Dies ist die Support Website des Buches::

  Das Python Praxisbuch
  Der große Profi-Leitfaden für Programmierer
  Farid Hajji
  Addison Wesley / Pearson Education
  ISBN 978-3-8273-2543-3 (Sep 2008), 1298 Seiten.

******************************************
 15. Webprogrammierung und Web Frameworks
******************************************

Webserver in Python
===================

Webserver aus der Python Standard Library
-----------------------------------------

BaseHTTPServer
^^^^^^^^^^^^^^

.. literalinclude:: ../att/webprog/basehttpserver.py

`basehttpserver.py <https://pythonbook.hajji.org/v1/att/webprog/basehttpserver.py>`_

.. literalinclude:: ../att/webprog/basehttpserver2.py

`basehttpserver2.py <https://pythonbook.hajji.org/v1/att/webprog/basehttpserver2.py>`_

.. literalinclude:: ../att/webprog/basehttpcalc.py

`basehttpcalc.py <https://pythonbook.hajji.org/v1/att/webprog/basehttpcalc.py>`_

SimpleHTTPServer
^^^^^^^^^^^^^^^^

.. literalinclude:: ../att/webprog/simplehttpserver.py

`simplehttpserver.py <https://pythonbook.hajji.org/v1/att/webprog/simplehttpserver.py>`_

CGIHTTPServer
^^^^^^^^^^^^^

.. literalinclude:: ../att/webprog/cgihttpserver.py

`cgihttpserver.py <https://pythonbook.hajji.org/v1/att/webprog/cgihttpserver.py>`_

.. literalinclude:: ../att/webprog/cgiprintenv.py

`cgiprintenv.py <https://pythonbook.hajji.org/v1/att/webprog/cgiprintenv.py>`_

wsgiref.simple_server
^^^^^^^^^^^^^^^^^^^^^

Eine einfache WSGI-Anwendung::

  def demo_app(environ,start_response):
      from StringIO import StringIO
      stdout = StringIO()
      print >>stdout, "Hello world!"
      print >>stdout
      h = environ.items(); h.sort()
      for k,v in h:
          print >>stdout, k,'=',`v`
      start_response("200 OK", [('Content-Type','text/plain')])
      return [stdout.getvalue()]

.. literalinclude:: ../att/webprog/wsgidemo.py

`wsgidemo.py <https://pythonbook.hajji.org/v1/att/webprog/wsgidemo.py>`_

.. literalinclude:: ../att/webprog/wsgicalc.py

`wsgicalc.py <https://pythonbook.hajji.org/v1/att/webprog/wsgicalc.py>`_

Webserver aus Drittanbietermodulen
----------------------------------

Webserver mit CherryPy
^^^^^^^^^^^^^^^^^^^^^^

URLs:

* `Die CherryPy Website <http://www.cherrypy.org/>`_ (einfacher: mit ``easy_install CherryPy`` installieren)
* `Manpage des Programms fetch <http://www.freebsd.org/cgi/man.cgi?query=fetch&apropos=0&sektion=0&manpath=FreeBSD+7.0-RELEASE&format=html>`_

Screenshots:

* `Screenshot der CherryPy Website <https://pythonbook.hajji.org/v1/img/webprog/Python-2.5.2-WebFrameworks-cherrypy.png>`_

.. literalinclude:: ../att/webprog/cherrypyhello.py

`cherrypyhello.py <https://pythonbook.hajji.org/v1/att/webprog/cherrypyhello.py>`_

.. literalinclude:: ../att/webprog/cherrypymapper.py

`cherrypymapper.py <https://pythonbook.hajji.org/v1/att/webprog/cherrypymapper.py>`_

.. literalinclude:: ../att/webprog/cherrypymapper2.py

`cherrypymapper2.py <https://pythonbook.hajji.org/v1/att/webprog/cherrypymapper2.py>`_

.. literalinclude:: ../att/webprog/cherrypysite.py

`cherrypysite.py <https://pythonbook.hajji.org/v1/att/webprog/cherrypysite.py>`_

.. literalinclude:: ../att/webprog/cherrypyform.py

`cherrypyform.py <https://pythonbook.hajji.org/v1/att/webprog/cherrypyform.py>`_

.. literalinclude:: ../att/webprog/cherrypycalc.py

`cherrypycalc.py <https://pythonbook.hajji.org/v1/att/webprog/cherrypycalc.py>`_

Twisted.Web Server
^^^^^^^^^^^^^^^^^^

URLs:

* `Grundlage dieses Abschnitts ist dieses HOWTO <http://twistedmatrix.com/projects/web/documentation/howto/using-twistedweb.html>`_

.. literalinclude:: ../att/webprog/twistedhelloworld.py

`twistedhelloworld.py <https://pythonbook.hajji.org/v1/att/webprog/twistedhelloworld.py>`_

.. literalinclude:: ../att/webprog/twistedurl1.py

`twistedurl1.py <https://pythonbook.hajji.org/v1/att/webprog/twistedurl1.py>`_

.. literalinclude:: ../att/webprog/twistedurl2.py

`twistedurl2.py <https://pythonbook.hajji.org/v1/att/webprog/twistedurl2.py>`_

.. literalinclude:: ../att/webprog/twistedwebcalc.py

`twistedwebcalc.py <https://pythonbook.hajji.org/v1/att/webprog/twistedwebcalc.py>`_

.. literalinclude:: ../att/webprog/twistedwebcalc2.py

`twistedwebcalc2.py <https://pythonbook.hajji.org/v1/att/webprog/twistedwebcalc2.py>`_

.. literalinclude:: ../att/webprog/twistedwebcalc3.py

`twistedwebcalc3.py <https://pythonbook.hajji.org/v1/att/webprog/twistedwebcalc3.py>`_

