How to drag and drop file with Python Selenium?

While I haven't used selenium recently, if you're working in a static workspace where you can control most everything I would recommend using PyAutoGUI. It isn't a dynamic solution, but it does contain a left mouse emulation feature for drag and drop.

In the provided example, the mouse moves from the 100,100 location towards the bottom of the screen by 100 pixels:

>>> pyautogui.moveTo(100,100)    #starting mouse location of 100,100
>>> pyautogui.dragTo(100,200, button='left')     # drag mouse to X of 100, Y of 200 while holding down left mouse button

You can setup a makeshift solution to your application if it can be done in a controlled environment every time where you know the resolution, location of the file explorer, etc.

I have run into issues in a windows env. before due to unexpected update screens. Food for thought...

The drag'n'drop of selenium is last time I checked broken.

I use the solution provided in How to simulate HTML5 Drag and Drop in Selenium Webdriver?

I don't know, maybe someone will find this example useful. When I searched for this information, I couldn't find anything. Made it minimally reproducible. And you can easily adapt it to your project.

    driver.get("https://www.dragdrop.com/test/")
    driver.sleep(3)
    upload_file = "test.jpeg"
    
    with open(upload_file, "rb") as f:
        content = f.read()
        b64_file = base64.b64encode(content).decode()
    
    # Find the drop zone
    drop_target = driver.find_element(By.ID, "demo-upload")
    
    # Perform a Drag&Drop via JS
    driver.execute_script("""
        const b64 = arguments[0];
        const target = arguments[1];
    
        function b64toBlob(b64Data, contentType = '', sliceSize = 512) {
            const byteCharacters = atob(b64Data);
            const byteArrays = [];
    
            for (let offset = 0; offset < byteCharacters.length; offset += sliceSize) {
                const slice = byteCharacters.slice(offset, offset + sliceSize);
                const byteNumbers = new Array(slice.length);
                for (let i = 0; i < slice.length; i++) {
                    byteNumbers[i] = slice.charCodeAt(i);
                }
                byteArrays.push(new Uint8Array(byteNumbers));
            }
    
            return new Blob(byteArrays, { type: contentType });
        }
    
        const blob = b64toBlob(b64, 'image/jpeg');
        const file = new File([blob], 'test.jpg', { type: 'image/jpeg' });
        const dt = new DataTransfer();
        dt.items.add(file);
    
        const eventNames = ['dragenter', 'dragover', 'drop'];
        for (const name of eventNames) {
            const event = new DragEvent(name, {
                dataTransfer: dt,
                bubbles: true,
                cancelable: true
            });
            target.dispatchEvent(event);
        }
        """, b64_file, drop_target)
    
    driver.sleep(10)