A practical guide for developing and deploying responsive, RESTful web applications using the Flask framework. The book covers fundamental concepts of web application development, starting with Python for CGI and the Web Server Gateway Interface (WSGI), before moving into the Flask framework and its dependencies like Werkzeug, Jinja2, and Click. It details URL routing, templating with Jinja2, handling static files, and managing HTTP requests and responses, including cookies and sessions. Furthermore, the book explores database integration with Flask, covering both relational (SQLAlchemy) and NoSQL (MongoEngine) databases, and introduces advanced Flask features such as WTForms for form validation, Flask-Login for user authentication, and Flask-Bootstrap for responsive design. Finally, the text addresses building REST APIs with Flask and deploying Flask applications on various platforms.
You can listen and download our episodes for free on more than 10 different platforms:
https://linktr.ee/cyber_security_summary
Get the Book now from Amazon:
https://www.amazon.com/Building-Web-Apps-Python-Flask/dp/9389898838?&linkCode=ll1&tag=cvthunderx-20&linkId=fe26488689a6a4043e5e98f6e416ed62&language=en_US&ref_=as_li_ss_tl
Discover our free courses in tech and cybersecurity, Start learning today:
https://linktr.ee/cybercode_academy
You can listen and download our episodes for free on more than 10 different platforms:
https://linktr.ee/cyber_security_summary
Get the Book now from Amazon:
https://www.amazon.com/Building-Web-Apps-Python-Flask/dp/9389898838?&linkCode=ll1&tag=cvthunderx-20&linkId=fe26488689a6a4043e5e98f6e416ed62&language=en_US&ref_=as_li_ss_tl
Discover our free courses in tech and cybersecurity, Start learning today:
https://linktr.ee/cybercode_academy
Mark as Played
Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Speaker 1 (00:00):
All right, curious minds, let's buckle up for another deep dive. Today.
We're peeling back the layers on something that's well practically
the backbone of our digital lives, building web applications and
our guide Python, a language cherished for its clarity and versatility,
paired with a truly fantastic framework called Flask.
Speaker 2 (00:19):
Yeah, it's really fascinating how Python is just exploded in popularity,
not just in data science, you know, but as real
go to for web development too, and Flask in particular.
It really embodies the elegance of Python. You know that
line from the zen of Python. Beautiful is better than ugly,
Explicit is better than implicit, Simple is better than complex.
Flask's whole design philosophy seems to resonate deeply with that
(00:40):
r's power through intelligent minimalism.
Speaker 1 (00:43):
That's a perfect way to put it. So our mission
today is to really uncover how Flask helps you create
everything from say, straightforward web pages to complex, full fledged applications.
We're going to try and give you a shortcut to
being well informed about its core concepts, surprising capabilities, and
maybe most importantly, why developers seem to love it so much.
(01:05):
Get ready for some genuine insights because we're starting from
the ground up and while building our understanding piece by piece.
So when we hear micro framework for Flask, my immediate
thought is sometimes maybe limited. Is that the right association
or is there a kind of subtle power in that
micro label, especially for developers just getting started.
Speaker 2 (01:22):
That's a great point. What's truly insightful about FLASK being
micro isn't it's limited, but that it's intentionally lean, really lean.
It provides the absolute essentials for web development, things like
routing incoming requests to the right function and managing the
outgoing responses. It's tagline development, one drop at a time
(01:43):
captures this perfectly. This lean approach is actually a powerful
insight because it means Flask deliberately avoids that common framework
blow problem you sometimes see. You're not dragging along dozens
of dependencies you might never use, which keeps your application fast, secure,
and frankly easier to understand from the ground up. It's
a deliberate choice for developer control, you know, over just
(02:04):
prescriptive convenience.
Speaker 1 (02:06):
I see right, So that flexibility means you can tailor
it precisely to your project's needs. Okay, so for those
just diving in one of the foundational tools, Flask does
give us the ones to start building that custom web application.
Speaker 2 (02:17):
Well. Flask cleverly wraps three powerful Python packages that forms
its lean core. First, there's verkzoit it's essentially a comprehensive
WSGI toolkit WSGI or web server gateway interface. It's like
a standard way for any web server think Apache and Jinx,
even the simple server you use for development to talk
(02:39):
to any Python web application.
Speaker 1 (02:40):
Okay, so it standardizes the communication.
Speaker 2 (02:43):
Exactly before WSGI, every server needed custom code to talk
to different Python apps. It was well a huge mess.
VERSOI simplifies this. It acts as the universal adapter basically,
so Flask doesn't have to worry about the specific web
server you're using. It's the engine handling that crucial HTTP
plum the low level stuff understood.
Speaker 1 (03:01):
So it's like a universal translator for web requests. Makes sense,
and once we have that request handled, the next challenge
is while presenting information right, How does Flask tackle the
visual dynamic side of web pages, making them engaging rather
than just you know, raw.