.. literalinclude:: ../att/webprog/twistedstaticfile.py

`twistedstaticfile.py <https://pythonbook.hajji.org/v1/att/webprog/twistedstaticfile.py>`_

.. literalinclude:: ../att/webprog/twistedstaticandcgi.py

`twistedstaticandcgi.py <https://pythonbook.hajji.org/v1/att/webprog/twistedstaticandcgi.py>`_

.. literalinclude:: ../att/webprog/twistedserverpy.py

`twistedserverpy.py <https://pythonbook.hajji.org/v1/att/webprog/twistedserverpy.py>`_

.. literalinclude:: ../att/webprog/webcalc.rpy
   :language: python

`webcalc.rpy <https://pythonbook.hajji.org/v1/att/webprog/webcalc.rpy>`_

.. literalinclude:: ../att/webprog/twistedserve_rpy_perl_php.py

`twistedserve_rpy_perl_php.py <https://pythonbook.hajji.org/v1/att/webprog/twistedserve_rpy_perl_php.py>`_

.. literalinclude:: ../att/webprog/test.pl
   :language: perl

`test.pl <https://pythonbook.hajji.org/v1/att/webprog/test.pl>`_

.. literalinclude:: ../att/webprog/test.php
   :language: php

`test.php <https://pythonbook.hajji.org/v1/att/webprog/test.php>`_

.. literalinclude:: ../att/webprog/twistedtarpit.py

`twistedtarpit.py <https://pythonbook.hajji.org/v1/att/webprog/twistedtarpit.py>`_

.. literalinclude:: ../att/webprog/twistedwebsvc.py

`twistedwebsvc.py <https://pythonbook.hajji.org/v1/att/webprog/twistedwebsvc.py>`_

Integration mit anderen Webservern
==================================

Lighttpd
--------

URLs:

* `Website von Lighttpd <http://www.lighttpd.net/>`_

`lighttpd_common.conf <https://pythonbook.hajji.org/v1/att/webprog/lighttpd_common.conf>`_

Lighttpd und CGI
^^^^^^^^^^^^^^^^

.. literalinclude:: ../att/webprog/lighttpd_cgi.conf

`lighttpd_cgi.conf <https://pythonbook.hajji.org/v1/att/webprog/lighttpd_cgi.conf>`_

Lighttpd und FastCGI
^^^^^^^^^^^^^^^^^^^^

.. literalinclude:: ../att/webprog/lighttpd_fastcgi.conf

`lighttpd_fastcgi.conf <https://pythonbook.hajji.org/v1/att/webprog/lighttpd_fastcgi.conf>`_

FastCGI-Server in Python mit flup
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

URLs:

* `Das flup Modul <http://www.saddi.com/software/flup/>`_ (mit ``easy_install flup`` installieren)

.. literalinclude:: ../att/webprog/fastcgi_server_helloworld.py

`fastcgi_server_helloworld.py <https://pythonbook.hajji.org/v1/att/webprog/fastcgi_server_helloworld.py>`_

.. literalinclude:: ../att/webprog/fastcgi_server_debug.py

`fastcgi_server_debug.py <https://pythonbook.hajji.org/v1/att/webprog/fastcgi_server_debug.py>`_

.. literalinclude:: ../att/webprog/fastcgi_server_webcalc.py

`fastcgi_server_webcalc.py <https://pythonbook.hajji.org/v1/att/webprog/fastcgi_server_webcalc.py>`_

Lighttpd und SCGI
^^^^^^^^^^^^^^^^^

.. literalinclude:: ../att/webprog/lighttpd_scgi.conf

`lighttpd_scgi.conf <https://pythonbook.hajji.org/v1/att/webprog/lighttpd_scgi.conf>`_

SCGI-Server in Python mit flup
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

.. literalinclude:: ../att/webprog/scgi_server_webcalc.py

`scgi_server_webcalc.py <https://pythonbook.hajji.org/v1/att/webprog/scgi_server_webcalc.py>`_

Python in Lighttpd integrieren
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Apache
------

URLs:

* `Website von Apache <http://httpd.apache.org/>`_

Apache und CGI
^^^^^^^^^^^^^^

Apache und FastCGI
^^^^^^^^^^^^^^^^^^

URLs:

* `Website des mod_fastcgi Moduls <http://www.fastcgi.com/>`_

Apache und SCGI
^^^^^^^^^^^^^^^

URLs:

* `Website des mod_scgi Moduls <http://www.mems-exchange.org/software/scgi/>`_

Apache und mod_python
^^^^^^^^^^^^^^^^^^^^^

URLs:

* `Extending and Embedding <http://docs.python.org/ext/embedding.html>`_
* `Website von mod_python <http://www.modpython.org/>`_

Wie das Einbetten eines Python-Interpreters in C-Code funktioniert:

.. code-block:: c

  #include <Python.h>
  
  int
  main(int argc, char *argv[])
  {
    Py_Initialize();
    PyRun_SimpleString("from time import time, ctime\n"
                       "print 'Today is', ctime(time())\n");
    Py_Finalize();
    return 0;
  }

Ein Ausschnitt aus der :file:`httpd.conf`::

  LoadModule python_module libexec/apache22/mod_python.so
  
  <IfModule mod_python.c>
    <Location /python>
      AddHandler mod_python .py
      PythonHandler mod_python.publisher
      PythonDebug On
    </Location>
  </IfModule>

.. literalinclude:: ../att/webprog/modpycalc.py

`modpycalc.py <https://pythonbook.hajji.org/v1/att/webprog/modpycalc.py>`_

Apache und WSGI
^^^^^^^^^^^^^^^

URLs:

