Where does API key go in Google Cloud Vision API?

Question

Want to use Google's Cloud Vision API for OCR. Using the python sample code here we have:

def detect_text(path):
"""Detects text in the file."""
client = vision.ImageAnnotatorClient()

with io.open(path, 'rb') as image_file:
    content = image_file.read()

image = types.Image(content=content)

response = client.text_detection(image=image)
texts = response.text_annotations
print('Texts:')

for text in texts:
    print('\n"{}"'.format(text.description))

    vertices = (['({},{})'.format(vertex.x, vertex.y)
                for vertex in text.bounding_poly.vertices])

    print('bounds: {}'.format(','.join(vertices)))

Where do I put my API key? I (obviously) can't authenticate without it.

Answer 1

From the docs ,

If you plan to use a service account with client library code, you need to set an environment variable.

Provide the credentials to your application code by setting the environment variable GOOGLE_APPLICATION_CREDENTIALS. Replace [PATH] with the location of the JSON file you downloaded in the previous step.

For example:

export GOOGLE_APPLICATION_CREDENTIALS="/home/user/Downloads/service-account-file.json"

So it looks like you should create a service account, download a credentials file, and set up an environmental variable to point to it.

Answer 2

There are two ways through which you can authenticate

1. Exporting the credential file as an environment variable. Here is a sample code:

from google.cloud import vision

def get_text_from_image(image_file):
        os.environ['GOOGLE_APPLICATION_CREDENTIALS'] = "./creds/xxxx-xxxxx.json"
        try:
            # process_image is a method to convert numpy array to bytestream
            # (not of interest in this context hence not including it here)
            byte_img = process_image_to_bytes(image_file)
            client = vision.ImageAnnotatorClient()
            image = vision.Image(content=byte_img)
            response = client.text_detection(image=image)
            texts = response.text_annotations
            return texts
        except BaseException as e:
            print(str(e))

os.environ['GOOGLE_APPLICATION_CREDENTIALS'] is doing the work here

2. Using oauth2

from google.cloud import vision
from google.oauth2 import service_account

def get_text_from_image(image_file):
        creds = service_account.Credentials.from_service_account_file("./creds/xxx-xxxxx.json")
        try:
            # process_image is a method to convert numpy array to bytestream
            # (not of interest in this context hence not including it here)
            byte_img = process_image_to_bytes(image_file)
            client = vision.ImageAnnotatorClient(credentials=creds)
            image = vision.Image(content=byte_img)
            response = client.text_detection(image=image)
            texts = response.text_annotations
            return texts
        except BaseException as e:
            print(str(e))

Here we are using the google-auth library to create a credential file from the JSON credential file and passing that object to ImageAnnotatorClient for authentication.

Hope these sample snippets helped you