Speaker 2 (03:15):
Data precisely, And that's where JINGA two comes in. It's
a fast and incredibly designer friendly templating engine. Just imagine
the nightmare of like concatenating huge strings of HTML inside
your Python code every time you wanted to change a
tiny piece of text or display a list.
Speaker 1 (03:31):
Oh yeah, that sounds awful, error.
Speaker 2 (03:33):
Prone, totally hard to read, maintenance nightmare. Jingaitwo solves this
by letting you create standard HTML files but with special placeholders.
Flask can then dynamically fill these placeholders with data from
your Python application. It really saves you from those old
days of writing a Python script that just generates a
massive one hundred line HTML string, a truly terrifying prospect
(03:55):
if you ever had.
Speaker 1 (03:56):
A debug it ah, I can imagine.
Speaker 2 (03:58):
This separation of concerns is almost like an active mercy
for developers. And finally, there's click that gives Flask its
powerful command line interface, making common tasks like running your
development server much easier and more consistent.
Speaker 1 (04:10):
So even with that minimal core, Flask gives you these
essential building blocks erksig, jinga to click, and then you
extend it with what you need. That really does highlight
the power and choice, yeah, rather than being forced into
some large opinionated framework.
Speaker 2 (04:24):
Okay, so once we have flasks core running. The next
big challenge is making our web pages interactive and well. Intelligent.
Users expect dynamic content and clean, readable URLs.
Speaker 1 (04:37):
How does flask help us move beyond those sort of
basic file based URLs to truly bring our pages to life.
Speaker 2 (04:44):
Yeah, that's where ur routing becomes a real game changer.
Gone are the days of those verbose chiabin scripts. Flask
uses a technique where you map clean, memorable URLs directly
to specific Python functions. Use a special decorator like at
app dot Real the decorator some Instead of a script name,
you might just have profile your name. Much more user
friendly and more predictable too for search engines and your
(05:05):
actual users.
Speaker 1 (05:06):
So can you make those URLs dynamic? Like if I
wanted a page for a specific user or maybe an
item in a store, could the URL reflect that specific ID?
Speaker 2 (05:15):
Absolutely? You can include variable parts writing your URL rules.
For example, at app dot root homelawls, we'll let you
capture a name directly from the URL path itself, and
Flask even has built in converters. You can specify the
type of variable you.
Speaker 1 (05:31):
Expect, oh, like an integer exactly.
Speaker 2 (05:33):
Like int dot id for an integer ID or float
dot price for a decimal price. It ensures you get
the data type you actually expect right out of the URL.
And for more complex stuff, functions like earle for help
you dynamically build URLs in your code so you're not
hard coding paths everywhere, which is brittle. Well, redirect lets
you programmatically send users to different pages like after they
(05:54):
successfully submit a form.
Speaker 1 (05:55):
That sounds really powerful for creating intuitive navigation and just
making URLs mix up to humans. You mentioned Jinga two
for content earlier. How did that make building dynamic web
pages less tedious than say, manually stringing together HTML and Python.
Speaker 2 (06:09):
Well, it's all about separating concerns really. Gingaitoo solves that
pain of mixing presentation logic with your application logic. It
lets you write standard HTML files, but the includes special
delimiters for the dynamic content. You'll see things like variables
to print expressions anything from a user's name to a product.
Speaker 1 (06:26):
Price okay, the double curly braces.
Speaker 2 (06:28):
Yep, and then percent statements percent curly braise with percent
signs for control flow.
Speaker 1 (06:33):
Control flow like if statements exactly.
Speaker 2 (06:36):
Like Ivil's conditions to show different content maybe based on
whether a user is logged in, or for loops to
iterate over a list of products and display each one.
Speaker 1 (06:44):
That's a really powerful distinction. So JINGA two lets us
bring a level of like intelligent logic directly into the
presentation layer, but without embedding raw Python code. What are
some of the most common ways developers leverage that well?
Speaker 2 (06:57):
It allows for incredibly flexible content generation. Two really common
features are macros and filters. Macros are essentially reusable blocks
and template code a bit like functions in Python. You
can define a navigation bar macro once, right, and then
you can just call it throughout your templates, maybe passing
in different arguments to highlight the active page.
Speaker 1 (07:18):
Ah, So reusable components.
Speaker 2 (07:20):
Precisely, and filters they let you transform data directly within
the template itself. I think like to easily convert text
uppercase right where you display it, or maybe to sort
of list before you loop through it in the HTML.
Speaker 1 (07:32):
That sounds incredibly handy for consistent formatting and yeah, data presentation.
And there's also something called template inheritance right that sounds
like a big efficiency booster, especially for larger projects.
Speaker 2 (07:43):
Oh yes, and it's a true game changer for maintaining
consistency and just reducing repetition. It really is just like
object oriented programming. You can define it, say, based dot
HTML template. This base template contains all the common elements
found on every page, headers, footers, navigation bars, maybe sidebars.
Speaker 1 (08:00):
The standard layout stuff exactly.
Speaker 2 (08:02):
The other child templates can simply use percent extends based
at HTML and then they just override specific sceptions usually
marked with block content percent with their own unique content.
