Google Cloud Platform presignURL using Go - google-cloud-platform

Question

Trying to upload a picture to Google Cloud Platform, I always get the same err "<?xml version='1.0' encoding='UTF-8'?><Error><Code>SignatureDoesNotMatch</Code><Message>The request signature we calculated does not match the signature you provided. Check your Google secret key and signing method.</Message><StringToSign>GOOG4-RSA-SHA256 20.................951Z".
I did add a service-account to the bucket with the role Storage Admin and Storage Object Admin as you can see on the pic
I have generated a Key(for the service account) and downloaded it as .json file, then I generate a presignURL using this code:
// key is the downloaded .json key file from the GCP service-account
// the return string is the presignedURL
func getPresignedURL(path, key string) (string, error) {
sakeyFile := filepath.Join(path, key)
saKey, err := ioutil.ReadFile(sakeyFile)
if err != nil {
log.Fatalln(err)
}
cfg, err := google.JWTConfigFromJSON(saKey)
if err != nil {
log.Fatalln(err)
}
bucket := "mybucket"
ctx := context.Background()
client, err := storage.NewClient(ctx)
if err != nil {
return "", fmt.Errorf("storage.NewClient: %v", err)
}
defer client.Close()
opts := &storage.SignedURLOptions{
Scheme: storage.SigningSchemeV4,
Method: "PUT",
Headers: []string{
"Content-Type:image/jpeg",
},
Expires: time.Now().Add(15 * time.Minute),
GoogleAccessID: cfg.Email,
PrivateKey: cfg.PrivateKey,
}
u, err := client.Bucket(bucket).SignedURL("mypic.jpeg", opts)
if err != nil {
return "", fmt.Errorf("Bucket(%q).SignedURL: %v", bucket, err)
}
return u, nil
}
The presignedURL looks good, something like this:
https://storage.googleapis.com/djedjepicbucket/mypic.jpeg?X-Goog-Algorithm=GOOG4-RSA-SHA256&X-Goog-Credential=djedje%40picstorage-363707.iam.gserviceaccount.com%2F20220926%2Fauto%2Fstorage%2Fgoog4_request&X-Goog-Date=20220926T081951Z&X-Goog-Expires=899&X-Goog Signature=3f330715d7a38ea08f99134a16f464fb............5ad800a7665dfb1440034ab1f5ab045252336&X-Goog-SignedHeaders=content-type%3Bhost
Then I read a file(picture) from disk and upload it using the presignURL
// the uri is the presignedURL
func newfileUploadRequest(uri string, params map[string]string, paramName, path string) (*http.Request, error) {
file, err := os.Open(path)
if err != nil {
return nil, err
}
defer file.Close()
body := &bytes.Buffer{}
writer := multipart.NewWriter(body)
if err != nil {
return nil, err
}
_, err = io.Copy(body, file)
for key, val := range params {
_ = writer.WriteField(key, val)
}
err = writer.Close()
if err != nil {
return nil, err
}
req, err := http.NewRequest("PUT", uri, body)
req.Header.Set("Content-Type", "image/jpeg")
return req, err
}
Then I exec the request
// the previous func
request, err := newfileUploadRequest(purl, extraParams, "picture", filepath.Join(path, "download.jpeg"))
if err != nil {
log.Fatal(err)
}
client := &http.Client{}
resp, err := client.Do(request)
if err != nil {
log.Fatal(err)
} else {
body := &bytes.Buffer{}
_, err := body.ReadFrom(resp.Body)
if err != nil {
log.Fatal(err)
}
resp.Body.Close()
fmt.Println(resp.StatusCode)
fmt.Println(resp.Header)
fmt.Println(body)
}
Unfortunatly, I always get the same error back
403
map[Alt-Svc:[h3=":443"; ma=2592000,h3-29=":443"; ma=2592000,h3-Q050=":443"; ma=2592000,h3-Q046=":443"; ma=2592000,h3-Q043=":443"; ma=2592000,quic=":443"; ma=2592000; v="46,43"] Content-Length:[884] Content-Type:[application/xml; charset=UTF-8] Date:[Mon, 26 Sep 2022 08:22:19 GMT] Server:[UploadServer] X-Guploader-Uploadid:[ADPyc......................ECL_4W]]
<?xml version='1.0' encoding='UTF-8'?><Error><Code>SignatureDoesNotMatch</Code><Message>The request signature we calculated does not match the signature you provided. Check your Google secret key and signing method.</Message><StringToSign>GOOG4-RSA-SHA256
20220926T081951Z
20220926/auto/storage/goog4_request
c5f36838af4......................8ffb56329c1eb27f</StringToSign><CanonicalRequest>PUT
/djedjepicbucket/mypic.jpeg
X-Goog-Algorithm=GOOG4-RSA-SHA256&X-Goog-Credential=djedje%40picstorage-363707.iam.gserviceaccount.com%2F20220926%2Fauto%2Fstorage%2Fgoog4_request&X-Goog-Date=20220926T081951Z&X-Goog-Expires=899&X-Goog-SignedHeaders=content-type%3Bhost
content-type:multipart/form-data; boundary=5be13cc........................dd6aef6823
host:storage.googleapis.com
content-type;host
UNSIGNED-PAYLOAD</CanonicalRequest></Error>
Actually I have tryied many other ways as well but I basically always get this(more or less) same err back, Does someone have an Idea what am I forgetting(I am on that for 2 days now...) ? Thank you
=============================
I edited the question, that code works perfectly

Answer 1

Found the answer, in the both getPresignedURL() and newfileUploadRequest() func, the Header must be set to "Content-Type:application/octet-stream"(or "Content-Type:image/jpeg" for instance if the picture need to be display using its URL), then the pic is uploaded without issue.