Visual Recognition error 400: Cannot execute learning task no classifier name given

I am using Visual Recognition curl command to add a classification to an image:

curl -u "user":"password"  \
-X POST \
-F "images_file=@image0.jpg" \
-F "classifier_ids=classifierlist.json" \
"https://gateway.watsonplatform.net/visual-recognition-beta/api/v2/classifiers?version=2015-12-02"

json file:

{
  "classifiers": [
    { 
        "name": "tomato",
        "classifier_id": "tomato_1",
        "created": "2016-03-23T17:43:11+00:00",
        "owner": "xyz"
    }
  ]
}

(Also tried without the classifiers array. Got the same error) and getting an error: {"code":400,"error":"Cannot execute learning task : no classifier name given"}

Is something wrong with the json?

Solution

To specify the classifiers you want to use you need to send a JSON object similar to:

{"classifier_ids": ["Black"]}

An example using Black as classifier id in CURL:

curl -u "user":"password"  \
-X POST \
-F "images_file=@image0.jpg" \
-F "classifier_ids={\"classifier_ids\":[\"Black\"]}"
"https://gateway.watsonplatform.net/visual-recognition-beta/api/v2/classify?version=2015-12-02"

If you want to list the classifier ids in a JSON file then:

curl -u "user":"password"  \
-X POST \
-F "images_file=@image0.jpg" \
-F "classifier_ids=@classifier_ids.json"
"https://gateway.watsonplatform.net/visual-recognition-beta/api/v2/classify?version=2015-12-02"

Where classifier_ids.json has:

{
 "classifier_ids": ["Black"]
}

You can test the Visual Recognition API in the API Explorer.
Learn more about the service in the documentation.