This ensures a really uniform look and feel across your
entire application without repeating all that boilerplate code everywhere. It
simplifies updates immensely too. Change the foot are at once
and based dot HTML and boom it updates on every page.
Speaker 1 (08:25):
That simplifies design hugely. And speaking of design, what about
the client side elements like JavaScript and CSS. They're crucial
for interactive and stylish web apps. How does flask candle Those.
Speaker 2 (08:36):
Flask integrates really seamlessly with these static assets. You typically
place your JavaScript files, your CSS, style sheets, images, fonts,
all that stuff in a dedicated static folder within your
project structure. Then class provide the helper function role for
static file name styles on CSS for example, this function
correctly generates the right URL path for these assets, making
(08:58):
sure they're properly served to the browser when needed. It's
all part of making your web application look great and
feel interactive without you having to manually manage all those paths.
Speaker 1 (09:06):
Okay, so far we've got dynamic content, clean URLs, good
looking pages. But a truly useful web app needs a brain, right,
a memory. How does flask approach something as fundamental as
data storage databases?
Speaker 2 (09:19):
Indeed, data persistence is absolutely crucial for almost any meaningful
web application, and Flask, true to its micro framework nature,
it doesn't force a specific database choice on you, which
is nice. It supports both traditional relational databases think Squite
postcres School my School and modern nukele databases like Mango
dB for SQL. Sure, you can use pythons built in DBAPI,
(09:43):
but the real power, and honestly, the ease of use,
comes with an object relational mapper or ARM like squalkaming
an ORM.
Speaker 1 (09:50):
Right, it certainly sounds like it streamlines a lot of
that boilerplate database code does using an RM, though, does
it introduce any trade offs or maybe a learning curve
developer should be aware.
Speaker 2 (10:00):
Of That's a fair question, and it really speaks to
the choices Flask and courages. Well, yeah, there's definitely an
initial learning curve to squalok me, especially with its more
powerful query and capabilities, the payoff is usually huge, and
Flask School to Me, which is an extension specifically for Flask,
simplifies this even further. Lets you interact with your database
using familiar Python objects and classes instead of writing raw,
(10:21):
often error prone sequl queries by hand.
Speaker 1 (10:23):
So you define classes that map to tables.
Speaker 2 (10:26):
Exactly, you define Python classes that map directly to your
database tables, so operations like creating records, reading them, updating,
deleting it all feels like simply manipulating Python objects. It
even handles complex relationships between tables pretty elegantly, like a
user having many posts or products belonging to categories. It
saves a lot of manual effort and potential bugs. The
(10:49):
trade off is maybe a slight abstraction penalty sometimes a
little overhead, but for most applications the productivity gains just
far outweigh it.
Speaker 1 (10:56):
That definitely makes database interaction feel much more pythonicuch more integrated.
And for no SQL databases, what's the Flasks story? There
are there similar tools yep for.
Speaker 2 (11:07):
No SQL databases like Manga deb which are fantastic for say,
flexible data models or handling massive scale Flask has extensions too,
m M. Popular ones are flaskb Mango and flaskmongo Engine
mongo Engine in particular, it's an object document mapper or ODM.
It provides similar benefits for no SQL as goalchemy does
for SQL. That Python object to database mapping. You define
(11:29):
Python classes that map to your NOSEQL documents, giving you
a consistent way to work with data regardless of the
underlying database type. It's that choice again, right, anybling you
to pick the right tool for your specific data needs.
Speaker 1 (11:41):
That gives you a ton of options for data storage. Yeah,
covering a really wide range of application needs. We've talked
about Flask being a micro framework that truly shines when
you add extensions beyond just database connectivity. What are some
other maybe essential extensions for building robust real world applications.
Speaker 2 (11:58):
Oh? Yeah, extensions are truly where flasks power ecosystem becomes apparent.
They're key for handling user input like forms on a
web page. FLASWTF is pretty much indispensable. It simplifies creating webforms, sure,
but critically it provides robust server side.
Speaker 1 (12:12):
Validation, server side validation okay.
Speaker 2 (12:15):
And CSRF protection. That's cross site request forgery protection. CSRS
is a nasty attack where like malicious websites trick users
into submitting unwided requests to your web application without them knowing.
Speaker 1 (12:28):
Oh wow, like deleting their account exactly.
Speaker 2 (12:31):
Yeah, imagine someone unknowingly deleting their own account just by
clicking a bad link on another site. Flas WTF adds
hidden tokens to your forms to prevent this. It ensures
requests genuinely originate from your site, so it makes your
forms much much more secure than just relying on client
side JavaScript validation alone. Plus, it handles everything from basic
text fields to complex validation rules like ensuring an email
(12:53):
looks like an email or a password matches its confirmation feel.
Speaker 1 (12:57):
User forms, validation and especially that security aspect absolutely key
for any interactive app, definitely, But what about managing who
can access what in your application? User authentication and permissions.
