Flask â Cookies
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A cookie is stored on a clientâs computer in the form of a text file. Its purpose is to remember and track data pertaining to a clientâs usage for better visitor experience and site statistics.
A Request object contains a cookieâs attribute. It is a dictionary object of all the cookie variables and their corresponding values, a client has transmitted. In addition to it, a cookie also stores its expiry time, path and domain name of the site.
In Flask, cookies are set on response object. Use make_response() function to get response object from return value of a view function. After that, use the set_cookie() function of response object to store a cookie.
Reading back a cookie is easy. The get() method of request.cookies attribute is used to read a cookie.
In the following Flask application, a simple form opens up as you visit â/â URL.
@app.route(''/'')
def index():
return render_template(''index.html'')
This HTML page contains one text input.
<html>
<body>
<form action = "/setcookie" method = "POST">
<p><h3>Enter userID</h3></p>
<p><input type = ''text'' name = ''nm''/></p>
<p><input type = ''submit'' value = ''Login''/></p>
</form>
</body>
</html>
The Form is posted to â/setcookieâ URL. The associated view function sets a Cookie name userID and renders another page.
@app.route(''/setcookie'', methods = [''POST'', ''GET''])
def setcookie():
if request.method == ''POST'':
user = request.form[''nm'']
resp = make_response(render_template(''readcookie.html''))
resp.set_cookie(''userID'', user)
return resp
âreadcookie.htmlâ contains a hyperlink to another view function getcookie(), which reads back and displays the cookie value in browser.
@app.route(''/getcookie'')
def getcookie():
name = request.cookies.get(''userID'')
return ''<h1>welcome ''+name+''</h1>''
Run the application and visit http://localhost:5000/
The result of setting a cookie is displayed like this −
The output of read back cookie is shown below.
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