* `Website des mod_wsgi Moduls <http://www.modwsgi.org/>`_

Ein Ausschnitt aus der :file:`httpd.conf`::

  LoadModule wsgi_module libexec/apache22/mod_wsgi.so
  
  LogLevel info
  
  <IfModule mod_wsgi.c>
      # 1. /wsgi should contain WSGI-apps.
      #    Note: the function name MUST be 'application'
      WSGIScriptAlias /wsgi/ /usr/local/www/apache22/wsgi-bin/
  
      # 2. Additional paths to look for python modules (:-separated)
      WSGIPythonPath "/usr/local/www/apache22/wsgi-bin"
  
      # 3. All applications within this directory will share the
      #    same python subinterpreter.
      <Directory /usr/local/www/apache22/wsgi-bin>
        WSGIApplicationGroup my-wsgi-scripts
        Order allow,deny
        Allow from all
      </Directory>
  </IfModule>

.. literalinclude:: ../att/webprog/hello.wsgi
   :language: python

`hello.wsgi <https://pythonbook.hajji.org/v1/att/webprog/hello.wsgi>`_

.. literalinclude:: ../att/webprog/wsgidebug.py

`wsgidebug.py <https://pythonbook.hajji.org/v1/att/webprog/wsgidebug.py>`_

.. literalinclude:: ../att/webprog/debug.wsgi
   :language: python

`debug.wsgi <https://pythonbook.hajji.org/v1/att/webprog/debug.wsgi>`_

.. literalinclude:: ../att/webprog/calc.wsgi
   :language: python

`calc.wsgi <https://pythonbook.hajji.org/v1/att/webprog/calc.wsgi>`_

WSGI
====

Was ist WSGI?
-------------

.. literalinclude:: ../att/webprog/hello.wsgi
   :language: python

`hello.wsgi <https://pythonbook.hajji.org/v1/att/webprog/hello.wsgi>`_

.. literalinclude:: ../att/webprog/wsgidummyapp.py

`wsgidummyapp.py <https://pythonbook.hajji.org/v1/att/webprog/wsgidummyapp.py>`_

.. literalinclude:: ../att/webprog/wsgidummyserver.py

`wsgidummyserver.py <https://pythonbook.hajji.org/v1/att/webprog/wsgidummyserver.py>`_

.. literalinclude:: ../att/webprog/wsgidummydemo.py

`wsgidummydemo.py <https://pythonbook.hajji.org/v1/att/webprog/wsgidummydemo.py>`_

URLs:

* `Informationen zu WSGI <http://www.wsgi.org/>`_

WSGI-Tools
----------

Die wsgiref.*-Module
^^^^^^^^^^^^^^^^^^^^

WSGI-Utils
^^^^^^^^^^

URLs:

* `Website der WSGI-Utils <http://www.owlfish.com/software/wsgiutils/>`_ (aber mit ``easy_install wsgiutils`` installieren)

flup
^^^^

Wurde weiter oben schon eingeführt.

Python Paste
^^^^^^^^^^^^

URLs:

* `Website von Paste <http://pythonpaste.org/>`_

Low-level-Programmierung mit CGI
================================

Hello, CGI World!
-----------------

.. literalinclude:: ../att/webprog/cgihello.py

`cgihello.py <https://pythonbook.hajji.org/v1/att/webprog/cgihello.py>`_

CGI-Umgebungsvariablen
----------------------

.. literalinclude:: ../att/webprog/cgiprintenv.py

`cgiprintenv.py <https://pythonbook.hajji.org/v1/att/webprog/cgiprintenv.py>`_

Screenshots:

* `Ausgabe von cgiprintenv.py <https://pythonbook.hajji.org/v1/img/webprog/Python-2.5.2-WebFrameworks-cgiprintenv.png>`_

Anwendung: Ein Web-Taschenrechner
---------------------------------

.. literalinclude:: ../att/webprog/cgicalc.py

`cgicalc.py <https://pythonbook.hajji.org/v1/att/webprog/cgicalc.py>`_

Ein Formular manuell auslesen
-----------------------------

.. literalinclude:: ../att/webprog/cgiformget.html
   :language: xml

`cgiformget.html <https://pythonbook.hajji.org/v1/att/webprog/cgiformget.html>`_

.. literalinclude:: ../att/webprog/cgiform.py

`cgiform.py <https://pythonbook.hajji.org/v1/att/webprog/cgiform.py>`_

.. literalinclude:: ../att/webprog/cgiformpost.html
   :language: xml

`cgiformpost.html <https://pythonbook.hajji.org/v1/att/webprog/cgiformpost.html>`_

Das cgi-Modul
-------------

.. literalinclude:: ../att/webprog/cgiform2.py

`cgiform2.py <https://pythonbook.hajji.org/v1/att/webprog/cgiform2.py>`_

.. literalinclude:: ../att/webprog/cgierror.py

`cgierror.py <https://pythonbook.hajji.org/v1/att/webprog/cgierror.py>`_

Screenshots:

* `Ausgabe von cgierror.py <https://pythonbook.hajji.org/v1/img/webprog/Python-2.5.2-WebFrameworks-cgierror.png>`_

Anwendung: Dateien uploaden
---------------------------

.. literalinclude:: ../att/webprog/cgiupload.py

`cgiupload.py <https://pythonbook.hajji.org/v1/att/webprog/cgiupload.py>`_

Das Formular, welches das Eingabefenster erzeugt:

.. code-block:: xml

  <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
       "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
  <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
    <head>
      <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
      <title>A simple file upload form</title>
    </head>
    <body>
      <h1>Upload a file to /tmp</h1>
      <form action="/cgiupload.py" method="POST"
            enctype="multipart/form-data">
        <input type="file" name="filename" />(File Name)<br />
        <input type="password" size="8" name="password" /> (User Password)<br />
        <input type="submit" value="Upload file"/>
      </form>
    </body>
  </html>