Speaker 2 (13:09):
Right, That's where flask login comes in. It's designed to
manage user sessions. It allows you to easily implement authentication,
logging users in and out. You can protect specific routes,
specific pages with a simple at login required decorator.
Speaker 1 (13:22):
At login required oh well.
Speaker 2 (13:24):
Ensuring only logged in users can access those certain pages,
and it conveniently tracks the current user object throughout their
session so you can easily personalized content or control access
based on who they are.
Speaker 1 (13:36):
Very useful and for making sure your app looks good
everywhere on any screen size, from a tiny phone to
a big desktop monitor. That's a huge challenge for web
developers these days.
Speaker 2 (13:47):
It really is. Flask Bootstrap is often the go to
answer there. It integrates the incredibly popular Bootstrap front end
framework directly into Flask. This makes it remarkably simple to
create riskleents of web designs, which means your application will
automatically adapt its layout and look great across all sorts
of devices and screen dimensions without you having to write
tons of complex custom CSS for each one.
Speaker 1 (14:09):
That saves a lot of time huge amounts.
Speaker 2 (14:11):
It even provides handy macros like quick form, which can
render your Flask WTF forms responsively using Bootstrap styles with
minimal effort. It's really about leveraging these powerful existing solutions
to make your app look polished and accessible.
Speaker 1 (14:25):
Quickly, so you really can build entire complex systems but
just picking and choosing the right extensions for your needs,
sort of bolting on functionality as required. That's true power. Yeah,
giving developers immense flexibility.
Speaker 2 (14:37):
Okay, So as our flask application grows, maybe from a
personal project to something really substantial, that single Python script
we started with can quickly become well a tangled mess.
How does flask help developers maintain sanity and structure in
these larger projects? Ah? This is precisely where blueprints become
incredibly useful, essential really for scale. And the real insight
(14:58):
with blueprints isn't just organization, It's about achieving true mardularity.
Imagine building let's say a complex educational portal. Maybe it
has distinct sections, an engineering institute and a management institute.
Each might have its own login page, its own course catalog,
different application forms, maybe even specific admin dashboards.
Speaker 1 (15:20):
Right, completely separate concern exactly.
Speaker 2 (15:22):
Instead of cramming all that logic into one giant, potentially
unmanageable Flask application file, you can make each institute a
separate blueprint.
Speaker 1 (15:30):
So a blueprint acts like a self contained module, almost
like a mini application within the main app, complete with
its own routes, its own templates, maybe even its own
static assets that we can just plug into the main
Flask gap.
Speaker 2 (15:41):
That's exactly it. A blueprint is a collection of related views,
your Python functions, handling requests, templates, static assets, and other
resources that all pertain to a specific, self contained part
of your application. They can't run on their own, they
need to be registered with the main app, but they
provide a fantastic, modular, reusable way to structure complex applications.
(16:03):
You define all the routes and logic for the engineering institute,
say in its own blueprint file or directory structure, and
then you just register it with the main Flask application.
This drastically improves organization maintainability. It even allows for code
reuse across different projects. If a blueprint is general enough.
Thinking back to an e commerce example, separate teams could
(16:23):
even work on, say the account management blueprint and the
proc catalog blueprint almost independently, minimizing merge conflicts speeding up development.
It's significant.
Speaker 1 (16:32):
That sounds a fantastic way to break down complexity and
just keep things tidy as projects grow. And you also
mentioned contexts earlier. How do those help Flask manage things
behind the scenes, especially when multiple users are hitting the
up at the same time.
Speaker 2 (16:46):
Right contexts. Flask uses application context and request contexts to
manage state efficiently. This is especially crucial in a multi
threaded environment where yeah, many users might hit your server
at the exact same moment. It like this. When you
walk into a busy workshop, you get assigned to your own workbench. Right,
that's your request context. It holds your specific tools, your
(17:07):
materials for the job you're doing right now, your current
project state. Okay, my personal workspace exactly. Meanwhile, the workshop
itself has general inventory, shared tools, maybe staff. That's the
application context the overall environment. Flask needs these contexts to
keep track of who is doing what at any given moment,
especially when potentially hundreds of people are working simultaneously. It's
(17:30):
how Flask ensures that when your code uses the request object,
it always refers to your specific current browser request, not
someone else's, and that current tap always points to the
correct application instance handling that request. It perfectly isolates each
user's interaction.
Speaker 1 (17:45):
Ah I see. So these contexts are flasks sort of
elegant solution to juggling multiple users and their unique interactions
all at once, making sure everything runs smoothly without any
data getting cross wired between requests precisely.
Speaker 2 (17:58):
These contexts also define when certain objects are actually available.
This prevents unexpected errors if you try to access a
request object when there isn't actually an incoming request being processed.
And for more advanced structuring, there's something called the application
factory pattern. This involves creating a function often named something
like creedypap that handles initializing your Flask application and all
(18:20):
its extensions. It's incredibly useful for things like testing where
you might need multiple clean instances of your app, or
for handling different configurations development versus production, or just when
you need to create instances of your app dynamically. You
can also run code automatically before or after these requests
using callback decorators like it before request and an after request.
