Python：即使關閉互聯網，響應代碼也會返回 200？

Question

一直在嘗試創建一個循環，即使網絡連接中斷（嘗試/除外塊），它也會繼續迭代。 在大多數情況下，它有效。 但是在執行過程中，當我在關閉 Wi-Fi 后測試響應代碼時，它仍然返回 200。似乎無法理解為什么會這樣。 我的意思是，200 意味着一個成功的請求，如果沒有 Wi-Fi 連接就不能發生，對吧？ 我讀到響應碼200是默認緩存的，是這個原因嗎？ 我能做些什么來克服這個問題？ 不能因為使用了后一種請求方法，對嗎？ 這是主要代碼。

base = datetime.datetime.today()
date_list = [base + datetime.timedelta(days=x) for x in range(numdays)]
date_str = [x.strftime("%d-%m-%Y") for x in date_list]

loop_starts = time.time()
for INP_DATE in date_str:
    try:
        # API to get planned vaccination sessions on a specific date in a given district.
        URL = f"https://cdn-api.co-vin.in/api/v2/appointment/sessions/public/findByDistrict?district_id=" \
              f"512&date={INP_DATE}"
        response = requests.get(URL, headers=browser_header)
        response.raise_for_status()

    except requests.exceptions.HTTPError as errh:
        print("Http Error:", errh)
    except requests.exceptions.ConnectionError as errc:
        print("Error Connecting:", errc)
    except requests.exceptions.Timeout as errt:
        print("Timeout Error:", errt)
    except requests.exceptions.RequestException as err:
        print("OOps: Something Else", err)

    finally:
        print(f'Response code: {response.status_code}') #Why do you always return 200?!

        #code not important to the question
        if response.ok:
            resp_json = response.json()
            # read documentation to understand following if/else tree
            if resp_json["sessions"]:
                print("Available on: {}".format(INP_DATE))
                if print_flag == 'y' or print_flag == 'Y':
                    for center in resp_json["sessions"]:  # printing each center
                        if center["min_age_limit"] <= age:
                            print("\t", "Name:", center["name"])
                            print("\t", "Block Name:", center["block_name"])
                            print("\t", "Pin Code:", center["pincode"])
                            #   print("\t", "Center:", center)
                            print("\t", "Min Age:", center['min_age_limit'])
                            print("\t Free/Paid: ", center["fee_type"])
                            if center['fee_type'] != "Free":
                                print("\t", "Amount:", center["fee"])
                            else:
                                center["fee"] = '-'
                            print("\t Available Capacity: ", center["available_capacity"])
                            if center["vaccine"] != '':
                                print("\t Vaccine: ", center["vaccine"])
                            else:
                                center["vaccine"] = '-'
                            print("\n\n")

                            # Sending text message when availability of vaccine >= 10
                            # Creating text to send to telegram

                            txt = f'Available on: {INP_DATE}\nName: {center["name"]}\nBlock ' \
                                  f'Name: {center["block_name"]}\nPinCode: {center["pincode"]}\n' \
                                  f'Min Age: {center["min_age_limit"]}\nFree/Paid: {center["fee_type"]}\n' \
                                  f'Amount: {center["fee"]}\nAvailable Capacity: {center["available_capacity"]}\n' \
                                  f'Vaccine: {center["vaccine"]}\n\nhttps://selfregistration.cowin.gov.in/'
                            if center["available_capacity"] >= 10:
                                to_url = 'https://api.telegram.org/bot{}/sendMessage?chat_id={}&text={}&parse_mode=' \
                                         'HTML'.format(token, chat_id, txt)
                                resp = requests.get(to_url)
                                print('Sent')
            else:
                print("No available slots on {}".format(INP_DATE))
        else:
            print("Response not obtained.") #Should output when net is off.

        time.sleep(25)  # Using 7 requests in 1 second. 100 requests per 5 minutes allowed. You do the math.
        #  timing the loop
        now = time.time()
        print("It has been {} seconds since the loop started\n".format(now - loop_starts))

