Hit n Trail

What is Flask Server?

• Built-in development server and debugger.
• Integrated support for unittesting support. 
• RESTful request dispatching. 
• Uses Jinja 2 templating. 
• Support for secure Cookies. 
• 100% WSGI 1.0 complaint. 
• Unicode based.
• Extensively documented.

 Installation 

Note: 

Installing Virtualenv

pip-python install virtualenv

[root@localhost dev]# pip-python install virtualenv

Downloading/unpacking virtualenv
Downloading virtualenv-1.7.tar.gz (2.1Mb): 2.1Mb downloaded
Running setup.py egg_info for package virtualenv

warning: no previously-included files matching '*.*' found under directory 'docs/_templates'

Installing collected packages: virtualenv

Running setup.py install for virtualenv

warning: no previously-included files matching '*.*' found under directory 'docs/_templates'

Installing virtualenv script to /usr/bin
Successfully installed virtualenv
Cleaning up...
[root@localhost dev]#

Setting up virtual environment with virtualenv

mkdir flaskTestServer
cd flaskTestServer
virtualenv venv

[root@localhost Dev]# mkdir flaskTestServer
[root@localhost Dev]# cd flaskTestServer/
[root@localhost flaskTestServer]# ll
total 0[root@localhost flaskTestServer]# virtualenv venv
New python executable in venv/bin/python
Installing setuptools............done.
Installing pip...............done.

[root@localhost flaskTestServer]# . venv/bin/activate
(venv)[root@localhost flaskTestServer]#

Installing Flask Server

(venv)[root@localhost flaskTestServer]# pip install flask

Example

from flask import Flask
app = Flask(__name__)
@app.route('/')
def hello_world():
    return 'Hello World!'
if __name__ == '__main__':
    app.run()

1. First we imported the Flask class. An instance of this class will be our WSGI application. The first argument is the name of the application’s module. If you are using a single module (as in this example), you should use __name__ because depending on if it’s started as application or imported as module the name will be different ('__main__' versus the actual import name). For more information, have a look at the Flask documentation.
2. Next we create an instance of this class. We pass it the name of the module or package. This is needed so that Flask knows where to look for templates, static files, and so on.
3. We then use the route() decorator to tell Flask what URL should trigger our function.
4. The function is given a name which is also used to generate URLs for that particular function, and returns the message we want to display in the user’s browser.
5. Finally we use the run() function to run the local server with our application. The if __name__ == '__main__': makes sure the server only runs if the script is executed directly from the Python interpreter and not used as imported module.

(venv)[root@localhost flaskTestServer]# python flaskHelloWorld.py
 * Running on http://127.0.0.1:5000/

What is Python-pip?

Dependencies of Python-pip

• Python 2.7: If you don't have python installed then you can follow the instruction from Tutorial Point.
• Python setup tools.
  In case if you don't have python-setup-tools then:
• Download the RPM installer package for python-setup-tools. In my case I am on Linux Fedora 14 and downloaded the RPM package file from here.
• Once you have downloaded the python-setup-tools RPM package file. Install it with RPM command from shell:
  

  rpm -i python-setuptools-0.6.14-3.fc14.noarch.rpm

• And its done for python-setup-tools.

Installing Python-pip

rpm -i python-pip-0.8.3-1.fc14.noarch.rpm

Using Python-pip

To get packages:

$ pip install {package_name}

$ pip-python install {package_name}

To uninstall a package:

$ pip-python uninstall {package_name}

To upgrade a package:

$ pip-python --upgrade {package_name}

• Get Python:
• Download the recent version of python from python.org.
• Run the setup file (python-.msc) and follow the install insrtuction. 
• Once the installation is complete, set the windows environment variable to point to the python installation folder.
• Right click on "My Computer".
• Select "properties". 
• Click on the button "Environment Variables" under the tab "Advanced".

• Add the path of python installation to the PATH variable, in my case its "D:\Python27\".

• Go to dos command line and type the command ">python", if it takes you to the python command line, then it works.

• Get Eclipse and install the PyDev plugin.
• Download a version of Eclipse IDE from here do the setup you need for other dev. 
• Now from Eclipse menu go to Help -> Install New Software. 
• Add the PyDev update site http://pydev.org/updates.

• Install the plugin. 
• Configuration of Eclipse. 
• From eclipse menu, open Window -> Preferences.
• Look for PyDev -> Interepreter - Python.

• Click on new and add the python.exe.
• For windows, it was under the python installation i.e. d:\python27.
• For linux, find it by running the command >which python

And all done, you are good to go... Play with python in eclipse.


Also check out my new post on Python-pip tool. 

Overview

What is Django ?

Why use Django?

• Django is fast and stable.
• It’s very scalable.
• Let’s you work outside the scope of the framework as required.
• Fast development and code readability.
• Very well documented.
• And the list goes on about Django’s pros over other web development frameworks.

Required Knowledge

• Should have the basic understanding of procedural and object-oriented programming: control structures (e.g. if, while, for), data structures (lists, hashes/dictionaries), variables, classes, objects, etc.
• At least hands on experience with programming in Python and understanding of how libraries work. If you don’t know python, click here.