when I use the method find_image_occurrence of Appium with python, always occurred TypeError: Object of type bytes is not JSON serializable

Question

import base64

def img_base64(img_path):
    if os.path.exists(img_path):
        with open(img_path, 'rb') as f_obj:
            image_data = f_obj.read()
            base64_d = base64.b64encode(image_data)
    return base64_d

master.save_screenshot(".\\screenshots\\test.png")

full_screenshot_base64 = img_base64(".\\screenshots\\test.png")
partial_screenshot_base64 = img_base64(".\\resource\\images\\suit_head.png")

master.update_settings({"getMatchedImageResult": True})
master.update_settings({"fixImageTemplateScale": True})

master.find_image_occurrence(base64_full_image=full_screenshot_base64, base64_partial_image=partial_screenshot_base64, visuallze=True)

When I run above python code, error message is:

raise TypeError(f'Object of type {o.__class__.__name__} '
TypeError: Object of type bytes is not JSON serializable

How should I solve this problem? Please help me, thank you!

According to the method description, the type of the parameter needs to be bytes, but the prompt is: Object of type bytes is not JSON serializable.

Answer 1

In case you never ended up solving this, I encountered a similar problem and the documentation around the implementation unfortunately leaves a bit to be desired.

The trick for me was using .decode("ascii"). Additionally, don't forget to start your Appium server (whether manually or programmatically) with the --use-plugins=images argument.

As an example, here is how I implemented it (the code isn't complete):

def load_image_base64(path: str):
    with open(path, "rb") as f:
        return base64.b64encode(f.read()).decode("ascii")

def compare_images(driver):
    reference = load_image_base64("./reference_images/menu_icon.png")
    target = load_image_base64("./runtime/dashboard_screenshot.png")
    driver.find_image_occurrence(base64_partial_image=target, base64_full_image=reference)

Hope this helps (you or anyone else in the future)!