi again,

Any feedback on this?

Thanks

[jamezp]

Well @dmandalidis, I owe you a huge apology. I asked you to start a discussion and it got lost in my inbox and now it's 2 months later. I'm really sorry about that.

It should only throw an exception if the response code was 200 and there was an attempt to extract content which is null. What I mean is if you simply did:

try (Response response = webTarget.request().get()) {
    final int status = response.getStatus();
    // do something
}

Then no exception should be thrown. Where it would be thrown is when you attempt to do something like response.readEntity(String.class) or if you did something like webTarget.request().get(String.class).

That said, if this is causing issues if you and you have some use-cases I'm definitely open to hearing about them.