Bagaimana menggunakan sesi

Django provides full support for anonymous sessions. The session framework lets you store and retrieve arbitrary data on a per-site-visitor basis. It stores data on the server side and abstracts the sending and receiving of cookies. Cookies contain a session ID -- not the data itself (unless you're using the cookie based backend).

Mengadakan sesi

Sesi diterapkan melalui potongan middleware 1.

Untuk mengadakan fungsi sesi, lakukan berikut:

• Sunting pengaturan MIDDLEWARE dan pastikan itu berisi 'django.contrib.sessions.middleware.SessionMiddleware'. settings.py bawaan yang dibuat oleh django-admin startproject telah mengaktifkan SessionMiddleware.

Jika anda tidak ingin menggunakan sesi, anda mungkin akan memindahkan baris SessionMiddleware dari MIDDLEWARE dan 'django.contrib.sessions' dari INSTALLED_APPS anda. Itu akan menyimpan anda sedikit diatas.

Konfigurasi mesin sesi

By default, Django stores sessions in your database (using the model django.contrib.sessions.models.Session). Though this is convenient, in some setups it's faster to store session data elsewhere, so Django can be configured to store session data on your filesystem or in your cache.

Menggunakan sesi didukung-basisdata

If you want to use a database-backed session, you need to add 'django.contrib.sessions' to your INSTALLED_APPS setting.

Setelah anda mengonfigurasi pemasangan, jalankan manage.py migrate untuk memasang tabel basisdata tunggal yang menyimpan data sesi.

Menggunakan sesi tembolok

For better performance, you may want to use a cache-based session backend.

To store session data using Django's cache system, you'll first need to make sure you've configured your cache; see the cache documentation for details.

Peringatan

You should only use cache-based sessions if you're using the Memcached or Redis cache backend. The local-memory cache backend doesn't retain data long enough to be a good choice, and it'll be faster to use file or database sessions directly instead of sending everything through the file or database cache backends. Additionally, the local-memory cache backend is NOT multi-process safe, therefore probably not a good choice for production environments.

Jika anda mempunyai banyak tembolok ditentukan di CACHES,Django akan menggunakan tembolok awalan. Untuk menggunakan tembolok lain, setel SESSION_CACHE_ALIAS ke nama dari tembolok tersebut.

Once your cache is configured, you have to choose between a database-backed cache or a non-persistent cache.

The cached database backend (cached_db) uses a write-through cache -- session writes are applied to both the cache and the database. Session reads use the cache, or the database if the data has been evicted from the cache. To use this backend, set SESSION_ENGINE to "django.contrib.sessions.backends.cached_db", and follow the configuration instructions for the using database-backed sessions.

The cache backend (cache) stores session data only in your cache. This is faster because it avoids database persistence, but you will have to consider what happens when cache data is evicted. Eviction can occur if the cache fills up or the cache server is restarted, and it will mean session data is lost, including logging out users. To use this backend, set SESSION_ENGINE to "django.contrib.sessions.backends.cache".

The cache backend can be made persistent by using a persistent cache, such as Redis with appropriate configuration. But unless your cache is definitely configured for sufficient persistence, opt for the cached database backend. This avoids edge cases caused by unreliable data storage in production.

Menggunakan sesi berdasarkan-berkas

Untuk menggunakan sesi berdasarkan-berkas, setel setelan SESSION_ENGINE menjadi "django.contrib.sessions.backends.file".

You might also want to set the SESSION_FILE_PATH setting (which defaults to output from tempfile.gettempdir(), most likely /tmp) to control where Django stores session files. Be sure to check that your web server has permissions to read and write to this location.

Menggunakan sesi berdasarkan-kue

To use cookies-based sessions, set the SESSION_ENGINE setting to "django.contrib.sessions.backends.signed_cookies". The session data will be stored using Django's tools for cryptographic signing and the SECRET_KEY setting.

Catatan

Sangat dianjurkan meninggalkan pengaturan SESSION_COOKIE_HTTPONLY pada True untuk mencegah akses ke data tersimpan dari JavaScript.

Peringatan

If the SECRET_KEY or SECRET_KEY_FALLBACKS are not kept secret and you are using the django.contrib.sessions.serializers.PickleSerializer, this can lead to arbitrary remote code execution.

