Python

Índex

General

Python 3

Python
  • The Pyhton tutorial
  • PEP
  • Python (Raspberry Pi)
  • PyPI: the Python package index
  • Python Documentation contents
  • Unicode
    • Solving Unicode Problems in Python 2.7
      • UnicodeDecodeError: ‘ascii’ codec can’t decode byte 0xd1 in position 1: ordinal not in range(128) (Why is this so hard??)
    • Django i18n
      • Use format instead of '%'
        • do not forget trailing 'u'
          • u'{} {} '.format(...)
      • Use 'u' before literals
      •     string = u'{:02d}:{:02d}:{:02d}'.format(hours, minutes, seconds)
            if days:
                if days==1:
                    string = u'{} {} '.format(days,_("day")) + string
                    #string = u"%d %s %s" % ( days, _("day"), string)
                else:
                    string = u'{} {} '.format(days,_("days")) + string
                    #string = u"%d %s %s" % ( days, _("days"), string)

    • File writing
      • import codecs
        filename = os.path.join(...)
        f = codecs.open(filename,mode='w',encoding='utf-8')
        f.write(content)
        f.close        ()
      • import codecs
        filename = os.path.join(...)
        f = codecs.open(filename,mode='w',encoding='utf-8')
        fitxer = File(f)
        fitxer.write(content)
        fitxer.close
  • Eines / Tools
    • virtualenv
    • pip (*) (package manager) (also installed when virtualenv is installed)
      • Installation of pip itself
        • From distribution
          • CentOS
            • sudo yum install python-pip
        • From source
          • download it:
          • install it:
            • # python setup.py install
      • Installation of packages
        • pip install package_name
      • Installation of a precise version of a package
        • pip install djangorestframework==0.4.0
      • alpha version
        • pip install -pre package_name
      • upgrade
        • pip install -U package_name
      • Problems
        • error fatal: Python.h: El fitxer o directori no existeix
          • Solució / Solution
            • Python 2.7
              • Mageia
                • urpmi lib64python-devel
            • Python 3
              • Mageia
                • urpmi lib64python3-devel
        • Download error on https://pypi.python.org/simple/: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:765) -- Some packages may not be found!
          • pip install fails with “connection error: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:598)”
          • Solution
            • openssl s_client -connect pypi.python.org:443
            • curl -sO http://cacerts.digicert.com/DigiCertHighAssuranceEVRootCA.crt
            • sudo cp DigiCertHighAssuranceEVRootCA.crt /etc/pki/ca-trust/source/anchors/
            • sudo update-ca-trust
          • Alternative solution?
            • sudo yum install ca-certificates
        • pip install --upgrade -r pip_requirements.txt
          • Could not find .egg-info directory in install record for setuptools from https://pypi.python.org/packages/25/4e/1b16cfe90856235a13872a6641278c862e4143887d11a12ac4905081197f/setuptools-28.8.0.tar.gz#md5=43d6eb25f60e8a2682a8f826ce9e3f42 in /home/.../env/lib/python2.7/site-packages
          • see also problems with Google API and httplib2
        • error: Installed distribution setuptools 0.9.8 conflicts with requirement setuptools>=17.1
          • Solució / Solution
            • pip install --upgrade setuptools
        • Error: pg_config executable not found.
          • Solució / Solution
            • Install postgresql devel
              • Mageia
                • urpmi postgresql9.4-devel
        • list of installed packages (it gives the version number):
          • pip freeze
      • easy_install
        • urpmi python-setuptools
        • sudo apt-get install python-setuptools
      • Invoke
      • Fabric
        • Instal·lació / Installation
          • pip install fabric
        • Fabric 2.x
          • See also: Invoke
          • Upgrading from 1.x
            • 1.x
              		 2.x
              put(local_file, remote_dir, use_sudo=True)
              		 from os.path import basename

              def sudo_put(c, local_path, remote_dirname):
                  """
                  Upload a local file to a remote dir, with sudo privileges
                  """
                  filename = basename(local_path)
                  remote_tmp_path = filename
                  remote_path = '{}/{}'.format(remote_dirname, filename)

                  print 'sudo_put: {} -> {}'.format(local_path, remote_path)
                 
                  c.put(local_path, remote=remote_tmp_path)
                  c.run("sudo sh -c 'mv {} {}'".format(remote_tmp_path, remote_path))

              ...
              sudo_put(c, local_file, remote_dir)


