How to get the JSON from the Body of a Request on Go
TIL that http.Response.Body
is a buffer, which means that once it has been read, it cannot be read again.
It's like a stream of water, you can see it and measure it as it passes but once it's gone, it's gone.
However, knowing this, there is a workaround, you need to "catch" the body and restore it:
// Read the Body content
var bodyBytes []byte
if context.Request().Body != nil {
bodyBytes, _ = ioutil.ReadAll(context.Request().Body)
}
// Restore the io.ReadCloser to its original state
context.Request().Body = ioutil.NopCloser(bytes.NewBuffer(bodyBytes))
// Continue to use the Body, like Binding it to a struct:
order := new(models.GeaOrder)
error := context.Bind(order)
Now, you can use context.Request().Body
somewhere else.
Sources:
http://grokbase.com/t/gg/golang-nuts/12adq8a2ys/go-nuts-re-reading-http-response-body-or-any-reader
https://medium.com/@xoen/golang-read-from-an-io-readwriter-without-loosing-its-content-2c6911805361
transistor
Updated on November 15, 2020Comments
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transistor over 3 years
I'm a newbie with Go, but so far I'm liking it very much.
I have a problem I can't figure out. I'm migrating an API from Node to Go and there is this log where I have to capture the Body of a POST AS IT IS and save it to a
jsonb
type column in a Postgresql database.This means I can't use a
struct
or anything predetermined.The POST is made with body raw
Content-Type: application/json
like so:{ "debug": false, "order_id_gea": 326064, "increment_id_gea": 200436102, "date": "2017-05-18T01:44:44+00:00", "total_amount": 10000.00, "currency": "MXN", "payment_method": "Referencia bancaria", "reference": "857374", "buyer": { "buyer_id_gea": 1234, "full_name": "Juan Perez Martinez", "email": "[email protected]", "phone": "5512341234" }, "products": [ { "sku":"PEP16114", "price": 10000.00, "currency": "MXN", "student": { "school_id_gea": 172, "grade_id_gea": 119, "level_id_gea": 36, "name": "Benancio", "last_name": "Perez", "second_last_name": "Garcia", "email": "[email protected]" } } ] }
On Node + Hapi is quite simple:
const payload = request.payload
and then I can access the JSON from
payload
.I am using Go with Echo, so
context
is a wrapper where I can findRequest() *http.Request
.I have tried the following, but everytime the result is empty or an error because it is empty:
var v interface{} err := json.NewDecoder(context.Request().Body).Decode(&v) if err != nil { return result, err } fmt.Println(v)
Result: EOF
--
m := echo.Map{} if err := context.Bind(&m); err != nil { return result, err } fmt.Println(m)
Result code 400, message EOF
--
body, error := ioutil.ReadAll(context.Request().Body) if error != nil { return result, error } fmt.Println(body)
Result []
--
What am I missing and/or doing wrong? Thanks!
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transistor over 6 yearsThank you @dave, but I get an error: runtime error: invalid memory address or nil pointer dereference