Sample code for calling the Google Cloud Vision API from Cloudflare Workers

client.ts

import { type GoogleKey } from 'cloudflare-workers-and-google-oauth'
import GoogleAuth from 'cloudflare-workers-and-google-oauth'

const SCOPES = ['https://www.googleapis.com/auth/cloud-platform']

export const execute = async <T>(
  gcpServiceAccount: string,
  endpoint: string,
  requestInit: RequestInit,
): Promise<{ result: boolean; data: T }> => {
  const googleAuth: GoogleKey = JSON.parse(gcpServiceAccount)

  const oauth = new GoogleAuth(googleAuth, SCOPES)
  const token = await oauth.getGoogleAuthToken()

  const res = await fetch(endpoint, {
    ...requestInit,
    headers: { ...requestInit.headers, Authorization: `Bearer ${token}` },
  })

  const data = await res.json<T>()

  if (!res.ok) {
    console.error(JSON.stringify(data))
    return { result: false, data }
  }

  console.log(JSON.stringify(data))
  return { result: true, data }
}

cloudvision.ts

import { execute } from './client'

// MEMO: see https://cloud.google.com/vision/docs/reference/rest/v1/images/annotate
const SAFE_SEARCH_ENDPOINT = 'https://vision.googleapis.com/v1/images:annotate'
type Likelihood =
  | 'UNKNOWN'
  | 'VERY_UNLIKELY'
  | 'UNLIKELY'
  | 'POSSIBLE'
  | 'LIKELY'
  | 'VERY_LIKELY'
type SafeSearchAnnotation = {
  adult: Likelihood
  spoof: Likelihood
  medical: Likelihood
  violence: Likelihood
  racy: Likelihood
}
type AnnotateImagesResponse = {
  responses: [
    {
      safeSearchAnnotation: SafeSearchAnnotation
    },
  ]
}

export const validSafeSearch = async (
  gcServiceAccountJson: string,
  imageUri: string,
): Promise<
  | { result: false; detections: null }
  | { result: true; detections: Array<SafeSearchAnnotation> }
> => {
  const { result, data } = await execute<AnnotateImagesResponse>(
    gcServiceAccountJson,
    SAFE_SEARCH_ENDPOINT,
    {
      method: 'POST',
      body: JSON.stringify({
        requests: [
          {
            image: {
              source: {
                imageUri,
              },
            },
            features: [{ type: 'SAFE_SEARCH_DETECTION' }],
          },
        ],
      }),
    },
  )

  if (!result) {
    return { result: false, detections: null }
  }

  return { result: true, detections: data.responses.map(res => res.safeSearchAnnotation) }
}