(18:42):
These give you really fine grain control over the whole
request life cycle.
Speaker 1 (18:46):
Wow, what a journey we've really been on today. From
truly understanding flasks, micro framework philosophy and its core dependencies
like ver seige, ginga to and click through bringing web
pages to life with that elegant URL routing and diemic
templates all the way to building robust applications with database integration,
secure user management, and then organizing for scale with these
(19:08):
modular blueprints and those crucial contexts.
Speaker 2 (19:11):
Yeah, it's truly fascinating. Here is how Flask, despite starting
with that minimalist core, it leverages this really rich ecosystem
of extensions and intelligent design patterns like blueprints and context
to become an incredibly powerful and flexible tool for web development.
It genuinely scales with your needs. It allows you to
focus on your application's unique logic rather than constantly reinventing
(19:32):
those foundational web components. It really embodies that Pythonic ideal,
doesn't it. Simplicity leading to profound capability, and.
Speaker 1 (19:38):
That really is the beauty of it. It's not just
about learning a framework. It feels like it's about understanding
of philosophy, a philosophy that empowers you to build sophisticated
web solutions efficiently, whether that's a small personal project or
you know, a large scale enterprise application supporting multiple teams, which.
Speaker 2 (19:55):
I think raises an important question for you, the listener.
Knowing Flask's philosoph now empowering choice, simplifying complex interactions, scaling
with intelligent modularity, what kind of ambitious problem maybe one
you previously thought was too complex for a micro framework.
Could you now envision tackling with flask
All right, curious minds, let's buckle up for another deep dive. Today.
We're peeling back the layers on something that's well practically
the backbone of our digital lives, building web applications and
our guide Python, a language cherished for its clarity and versatility,
paired with a truly fantastic framework called Flask.
Speaker 2 (00:19):
Yeah, it's really fascinating how Python is just exploded in popularity,
not just in data science, you know, but as real
go to for web development too, and Flask in particular.
It really embodies the elegance of Python. You know that
line from the zen of Python. Beautiful is better than ugly,
Explicit is better than implicit, Simple is better than complex.
Flask's whole design philosophy seems to resonate deeply with that
(00:40):
r's power through intelligent minimalism.
Speaker 1 (00:43):
That's a perfect way to put it. So our mission
today is to really uncover how Flask helps you create
everything from say, straightforward web pages to complex, full fledged applications.
We're going to try and give you a shortcut to
being well informed about its core concepts, surprising capabilities, and
maybe most importantly, why developers seem to love it so much.
(01:05):
Get ready for some genuine insights because we're starting from
the ground up and while building our understanding piece by piece.
So when we hear micro framework for Flask, my immediate
thought is sometimes maybe limited. Is that the right association
or is there a kind of subtle power in that
micro label, especially for developers just getting started.
Speaker 2 (01:22):
That's a great point. What's truly insightful about FLASK being
micro isn't it's limited, but that it's intentionally lean, really lean.
It provides the absolute essentials for web development, things like
routing incoming requests to the right function and managing the
outgoing responses. It's tagline development, one drop at a time
(01:43):
captures this perfectly. This lean approach is actually a powerful
insight because it means Flask deliberately avoids that common framework
blow problem you sometimes see. You're not dragging along dozens
of dependencies you might never use, which keeps your application fast, secure,
and frankly easier to understand from the ground up. It's
a deliberate choice for developer control, you know, over just
(02:04):
prescriptive convenience.
Speaker 1 (02:06):
I see right, So that flexibility means you can tailor
it precisely to your project's needs. Okay, so for those
just diving in one of the foundational tools, Flask does
give us the ones to start building that custom web application.
Speaker 2 (02:17):
Well. Flask cleverly wraps three powerful Python packages that forms
its lean core. First, there's verkzoit it's essentially a comprehensive
WSGI toolkit WSGI or web server gateway interface. It's like
a standard way for any web server think Apache and Jinx,
even the simple server you use for development to talk
(02:39):
to any Python web application.
Speaker 1 (02:40):
Okay, so it standardizes the communication.
Speaker 2 (02:43):
Exactly before WSGI, every server needed custom code to talk
to different Python apps. It was well a huge mess.
VERSOI simplifies this. It acts as the universal adapter basically,
so Flask doesn't have to worry about the specific web
server you're using. It's the engine handling that crucial HTTP
plum the low level stuff understood.
Speaker 1 (03:01):
So it's like a universal translator for web requests. Makes sense,
and once we have that request handled, the next challenge
is while presenting information right, How does Flask tackle the
visual dynamic side of web pages, making them engaging rather
than just you know, raw.
Speaker 2 (03:15):
Data precisely, And that's where JINGA two comes in. It's
a fast and incredibly designer friendly templating engine. Just imagine
the nightmare of like concatenating huge strings of HTML inside
your Python code every time you wanted to change a
tiny piece of text or display a list.