          • Documentation (2.1)
        • Fabric 1.x documentation
        • Utilització / Usage
          • <task name>:<arg>,<kwarg>=<value>,...
        • debug from Eclipse
          • fabfile.py
            • ...
              from fabric.main import main

              if __name__ == '__main__':
                  import sys
                  sys.argv = ['fab', '-f', __file__, 'my_task']
                  main()
        • Exemples / Examples
          • put('toto.sh', '/usr/local/bin/', mode=int('755', 8), use_sudo=True)
        • Context managers
          • with ...
        • Error management
          • ignore
            • with settings(warn_only=True):
          • capture failure
            • result = local('grunt')
              if result.failed:
                  print "Grunt is not installed."
                  abort('Grunt not found')
          • Python try
            • try:
                  sudo('...')
              except Exception as e:
                  ...
                  abort('...')
        • env definitions
          • fabfile.py
            • from fabric.api import *

              # remote user and group
              env.remote_user = 'myuser'
              env.remote_group = 'mygroup'

              # project
              env.project_name = 'my_project'
              env.project_dir = '/home/%(remote_user)s/%(project_name)s' % env
        • run locally
          • running fabric script locally
          • Optionally avoid using ssh if going to localhost #98
          • fabfile.py
            • # by default, actions are performed remotely.
              # to perform them localy, e.g.: "fab localhost create_virtualenv"
              env.run_as = 'remote'
              env.run = run
              env.sudo = sudo
              env.hosts = ['...',]
              env.key_filename = '~/.ssh/keys/key_for_remote.pem'

              def localhost():
                  """
                  Set environment for local execution
                  """
                  env.run_as = 'local'
                  env.run = local
                  env.sudo = local
                  env.hosts = []
            • with lcd()
                  ...
        • capture
          • run remotelly and get the value
            • result = sudo(...)
            • result = run(...)
          • run locally and get the value
            • result = local(..., capture=True)
        • crontab
        • files
          • put
            • rsync_project
              • How do I copy a directory to a remote machine using Fabric?
              • Example
                • from fabric.contrib.project import rsync_project

                  rsync_project(local_dir='.', remote_dir='/var/www', exclude=('.git','tmp',) )
              • Ignore files indicated by .gitignore
              • Ignore untracked files and files indicated by .gitignore
                • untracked_files_zero = local('git -C .. ls-files -z -o --exclude-standard --directory', capture=True)
                  untracked_files = untracked_files_zero.split('\0')
                  print "untracked_files: {}".format(untracked_files)
                  excluded_files = untracked_files + ['.git','tmp']
                  rsync_project(local_dir='.', remote_dir=env.project_dir, exclude=excluded_files, extra_opts="--filter=':- .gitignore'" )
            • append
              • append a line
                • from fabric.contrib.files import append
                  ...
                      append('/etc/sysconfig/toto','this line has been appended to the end')
              • append several lines:
                • from fabric.contrib.files import append
                  ...
                      text = """
                  first_line = "value1"
                  second_line = "value2"
                  """
                      append('/etc/sysconfig/toto', text, use_sudo=True)
            • sed
              • single quotes in sed
              • replace a line that starts with "host    all             all             127.0.0.1" by "host    all             all             127.0.0.1/32            md5"
                • from fabric.contrib.files import sed
                  ...
                      # /var/lib/pgsql/data/pg_hba.conf
                      # host    all             all             127.0.0.1/32            md5
                      sed('/var/lib/pgsql/data/pg_hba.conf',
                          'host    all             all             127.0.0.1/32            ident',
                          'host    all             all             127.0.0.1/32            md5',
                          use_sudo=True )
                •     env.sudo('sudo sed -e "/^host    all             all             127.0.0.1/ c\host    all             all             127.0.0.1/32            md5" -i /var/lib/pgsql/data/pg_hba.conf')
          • Certificat de servidor / Server certificate
            • certificate for https connections (curl will not need to specify --cacert)
              • # add myserver self-signed certificate to the list of trust ca certificates
                put('myserver.example.org.crt', '/etc/pki/ca-trust/source/anchors/', use_sudo=True)
                env.sudo('update-ca-trust')
          • dependencies
            • fabfile.py
              • # list of dependencies to install
                env.install_cmd = 'yum install -y'
                env.dependencies = ['gcc', 'git', 'python-virtualenv', 'mariadb',]

                def install_dependencies():
                    """
                    Install the system dependencies for the project
                    """
                    env.sudo(env.install_cmd + " " + "epel-release")
                    env.sudo(env.install_cmd + " " + " ".join(env.dependencies))
          • virtualenv
            • Getting virtualenv(wrapper) and Fabric to play nice
            • Activate a virtualenv via fabric as deploy user
            • fabfile.py
              • from contextlib import contextmanager as _contextmanager