Den Zustand clientseitig erhalten
---------------------------------

Zustand als Teil der URL
^^^^^^^^^^^^^^^^^^^^^^^^

.. literalinclude:: ../att/webprog/cgistate_pathinfo.py

`cgistate_pathinfo.py <https://pythonbook.hajji.org/v1/att/webprog/cgistate_pathinfo.py>`_

hidden-Felder
^^^^^^^^^^^^^

Ein Formular mit einem Hidden-Feld:

.. code-block:: xml

  <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
       "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
  <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
    <head>
      <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
      <title>CGI Counter 2</title>
    </head>
    <body>
      <p>Current counter value: 4</p>
      <form action="/cgi-bin/cgistate_hiddenfields.py" method="POST">
        <input type="hidden" name="state" value="4" />
        <input type="submit" value="Increment counter"/>
      </form>
    </body>
  </html>

.. literalinclude:: ../att/webprog/cgistate_hiddenfields.py

`cgistate_hiddenfields.py <https://pythonbook.hajji.org/v1/att/webprog/cgistate_hiddenfields.py>`_

Cookies
^^^^^^^

.. literalinclude:: ../att/webprog/cgistate_cookies.py

`cgistate_cookies.py <https://pythonbook.hajji.org/v1/att/webprog/cgistate_cookies.py>`_

Screenshots:

* `Das Cookie aus cgistate_cookies.py in Elinks <https://pythonbook.hajji.org/v1/img/webprog/Python-2.5.2-WebFrameworks-cgicookies-headers.png>`_

Den Zustand fälschungssicherer machen
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Screenshots:

* `Man kann Cookies browserseite fälschen <https://pythonbook.hajji.org/v1/img/webprog/Python-2.5.2-WebFrameworks-cgicookies.png>`_
* `Das Cookie aus cgistate_cryptcookies.py in Elinks <https://pythonbook.hajji.org/v1/img/webprog/Python-2.5.2-WebFrameworks-cgicryptcookies-headers.png>`_
* `Vor der Fälschung des Cookies <https://pythonbook.hajji.org/v1/img/webprog/Python-2.5.2-WebFrameworks-cgicryptcookies-beforetampering.png>`_
* `Das Cookie wird gefälscht <https://pythonbook.hajji.org/v1/img/webprog/Python-2.5.2-WebFrameworks-cgicryptcookies-tampering.png>`_
* `Die Fälschung wird erkannt <https://pythonbook.hajji.org/v1/img/webprog/Python-2.5.2-WebFrameworks-cgicryptcookies-aftertampering.png>`_

URLs:

* `Das Web Developer Firefox Plugin <http://chrispederick.com/work/web-developer/>`_
* `Die pycrypto Website <http://www.amk.ca/python/code/crypto.html>`_ (mit ``easy_install pycrypto`` installieren)
* `A Secure Cookie Protocol by Alex X. Liu et. al. <http://www.cse.msu.edu/~alexliu/publications/Cookie/cookie.pdf>`_ (PDF)

.. literalinclude:: ../att/webprog/cgistate_cookies.py

`cgistate_cookies.py <https://pythonbook.hajji.org/v1/att/webprog/cgistate_cookies.py>`_

.. literalinclude:: ../att/webprog/cryptutils.py

`cryptutils.py <https://pythonbook.hajji.org/v1/att/webprog/cryptutils.py>`_

.. literalinclude:: ../att/webprog/cryptutils_demo.py

`cryptutils_demo.py <https://pythonbook.hajji.org/v1/att/webprog/cryptutils_demo.py>`_

.. literalinclude:: ../att/webprog/cryptcookie.py

`cryptcookie.py <https://pythonbook.hajji.org/v1/att/webprog/cryptcookie.py>`_

.. literalinclude:: ../att/webprog/cgistate_cryptcookies.py

`cgistate_cryptcookies.py <https://pythonbook.hajji.org/v1/att/webprog/cgistate_cryptcookies.py>`_

.. literalinclude:: ../att/webprog/securecookieprotocol.py

`securecookieprotocol.py <https://pythonbook.hajji.org/v1/att/webprog/securecookieprotocol.py>`_

Den Zustand serverseitig erhalten
---------------------------------

Sitzungen
^^^^^^^^^

Die grundlegende Vorgehenseweise bei Sitzungen (Pseudocode)::

  def handle_request(req):
  
      session = DB_Session(session_time=300)  # 5 minutes = 300 secs. sessions
      cookie  = req.getCookie('session')      # decrypt and verify, else None
      
      if cookie:
          sess_id = cookie.getSessionID()
	  if session.session_valid(sess_id):
              if req.getCommand() == LOGOUT:
                  session.session_remove(sess_id)
                  send_cookie(create_cookie(LOGGED_OUT))
                  confirmLogoutToUser()
                  send_login_form()
              else:
                  do_something_with_session_and_request(sess_id, req)
                  session.session_extend_time(sess_id)
                  send_some_reply()
          else:
	      sendErrorToUser(INVALID_OR_EXPIRED_SESSION)
	      send_login_form()
      
      else:
          if req.hasLoginCredentials():
              username, password = req.loginCredentials()
              if verify_credentials(username, password):
                  sess_id = session.session_create(username)
                  send_cookie(create_cookie(sess_id)) # encrypt and sign cookie
                  confirmLoginToUser()
                  show_logged_in_page()
              else:
                  sendErrorToUser(INVALID_USER)
                  send_login_form()
          else:
              send_login_form()
    
      session.close()