An attacker in possession of the SECRET_KEY or SECRET_KEY_FALLBACKS can not only generate falsified session data, which your site will trust, but also remotely execute arbitrary code, as the data is serialized using pickle.

If you use cookie-based sessions, pay extra care that your secret key is always kept completely secret, for any system which might be remotely accessible.

Data sesi ditandatangi tetapi tidak disandikan

When using the cookies backend the session data can be read by the client.

A MAC (Message Authentication Code) is used to protect the data against changes by the client, so that the session data will be invalidated when being tampered with. The same invalidation happens if the client storing the cookie (e.g. your user's browser) can't store all of the session cookie and drops data. Even though Django compresses the data, it's still entirely possible to exceed the common limit of 4096 bytes per cookie.

Tidak ada jaminan kesegaran

Note also that while the MAC can guarantee the authenticity of the data (that it was generated by your site, and not someone else), and the integrity of the data (that it is all there and correct), it cannot guarantee freshness i.e. that you are being sent back the last thing you sent to the client. This means that for some uses of session data, the cookie backend might open you up to replay attacks. Unlike other session backends which keep a server-side record of each session and invalidate it when a user logs out, cookie-based sessions are not invalidated when a user logs out. Thus if an attacker steals a user's cookie, they can use that cookie to login as that user even if the user logs out. Cookies will only be detected as 'stale' if they are older than your SESSION_COOKIE_AGE.

Penampilan

Finally, the size of a cookie can have an impact on the speed of your site.

Menggunakan sesi dalam tampilan

When SessionMiddleware is activated, each HttpRequest object -- the first argument to any Django view function -- will have a session attribute, which is a dictionary-like object.

You can read it and write to request.session at any point in your view. You can edit it multiple times.

class backends.base.SessionBase

This is the base class for all session objects. It has the following standard dictionary methods:

__getitem__(key)

Contoh: fav_color = request.session['fav_color']

__setitem__(key, value)

Contoh: request.session['fav_color'] = 'blue'

__delitem__(key)

Example: del request.session['fav_color']. This raises KeyError if the given key isn't already in the session.

__contains__(key)

Contoh: 'fav_color' dalam request.session

get(key, default=None)

Contoh: fav_color = request.session.get('fav_color', 'red')

pop(key, default=__not_given)

Contoh: fav_color = request.session.pop('fav_color', 'blue')

keys()

items()

setdefault()

clear()

Dia juga mempunyai cara ini:

flush()

Deletes the current session data from the session and deletes the session cookie. This is used if you want to ensure that the previous session data can't be accessed again from the user's browser (for example, the django.contrib.auth.logout() function calls it).

set_test_cookie()

Sets a test cookie to determine whether the user's browser supports cookies. Due to the way cookies work, you won't be able to test this until the user's next page request. See Setting test cookies below for more information.

test_cookie_worked()

Returns either True or False, depending on whether the user's browser accepted the test cookie. Due to the way cookies work, you'll have to call set_test_cookie() on a previous, separate page request. See Setting test cookies below for more information.

delete_test_cookie()

Menghapus kue percobaan. Gunakan ini untuk membersihkan diri anda sendiri.

get_session_cookie_age()

Returns the value of the setting SESSION_COOKIE_AGE. This can be overridden in a custom session backend.

set_expiry(value)

Setel waktu kadaluarsa untuk sesi. Anda dapat melewatkan sejumlah nilai berbeda:

• If value is an integer, the session will expire after that many seconds of inactivity. For example, calling request.session.set_expiry(300) would make the session expire in 5 minutes.
• If value is a datetime or timedelta object, the session will expire at that specific date/time.
• If value is 0, the user's session cookie will expire when the user's web browser is closed.
• If value is None, the session reverts to using the global session expiry policy.

Reading a session is not considered activity for expiration purposes. Session expiration is computed from the last time the session was modified.

get_expiry_age()

Returns the number of seconds until this session expires. For sessions with no custom expiration (or those set to expire at browser close), this will equal SESSION_COOKIE_AGE.

Fungsi ini menerima dua pilihan argumen katakunci:

• modification: last modification of the session, as a datetime object. Defaults to the current time.
• expiry: expiry information for the session, as a datetime object, an int (in seconds), or None. Defaults to the value stored in the session by set_expiry(), if there is one, or None.

Catatan

This method is used by session backends to determine the session expiry age in seconds when saving the session. It is not really intended for usage outside of that context.