                # remote user and group
                env.remote_user = 'my_user'
                env.remote_group = 'my_group'

                # virualenv directory
                env.virtualenv_directory = '/opt/p27'
                env.virtualenv_activate = 'source %(virtualenv_directory)s/bin/activate' % env

                def create_virtualenv():
                    """
                    Create the virtualenv
                    """
                    env.sudo('mkdir -p %(virtualenv_directory)s' % env)
                    env.sudo('chown %(remote_user)s.%(remote_group)s %(virtualenv_directory)s' % (env) )
                    env.run('virtualenv %(virtualenv_directory)s' % env)

                @_contextmanager
                def virtualenv():
                    """
                    Activate the virtualenv
                    """
                    with cd(env.virtualenv_directory):
                        with prefix(env.virtualenv_activate):
                            yield

                def install_pip_dependencies():
                    """
                    Install the pip dependencies
                    """
                    with virtualenv():
                        if env.run_as == 'remote':
                            put('pip_requirements.txt', 'pip_requirements.txt')
                        env.run('pip install -r pip_requirements.txt')
          • Django
            • fabfile.py
              • def django_setup():
                    """
                    Django: migrate, createsuperuser, collectstatic
                    """
                    with virtualenv():
                        with cd(env.project_dir):
                            env.run('python manage.py migrate')
                            env.run('python manage.py createsuperuser')
                            env.run('python manage.py collectstatic')
                            env.run('python manage.py loaddata auth_initial')

                def django_update():
                    """
                    Django: migrate, collectstatic
                    """
                    with virtualenv():
                        with cd(env.project_dir):
                            env.run('python manage.py migrate')
                            env.run('python manage.py collectstatic')
          • Nginx
            • fabfile.py
              • def nginx_setup():
                    """
                    Configure and start nginx
                    """
                    env.sudo('chmod 755 /home/centos')
                    env.sudo('mkdir -p /etc/uwsgi/vassals/')
                    if env.run_as == 'remote':
                        # nginx
                        put('nginx-uwsgi/%(project_name)s_nginx.conf' % env, '/etc/nginx/conf.d/', use_sudo=True)
                        # remove default site from nginx.conf
                        put('nginx-uwsgi/nginx.conf', '/etc/nginx/', use_sudo=True)
                        put('nginx-uwsgi/nginx.pp', '/etc/nginx/', use_sudo=True)
                       
                        # uwsgi       
                        put('nginx-uwsgi/uwsgi_params', '/etc/uwsgi/', use_sudo=True)
                        put('nginx-uwsgi/emperor.ini', '/etc/uwsgi/', use_sudo=True)
                        put('nginx-uwsgi/%(project_name)s_uwsgi.ini' % env, '/etc/uwsgi/vassals/', use_sudo=True)
                        put('nginx-uwsgi/emperor.uwsgi.service', '/etc/systemd/system/', use_sudo=True)
                        # socket in /run/ (http://uwsgi-docs.readthedocs.org/en/latest/Systemd.html#putting-sockets-in-run)
                        #put('nginx-uwsgi/emperor.uwsgi.socket', '/etc/systemd/system/', use_sudo=True)
                        #put('nginx-uwsgi/emperor.uwsgi.conf', '/etc/tmpfiles.d/', use_sudo=True)
                   
                    # custom selinux policy module (http://axilleas.me/en/blog/2013/selinux-policy-for-nginx-and-gitlab-unix-socket-in-fedora-19/)
                    env.sudo('semodule -i /etc/nginx/nginx.pp')
                    # activate selinux
                    env.sudo('setenforce 1')

                    # enable and start nginx
                    env.sudo('systemctl enable nginx.service')
                    env.sudo('systemctl restart nginx.service')
                  
                    # enable and start uwsgi
                    env.sudo('systemctl enable emperor.uwsgi.service')
                    env.sudo('systemctl restart emperor.uwsgi.service')
                  
                    # configure firewall
                    #env.sudo('firewall-cmd --permanent --zone=public --add-service=http')
                    #env.sudo('firewall-cmd --permanent --zone=public --add-service=https')
                    #env.sudo('firewall-cmd --reload')


                def nginx_restart():
                    """
                    Restart nginx and wsgi
                    """

