Google存储桶SignedUrls 403

Question

I'm doing a simple rest API which does the following:

• get base64 encoded image
• decode it
• stores it on on specific google bucket

Now, on the GET verb, my api returns a signed url targeting the bucket image.

I've coded a test that works:

    initialization stuff
    ...
    BeforeEach(func() {
        mockStringGenerator.On("GenerateUuid").Return("image1")

        // First store
        image, _ = ioutil.ReadFile("test_data/DSCF6458.JPG")
        encodedImage = b64.RawStdEncoding.EncodeToString(image)
        fileName, storeError = storage.Store(ctx, encodedImage, "image/jpeg")

        // Then get
        uri, getError = storage.Get(ctx, fileName)
        getResponse, _ = http.Get(uri)

        // Finally delete
        deleteError = storage.Delete(ctx, fileName)
    })

    // Only 1 test to avoid making too much connexion
    It("should create, get and delete the image", func() {
        // Store
        Expect(storeError).To(BeNil())
        Expect(fileName).To(Equal("image1.jpg"))

        // Get
        Expect(getError).To(BeNil())
        Expect(getResponse.StatusCode).To(Equal(http.StatusOK))
        b, _ := ioutil.ReadAll(getResponse.Body)
        Expect(b).To(Equal(image))

        // Delete
        Expect(deleteError).To(BeNil())
    })

But when I run the .exe and try to make ssome request with postman, I get a 403 error in the signed url:

<?xml version='1.0' encoding='UTF-8'?>
<Error>
    <Code>AccessDenied</Code>
    <Message>Access denied.</Message>
    <Details>Anonymous caller does not have storage.objects.get access to teddycare-images/08d8c508-d97d-48d3-947b-a7f216f622db.jpg.</Details>
</Error>

Any ideas ? I really don't understand... Save me guys

[EDIT] Here after the code I use to create signedUrl:

func (s *GoogleStorage) Get(ctx context.Context, fileName string) (string, error) {
    url, err := storage.SignedURL(s.Config.BucketImagesName, fileName, &storage.SignedURLOptions{
        GoogleAccessID: s.Config.BucketServiceAccountDetails.ClientEmail,
        PrivateKey:     []byte(s.Config.BucketServiceAccountDetails.PrivateKey),
        Method:         http.MethodGet,
        Expires:        time.Now().Add(time.Second * 180),
    })
    if err != nil {
        return "", err
    }
    return url, nil
}

Answer 1

Ok, after I woke up, I found the answer. It turns out that when the json is marshalized into string, all the special characters are encoded.

Example: & -> \u0026

So the url I tested in my UT had &, while the url returned by the api had \u0026, and google does not seem to have the same behaviour on both cases.

So the solution is to disable HTML escaping:

encoder := json.NewEncoder(w)
encoder.SetEscapeHTML(false)
return encoder.Encode(response)