In particular, while it is possible to determine the remaining lifetime of a session just when you have the correct modification value and the expiry is set as a datetime object, where you do have the modification value, it is more straight-forward to calculate the expiry by-hand:

expires_at = modification + timedelta(seconds=settings.SESSION_COOKIE_AGE)

get_expiry_date()

Returns the date this session will expire. For sessions with no custom expiration (or those set to expire at browser close), this will equal the date SESSION_COOKIE_AGE seconds from now.

This function accepts the same keyword arguments as get_expiry_age(), and similar notes on usage apply.

get_expire_at_browser_close()

Returns either True or False, depending on whether the user's session cookie will expire when the user's web browser is closed.

clear_expired()

Memindahkan sesi kadaluarsa dari penyimpanan sesi. Metode kelas ini dipanggil oleh clearsessions.

cycle_key()

Creates a new session key while retaining the current session data. django.contrib.auth.login() calls this method to mitigate against session fixation.

Serialisasi sesi

By default, Django serializes session data using JSON. You can use the SESSION_SERIALIZER setting to customize the session serialization format. Even with the caveats described in Tulis serialisasi anda sendiri, we highly recommend sticking with JSON serialization especially if you are using the cookie backend.

For example, here's an attack scenario if you use pickle to serialize session data. If you're using the signed cookie session backend and SECRET_KEY (or any key of SECRET_KEY_FALLBACKS) is known by an attacker (there isn't an inherent vulnerability in Django that would cause it to leak), the attacker could insert a string into their session which, when unpickled, executes arbitrary code on the server. The technique for doing so is simple and easily available on the internet. Although the cookie session storage signs the cookie-stored data to prevent tampering, a SECRET_KEY leak immediately escalates to a remote code execution vulnerability.

Bundled serializers

class serializers.JSONSerializer

A wrapper around the JSON serializer from django.core.signing. Can only serialize basic data types.

In addition, as JSON supports only string keys, note that using non-string keys in request.session won't work as expected:

>>> # initial assignment
>>> request.session[0] = "bar"
>>> # subsequent requests following serialization & deserialization
>>> # of session data
>>> request.session[0]  # KeyError
>>> request.session["0"]
'bar'

Similarly, data that can't be encoded in JSON, such as non-UTF8 bytes like '\xd9' (which raises UnicodeDecodeError), can't be stored.

See the Tulis serialisasi anda sendiri section for more details on limitations of JSON serialization.

class serializers.PickleSerializer

Supports arbitrary Python objects, but, as described above, can lead to a remote code execution vulnerability if SECRET_KEY or any key of SECRET_KEY_FALLBACKS becomes known by an attacker.

Ditinggalkan sejak versi 4.1: Due to the risk of remote code execution, this serializer is deprecated and will be removed in Django 5.0.

Tulis serialisasi anda sendiri

Note that the JSONSerializer cannot handle arbitrary Python data types. As is often the case, there is a trade-off between convenience and security. If you wish to store more advanced data types including datetime and Decimal in JSON backed sessions, you will need to write a custom serializer (or convert such values to a JSON serializable object before storing them in request.session). While serializing these values is often straightforward (DjangoJSONEncoder may be helpful), writing a decoder that can reliably get back the same thing that you put in is more fragile. For example, you run the risk of returning a datetime that was actually a string that just happened to be in the same format chosen for datetimes).

Your serializer class must implement two methods, dumps(self, obj) and loads(self, data), to serialize and deserialize the dictionary of session data, respectively.

Panduan obyek sesi

• Use normal Python strings as dictionary keys on request.session. This is more of a convention than a hard-and-fast rule.
• Kunci dictionary sesi yang dimulai dengan garis bawah adalah dipesan untuk penggunaan dalam oleh Django.
• Jangan menimpa request.session dengan obyek baru, dan jangan mengakses atau menyetel atributnya. Gunakan itu seperti dictionary Python.

Contoh

Tampilan sederhana ini menyetel sebuah variabel has_commented menjadi True setelah pengguna menempatkan sebuah komentar. Itu tidak membuat pengguna menempatkan komentar lebih dari satu:

def post_comment(request, new_comment):
    if request.session.get("has_commented", False):
        return HttpResponse("You've already commented.")
    c = comments.Comment(comment=new_comment)
    c.save()
    request.session["has_commented"] = True
    return HttpResponse("Thanks for your comment!")

