How to authenticate Google Cloud Vision via HTTP Request

Question

I am trying to use Google Cloud Vision via a rest http request using c#. As described here, I tried to authenticate with the api key as a parameter:

string uri = "https://vision.googleapis.com/v1/images:annotate?key=" + API_KEY;
HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Post, uri);
[...]
response = await client.SendAsync(request);

However, I always get a 403 PERMISSION DENIED Code:

Cloud Vision API has not been used in project XXXXX before or it is disabled. Enable it by visiting https://console.developers.google.com/apis/api/vision.googleapis.com/overview?project=XXXXXXX then retry. If you enabled this API recently, wait a few minutes for the action to propagate to our systems and retry.

Of course I checked, The API is activated, enabled and there are no API restrictions:

Since there seemed to exist some problems with that authentication method, especially with cloud vision, I tried authentication via an access token of a service account that I created. I gave the service account full access just to be sure that there is no issue with the rights of the service account:

string uri = "https://vision.googleapis.com/v1/images:annotate";
HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Post, uri);
request.Headers.Add("Authorization", "Bearer " + ACCESS_TOKEN);
response = await client.SendAsync(request);

Still, same error message. Same goes with curl:

curl -k -X POST -H "Content-Type:application/json" 
-d "@{REQUEST_AS_JSON_OR_PATH_TO_JSON-FILE}" 
https://vision.googleapis.com/v1/images:annotate?key={API_KEY}

What am I missing out?

Exatex Exatex · Accepted Answer · 2018-06-02T20:48:16

Turned out it is NOT sufficient to activate an API key (even when its without any restrictions), but one needs to actively go to the Google console menu -> APIs and Services -> Library -> Search for "Cloud Vision" -> klick on the Cloud vision API and activate it. It takes a couple of minutes. The status of this is not shown in your dashboard.

Then, you can simply authenticate with the api key as URL parameter.

How to authenticate Google Cloud Vision via HTTP Request

1 Answers