net/http: FormFile size different from original zip file

[Chrestkoo]

What version of Go are you using (go version)?

$ go version golang:1.17.5
$ docker image: golang:1.17.5-stretch

Does this issue reproduce with the latest release?

Don't know.

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
GO111MODULE=""

GOARCH="amd64"

GOBIN=""

GOCACHE="/home/gcc/.cache/go-build"

GOENV="/home/gcc/.config/go/env"

GOEXE=""

GOEXPERIMENT=""

GOFLAGS=""

GOHOSTARCH="amd64"

GOHOSTOS="linux"

GOINSECURE=""

GOMODCACHE="/go/pkg/mod"

GONOPROXY=""

GONOSUMDB=""

GOOS="linux"

GOPATH="/go"

GOPRIVATE=""

GOPROXY="https://proxy.golang.org,direct"

GOROOT="/usr/local/go"

GOSUMDB="sum.golang.org"

GOTMPDIR=""

GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64"

GOVCS=""

GOVERSION="go1.17.5"

GCCGO="gccgo"

AR="ar"

CC="gcc"

CXX="g++"

CGO_ENABLED="1"

GOMOD="/dev/null"

CGO_CFLAGS="-g -O2"

CGO_CPPFLAGS=""

CGO_CXXFLAGS="-g -O2"

CGO_FFLAGS="-g -O2"

CGO_LDFLAGS="-g -O2"

PKG_CONFIG="pkg-config"

GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build2669985125=/tmp/go-build -gno-record-gcc-switches"

What did you do?

Use Postman to call created api. Code only retrieve post form file value of the api. The file is zip file.
So far it is just happend on receiving zip file. Text file is tried and no issue.

func HandleAddTranslationResourcesFileReqTest(w http.ResponseWriter, req *http.Request) err {
	if err := req.ParseMultipartForm(32 << 20); err != nil {
		return err
	}

	file, header, err := req.FormFile("transSourceFile")
	if err != nil {
		return err
	}
	defer file.Close()
	fmt.Println("header.Size:", header.Size)
        return nil
}

What did you expect to see?

Expect to see the same zip file size [header.Size] with origin file.

What did you see instead?

I see different zip file size [header.Size] with origin file.

[seankhliao]

what's the actual difference you see?
have you verified that the complete file was uploaded?
what's the difference between the file contents you get and the file you sent?

[Chrestkoo]

i had compare uploaded file and origin file.
the comparison result as the 1drv.ms/u/s!ApOAtDwy99qQ9mMnjoPa-iKdXEIg?e=DLK3Ug
the zip file and generated file as in https://1drv.ms/u/s!ApOAtDwy99qQ9ma_VcldR7TOGtmU?e=5xg7Ez

This case only happend in server and zip file. My local M1 Macbook Pro does not have this issue.

[seankhliao]

Seems like something else is interfering with your request.
Not much we can do about that

[Chrestkoo]

I have no idea on this and I know this case does not happen on non-zip file. I suspect development environment is the cause.

[seankhliao]

Given that this seems likely to be a local environment issue, I'm going to close this for now. Feel free file a new one if you believe it's an error in net/http and have a reproducer for it.