.. literalinclude:: ../att/webprog/session.py

`session.py <https://pythonbook.hajji.org/v1/att/webprog/session.py>`_

Datenbankbasierte Sitzungen
^^^^^^^^^^^^^^^^^^^^^^^^^^^

.. literalinclude:: ../att/webprog/session_dbapi.py

`session_dbapi.py <https://pythonbook.hajji.org/v1/att/webprog/session_dbapi.py>`_

Dateibasierte Sitzungen
^^^^^^^^^^^^^^^^^^^^^^^

Nachteile von CGI
-----------------

Webclients
==========

Low-level HTTP Protokoll mit httplib
------------------------------------

Einfache Webclients mit urllib
------------------------------

Flexiblere Webclients mit urllib2
---------------------------------

Eine Seite anfordern
^^^^^^^^^^^^^^^^^^^^

Eine URL herunterladen::

  import urllib2
  theurl = 'https://pythonbook.hajji.org/examples/net/test.html'
  
  f = urllib2.urlopen(theurl)
  data = f.read()
  f.close()

Man kann auch zeilenweise iterieren::

  f = urllib2.urlopen(theurl)
  for line in f:
      thelist.append(line)
  f.close()

.. literalinclude:: ../att/webprog/fetchchunked.py

`fetchchunked.py <https://pythonbook.hajji.org/v1/att/webprog/fetchchunked.py>`_

Einen Teil einer Seite anfordern
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Alles, mit Ausnahme der 30 ersten Bytes laden::

  import urllib2
  
  opener = urllib2.build_opener()
  opener.addheaders = [('Range', 'bytes=30-'), ('User-agent', 'mybot/0.0')]
  op = opener.open('https://pythonbook.hajji.org/examples/net/test.html')
  data = op.read()

Webclients mit Twisted
----------------------

.. literalinclude:: ../att/webprog/twisted_fetcher.py

`twisted_fetcher.py <https://pythonbook.hajji.org/v1/att/webprog/twisted_fetcher.py>`_

Templating Engines
==================

URLs:

* `Templating Module in Python <http://wiki.python.org/moin/Templating>`_

Templating für arme Leute
-------------------------

Stringinterpolation
^^^^^^^^^^^^^^^^^^^

.. literalinclude:: ../att/webprog/template1.txt

`template1.txt <https://pythonbook.hajji.org/v1/att/webprog/template1.txt>`_

.. literalinclude:: ../att/webprog/template2.txt

`template2.txt <https://pythonbook.hajji.org/v1/att/webprog/template2.txt>`_

.. literalinclude:: ../att/webprog/template3.txt

`template3.txt <https://pythonbook.hajji.org/v1/att/webprog/template3.txt>`_

string.Template
^^^^^^^^^^^^^^^

Screenshots:

* `Dokumentation zum Modul string.Template <https://pythonbook.hajji.org/v1/img/webprog/Python-2.5.2-WebFrameworks-templatestrings.png>`_

.. literalinclude:: ../att/webprog/template4.txt

`template4.txt <https://pythonbook.hajji.org/v1/att/webprog/template4.txt>`_

Text-basiertes Templating
-------------------------

Mako
^^^^

Screenshots:

* `Website des Mako Moduls (Screenshot) <https://pythonbook.hajji.org/v1/img/webprog/Python-2.5.2-WebFrameworks-mako.png>`_

URLs:

* `Website des Mako Moduls <http://www.makotemplates.org/>`_ (aber mit ``easy_install Mako`` installieren)