Speaker 1 (03:31):
Oh yeah, that sounds awful, error.
Speaker 2 (03:33):
Prone, totally hard to read, maintenance nightmare. Jingaitwo solves this
by letting you create standard HTML files but with special placeholders.
Flask can then dynamically fill these placeholders with data from
your Python application. It really saves you from those old
days of writing a Python script that just generates a
massive one hundred line HTML string, a truly terrifying prospect
(03:55):
if you ever had.
Speaker 1 (03:56):
A debug it ah, I can imagine.
Speaker 2 (03:58):
This separation of concerns is almost like an active mercy
for developers. And finally, there's click that gives Flask its
powerful command line interface, making common tasks like running your
development server much easier and more consistent.
Speaker 1 (04:10):
So even with that minimal core, Flask gives you these
essential building blocks erksig, jinga to click, and then you
extend it with what you need. That really does highlight
the power and choice, yeah, rather than being forced into
some large opinionated framework.
Speaker 2 (04:24):
Okay, so once we have flasks core running. The next
big challenge is making our web pages interactive and well. Intelligent.
Users expect dynamic content and clean, readable URLs.
Speaker 1 (04:37):
How does flask help us move beyond those sort of
basic file based URLs to truly bring our pages to life.
Speaker 2 (04:44):
Yeah, that's where ur routing becomes a real game changer.
Gone are the days of those verbose chiabin scripts. Flask
uses a technique where you map clean, memorable URLs directly
to specific Python functions. Use a special decorator like at
app dot Real the decorator some Instead of a script name,
you might just have profile your name. Much more user
friendly and more predictable too for search engines and your
(05:05):
actual users.
Speaker 1 (05:06):
So can you make those URLs dynamic? Like if I
wanted a page for a specific user or maybe an
item in a store, could the URL reflect that specific ID?
Speaker 2 (05:15):
Absolutely? You can include variable parts writing your URL rules.
For example, at app dot root homelawls, we'll let you
capture a name directly from the URL path itself, and
Flask even has built in converters. You can specify the
type of variable you.
Speaker 1 (05:31):
Expect, oh, like an integer exactly.
Speaker 2 (05:33):
Like int dot id for an integer ID or float
dot price for a decimal price. It ensures you get
the data type you actually expect right out of the URL.
And for more complex stuff, functions like earle for help
you dynamically build URLs in your code so you're not
hard coding paths everywhere, which is brittle. Well, redirect lets
you programmatically send users to different pages like after they
(05:54):
successfully submit a form.
Speaker 1 (05:55):
That sounds really powerful for creating intuitive navigation and just
making URLs mix up to humans. You mentioned Jinga two
for content earlier. How did that make building dynamic web
pages less tedious than say, manually stringing together HTML and Python.
Speaker 2 (06:09):
Well, it's all about separating concerns really. Gingaitoo solves that
pain of mixing presentation logic with your application logic. It
lets you write standard HTML files, but the includes special
delimiters for the dynamic content. You'll see things like variables
to print expressions anything from a user's name to a product.
Speaker 1 (06:26):
Price okay, the double curly braces.
Speaker 2 (06:28):
Yep, and then percent statements percent curly braise with percent
signs for control flow.
Speaker 1 (06:33):
Control flow like if statements exactly.
Speaker 2 (06:36):
Like Ivil's conditions to show different content maybe based on
whether a user is logged in, or for loops to
iterate over a list of products and display each one.
Speaker 1 (06:44):
That's a really powerful distinction. So JINGA two lets us
bring a level of like intelligent logic directly into the
presentation layer, but without embedding raw Python code. What are
some of the most common ways developers leverage that well?
Speaker 2 (06:57):
It allows for incredibly flexible content generation. Two really common
features are macros and filters. Macros are essentially reusable blocks
and template code a bit like functions in Python. You
can define a navigation bar macro once, right, and then
you can just call it throughout your templates, maybe passing
in different arguments to highlight the active page.
Speaker 1 (07:18):
Ah, So reusable components.
Speaker 2 (07:20):
Precisely, and filters they let you transform data directly within
the template itself. I think like to easily convert text
uppercase right where you display it, or maybe to sort
of list before you loop through it in the HTML.
Speaker 1 (07:32):
That sounds incredibly handy for consistent formatting and yeah, data presentation.
And there's also something called template inheritance right that sounds
like a big efficiency booster, especially for larger projects.
Speaker 2 (07:43):
Oh yes, and it's a true game changer for maintaining
consistency and just reducing repetition. It really is just like
object oriented programming. You can define it, say, based dot
HTML template. This base template contains all the common elements
found on every page, headers, footers, navigation bars, maybe sidebars.
Speaker 1 (08:00):
The standard layout stuff exactly.
Speaker 2 (08:02):
The other child templates can simply use percent extends based
at HTML and then they just override specific sceptions usually
marked with block content percent with their own unique content.
This ensures a really uniform look and feel across your
entire application without repeating all that boilerplate code everywhere. It
simplifies updates immensely too. Change the foot are at once
and based dot HTML and boom it updates on every page.
