Flask
[Pages:66]Flask
#flask
Table of Contents
About
1
Chapter 1: Getting started with Flask
2
Remarks
2
Versions
2
Examples
2
Installation - Stable
2
Hello World
3
Installation - Latest
3
Installation - Development
3
sphinx
3
py.test
4
tox
4
Chapter 2: Accessing request data
5
Introduction
5
Examples
5
Accessing query string
5
Combined form and query string
5
Accessing form fields
6
Chapter 3: Authorization and authentication
7
Examples
7
Using flask-login extension
7
General idea
7
Create a LoginManager
7
Specify a callback used for loading users
7
A class representing your user
8
Logging the users in
8
I have logged in a user, what now?
9
Logging users out
10
What happens if a user is not logged in and I access the current_user object?
10
What next?
10
Timing out the login session
11
Chapter 4: Blueprints
12
Introduction
12
Examples
12
A basic flask blueprints example
12
Chapter 5: Class-Based Views
14
Examples
14
Basic example
14
Chapter 6: Custom Jinja2 Template Filters
15
Syntax
15
Parameters
15
Examples
15
Format datetime in a Jinja2 template
15
Chapter 7: Deploying Flask application using uWSGI web server with Nginx
16
Examples
16
Using uWSGI to run a flask application
16
Installing nginx and setting it up for uWSGI
17
Enable streaming from flask
18
Set up Flask Application, uWGSI, Nginx - Server Configurations boiler template (default, p
19
Chapter 8: File Uploads
24
Syntax
24
Examples
24
Uploading Files
24
HTML Form
24
Python Requests
24
Save uploads on the server
25
Passing data to WTForms and Flask-WTF
25
PARSE CSV FILE UPLOAD AS LIST OF DICTIONARIES IN FLASK WITHOUT SAVING
26
Chapter 9: Flask on Apache with mod_wsgi
28
Examples
28
WSGI Application wrapper
28
Apache sites-enabled configuration for WSGI
28
Chapter 10: Flask-SQLAlchemy
30
Introduction
30
Examples
30
Installation and Initial Example
30
Relationships: One to Many
30
Chapter 11: Flask-WTF
32
Introduction
32
Examples
32
A simple Form
32
Chapter 12: Message Flashing
33
Introduction
33
Syntax
33
Parameters
33
Remarks
33
Examples
33
Simple Message Flashing
33
Flashing With Categories
34
Chapter 13: Pagination
35
Examples
35
Pagination Route Example with flask-sqlalchemy Paginate
35
Rendering pagination in Jinja
35
Chapter 14: Redirect
37
Syntax
37
Parameters
37
Remarks
37
Examples
37
Simple example
37
Passing along data
37
Chapter 15: Rendering Templates
39
Syntax
39
Examples
39
render_template Usage
39
Chapter 16: Routing
41
Examples
41
Basic Routes
41
Catch-all route
42
Routing and HTTP methods
43
Chapter 17: Sessions
44
Remarks
44
Examples
44
Using the sessions object within a view
44
Chapter 18: Signals
46
Remarks
46
Examples
46
Connecting to signals
46
Custom signals
46
Chapter 19: Static Files
48
Examples
48
Using Static Files
48
Static Files in Production (served by frontend webserver)
49
Chapter 20: Testing
52
Examples
52
Testing our Hello World app
52
Introduction
52
Defining the test
52
Running the test
53
Testing a JSON API implemented in Flask
53
Testing this API with pytest
53
Accessing and manipulating session variables in your tests using Flask-Testing
54
Chapter 21: Working with JSON
57
Examples
57
Return a JSON Response from Flask API
57
Try it with curl
57
Other ways to use jsonify()
57
Receiving JSON from an HTTP Request
57
Try it with curl
58
Credits
59
About
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1
Chapter 1: Getting started with Flask
Remarks
Flask is a Python web application micro-framework built on top of the Werkzeug WSGI library. Flask may be "micro", but it's ready for production use on a variety of needs.
The "micro" in micro-framework means Flask aims to keep the core simple but extensible. Flask won't make many decisions for you, such as what database to use, and the decisions that it does make are easy to change. Everything is up to you, so that Flask can be everything you need and nothing you don't.
The community supports a rich ecosystem of extensions to make your application more powerful and even easier to develop. As your project grows you are free to make the design decisions appropriate for your requirements.
Versions
Version Code Name Release Date
0.12
Punsch
2016-12-21
0.11
Absinthe
2016-05-29
0.10
Limoncello 2013-06-13
Examples
Installation - Stable
Use pip to install Flask in a virtualenv.
pip install flask
Step by step instructions for creating a virtualenv for your project:
mkdir project && cd project python3 -m venv env # or `virtualenv env` for Python 2 source env/bin/activate pip install flask
Never use sudo pip install unless you understand exactly what you're doing. Keep your project in a local virtualenv, do not install to the system Python unless you are using the system package
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