                    # restart nginx
                    env.sudo('systemctl restart nginx.service')
                  
                    # restart uwsgi
                    env.sudo('systemctl restart emperor.uwsgi.service')
          • Database
            • fabfile.py
              • # database
                env.mysql_host = 'localhost'
                env.mysql_database = 'mydatabase_db'
                env.mysql_user = 'my_user'
                env.mysql_password = 'my_password'
                env.mysql_master_user = 'root'

                def database_setup():
                    """
                    Setup database service
                    """
                    env.sudo("systemctl enable mariadb.service")
                    env.sudo("systemctl start mariadb.service")
                    env.sudo("mysql_secure_installation")


                def database_create():
                    """
                    Create the sql database
                    """
                    env.run('echo "CREATE DATABASE IF NOT EXISTS %(mysql_database)s; \
                GRANT ALL ON %(mysql_database)s.* TO \'%(mysql_user)s\'@\'%%\' IDENTIFIED BY \'%(mysql_password)s\'; \
                FLUSH PRIVILEGES;" | \
                mysql -h %(mysql_host)s -u %(mysql_master_user)s -p' % (env) )


                def database_delete():
                    """
                    Delete the sql database
                    """
                    env.run('echo "DROP DATABASE %(mysql_database)s;" | \
                mysql -h %(mysql_host)s -u %(mysql_master_user)s -p' % (env) )
          • Git
            • fabfile.py
              • def ssh_config():
                    """
                    Add fabuser_bitbucket_support to ~/.ssh/config
                    """
                    text = """
                Host fabuser-bitbucket
                     HostName bitbucket.org
                     IdentityFile ~/.ssh/fabuser_bitbucket
                    """
                    append('%s/config' % env.ssh_dir, text )
                    env.run('chmod 600 %s/config' % env.ssh_dir)

                def git_clone():
                    """
                    Clone from git
                    """
                    #git_user = 'francesc_pinyol_margalef'
                    with settings(warn_only=True):
                        with settings(warn_only=True):
                            if env.run("test -d %s" % env.project_dir).failed:
                                env.run("git clone git@fabuser-bitbucket:%(bitbucket_account)s/%(project_name)s.git %(project_dir)s" % (env) )


                def git_pull():
                    """
                    Pull from git
                    """
                    with cd(env.project_dir):
                        env.run("git pull")
        • Empaquetament / Packaging
      • Multiple platforms
      • Python path:
        • /usr/local/lib/python2.7/dist-packages/...
        • print path:
          • python
            • import sys
              sys.path
        • set path:
          • python
            • import sys
              sys.path.append("/my/path")
          • Django:
            • /etc/apache2/mods-available/wsgi.conf
              • WSGIPythonPath ...
        • recursively create directory if it does not exist:
          • # create the directory if it does not exist
            father_dir = os.path.dirname(filename)
            if not os.path.exists(father_dir):
                os.makedirs(father_dir)
                print "creating directory: %s" % father_dir
        • get home dir:
          • from os.path import expanduser
            home = expanduser("~")
        • get absolute dir inside home:
          • from os.path import expanduser
            my_dir = expanduser("~/my_dir")
      • Python for MS Windows:
      • HTML parsing
      • Logging
      • Nginx

      Biblioteques / Libraries
      • Useful modules
        • Dades / Data
        • Bases de dades / Databases
        • Imatges / Images
        • Criptografia / Cryptography
        • Xarxa / Network
          • Twisted
          • stomp.py
            • Problemes / Problems
              • UnicodeEncodeError: 'ascii' codec can't encode character ...
                • Solution
                  • /usr/local/lib/python2.7/dist-packages/stomp/protocol.py
                    • #body = encode(body)
        • Processos / Processes
          • 17.1 subprocess (2) (3)
            • subprocess.run (>=3.5)
            • Older high-level API
              • old
                		 new
                subprocess.call(...) run(...)
                subprocess.check_call(...) run(..., check=True)
                subprocess.check_output(...) run(..., check=True, stdout=subprocess.PIPE).stdout
          • Exemples / Examples
            • ...
              • import shlex, subprocess

                command = '...'
                parameters = '...'
                command_line = "{0} {1}".format(command, parameters)
                args = shlex.split(command_line)

                try:
                    completed_process = subprocess.run(args, check=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
                    print(completed_process.stdout.decode('utf-8'))
                except Exception as e:
                    print("ERROR: {0}".format(e))
                    print("ERROR stdout: {0}".format(e.stdout.decode('utf-8')))
                    print("ERROR stderr: {0}".format(e.stderr.decode('utf-8')))
                ...
        • SSH
          • Paramiko
            • Documentation
            • Example
              • import paramiko

                client = paramiko.SSHClient()
                #client.load_system_host_keys()
                k = paramiko.RSAKey.from_private_key_file('/home/my_user/.ssh/keys/remoteserver.pem')
                client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
                client.connect('remoteserver.example.org', username='myremoteuser', pkey=k)
                ssh_stdin, ssh_stdout, ssh_stderr = client.exec_command('ls -ltr')

                for line in ssh_stdout:
                    print line
        • SVG
          • Creating Simple SVG from Python
          • pySVG
          • svgwrite
            • Documentation
            • mozman / svgwrite (github)
            • utf-8
              • # save svg to file
                from xml.etree.ElementTree import tostring
                dwg.tostring = lambda self=dwg: tostring(self.get_xml()).decode("utf-8")
                dwg.save(pretty=True)
          • convert svg to image
            • Convert SVG to PNG in Python
            • CairoSVG (Python3)
              • install Python3 and virtualenv
              • pip3 install cairosvg
              • as command:
                • cairosvg image.svg [--output_width 200] -o image.png
              • as library:
                • import cairosvg
                  cairosvg.svg2pdf(url='image.svg',                   output_width=200, write_to='image.pdf')
            • pyrsvg (librsvg)
              • pyrsvg How to use librsvg from Python (Cairo)
              • Installation
                • Mageia
                  • urpmi gnome-python-desktop
                    • /usr/lib64/python2.7/site-packages/gtk-2.0/rsvg.so
                    • /usr/share/doc/gnome-python-desktop/rsvg/rsvg-cairo.py
                • Ubuntu
              • Ús / Usage
                • virtualenv --system-site-packages env
                • souce env/bin/activate
                • python toto.py
                • toto.py
                  • import cairo
                    import rsvg
                    ...
        • FTP
          • libftp (2.7)
            • upload local or remote file to ftp:
              • # python 3
                import os
                import ftplib
                import urllib.request
                from urllib.parse import urlparse

                host = '...'
                username = '...'
                password = '...'

                #origin = '/tmp/toto.txt'
                origin = 'https://...'
                local_basename = os.path.basename(origin)
                remote_dirname = 'toto_dir_2'
                remote_path = os.path.join(remote_dirname, local_basename)

                print("ftp upload: {0} -> {1}".format(origin, remote_path))

                o = urlparse(origin)
                print("sheme: {}".format(o.scheme))

                if o.scheme:
                    filehandle = urllib.request.urlopen(origin)
                else:
                    filehandle = open(origin, 'rb')


                with ftplib.FTP(host, username, password) as ftp:
                    # create dir
                    try:
                        print("creating remote dir: {}".format(remote_dirname))
                        ftp.mkd(remote_dirname)
                    except Exception as e:
                        print("WARNING when creating dir: {} - {}".format(e, type(e)))

                    # upload file
                    try:
                        print("uploading: {0} -> {1}".format(origin, remote_path))
                        ftp.storbinary("STOR {0}".format(remote_path), filehandle)
                    except Exception as e:
                        print("ERROR when uploading file: {}".format(e))

                print("done")

            • upload remote http file directly to ftp (Python - Transfer a file from HTTP(S) URL to FTP/Dropbox without disk writing (chunked upload)):
              • ...
                import urllib
                ...
                filehandle = urllib.request.urlopen(origin_url)
                ...
        • HTTP / HTTPS
              • post
                • import requests

                  address = ...
                  payload = {'toto_key':'toto_value',}
                  r = requests.post(address, payload)
              • jwt + get
                • import requests
                  from pprint import pprint

                  backend_url = 'http://127.0.0.1:8000'

                  # jwt token
                  # file toto_admin.txt contains the password
                  password = open('toto_admin.txt', 'r').read().strip()
                  payload_credentials = {
                                         'username': 'admin',
                                         'password': password
                                         }
                  r = requests.post(backend_url+'/api-token-auth/', data=payload_credentials)
                  token = r.json()['token']

                  r = requests.get('%s/v1/api/totos/' % (backend_url), headers={'Authorization':'JWT %s'%token})
                  pprint( r.json() )
              • upload (e.g. with Django Restframework)
                • POST a Multipart-Encoded File
                • Exemple / Example:
                  • models.py
                    • class MyModel(models.Model):
                          field_1 = models.FileField(...)
                          field_2 = ...
                          field_3 = ...
                  • upload_test.py
                    • import requests

                      url = 'http...'
                      payload = {'field_2': '...', 'field_3': '...'}
                      headers = {}
                      headers['...'] = '...'
                      files = {'field_1': open('/tmp/toto.png', 'rb')}
                      r = requests.post(url, payload, headers=headers, files=files)
              • HTTPS
            • Problemes / Problems
              • empty request.DATA when receiving a put/patch:
                • Solució / Solution
                  • check that there is a trailing "/". Otherwise, requests receives a 30x and data is lost on the second url
              • claudàtors en el payload / square brackets in payload
                • Solució / Solution: explicit conversion to json, with json header
                  • import requests
                    import json

                    payload = {
                               'toto':['first element','second element'],
                               }
                    r = requests.post(address, headers={'Content-Type':'application/json'}, data=json.dumps(payload))
                  • import requests
                    import json

                    # get token as usual
                    ...
                    token = ...

                    payload = {
                               'toto':['first element','second element'],
                               }
                    r = requests.post(address, headers={'Authorization':'JWT %s'%token, 'Content-Type':'application/json'}, data=json.dumps(payload))
          • pycurl (curl)
            • Exemple HHTPS / HTTPS Example
              • import pycurl
                curl = pycurl.Curl()
                curl.setopt(pycurl.CAINFO, "ca.crt")
                curl.setopt(pycurl.SSL_VERIFYPEER, 1)
                curl.setopt(pycurl.SSL_VERIFYHOST, 2)
                curl.setopt(pycurl.URL, "https://server_name/")
                curl.perform()
      • PyGObject (based on GObject)

        		•  C
          		 Python
          • import gi
            gi.require_version("Gtk", "3.0")
            from gi.repository import Gtk

          		-
          		 PyGObject
          • virtualenv: pip install pygobject
            • dependències / dependencies:
              • urpmi lib64girepository-devel gobject-introspection
              • yum install gcc gobject-introspection-devel cairo-gobject-devel freetype-devel
              • apt-get ...
          • urpmi [python-gobject] python3-gobject3
          • yum install python34-gobject
          • apt-get ...
          GObject libraries:
          • /usr/lib[64]/girepository-1.0/
          • GI_TYPELIB_PATH
          		 GLib
          • GLib-2.0.typelib
          Gtk
          • Gtk-2.0.typelib
          • Gtk-3.0.typelib
          GStreamer
          • Gst-1.0.typelib
          • Gst...1.0.typelib
          • GES-1.0.typelib
          ...

        • Instal·lació / Installation
          • Sistema / System
            • CentOS
              • sudo yum install python34-gobject
            • Mageia
              • urpmi ...
          • Virtualenv + pip
            • Dependències / Dependencies
              • Install virtualenv
              • CentOS
                • sudo yum install gobject-introspection-devel cairo-gobject-devel freetype-devel
              • Mageia
                • urpmi lib64girepository-devel gobject-introspection
            • virtualenv-3.5 env (CentOS: virtualenv-3 --python python36 env)
            • source env/bin/activate
            • [pip install --upgrade pip]
            • pip install pygobject
        • Libraries are retrieved from:
          • standard location:
            • /usr/lib64/girepository-1.0/*.typelib
          • non-standard location (e.g. GStreamer compiled from source and installed into /usr/local)
            • export GI_TYPELIB_PATH=/usr/local/lib/girepository-1.0
        • PyGObject API Reference
        • Exemple / Example
          • import gi
            gi.require_version("Gtk", "3.0")
            from gi.repository import Gtk

            window = Gtk.Window(title="Hello World")
            window.show()
            window.connect("destroy", Gtk.main_quit)
            Gtk.main()
      • Parsing
      • Fulls de càlcul / Spreadsheet

      Celery
      • ...
      • Celery with Django
      • Arquitectura / Architecture
      • First steps with Celery
        1. install a message broker (message transport)
          • RabbitMQ (AMQP)
            • RabbitMQ
            • Configuració / Setup (Django: same as in settings.py BROKER_URL)
              1. rabbitmqctl add_user myuser mypassword
              2. rabbitmqctl add_vhost myvhost
              3. rabbitmqctl set_permissions -p myvhost myuser ".*" ".*" ".*"
            • check settings:
              • rabbitmqctl list_users
              • rabbitmqctl list_vhosts
              • rabbitmqctl list_permissions -p myvhost
          • Amazon SQS
        2. install celery (dependencies automatically installed: pytz billiard kombu anyjson amqp)
          • pip install celery
        3. check that celery is working
      • command line

        		•



          		example
          celery






                     		-b <broker>
          		 -A <module>

                     		worker (start a single worker)
                     		-Q <queue1>,<queue2>
          --hostname=<node_name>@<host> (default: celery@localhost.localdomain)
          multi (start several named workers)
          • start <node_name_1> [<node_name_2>, ...]
            • --pidfile=/var/run/celery/%n.pid
            • --logfile=/var/log/celery/%n%I.log
          • restart <node_name> [<node_name_2>, ...]
          • stop <node_name> [<node_name_2>, ...]
          • stopwait <node_name> [<node_name_2>, ...]
          		-c <number_processes> (default: number of CPUs)

          		inspect
          • active
          		--destination=celery@example.com

          		control
          • enable_events
          • disable_events
          • rate_limit tasks.add 10/m



          		events
                     		--dump

          		status
          		celery -b amqp://<celery_user>:<celery_password>@<rabbitmq_server/><celery_vhost> status

          		...



      		• celery.py
        		 tasks.py
        		 worker
        		 usage


        		tasks.py
        • from celery import Celery

          app = Celery('tasks', broker='pyamqp://guest@localhost//')

          @app.task
          def add(x, y):
              return x + y
        		 celery -A tasks worker --loglevel=info
        • from tasks import add

          result = add.delay(4, 4)
          result.ready()
          result.successful()
          result.get()
          result.failed()
          res.state
          res.id

        		proj/rabbitmq.txt
        • amqp://<celery_user>:<celery_password>@<rabbitmq_server/><celery_vhost>
        proj/celery.py
        • from __future__ import absolute_import, unicode_literals
          from celery import Celery

          app = Celery('proj',
                       broker=open('rabbitmq.txt','r').read().strip(),
                       backend='rpc://',
                       include=['proj.tasks'])

          # Optional configuration, see the application user guide.
          app.conf.update(
              result_expires=3600,
          )

          if __name__ == '__main__':
              app.start()
        		 proj/__init__.py

        proj/tasks.py
        • from __future__ import absolute_import, unicode_literals
          from .celery import app

          @app.task
          def add(x, y):
              return x + y

          @app.task
          def mul(x, y):
              return x * y

          @app.task
          def xsum(numbers):
              return sum(numbers)

        		 (from proj parent dir)
        celery -A proj worker -l info
        		 (from proj parent dir)
        • from proj.tasks import add

          result = add.delay(4, 4)
        Django
        mysite/myproject/settings.py
        • # celery
          BROKER_URL = 'amqp://myuser:mypassword@localhost/myvhost'
        		mysite/myproject/celery.py
        • from __future__ import absolute_import
          import os
          from celery import Celery
          from django.conf import settings

          # set the default Django settings module for the 'celery' program.
          os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'myproject.settings')

          app = Celery('myproject')

          # Using a string here means the worker will not have to
          # pickle the object when using Windows.
          app.config_from_object('django.conf:settings')

          # access to mysite/*/tasks.py
          app.autodiscover_tasks(lambda: settings.INSTALLED_APPS)

          # access to mysite/myproject/tasks.py
          app.autodiscover_tasks(lambda: ('myproject',))

          @app.task(bind=True)
          def debug_task(self):
              print('Request: {0!r}'.format(self.request))
        		 mysite/myproject/__init__.py
        • from __future__ import absolute_import

          # This will make sure the app is always imported when
          # Django starts so that shared_task will use this app.
          from .celery import app as celery_app
        mysite/myproject/tasks.py
        • from __future__ import absolute_import
          import logging
          from celery import shared_task

          logger = logging.getLogger(__name__)

          @shared_task
          def add(x, y):
              logger.info("adding...")
              return x + y
        mysite/myapp/tasks.py
        • from __future__ import absolute_import
          import logging
          from celery import shared_task

          logger = logging.getLogger(__name__)

          @shared_task
          def mul(x, y):
              logger.info("multiplying...")
              return x * y
        		 celery -A myproject worker -l info

        		 e.g.: mysite/myapp/views.py
        • from myapp.tasks import mul

          result = mul.delay(3, 4)

      • Next steps
      • User Guide
      • Progrés / Progress
      • ...

      Exemples / Examples
      • Python Command Line Arguments Examples

        		•
          		list of arguments
          		 number of arguments
          		 script
          		 argument






          sys
          		 import sys
          		 # including script
          sys.argv          		 # including script
          len(sys.argv)          		 sys.argv[0] sys.argv[1]
          sys.argv[2]
          ...
          getopt
          		 import sys, getopt


          		try:
              myopts, args = getopt.getopt(sys.argv[1:],"i:o:")
          except getopt.GetoptError as e:
              print (str(e))
              print("Usage: %s -i input -o output" % sys.argv[0])
              sys.exit(2)
           
          for o, a in myopts:
              if o == '-i':
                  ifile=a
              elif o == '-o':
                  ofile=a
          argparse



          		import argparse
          parser = argparse.ArgumentParser(description='ADD YOUR DESCRIPTION HERE')
          parser.add_argument('-i','--input', help='Input file name', required=True)
           parser.add_argument('-t','--title', metavar='titol', help='Input file name', required=False)
           parser.add_argument('-n','--number', type=int, help='Input file name', required=True)
          parser.add_argument('first_parameter', help='...')

          parser.add_argument('parameter_1')
          parser.add_argument('parameter_2')
          parser.add_argument('--disable', dest='is_enabled', action='store_false', required=False)
          parser.add_argument('-t', '--title', metavar='titol',
                              help='title to be put in field s= in sdp file',
                              required=False)
             
          args = parser.parse_args()
          print(args)
          print("parameter_1: {0}".format(args.parameter_1))
          print("title: {0}".format(args.titol))

      • print
        • print ("nombre_args: %d" % nombre_args)
      • Fusió d'intervals / Merge intervals

      IDE
      • Comparison of integrated development environments: Python (wp)
      • IDLE (wp)
      • PyDev (Eclipse)
        • Installation
          • Help -> Install new software -> Add ...:
            • PyDev - http://pydev.org/updates
        • Django
        • New project
          • workspace: ~/src/djcode/
          • project name: nom_projecte
          • will create (according to new directory layout in Django 1.4):
            • ~/src/djcode/
              • nom_projecte/
                • .project
                  • <name>nom_projecte</name>
                • .pydevproject
                • sqlite.db
                • nom_projecte/
                  • settings.py
                  • ...
          • nom_projecte can be renamed to nom_projecte_pare (if you get the error "out of sync with file system", do a Refresh) (but DATABASES in settings.py is not updated):
            • ~/src/djcode/
              • nom_projecte_pare/
                • .project
                  • <name>nom_projecte_pare</name>
                • .pydevproject
                • sqlite.db
                • nom_projecte/
                  • settings.py
                  • ...
          • les noves aplicacions (nom_projecte_pare -> Django -> create new app) es crearan dins de nom_projecte (de fet, dins del directori especificat a .pydevproject com a DJANGO_MANAGE_LOCATION)
        • virtualenv
          • Integrar Virtualenv con Eclipse (PyDev)
          • Pydev and virtualenv
          • passos / steps
            • general configuration:
              • Window -> Preferences -> PyDev -> Interpreter - Python: New...
                • Interpreter Name: python-PYTHON27
                • Interpreter Executable: /opt/PYTHON27/bin/python
            • on your project:
              • Properties -> PyDev - Interpreter/Grammar
                • Interpreter: python-PYTHON27
        • Problems
          • debugging suspends on caught exceptions ("VariableDoesNotExist: Failed lookup for key...") related to Django templates:
            • Solució / Solution
              • PyDev -> Manage exception breakpoints
                • Uncheck: "Suspend on django template render exceptions"
          • Unable to read repository at http://pydev.org/updates/content.xml Transport initialization error..
            • Solution:
              • rm ~/.eclipse
              • eclipse
          • New added library (e.g. by using pip) not detected
            • Solution:
              • Window -> Preferences -> PyDev -> Interpreter - Python Interpreter -> Remove -> AutoConfig
        • Existing code (1.3)
          • djcode/
            • mysite/
              • settings.py
              • mystite.db
              • polls/

      GUI
      • tkinter

      Frameworks

      Google API

      http://www.francescpinyol.cat/python.html
      Primera versió: / First version: 24 VIII 2015
      Darrera modificació: 19 de juny de 2019 / Last update: 19th June 2019

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