if error happens by io.Copy, can I set the status Code of w after io.Copy?
Am Do., 7. Okt. 2021 um 13:41 Uhr schrieb RiSi <a0r2...@gmail.com>:
>
> *w.Header().Set("Content-Type", "application/xml")*
>
> *_, err:=io.Copy(w,src) *
>
> *if err!=nil{*
> *re := &res{ Message: "Error happened",}*
>
>
>
> *w.Header().Set("Content-Type", "application/json")w.WriteHeader(599)
> //sample status codeerr = json.NewEncoder(w).Encode(re)*
> *}//if*
>
> *the part after err!=nil should be removed?*
>
> Am Do., 7. Okt. 2021 um 13:29 Uhr schrieb Axel Wagner <
> axel.wagner...@googlemail.com>:
>
>> As I said in your last thread:
>> https://groups.google.com/g/golang-nuts/c/I5gwXr1kOA0/m/oIVYRgBoAQAJ
>> What you want is impossible, based on how HTTP works. The status of a
>> request must be determined *before* any of the body is written. So, if
>> writing the body fails, there is nothing more you can do - you can only
>> ignore that. And it's not an abnormal condition for the writing of a body
>> to fail, as clients may disconnect at any time.
>>
>> The best you can do is
>> a) write the body to an in-memory buffer, to make sure all bytes that
>> need to be written are correctly determined,
>> b) then set tany headers (e.g. content-type) and status as appropriate and
>> c) write out the body, ignoring any errors - or at best, increment a
>> metric or logging it.
>>
>> That is, IMO, the best you can do with HTTP. There is no guarantee the
>> body can be written, before you try do it and you can't set the status
>> after you start writing the body. But if the actual *Write* fails (as
>> opposed to the Read part of an io.Copy) you can at least be reasonably sure
>> that the problem is some network issue or client disconnect you can't do
>> anything about, so it's fine to ignore (from an application perspective).
>>
>> On Thu, Oct 7, 2021 at 1:12 PM RS <a0r2...@gmail.com> wrote:
>>
>>> Best practice in following scenario:
>>>
>>> In my func for an endpoint (handler) with func hello(w
>>> http.ResponseWriter, req *http.Request)
>>> I call another server get the resp.Body (Body io.ReadCloser) and want to
>>> write this Body in w (ResponseWriter ).
>>> What is best practice?
>>> I have already copied directly Body to w via io.Copy.
>>> I want but make sure that the whole body is sent to client.
>>> With io.Copy I am not sure if this is guaranteed.
>>> And I would like to set status to 500 in case io.Copy returns err.
>>>
>>> Could you please help me on this?
>>>
>>>
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