如何實時更新txt中的Python個變量？

Question

我有下面的代碼誰做的工作，它寫入我的 txt 文件，但它只需要最后一個 http 請求。 計數器似乎不起作用，但是當我使用全局變量時它起作用了。 我嘗試了不同的方法，甚至使用字典。 誰能指出我做錯了什么？

@app.route('/request-counter', methods=['GET', 'POST', 'DELETE', 'PUT'])
def write_to_request_counts_txt():
   file = open("request_counts.txt", "w")
   counter_GET = 0
   counter_POST = 0
   counter_DELETE = 0
   counter_PUT = 0
   if request.method == 'GET':
      counter_GET += 1
   if request.method == 'POST':
      counter_POST += 1
   if request.method == 'DELETE':
      counter_DELETE += 1
   if request.method == 'PUT':
      counter_PUT += 1
   file.write(f'GET: {counter_GET} POST: {counter_POST} DELETE: {counter_DELETE} PUT: 
   {counter_PUT}')
   file.close()
   return render_template('index.html')

Answer 1

正如 Barmar 所說，您應該閱讀該文件。

類似於下面的代碼：

@app.route('/request-counter', methods=['GET', 'POST', 'DELETE', 'PUT'])
def write_to_request_counts_txt():
    with open("request_counts.txt", "r") as r:
       line = r.read()

    line_list = line.split(';')
    counter_GET = int(line_list[0].split(":")[1].strip(" "))
    counter_POST = int(line_list[1].split(":")[1].strip(" "))
    counter_DELETE = int(line_list[2].split(":")[1].strip(" "))
    counter_PUT = int(line_list[3].split(":")[1].strip(" "))
    if request.method == 'GET':
      counter_GET += 1
    if request.method == 'POST':
      counter_POST += 1
    if request.method == 'DELETE':
      counter_DELETE += 1
    if request.method == 'PUT':
      counter_PUT += 1

    with open("request_counts.txt", "w") as w:
        w.write(f'GET: {counter_GET} ;POST: {counter_POST} ;DELETE: {counter_DELETE} ;PUT: {counter_PUT}')

    return render_template('index.html')

我沒有測試代碼。

我選擇使用類似 csv 的字符串方法。 但是您可以使用正則表達式獲得相同的結果。 而且您不需要更改文件內容格式。