This simplistic view logs in a "member" of the site:

def login(request):
    m = Member.objects.get(username=request.POST["username"])
    if m.check_password(request.POST["password"]):
        request.session["member_id"] = m.id
        return HttpResponse("You're logged in.")
    else:
        return HttpResponse("Your username and password didn't match.")

...Dan satu ini mencatat anggota keluar, menurut pada login() diatas:

def logout(request):
    try:
        del request.session["member_id"]
    except KeyError:
        pass
    return HttpResponse("You're logged out.")

The standard django.contrib.auth.logout() function actually does a bit more than this to prevent inadvertent data leakage. It calls the flush() method of request.session. We are using this example as a demonstration of how to work with session objects, not as a full logout() implementation.

Mengatur kue percobaan

As a convenience, Django provides a way to test whether the user's browser accepts cookies. Call the set_test_cookie() method of request.session in a view, and call test_cookie_worked() in a subsequent view -- not in the same view call.

This awkward split between set_test_cookie() and test_cookie_worked() is necessary due to the way cookies work. When you set a cookie, you can't actually tell whether a browser accepted it until the browser's next request.

It's good practice to use delete_test_cookie() to clean up after yourself. Do this after you've verified that the test cookie worked.

Ini adalah contoh penggunaan khas:

from django.http import HttpResponse
from django.shortcuts import render


def login(request):
    if request.method == "POST":
        if request.session.test_cookie_worked():
            request.session.delete_test_cookie()
            return HttpResponse("You're logged in.")
        else:
            return HttpResponse("Please enable cookies and try again.")
    request.session.set_test_cookie()
    return render(request, "foo/login_form.html")

Menggunakan sesi di luar tampilan

Catatan

The examples in this section import the SessionStore object directly from the django.contrib.sessions.backends.db backend. In your own code, you should consider importing SessionStore from the session engine designated by SESSION_ENGINE, as below:

>>> from importlib import import_module
>>> from django.conf import settings
>>> SessionStore = import_module(settings.SESSION_ENGINE).SessionStore

An API is available to manipulate session data outside of a view:

>>> from django.contrib.sessions.backends.db import SessionStore
>>> s = SessionStore()
>>> # stored as seconds since epoch since datetimes are not serializable in JSON.
>>> s["last_login"] = 1376587691
>>> s.create()
>>> s.session_key
'2b1189a188b44ad18c35e113ac6ceead'
>>> s = SessionStore(session_key="2b1189a188b44ad18c35e113ac6ceead")
>>> s["last_login"]
1376587691

SessionStore.create() is designed to create a new session (i.e. one not loaded from the session store and with session_key=None). save() is designed to save an existing session (i.e. one loaded from the session store). Calling save() on a new session may also work but has a small chance of generating a session_key that collides with an existing one. create() calls save() and loops until an unused session_key is generated.

Jika Anda menggunakan backend django.contrib.sessions.backends.db, tiap sesi adalah model Django biasa. Model Session didefinisikan dalam django/contrib/sessions/models.py. Karena ini adalah model biasa, anda dapat mengakses sesi menggunakan API basis data Django biasa:

>>> from django.contrib.sessions.models import Session
>>> s = Session.objects.get(pk="2b1189a188b44ad18c35e113ac6ceead")
>>> s.expire_date
datetime.datetime(2005, 8, 20, 13, 35, 12)

Note that you'll need to call get_decoded() to get the session dictionary. This is necessary because the dictionary is stored in an encoded format:

>>> s.session_data
'KGRwMQpTJ19hdXRoX3VzZXJfaWQnCnAyCkkxCnMuMTExY2ZjODI2Yj...'
>>> s.get_decoded()
{'user_id': 42}

Ketika sesi disimpan

By default, Django only saves to the session database when the session has been modified -- that is if any of its dictionary values have been assigned or deleted:

# Session is modified.
request.session["foo"] = "bar"

# Session is modified.
del request.session["foo"]

# Session is modified.
request.session["foo"] = {}

# Gotcha: Session is NOT modified, because this alters
# request.session['foo'] instead of request.session.
request.session["foo"]["bar"] = "baz"

In the last case of the above example, we can tell the session object explicitly that it has been modified by setting the modified attribute on the session object:

request.session.modified = True

To change this default behavior, set the SESSION_SAVE_EVERY_REQUEST setting to True. When set to True, Django will save the session to the database on every single request.