Speaker 1 (08:25):
That simplifies design hugely. And speaking of design, what about
the client side elements like JavaScript and CSS. They're crucial
for interactive and stylish web apps. How does flask candle Those.
Speaker 2 (08:36):
Flask integrates really seamlessly with these static assets. You typically
place your JavaScript files, your CSS, style sheets, images, fonts,
all that stuff in a dedicated static folder within your
project structure. Then class provide the helper function role for
static file name styles on CSS for example, this function
correctly generates the right URL path for these assets, making
(08:58):
sure they're properly served to the browser when needed. It's
all part of making your web application look great and
feel interactive without you having to manually manage all those paths.
Speaker 1 (09:06):
Okay, so far we've got dynamic content, clean URLs, good
looking pages. But a truly useful web app needs a brain, right,
a memory. How does flask approach something as fundamental as
data storage databases?
Speaker 2 (09:19):
Indeed, data persistence is absolutely crucial for almost any meaningful
web application, and Flask, true to its micro framework nature,
it doesn't force a specific database choice on you, which
is nice. It supports both traditional relational databases think Squite
postcres School my School and modern nukele databases like Mango
dB for SQL. Sure, you can use pythons built in DBAPI,
(09:43):
but the real power, and honestly, the ease of use,
comes with an object relational mapper or ARM like squalkaming
an ORM.
Speaker 1 (09:50):
Right, it certainly sounds like it streamlines a lot of
that boilerplate database code does using an RM, though, does
it introduce any trade offs or maybe a learning curve
developer should be aware.
Speaker 2 (10:00):
Of That's a fair question, and it really speaks to
the choices Flask and courages. Well, yeah, there's definitely an
initial learning curve to squalok me, especially with its more
powerful query and capabilities, the payoff is usually huge, and
Flask School to Me, which is an extension specifically for Flask,
simplifies this even further. Lets you interact with your database
using familiar Python objects and classes instead of writing raw,
(10:21):
often error prone sequl queries by hand.
Speaker 1 (10:23):
So you define classes that map to tables.
Speaker 2 (10:26):
Exactly, you define Python classes that map directly to your
database tables, so operations like creating records, reading them, updating,
deleting it all feels like simply manipulating Python objects. It
even handles complex relationships between tables pretty elegantly, like a
user having many posts or products belonging to categories. It
saves a lot of manual effort and potential bugs. The
(10:49):
trade off is maybe a slight abstraction penalty sometimes a
little overhead, but for most applications the productivity gains just
far outweigh it.
Speaker 1 (10:56):
That definitely makes database interaction feel much more pythonicuch more integrated.
And for no SQL databases, what's the Flasks story? There
are there similar tools yep for.
Speaker 2 (11:07):
No SQL databases like Manga deb which are fantastic for say,
flexible data models or handling massive scale Flask has extensions too,
m M. Popular ones are flaskb Mango and flaskmongo Engine
mongo Engine in particular, it's an object document mapper or ODM.
It provides similar benefits for no SQL as goalchemy does
for SQL. That Python object to database mapping. You define
(11:29):
Python classes that map to your NOSEQL documents, giving you
a consistent way to work with data regardless of the
underlying database type. It's that choice again, right, anybling you
to pick the right tool for your specific data needs.
Speaker 1 (11:41):
That gives you a ton of options for data storage. Yeah,
covering a really wide range of application needs. We've talked
about Flask being a micro framework that truly shines when
you add extensions beyond just database connectivity. What are some
other maybe essential extensions for building robust real world applications.
Speaker 2 (11:58):
Oh? Yeah, extensions are truly where flasks power ecosystem becomes apparent.
They're key for handling user input like forms on a
web page. FLASWTF is pretty much indispensable. It simplifies creating webforms, sure,
but critically it provides robust server side.
Speaker 1 (12:12):
Validation, server side validation okay.
Speaker 2 (12:15):
And CSRF protection. That's cross site request forgery protection. CSRS
is a nasty attack where like malicious websites trick users
into submitting unwided requests to your web application without them knowing.
Speaker 1 (12:28):
Oh wow, like deleting their account exactly.
Speaker 2 (12:31):
Yeah, imagine someone unknowingly deleting their own account just by
clicking a bad link on another site. Flas WTF adds
hidden tokens to your forms to prevent this. It ensures
requests genuinely originate from your site, so it makes your
forms much much more secure than just relying on client
side JavaScript validation alone. Plus, it handles everything from basic
text fields to complex validation rules like ensuring an email
(12:53):
looks like an email or a password matches its confirmation feel.
Speaker 1 (12:57):
User forms, validation and especially that security aspect absolutely key
for any interactive app, definitely, But what about managing who
can access what in your application? User authentication and permissions.
Speaker 2 (13:09):
Right, That's where flask login comes in. It's designed to
manage user sessions. It allows you to easily implement authentication,
logging users in and out. You can protect specific routes,
specific pages with a simple at login required decorator.
