[AI 웹개발 취업캠프] Python FLASK로 웹사이트 만들기(2)

Flask 기초

• virtual Environment - An isolated workspace for managing Python project dependencies independently.
• Anaconda 사용

conda create --name myvenv

• conda = invoke the Conda package manager.
• create = create a new environment
• --name = This flag specifies that you're about to provide the name of the new environment.
• myvenv = environment name

 

Flask Hello World

예시:

# Import the Flask class from the flask module
from flask import Flask

# Create an instance of the Flask class
# The argument __name__ helps Flask determine the root path of the application
app = Flask(__name__)

# Decorator to tell Flask what URL should trigger our function
@app.route('/')
def index():
    # This function will be triggered when the user accesses the root URL ('/')
    return '<h1>Hello World!</h1>'  # Returns an HTML string to be displayed in the browser

# This is a Python built-in variable which evaluates to the name of the current module.
# If the module is being run (as opposed to being imported), its value will be "__main__".
if __name__ == '__main__':
    # This means that we are running this module directly, and not importing it.
    app.run()  # Start the Flask development server

 

Web application Router

예시:

from flask import Flask
app = Flask(__name__)

# 127.0.0.1:5000
@app.route('/')
def index():
    return '<h1>Hello Puppy!</h1>'

# 127.0.0.1:5000/information
@app.route('/information')
def info():
    return '<h1>Puppies are cute!</h1>'

if __name__ == '__main__':
    app.run()

 

Dynamic Rountes

• Dynamic Routes - enable URLs to have variable segments, which are then passed as parameters to the corresponding function.

예시:

from flask import Flask
app = Flask(__name__)



# Decorator with a dynamic route.
# The portion <name> in the route is a variable part, 
# and it will be passed as an argument to the decorated function.
@app.route('/puppy/<name>')
def puppy(name):
    # The name parameter will capture the dynamic part of the URL.
    # For example, if the user visits '/puppy/Rex', then 'Rex' 
    # will be passed as the 'name' argument to this function.
    
    # The formatted string will display the captured name in the 
    # resulting HTML page.
    return '<h1>This is a page for {}<h1>'.format(name)

if __name__ == '__main__':
    app.run()

 

Debug mode

• Debug mode - provides detailed error messages and allows for live code reloading during development.
  • Also gives us access to a console in the browser!

예시:

# Never have debug=True for production apps!
app.run(debug=True)

 

Flask 라우팅 연습문제

• Make Puppy Latin name page

from flask import Flask
from flask import request

app = Flask(__name__)


@app.route('/')
def index():
    return "<h1>Welcome! Go to /puppy_latin/name to see your name in puppy latin!</h1>"

@app.route('/puppy_latin/<name>')
def puppylatin(name):

    pupname = ''
    
    if name[-1]=='y':
        puppyname = name[:-1]+'iful'
    else:
        puppyname = name+'y'

    return "<h1>Hi {}! Your puppylatin name is {} </h1>".format(name,puppyname)


if __name__ == '__main__':
    app.run(debug=True)

 

Basic Templates

• Basic Templates - dynamic generation of HTML content using placeholders and control structures, stored in a "templates" folder.

from flask import Flask, render_template
app = Flask(__name__)


@app.route('/')
def index():
    # Connecting to a template (html file)
    # By default, Flask looks in a folder named 'templates' for the given filename.
    return render_template('00-Basic-Template.html')

if __name__ == '__main__':
    app.run(debug=True)
    

• Jinja templating - allows embedding Python variables directly into HTML files.

예시:

{{variable}}    

HTML 예시:

<h1>Basic variable insert: {{name}}!</h1>
<!-- Recall that we set mylist=letters in the .py file. -->
<!-- You could use whatever variable names you want -->
<h1>List example: {{mylist}}</h1>
<!-- We can index the list as well -->
<h1>Indexing the list for the first letter: {{mylist[0]}}</h1>
<!-- We can also use dictionaries -->
<h1>Puppy name from dictionary: {{mydict['pup_name']}}</h1>

Python 예시:

@app.route('/advpuppy/<name>')
def adv_puppy_name(name):
    letters = list(name)
    pup_dict = {'pup_name':name}
    return render_template('01-Template-Variables.html',
                           name=name,mylist=letters,mydict=pup_dict)

• Jinja grants access to control flow structures, such as for loops and if statements, within templates.

예시:

{% %}

예시:

# for loop
<ul>
	{% for item in mylist %}
	<li>{{item}}</li>
	{% endfor %}
</ul>


# if statement
{% if item in list %}
	<p>Found you in the list of item</p>
{% else %}
	<p>Hmm, item isn't in this list.</p>
{% endif %}

 

Template Inheritance

• Template Inheritance - base templates to reuse and override specific sections of other pages, ensuring consistency and reducing redundancy.

예시:

# Base HTML

... original code ...

    {% block content %}
    {% endblock %}

... original code ...

Inheritance:

# other page

{% extends "04-base.html"%}
{% block content %}
<h1>This is the home page.</h1>
<h2>Go to /puppy/name</h2>
{% endblock %}

• Filters - change or format data in templates, don't need to be edited in Python

예시:

{{ variable | filter }}

{{ name | capitalize }}

• url_for - generates URLs for view functions

예시:

{{ url_for('view_name') }}

{{ url_for('index') }}

# for static file 

{{ url_for('folder_name', file_name) }}

 

(수정중)

 

 

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