Note that the session cookie is only sent when a session has been created or modified. If SESSION_SAVE_EVERY_REQUEST is True, the session cookie will be sent on every request.

Similarly, the expires part of a session cookie is updated each time the session cookie is sent.

Sesi tidak disimpan jika kode keadaan tanggapan adalah 500.

Browser-length sessions vs. persistent sessions

You can control whether the session framework uses browser-length sessions vs. persistent sessions with the SESSION_EXPIRE_AT_BROWSER_CLOSE setting.

By default, SESSION_EXPIRE_AT_BROWSER_CLOSE is set to False, which means session cookies will be stored in users' browsers for as long as SESSION_COOKIE_AGE. Use this if you don't want people to have to log in every time they open a browser.

If SESSION_EXPIRE_AT_BROWSER_CLOSE is set to True, Django will use browser-length cookies -- cookies that expire as soon as the user closes their browser. Use this if you want people to have to log in every time they open a browser.

This setting is a global default and can be overwritten at a per-session level by explicitly calling the set_expiry() method of request.session as described above in using sessions in views.

Catatan

Some browsers (Chrome, for example) provide settings that allow users to continue browsing sessions after closing and reopening the browser. In some cases, this can interfere with the SESSION_EXPIRE_AT_BROWSER_CLOSE setting and prevent sessions from expiring on browser close. Please be aware of this while testing Django applications which have the SESSION_EXPIRE_AT_BROWSER_CLOSE setting enabled.

Membersihkan toko sesi

As users create new sessions on your website, session data can accumulate in your session store. If you're using the database backend, the django_session database table will grow. If you're using the file backend, your temporary directory will contain an increasing number of files.

To understand this problem, consider what happens with the database backend. When a user logs in, Django adds a row to the django_session database table. Django updates this row each time the session data changes. If the user logs out manually, Django deletes the row. But if the user does not log out, the row never gets deleted. A similar process happens with the file backend.

Django does not provide automatic purging of expired sessions. Therefore, it's your job to purge expired sessions on a regular basis. Django provides a clean-up management command for this purpose: clearsessions. It's recommended to call this command on a regular basis, for example as a daily cron job.

Note that the cache backend isn't vulnerable to this problem, because caches automatically delete stale data. Neither is the cookie backend, because the session data is stored by the users' browsers.

Pengaturan

Sedikit Django settings 1 memberikan anda mengendalikan terhadap perilaku sesi:

• SESSION_CACHE_ALIAS
• SESSION_COOKIE_AGE
• SESSION_COOKIE_DOMAIN
• SESSION_COOKIE_HTTPONLY
• SESSION_COOKIE_NAME
• SESSION_COOKIE_PATH
• SESSION_COOKIE_SAMESITE
• SESSION_COOKIE_SECURE
• SESSION_ENGINE
• SESSION_EXPIRE_AT_BROWSER_CLOSE
• SESSION_FILE_PATH
• SESSION_SAVE_EVERY_REQUEST
• SESSION_SERIALIZER

Keamanan sesi

Subdomains within a site are able to set cookies on the client for the whole domain. This makes session fixation possible if cookies are permitted from subdomains not controlled by trusted users.

For example, an attacker could log into good.example.com and get a valid session for their account. If the attacker has control over bad.example.com, they can use it to send their session key to you since a subdomain is permitted to set cookies on *.example.com. When you visit good.example.com, you'll be logged in as the attacker and might inadvertently enter your sensitive personal data (e.g. credit card info) into the attacker's account.

Another possible attack would be if good.example.com sets its SESSION_COOKIE_DOMAIN to "example.com" which would cause session cookies from that site to be sent to bad.example.com.

Rincian teknik

• The session dictionary accepts any json serializable value when using JSONSerializer.
• Data sesi disimpan dalam tabel basisdata bernama django_session .
• Django hanya mengirim kue jika itu dibutuhkan. Jika anda tidak menyetel data sesi, itu tidak akan mengirim kue sesi.

Obyek SessionStore

Ketika bekerja dengan sesi di dalam, Django menggunakan sebuah sesi menyimpan obyek dari mesin sesi sesuai. Secara kebiasaan, sesi menyimpan kelas obyek dinamai SessionStore dan ditempatkan dalam model dirancang oleh SESSION_ENGINE.

