On Thu, Oct 7, 2021 at 1:43 PM RiSi <a0r2...@gmail.com> wrote:
> if error happens by io.Copy, can I set the status Code of w after io.Copy?
>
No. io.Copy might have already written parts of the body. You can't set the
status after parts of the body have been written.
>
>
> 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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>>>>
>>>
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