.. literalinclude:: ../att/webprog/mako1.txt
   :language: mako

`mako1.txt <https://pythonbook.hajji.org/v1/att/webprog/mako1.txt>`_

.. literalinclude:: ../att/webprog/mako1.txt.py

`mako1.txt.py <https://pythonbook.hajji.org/v1/att/webprog/mako1.txt.py>`_

.. literalinclude:: ../att/webprog/mako_header.txt
   :language: mako

`mako_header.txt <https://pythonbook.hajji.org/v1/att/webprog/mako_header.txt>`_

.. literalinclude:: ../att/webprog/mako_footer.txt
   :language: mako

`mako_footer.txt <https://pythonbook.hajji.org/v1/att/webprog/mako_footer.txt>`_

.. literalinclude:: ../att/webprog/mako_main.txt
   :language: mako

`mako_main.txt <https://pythonbook.hajji.org/v1/att/webprog/mako_main.txt>`_

.. literalinclude:: ../att/webprog/mako_all.txt
   :language: mako

`mako_all.txt <https://pythonbook.hajji.org/v1/att/webprog/mako_all.txt>`_

.. literalinclude:: ../att/webprog/showmako.py

`showmako.py <https://pythonbook.hajji.org/v1/att/webprog/showmako.py>`_

.. literalinclude:: ../att/webprog/mako2.txt
   :language: mako

`mako2.txt <https://pythonbook.hajji.org/v1/att/webprog/mako2.txt>`_

.. literalinclude:: ../att/webprog/mako3.txt
   :language: mako

`mako3.txt <https://pythonbook.hajji.org/v1/att/webprog/mako3.txt>`_

.. literalinclude:: ../att/webprog/mako4.txt
   :language: mako

`mako4.txt <https://pythonbook.hajji.org/v1/att/webprog/mako4.txt>`_

.. literalinclude:: ../att/webprog/mako5.txt
   :language: mako

`mako5.txt <https://pythonbook.hajji.org/v1/att/webprog/mako5.txt>`_

.. literalinclude:: ../att/webprog/mako6.txt
   :language: mako

`mako6.txt <https://pythonbook.hajji.org/v1/att/webprog/mako6.txt>`_

.. literalinclude:: ../att/webprog/mako7.txt
   :language: mako

`mako7.txt <https://pythonbook.hajji.org/v1/att/webprog/mako7.txt>`_

.. literalinclude:: ../att/webprog/mako8.txt
   :language: mako

`mako8.txt <https://pythonbook.hajji.org/v1/att/webprog/mako8.txt>`_

.. literalinclude:: ../att/webprog/makocalc.txt
   :language: mako

`makocalc.txt <https://pythonbook.hajji.org/v1/att/webprog/makocalc.txt>`_

.. literalinclude:: ../att/webprog/mako9.txt
   :language: mako

`mako9.txt <https://pythonbook.hajji.org/v1/att/webprog/mako9.txt>`_

.. literalinclude:: ../att/webprog/mako10.txt
   :language: mako

`mako10.txt <https://pythonbook.hajji.org/v1/att/webprog/mako10.txt>`_

.. literalinclude:: ../att/webprog/mako11.txt
   :language: mako

`mako11.txt <https://pythonbook.hajji.org/v1/att/webprog/mako11.txt>`_

.. literalinclude:: ../att/webprog/mako12.txt
   :language: mako

`mako12.txt <https://pythonbook.hajji.org/v1/att/webprog/mako12.txt>`_

.. literalinclude:: ../att/webprog/mako13.txt
   :language: mako

`mako13.txt <https://pythonbook.hajji.org/v1/att/webprog/mako13.txt>`_

.. literalinclude:: ../att/webprog/mako14.txt
   :language: mako

`mako14.txt <https://pythonbook.hajji.org/v1/att/webprog/mako14.txt>`_

.. literalinclude:: ../att/webprog/mako15.txt
   :language: mako

`mako15.txt <https://pythonbook.hajji.org/v1/att/webprog/mako15.txt>`_

.. literalinclude:: ../att/webprog/mako16.txt
   :language: mako

`mako16.txt <https://pythonbook.hajji.org/v1/att/webprog/mako16.txt>`_

.. literalinclude:: ../att/webprog/mako17.txt
   :language: mako

`mako17.txt <https://pythonbook.hajji.org/v1/att/webprog/mako17.txt>`_

.. mako18.txt contains umlauts, non suitable for Sphinx...

`mako18.txt <https://pythonbook.hajji.org/v1/att/webprog/mako18.txt>`_

Cheetah
^^^^^^^

URLs:

* `Website von Cheetah <http://www.cheetahtemplate.org/>`_

.. literalinclude:: ../att/webprog/cheetah1.txt

`cheetah1.txt <https://pythonbook.hajji.org/v1/att/webprog/cheetah1.txt>`_

XML-basiertes Templating
------------------------

Genshi
^^^^^^

Screenshots:

* `Website von Genshi (Screenshot) <https://pythonbook.hajji.org/v1/img/webprog/Python-2.5.2-WebFrameworks-genshi.png>`_

URLs:

* `Website von Genshi <http://genshi.edgewall.org/>`_ (aber mit ``easy_install Genshi`` installieren)

.. literalinclude:: ../att/webprog/genshi1.txt
   :language: xml

`genshi1.txt <https://pythonbook.hajji.org/v1/att/webprog/genshi1.txt>`_

.. literalinclude:: ../att/webprog/showgenshi.py

`showgenshi.py <https://pythonbook.hajji.org/v1/att/webprog/showgenshi.py>`_

.. literalinclude:: ../att/webprog/genshi2.txt
   :language: xml

`genshi2.txt <https://pythonbook.hajji.org/v1/att/webprog/genshi2.txt>`_

.. literalinclude:: ../att/webprog/genshi3.txt
   :language: xml

`genshi3.txt <https://pythonbook.hajji.org/v1/att/webprog/genshi3.txt>`_

.. literalinclude:: ../att/webprog/genshi4.txt
   :language: xml

`genshi4.txt <https://pythonbook.hajji.org/v1/att/webprog/genshi4.txt>`_

.. literalinclude:: ../att/webprog/genshi5.html
   :language: xml

`genshi5.html <https://pythonbook.hajji.org/v1/att/webprog/genshi5.html.txt>`_

.. literalinclude:: ../att/webprog/genshi6.html
   :language: xml

`genshi6.html <https://pythonbook.hajji.org/v1/att/webprog/genshi6.html.txt>`_

.. literalinclude:: ../att/webprog/genshi7.html
   :language: xml

`genshi7.html <https://pythonbook.hajji.org/v1/att/webprog/genshi7.html.txt>`_

.. literalinclude:: ../att/webprog/genshi8.html
   :language: xml

`genshi8.html <https://pythonbook.hajji.org/v1/att/webprog/genshi8.html.txt>`_

.. literalinclude:: ../att/webprog/genshi9.html
   :language: xml

`genshi9.html <https://pythonbook.hajji.org/v1/att/webprog/genshi9.html.txt>`_

.. literalinclude:: ../att/webprog/genshi10.html
   :language: xml

`genshi10.html <https://pythonbook.hajji.org/v1/att/webprog/genshi10.html.txt>`_

.. literalinclude:: ../att/webprog/genshi11.html
   :language: xml

`genshi11.html <https://pythonbook.hajji.org/v1/att/webprog/genshi11.html>`_

.. literalinclude:: ../att/webprog/genshi12.html
   :language: xml

`genshi12.html <https://pythonbook.hajji.org/v1/att/webprog/genshi12.html.txt>`_

.. literalinclude:: ../att/webprog/genshicalc.html
   :language: xml

`genshicalc.html <https://pythonbook.hajji.org/v1/att/webprog/genshicalc.html.txt>`_

.. literalinclude:: ../att/webprog/genshi13.html
   :language: xml

`genshi13.html <https://pythonbook.hajji.org/v1/att/webprog/genshi13.html.txt>`_

Kid
^^^

URLs:

* `Website von Kid <http://www.kid-templating.org/>`_

Weitere Templating Systeme
--------------------------

URLs:

* `Nevow <http://divmod.org/trac/wiki/DivmodNevow>`_
* `SimpleTAL <http://www.owlfish.com/software/simpleTAL/>`_
* `Python Servlet Engine <http://nick.borko.org/pse/index.html>`_
* `Qpy <http://www.mems-exchange.org/software/qpy/>`_
* `Evoque <http://evoque.gizmojo.org/>`_

Web Frameworks
==============

Django
------

Screenshots:

* `Screenshot der Django Website <https://pythonbook.hajji.org/v1/img/webprog/Python-2.5.2-WebFrameworks-django.png>`_

Django installieren
^^^^^^^^^^^^^^^^^^^

URLs:

* `Website von Django <http://www.djangoproject.com/>`_
* `Die im Buch verwendete Version <http://media.djangoproject.com/releases/0.96/Django-0.96.2.tar.gz>`_

Ein Django-Projekt starten
^^^^^^^^^^^^^^^^^^^^^^^^^^

Screenshots:

* `Die Default-Seite eines leeren Django-Projekts <https://pythonbook.hajji.org/v1/img/webprog/Python-2.5.2-WebFrameworks-django-01.png>`_

Eine Datenbank anbinden
^^^^^^^^^^^^^^^^^^^^^^^

Modelle definieren
^^^^^^^^^^^^^^^^^^

.. literalinclude:: ../att/webprog/models.py

`models.py <https://pythonbook.hajji.org/v1/att/webprog/models.py>`_

Das Modell ausprobieren
^^^^^^^^^^^^^^^^^^^^^^^

Die Admin-Site
^^^^^^^^^^^^^^

Screenshots:

* `Login in die Admin Site <https://pythonbook.hajji.org/v1/img/webprog/Python-2.5.2-WebFrameworks-django-02.png>`_
* `In die Admin Site gerade eingeloggt <https://pythonbook.hajji.org/v1/img/webprog/Python-2.5.2-WebFrameworks-django-03.png>`_
* `Einen Artikel in der Admin-Site verändern <https://pythonbook.hajji.org/v1/img/webprog/Python-2.5.2-WebFrameworks-django-04.png>`_

Die öffentliche Sicht
^^^^^^^^^^^^^^^^^^^^^

.. literalinclude:: ../att/webprog/urls.py

`urls.py <https://pythonbook.hajji.org/v1/att/webprog/urls.py>`_

Screenshots:

* `Page not found <https://pythonbook.hajji.org/v1/img/webprog/Python-2.5.2-WebFrameworks-django-05.png>`_

.. literalinclude:: ../att/webprog/views.py

`views.py <https://pythonbook.hajji.org/v1/att/webprog/views.py>`_

.. literalinclude:: ../att/webprog/index.html
   :language: xml

`index.html <https://pythonbook.hajji.org/v1/att/webprog/index.html.txt>`_

.. literalinclude:: ../att/webprog/article.html
   :language: xml

`article.html <https://pythonbook.hajji.org/v1/att/webprog/article.html.txt>`_

Screenshots:

* `Die öffentliche (noch nicht geskinnte) Sicht eines Artikels <https://pythonbook.hajji.org/v1/img/webprog/Python-2.5.2-WebFrameworks-django-06.png>`_

.. literalinclude:: ../att/webprog/talkback.html
   :language: xml

`talkback.html <https://pythonbook.hajji.org/v1/att/webprog/talkback.html.txt>`_

.. literalinclude:: ../att/webprog/newtalkback.html
   :language: xml

`newtalkback.html <https://pythonbook.hajji.org/v1/att/webprog/newtalkback.html.txt>`_

Was noch zu berücksichtigen ist
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Weitere Web Frameworks
----------------------

URLs:

* `web.py <http://webpy.org/>`_
* `web2.py <http://www.web2py.com/>`_
* `Webware <http://www.webwareforpython.org/>`_
* `Pylons <http://pylonshq.com>`_
* `Turbo Gears <http://www.turbogears.org/>`_

Zope, Plone et. al.
===================

Screenshots:

* `Screenshot der Zope Website <https://pythonbook.hajji.org/v1/img/webprog/Python-2.5.2-WebFrameworks-zope.png>`_

URLs:

* `Die Zope Website <http://www.zope.org/>`_
* `Die Plone Website <http://plone.org/>`_

Zope und Plone zusammen installieren
------------------------------------

Erste Schritte in Zope
----------------------

Screenshots:

* `Das Zope Management Interface (ZMI) <https://pythonbook.hajji.org/v1/img/webprog/Python-2.5.2-PbWebFrameworks-zope-zmi.png>`_
* `Das Zope Template editieren <https://pythonbook.hajji.org/v1/img/webprog/Python-2.5.2-PbWebFrameworks-zope-zpt.png>`_
* `Das Demo Template editieren <https://pythonbook.hajji.org/v1/img/webprog/Python-2.5.2-PbWebFrameworks-zope-demo.png>`_
* `Gebundene Variablen (Bindings) <https://pythonbook.hajji.org/v1/img/webprog/Python-2.5.2-PbWebFrameworks-zope-demobindings.png>`_

Erzeugt man ein Script (Python), erhält man von Zope erst folgenden
Anfangscode::

  # Example code:
  
  # Import a standard function, and get the HTML request and response objects.
  from Products.PythonScripts.standard import html_quote
  request = container.REQUEST
  RESPONSE =  request.RESPONSE
  
  # Return a string identifying this script.
  print "This is the", script.meta_type, '"%s"' % script.getId(),
  if script.title:
      print "(%s)" % html_quote(script.title),
  print "in", container.absolute_url()
  return printed