All SessionStore classes available in Django inherit from SessionBase and implement data manipulation methods, namely:

• exists()
• create()
• save()
• delete()
• load()
• clear_expired()

In order to build a custom session engine or to customize an existing one, you may create a new class inheriting from SessionBase or any other existing SessionStore class.

You can extend the session engines, but doing so with database-backed session engines generally requires some extra effort (see the next section for details).

Memperpanjang mesin sesi didukung-basisdata

Creating a custom database-backed session engine built upon those included in Django (namely db and cached_db) may be done by inheriting AbstractBaseSession and either SessionStore class.

AbstractBaseSession and BaseSessionManager are importable from django.contrib.sessions.base_session so that they can be imported without including django.contrib.sessions in INSTALLED_APPS.

class base_session.AbstractBaseSession

Model sesi berdasarkan abstrak.

session_key

Primary key. The field itself may contain up to 40 characters. The current implementation generates a 32-character string (a random sequence of digits and lowercase ASCII letters).

session_data

String mengandung sebyag dictionary sesi disandikan dan diserialisasikan.

expire_date

Menunjuk datetime ketika sesi kadaluarsa.

Sesi kadaluarsa tidak tersedia ke seorang pengguna, bagaimanapun, mereka masih disimpan dalam basisdata sampai perintah pengelolaan clearsessions berjalan.

classmethod get_session_store_class()

Mengembalikan kelas penyimpanan sesi untuk digunakan dengan model sesi ini.

get_decoded()

Mengembalikan data sesi diterjemahkan.

Penterjemahan dilakukan oleh kelas penyimpanan sesi.

Anda dapat juga menyesuaikan pengelola model dengan mensubkelaskan BaseSessionManager:

class base_session.BaseSessionManager

encode(session_dict)

Mengembalikan dictionary sesi diberikan terserialisasi dan disandikan sebagai sebuah string.

Penyandian dialkukan oleh kelas penyimpanan sesi diikat ke kelas model.

save(session_key, session_dict, expire_date)

Saves session data for a provided session key, or deletes the session in case the data is empty.

Customization of SessionStore classes is achieved by overriding methods and properties described below:

class backends.db.SessionStore

Menerapkan penyimpanan sesi backend-basisdata.

classmethod get_model_class()

Kesampingkan metode ini untuk mengembalikan sebuah penyesuaian model sesi jika anda butuh satu.

create_model_instance(data)

Mengembalikan sebuah instance baru dari obyek model sesi, yang mewakili keadaan sesi saat ini.

Kesampingkan metode ini menyediakan kemampuan merubah data model sesi sebelum itu disimpan ke basisdata.

class backends.cached_db.SessionStore

Implements cached database-backed session store.

cache_key_prefix

Sebuah awalan ditambahkan ke kunci sesi untuk membangun string kunci cache.

Contoh

The example below shows a custom database-backed session engine that includes an additional database column to store an account ID (thus providing an option to query the database for all active sessions for an account):

from django.contrib.sessions.backends.db import SessionStore as DBStore
from django.contrib.sessions.base_session import AbstractBaseSession
from django.db import models


class CustomSession(AbstractBaseSession):
    account_id = models.IntegerField(null=True, db_index=True)

    @classmethod
    def get_session_store_class(cls):
        return SessionStore


class SessionStore(DBStore):
    @classmethod
    def get_model_class(cls):
        return CustomSession

    def create_model_instance(self, data):
        obj = super().create_model_instance(data)
        try:
            account_id = int(data.get("_auth_user_id"))
        except (ValueError, TypeError):
            account_id = None
        obj.account_id = account_id
        return obj

Jika anda sedang berpindah dari sesi cached_db siap-pakai Django ke satu penyesuaian berdasarkan pada cached_db, anda harus menimpa awalan kunci cache untuk mencegah bentrokan namespace:

class SessionStore(CachedDBStore):
    cache_key_prefix = "mysessions.custom_cached_db_backend"

    # ...

ID Sesi dalam URL

The Django sessions framework is entirely, and solely, cookie-based. It does not fall back to putting session IDs in URLs as a last resort, as PHP does. This is an intentional design decision. Not only does that behavior make URLs ugly, it makes your site vulnerable to session-ID theft via the "Referer" header.