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HTTP Session (Persistent Cookies & Headers)

Zero-dependency Python snippets for HTTP sessions (persistent cookies, headers) using the standard library.

5 snippets available in this sub-category.

Simple

Simple HTTP session with cookies

http session cookies get opener web

Simple HTTP session with cookies

import urllib.request
import http.cookiejar

# Create a CookieJar to store cookies
cookie_jar = http.cookiejar.CookieJar()
handler = urllib.request.HTTPCookieProcessor(cookie_jar)
opener = urllib.request.build_opener(handler)

# Perform a GET request (cookies will be stored)
url = "https://httpbin.org/cookies/set?mycookie=value"
response = opener.open(url)
print(response.read().decode("utf-8"))

# Perform another request (cookies sent automatically)
url2 = "https://httpbin.org/cookies"
response2 = opener.open(url2)
print(response2.read().decode("utf-8"))

Notes

  • Uses http.cookiejar.CookieJar for cookie persistence
  • opener handles all requests with shared cookies

HTTP session with custom headers

http session headers cookies opener web

HTTP session with custom headers

import urllib.request
import http.cookiejar

cookie_jar = http.cookiejar.CookieJar()
handler = urllib.request.HTTPCookieProcessor(cookie_jar)
opener = urllib.request.build_opener(handler)

url = "https://httpbin.org/headers"
headers = {"User-Agent": "stdlib-sniper/1.0", "X-Test": "session"}
req = urllib.request.Request(url, headers=headers)
response = opener.open(req)
print(response.read().decode("utf-8"))

Notes

  • Custom headers can be set per request
  • Cookies persist across requests

Complex

Simulate login and session persistence

http session login cookies post opener web

Simulate login and session persistence

import urllib.request
import urllib.parse
import http.cookiejar

cookie_jar = http.cookiejar.CookieJar()
handler = urllib.request.HTTPCookieProcessor(cookie_jar)
opener = urllib.request.build_opener(handler)

# Simulate login (POST)
login_url = "https://httpbin.org/cookies/set/sessioncookie/123456"
login_data = {}  # No data needed for httpbin, but typically you'd send credentials
opener.open(login_url, data=urllib.parse.urlencode(login_data).encode("utf-8"))

# Access a page that requires the session cookie
protected_url = "https://httpbin.org/cookies"
response = opener.open(protected_url)
print(response.read().decode("utf-8"))

Notes

  • In real scenarios, send credentials in login_data
  • Session cookies persist for the opener's lifetime

Error handling and edge cases

http session error cookies opener web

HTTP session error handling

import urllib.request
import http.cookiejar

cookie_jar = http.cookiejar.CookieJar()
handler = urllib.request.HTTPCookieProcessor(cookie_jar)
opener = urllib.request.build_opener(handler)

try:
    url = "https://httpbin.org/status/403"
    response = opener.open(url)
    print(response.read().decode("utf-8"))
except urllib.error.HTTPError as e:
    print(f"HTTP error: {e.code} {e.reason}")
except Exception as e:
    print(f"Unexpected error: {e}")

Notes

  • Always handle HTTPError and general exceptions
  • Session persists even after errors unless reset

Edge Cases

http session cookies manual edge-case web

Session reset and manual cookie management

import http.cookiejar

# Resetting session (new CookieJar)
cookie_jar = http.cookiejar.CookieJar()  # New session, no cookies

# Manual cookie manipulation
for cookie in cookie_jar:
    print(cookie.name, cookie.value)
# You can add/remove cookies manually if needed

Notes

  • Creating a new CookieJar resets the session
  • Manual cookie management is rarely needed but possible

🔗 Cross-References

🏷️ Tags

http, session, cookies, headers, login, opener, error, manual, edge-case, web

📝 Notes

  • Sessions are useful for login, authentication, and stateful APIs
  • For advanced cookie handling, see http.cookiejar docs
  • For thread safety, use a separate opener per thread
  • For persistent cookies across runs, use MozillaCookieJar or LWPCookieJar