Wir könnten es z.B. so verändern::

  request = container.REQUEST
  
  print "We've got the following container.REQUEST object:"
  print request
  
  return printed

Der Webrechner in Zope besteht aus einem ZPT :file:`zopecalc_pt`, das
so aussieht:

.. code-block:: xml

  <html>
    <head>
      <title tal:content="template/title">The title</title>
      <meta http-equiv="content-type" content="text/html;charset=utf-8">
    </head>
    <body>
      <form action="zopecalc" method='POST'>
        <input type="text" size="20" name="arg1" value="number 1" />
        <select name="op">
          <option>add</option>
          <option>sub</option>
          <option>mul</option>
          <option>div</option>
        </select>
        <input type="text" size="20" name="arg2" value="number 2" />
        <br />
        <input type="submit" value="Calculate" />
        <input type="reset" value="Clear fields" />
      </form>
    </body>
  </html>

und aus dem dazu passenden Script (Python) :file:`zopecalc`, der davon
aufgerufen wird und so aussieht::

  if len(traverse_subpath) == 3:
      # extract arguments from PATH_INFO...
      op, arg1, arg2 = traverse_subpath
  else:
      # or from GET or POSt parameters.
      op   = container.REQUEST.form.get('op', None)
      arg1 = container.REQUEST.form.get('arg1', None)
      arg2 = container.REQUEST.form.get('arg2', None)
  
  # called the first time w/o args? send form to user
  if op is None or arg1 is None or arg2 is None:
      pt = context.zopecalc_pt
      return pt()
  
  if op not in ('add', 'sub', 'mul', 'div'):
      return 'Invalid operator. Use one of add, sub, mul or div'
  
  result = 'No result yet'
  try:
      numarg1 = float(arg1)
      numarg2 = float(arg2)
      if op == 'add': result = numarg1 + numarg2
      elif op == 'sub': result = numarg1 - numarg2
      elif op == 'mul': result = numarg1 * numarg2
      elif op == 'div':
          if numarg2 == 0: result = 'NaN'
          else:            result = numarg1 / numarg2
  except ValueError:
      return 'Invalid arguments. Use only numerical arguments.'
  except TypeError:
      return 'Invalid arguments. Missing one or both argument.'
  
  return str(result)

Macros in Plone
---------------

Das Script (Python) :file:`plonecalc` sieht so aus::

  if len(traverse_subpath) == 3:
      # extract arguments from PATH_INFO...
      op, arg1, arg2 = traverse_subpath
  else:
      # or from GET or POSt parameters.
      op   = container.REQUEST.form.get('op', None)
      arg1 = container.REQUEST.form.get('arg1', None)
      arg2 = container.REQUEST.form.get('arg2', None)
  
  # This will be our return template
  pt = context.plonecalc_pt
  
  # called the first time w/o args? send form to user
  if op is None or arg1 is None or arg2 is None:
      return pt()
  
  if op not in ('add', 'sub', 'mul', 'div'):
      return pt(result='Invalid operator. Use one of add, sub, mul or div')
  
  result = 'No result yet'
  try:
      numarg1 = float(arg1)
      numarg2 = float(arg2)
      if op == 'add': result = numarg1 + numarg2
      elif op == 'sub': result = numarg1 - numarg2
      elif op == 'mul': result = numarg1 * numarg2
      elif op == 'div':
          if numarg2 == 0: result = 'NaN'
          else:            result = numarg1 / numarg2
  except ValueError:
      return pt(result='Invalid arguments. Use only numerical arguments.')
  except TypeError:
      return pt(result='Invalid arguments. Missing one or both argument.')
  
  # Now return result in a template
  return pt(result=str(result))

Das dazu passende Zope Page Template :file:`plone_calc_pt` lautet:

.. code-block:: xml

  <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en"
        xmlns:tal="http://xml.zope.org/namespaces/tal"
        xmlns:metal="http://xml.zope.org/namespaces/metal"
        xmlns:i18n="http://xml.zope.org/namespaces/i18n"
        lang="en"
        metal:use-macro="here/main_template/macros/master"
        i18n:domain="plone">
  
  <body>
    <div metal:fill-slot="main">
    
      <h1>The Plone Calculator</h1>
      
      <div tal:condition="exists:options/result">
      
        <h2>Previous results</h2>
        The result of the previous calculation was
        <b tal:content="options/result">
          placeholder for result
        </b>.
        
        <h2>New calculation</h2>
      </div>
      
      <form method="POST" action="plonecalc">
        <input type="text" size="20" name="arg1" value="111" />
        <select name="op">
        
          <option>add</option>
          <option>sub</option>
          <option>mul</option>
          <option>div</option>
        </select>
        <input type="text" size="20" name="arg2" value="222" />
        <br />
        
        <input type="submit" value="Calculate" />
        <input type="reset" value="Clear fields" />
      </form>
    </div>
  
  </body>
  
  </html>

Screenshot:

* `Der Plonerechner sieht dann so aus <https://pythonbook.hajji.org/v1/img/webprog/Python-2.5.2-PbWebFrameworks-plone-plonecalc.png>`_

Wikis
=====

URLs:

* `MoinMoin <http://moinmo.in/>`_
* `Trac <http://trac.edgewall.org/>`_

Lose Enden
==========

URLs:

* `Python Imaging Library (PIL) <http://www.pythonware.com/products/pil/index.htm>`_
* `GD Bibliothek <http://newcenturycomputers.net/projects/gdmodule.html>`_
* `ReportLab Toolkit zum Erzeugen von PDF-Dateien <http://www.reportlab.org/rl_toolkit.html>`_

Zusammenfassung
===============