JSONDecodeError：期望值：Keras+Rest API 应用程序的第 1 行第 1 列（字符 0）

Posted 2023-03-15

【中文标题】JSONDecodeError：期望值：Keras+Rest API 应用程序的第 1 行第 1 列（字符 0）

【英文标题】：JSONDecodeError: Expecting value: line 1 column 1 (char 0) for Keras+Rest API Application

【发布时间】：2020-02-19 05:50:29

【问题描述】：

我正在尝试从我的 keras 模型返回 HTTP 响应。

@app.route("/predict", methods=["POST"])
def predict():
    # initialize the data dictionary that will be returned from the
    # view
    data = "success": False

    # ensure an image was properly uploaded to our endpoint
    if flask.request.method == "POST":
        if flask.request.files.get("image"):
            # read the image in PIL format
            image = flask.request.files["image"].read()
            image = Image.open(io.BytesIO(image))

            # preprocess the image and prepare it for classification
            image = prepare_image(image, target=(224, 224))

            proba = model.predict(image)[0]
            idx = np.argmax(proba)
            label = lb.classes_[idx]
            r = "label": label, "probability": float(proba[idx] * 100)
            y = json.dumps(r)

    # return the data dictionary as a JSON response
    return y


if __name__ == "__main__":
    print(("* Loading Keras model and Flask starting server..."
        "please wait until server has fully started"))
    load_my_model()
    app.run()


import requests

# initialize the Keras REST API endpoint URL along with the input
# image path
KERAS_REST_API_URL = "http://localhost:5000/my_predict"
IMAGE_PATH = "dog.jpg"

# load the input image and construct the payload for the request
image = open(IMAGE_PATH, "rb").read()
payload = "image": image

# submit the request
r = requests.post(KERAS_REST_API_URL, files=payload).json()

# ensure the request was successful
if r["success"]:
    # loop over the predictions and display them
    for (i, result) in enumerate(r["predictions"]):
        print(". : :.4f".format(i + 1, result["label"],
            result["probability"]))

# otherwise, the request failed
else:
    print("Request failed”)

第一部分运行：

正在加载 Keras 模型和 Flask 启动服务器...请等待服务器完全启动 服务 Flask 应用“

ma​​in

”（延迟加载） 环境：生产 警告：这是一个开发服务器。不要在生产部署中使用它。 请改用生产 WSGI 服务器。 调试模式：关闭 在http://127.0.0.1:5000/ 上运行

但下一部分给了我：JSONDecodeError: Expecting value: line 1 column 1 (char 0)

【问题讨论】：

你试过我的答案了吗？需要更多解释吗？

【参考方案1】：

您可以查看this，这是一个关于如何通过发布请求发送图像的示例，您不需要发送 json，只需发送图像： 导入cv2

# prepare headers for http request
content_type = 'image/jpeg'
headers = 'content-type': content_type

img = cv2.imread('lena.jpg')
# encode image as jpeg
_, img_encoded = cv2.imencode('.jpg', img)
# send http request with image and receive response
response = requests.post(url, data=img_encoded.tostring(), headers=headers)
# decode response
print(json.loads(response.text))

仅在烧瓶服务器上解码图像：

import cv2

# convert string of image data to uint8
nparr = np.fromstring(flask.request.data, np.uint8)
# decode image
img = cv2.imdecode(nparr, cv2.IMREAD_COLOR)

# do some fancy processing here....