Question

我读过How to use the Google Vision API for text detection from base64 encoded image?但它根本没用。 Cloud client library对我来说是不受欢迎的，因为我在OCR之前和期间进行了许多图像处理（例如旋转，裁剪，调整大小等）。将它们保存为新文件并将其重新读取为Google Vision API的输入效率非常低。

因此，我直接检查了发布请求的文档：

以下是导致失败的最低代码：

import base64
import requests
import io

# Read the image file and transform it into a base64 string
with io.open("photos/foo.jpg", 'rb') as image_file:
    image = image_file.read()
content = base64.b64encode(image)

# Prepare the data for request
# Format copied from https://cloud.google.com/vision/docs/ocr
sending_request = {
  "requests": [
    {
      "image": {
        "content": content
      },
      "features": [
        {
          "type": "TEXT_DETECTION"
        }
      ]
    }
  ]
}

# Send the request and get the response
# Format copied from https://cloud.google.com/vision/docs/using-python
response = requests.post(
    url='https://vision.googleapis.com/v1/images:annotate?key={}'.format(API_KEY),
    data=sending_request,
    headers={'Content-Type': 'application/json'}
)

# Then get 400 code
response
# <Response [400]>
print(response.text)
{
  "error": {
    "code": 400,
    "message": "Invalid JSON payload received. Unexpected token.\nrequests=image&reque\n^",
    "status": "INVALID_ARGUMENT"
  }
}

我去了我的控制台，发现google.cloud.vision.v1.ImageAnnotator.BatchAnnotateImages确实存在请求错误，但我不知道发生了什么。是因为data中发送requests.post的格式错误了吗？

Answer 1

错误"message": "Invalid JSON payload received. Unexpected token.\nrequests=image&reque\n^",表示您传递的是非json格式，需要是json。因此，您应该将其转换为json并将其传递给请求，如下所示。

response = requests.post(
url='https://vision.googleapis.com/v1/images:annotate?key={}'.format(API_KEY),
# import json module
# dumps the object to JSON
data=json.dumps(sending_request), 
headers={'Content-Type': 'application/json'}

它会触发typeError: Object of type 'bytes' is not JSON serializable at the line of json.dumps([sending_request])，因为您没有解码b64encode图像。所以，首先执行此操作并发送请求

content = base64.b64encode(image).decode('UTF-8')

来自Google Vision API OCR的响应400，其中包含指定图像的base64字符串

1 个答案: