Tutorial: Work with Python in Visual Studio.; 3 minutes to read +3; In this article. Python is a popular programming language that is reliable, flexible, easy to learn, free to use on all operating systems, and supported by both a strong developer community and many free libraries.
- Flask Tutorial
- Flask Useful Resources
Capture the printed output of the Python program. Have the Python program write the desired output to a well-defined file, and just ignore all other output. Check sub-process return status and act accordingly. You might want to use an embedded Python interpreter as part of a web page that executes user entered Python in a restricted environment. At least in Windows 7 and Python 3.1, os.system in Windows wants the command line double-quoted if there are spaces in path to the command. For example: TheCommand = 'C:Tempa b cNotepad.exe' os.system(TheCommand) A real-world example that was stumping me was cloning a drive in VirtualBox.
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In order to test Flask installation, type the following code in the editor as Hello.py
Importing flask module in the project is mandatory. An object of Flask class is our WSGI application.
Flask constructor takes the name of current module (__name__) as argument.
The route() function of the Flask class is a decorator, which tells the application which URL should call the associated function.
- The rule parameter represents URL binding with the function.
- The options is a list of parameters to be forwarded to the underlying Rule object.
In the above example, ‘/’ URL is bound with hello_world() function. Hence, when the home page of web server is opened in browser, the output of this function will be rendered.
Finally the run() method of Flask class runs the application on the local development server.
All parameters are optional
Sr.No. | Parameters & Description |
---|---|
1 | host Hostname to listen on. Defaults to 127.0.0.1 (localhost). Set to ‘0.0.0.0’ to have server available externally |
2 | port Defaults to 5000 |
3 | debug Defaults to false. If set to true, provides a debug information |
4 | options To be forwarded to underlying Werkzeug server. |
The above given Python script is executed from Python shell.
A message in Python shell informs you that
Open the above URL (localhost:5000) in the browser. ‘Hello World’ message will be displayed on it.
Debug mode
A Flask application is started by calling the run() method. However, while the application is under development, it should be restarted manually for each change in the code. To avoid this inconvenience, enable debug support. The server will then reload itself if the code changes. It will also provide a useful debugger to track the errors if any, in the application.
The Debug mode is enabled by setting the debug property of the application object to True before running or passing the debug parameter to the run() method.
Introduction
All Python libraries (i.e. application packages) that you download using a package manager (e.g. pip) are distributed using a utility dedicated to do the job. These utilities create “Python distributions” which are basically versioned (and compressed) archives. All related elements to what’s being distributed, such as source files and resource files, are contained within it.
In this DigitalOcean article, we are going to talk about the necessary tools for distribution and go over the key steps to allow you to package your own useful libraries, modules, or applications – which should help you when deploying your project on a droplet or sharing on the internet.
Python Distributions and Packages
Even if you have worked only a little with Python, you will be familiar with the concept of using a package manager (e.g. pip, easy_install) to download modules and libraries (e.g. application development frameworks) which are then imported and used to create a new one.
These package management tools, operating locally, connect to a source (i.e. Python Package Index - PyPI) and perform a desired action (e.g. search and install) as they work these resources which are actually called Python distributions.
The way to distribute an application consists of wrapping its directory with some must-have files (along with a few recommended ones), specifying related elements (e.g. resources, dependencies etc.) and releasing it or using it elsewhere…that simple.
Note: You are highly encouraged to work with virtual environments to isolate Python downloads, modules, and applications you are working with.
Python Packages
In Python, a package [technically] is an importable directory (with
__init__.py
) containing source files (i.e. modules). This shall not be confused with operating-system packages, which are [technically] actual applications (i.e. a Debian package). However, it must be noted that Python distributions are indeed called packages as well.Example package structure:
Python Applications
Although anything from a single file to one with hundreds scattered across various packages can be considered an application in Python, in most realistic scenarios, an application will consist of multiple modules and a certain amount of external imports (from libraries).
Example application structure:
Python Distribution Tools and Libraries
Given the popular nature of Python and the rich amount of third-party libraries / applications written for it, a simpler and unified way of distributing has always been a necessity. There have been several different tools and libraries used for creating Python distributions.
In order to deal with the tasks of distribution, Python distribution utilities toolset distutils was created.
Python Package Index (PyPI)
Python Package Index, or PyPI, is a central [online] repository for projects (Python distributions). Cricut desktop app mac. Package managing tools such as pip use this repository in order to host, find and install them.
Getting Started
Let's begin with creating a simple, general Python flask application [structure] which we then can use to package.
Python Run Program Command
Creating the Application Structure
We aim to create an example that resembles most real-world projects. Therefore, it will be best to imagine a scenario with modularised components.
Example structure:
Create the folders:
Edit run.py using nano:
Place the contents: How do i unistall and app on my mac.
Save and exit using CTRL+X and confirm with with Y.
Edit config.py using nano:
Place the contents:
Save and exit using
CTRL+X
and confirm with with Y
.Edit app/init.py using nano:
Place the contents:
Save and exit using CTRL+X and confirm with with Y.
Edit app/module_one/controllers.py using nano:
Place the contents:
Save and exit using
CTRL+X
and confirm with with Y
.Place the contents:
Edit app/templates/module_one/hello.html using nano:
Place the contents:
<pre>
<!DOCTYPE html>
<html lang=“en”>
<head>
<title>{% block title %}My Site{% endblock %}</title>
{% block css %}
{% endblock %}
<meta name=“viewport” content=“width=device-width, initial-scale=1.0”>
</head>
<body>
Hello, world!
</body>
</html>
</pre>
<!DOCTYPE html>
<html lang=“en”>
<head>
<title>{% block title %}My Site{% endblock %}</title>
{% block css %}
{% endblock %}
<meta name=“viewport” content=“width=device-width, initial-scale=1.0”>
</head>
<body>
Hello, world!
</body>
</html>
</pre>
Save and exit using CTRL+X and confirm with with Y.
Beginning with Application Distribution / Packaging
Having created an exemplary application structure of a web site that uses flask, we can continue with taking the first step into preparing the distribution.
Altering the Folder Structure
Python Run Application
In order to package our application well, we need to make some additions to our folder structure.
Alter the folder structure to create necessary files:
Create the setup.py
Place the below self explanatory contents:
Save and exit using CTRL+X and confirm with with Y.
Create the MANIFEST.in
If you need to ship extra directories (e.g. static or templates), you need to explicitly state them in the manifest to be packaged. We will do this inside the
MANIFEST.in
.Place the below self explanatory contents:
Save and exit using CTRL+X and confirm with with Y.
And that’s it! Your Python distribution package is ready to be installed and shipped.
Additional Files
Please remember that in order to have a complete distribution, your file/directory must contain (and linked):
README.txt
MANIFEST.in
LICENSE.txt
Working With the Distribution Ready Application
As we have finalized creation of our application followed by making necessary amendments to the file structure to prepare it for a flawless distribution build, we can begin with going through the packaging operations.
How to Create The Distribution File
In order to generate a distribution file copy, run the following: Personal finance apps.
This command will go through your setup, print out the operations being performed and generate a tar archive inside the newly created
dist
directory, similar to:Note: Since we did not populate all the sub-folders (i.e. static) and worked with additional files (e.g.
README.txt
), you might see some warnings during the creation process.How to Install The Application
From now on, your application can be installed and used by others using the
setup.py
file created.In order to install the application, run the following:
If this installation is for development and the requirements are also to be installed, run the following:
How to Share Your Application
If you would like to share your code on the Python Packaging Index, you can do so by initiating the “register” procedure as per the following:
Run A Python File
You will need to complete the procedure by following the on-screen instructions.
How To Get Python To Run
If you have a registered login, in order to just upload, you can use the following:
How to Create Packages of Your Application’s New Versions
- Edit the
setup.py
file with a text editor (e.g. nano) and set the new version number:version='0.1.1'
- Edit the CHANGES.txt to reflect the changes
- Make the necessary adjustments to the LICENSE.txt and README.txt
- How to see all running apps on mac. Upload your code following the previous step.
<div class=“author”>Submitted by: <a
href=“https://twitter.com/ostezer”>O.S. Tezer</a></div>
href=“https://twitter.com/ostezer”>O.S. Tezer</a></div>