Answer 1

像這樣重寫你的代碼

1. 在網絡異常的情況下響應沒有被覆蓋，所以response是之前的值
2. finally是陷阱，因為即使捕獲到異常也會執行代碼，這不是您想要的
3. 在您的異常中使用continue重試

base = datetime.datetime.today()
date_list = [base + datetime.timedelta(days=x) for x in range(numdays)]
date_str = [x.strftime("%d-%m-%Y") for x in date_list]

loop_starts = time.time()
for INP_DATE in date_str:
    try:
        # API to get planned vaccination sessions on a specific date in a given district.
        URL = f"https://cdn-api.co-vin.in/api/v2/appointment/sessions/public/findByDistrict?district_id=" \
              f"512&date={INP_DATE}"
        response = requests.get(URL, headers=browser_header)
        response.raise_for_status()

    except requests.exceptions.HTTPError as errh:
        print("Http Error:", errh)
        continue
    except requests.exceptions.ConnectionError as errc:
        print("Error Connecting:", errc)
        continue
    except requests.exceptions.Timeout as errt:
        print("Timeout Error:", errt)
        continue
    except requests.exceptions.RequestException as err:
        print("OOps: Something Else", err)
        continue

    # will now only been displayed when you DO have a 200
    print(f'Response code: {response.status_code}') #Why do you always return 200?!

    #code not important to the question
    resp_json = response.json()
    # read documentation to understand following if/else tree
    if not resp_json["sessions"]:
        print("No available slots on {}".format(INP_DATE))
        continue

    print("Available on: {}".format(INP_DATE))
    if print_flag != 'y' and print_flag != 'Y':
        continue

    for center in resp_json["sessions"]:  # printing each center
        if center["min_age_limit"] > age:
            continue
        print("\t", "Name:", center["name"])
        print("\t", "Block Name:", center["block_name"])
        print("\t", "Pin Code:", center["pincode"])
        #   print("\t", "Center:", center)
        print("\t", "Min Age:", center['min_age_limit'])
        print("\t Free/Paid: ", center["fee_type"])
        if center['fee_type'] != "Free":
            print("\t", "Amount:", center["fee"])
        else:
            center["fee"] = '-'
        print("\t Available Capacity: ", center["available_capacity"])
        if center["vaccine"] != '':
            print("\t Vaccine: ", center["vaccine"])
        else:
            center["vaccine"] = '-'
        print("\n\n")

        # Sending text message when availability of vaccine >= 10
        # Creating text to send to telegram

        txt = f'Available on: {INP_DATE}\nName: {center["name"]}\nBlock ' \
              f'Name: {center["block_name"]}\nPinCode: {center["pincode"]}\n' \
              f'Min Age: {center["min_age_limit"]}\nFree/Paid: {center["fee_type"]}\n' \
              f'Amount: {center["fee"]}\nAvailable Capacity: {center["available_capacity"]}\n' \
              f'Vaccine: {center["vaccine"]}\n\nhttps://selfregistration.cowin.gov.in/'
        if center["available_capacity"] >= 10:
            to_url = 'https://api.telegram.org/bot{}/sendMessage?chat_id={}&text={}&parse_mode=' \
                     'HTML'.format(token, chat_id, txt)
            resp = requests.get(to_url)
            print('Sent')

    time.sleep(25)  # Using 7 requests in 1 second. 100 requests per 5 minutes allowed. You do the math.
    #  timing the loop
    now = time.time()
    print("It has been {} seconds since the loop started\n".format(now - loop_starts))

Answer 2

正如其他人評論和回復的那樣， finally在這里不合適。 allan.simon 提供了在異常處理程序中使用continue的解決方案。 這當然是一個很好的解決方案。

另一種解決方案（不一定更好）：用else替換finally 。 try語句中的else子句“如果控制流離開 try 套件，沒有引發異常，並且沒有執行 return、continue 或 break 語句，則執行。” （引用文檔）。 這正是您在finally中嘗試做的事情。