Speaker 1 (13:22):
At login required oh well.
Speaker 2 (13:24):
Ensuring only logged in users can access those certain pages,
and it conveniently tracks the current user object throughout their
session so you can easily personalized content or control access
based on who they are.
Speaker 1 (13:36):
Very useful and for making sure your app looks good
everywhere on any screen size, from a tiny phone to
a big desktop monitor. That's a huge challenge for web
developers these days.
Speaker 2 (13:47):
It really is. Flask Bootstrap is often the go to
answer there. It integrates the incredibly popular Bootstrap front end
framework directly into Flask. This makes it remarkably simple to
create riskleents of web designs, which means your application will
automatically adapt its layout and look great across all sorts
of devices and screen dimensions without you having to write
tons of complex custom CSS for each one.
Speaker 1 (14:09):
That saves a lot of time huge amounts.
Speaker 2 (14:11):
It even provides handy macros like quick form, which can
render your Flask WTF forms responsively using Bootstrap styles with
minimal effort. It's really about leveraging these powerful existing solutions
to make your app look polished and accessible.
Speaker 1 (14:25):
Quickly, so you really can build entire complex systems but
just picking and choosing the right extensions for your needs,
sort of bolting on functionality as required. That's true power. Yeah,
giving developers immense flexibility.
Speaker 2 (14:37):
Okay, So as our flask application grows, maybe from a
personal project to something really substantial, that single Python script
we started with can quickly become well a tangled mess.
How does flask help developers maintain sanity and structure in
these larger projects? Ah? This is precisely where blueprints become
incredibly useful, essential really for scale. And the real insight
(14:58):
with blueprints isn't just organization, It's about achieving true mardularity.
Imagine building let's say a complex educational portal. Maybe it
has distinct sections, an engineering institute and a management institute.
Each might have its own login page, its own course catalog,
different application forms, maybe even specific admin dashboards.
Speaker 1 (15:20):
Right, completely separate concern exactly.
Speaker 2 (15:22):
Instead of cramming all that logic into one giant, potentially
unmanageable Flask application file, you can make each institute a
separate blueprint.
Speaker 1 (15:30):
So a blueprint acts like a self contained module, almost
like a mini application within the main app, complete with
its own routes, its own templates, maybe even its own
static assets that we can just plug into the main
Flask gap.
Speaker 2 (15:41):
That's exactly it. A blueprint is a collection of related views,
your Python functions, handling requests, templates, static assets, and other
resources that all pertain to a specific, self contained part
of your application. They can't run on their own, they
need to be registered with the main app, but they
provide a fantastic, modular, reusable way to structure complex applications.
(16:03):
You define all the routes and logic for the engineering institute,
say in its own blueprint file or directory structure, and
then you just register it with the main Flask application.
This drastically improves organization maintainability. It even allows for code
reuse across different projects. If a blueprint is general enough.
Thinking back to an e commerce example, separate teams could
(16:23):
even work on, say the account management blueprint and the
proc catalog blueprint almost independently, minimizing merge conflicts speeding up development.
It's significant.
Speaker 1 (16:32):
That sounds a fantastic way to break down complexity and
just keep things tidy as projects grow. And you also
mentioned contexts earlier. How do those help Flask manage things
behind the scenes, especially when multiple users are hitting the
up at the same time.
Speaker 2 (16:46):
Right contexts. Flask uses application context and request contexts to
manage state efficiently. This is especially crucial in a multi
threaded environment where yeah, many users might hit your server
at the exact same moment. It like this. When you
walk into a busy workshop, you get assigned to your own workbench. Right,
that's your request context. It holds your specific tools, your
(17:07):
materials for the job you're doing right now, your current
project state. Okay, my personal workspace exactly. Meanwhile, the workshop
itself has general inventory, shared tools, maybe staff. That's the
application context the overall environment. Flask needs these contexts to
keep track of who is doing what at any given moment,
especially when potentially hundreds of people are working simultaneously. It's
(17:30):
how Flask ensures that when your code uses the request object,
it always refers to your specific current browser request, not
someone else's, and that current tap always points to the
correct application instance handling that request. It perfectly isolates each
user's interaction.
Speaker 1 (17:45):
Ah I see. So these contexts are flasks sort of
elegant solution to juggling multiple users and their unique interactions
all at once, making sure everything runs smoothly without any
data getting cross wired between requests precisely.
Speaker 2 (17:58):
These contexts also define when certain objects are actually available.
This prevents unexpected errors if you try to access a
request object when there isn't actually an incoming request being processed.
And for more advanced structuring, there's something called the application
factory pattern. This involves creating a function often named something
like creedypap that handles initializing your Flask application and all
(18:20):
its extensions. It's incredibly useful for things like testing where
you might need multiple clean instances of your app, or
for handling different configurations development versus production, or just when
you need to create instances of your app dynamically. You
can also run code automatically before or after these requests
using callback decorators like it before request and an after request.
(18:42):
These give you really fine grain control over the whole
request life cycle.
Speaker 1 (18:46):
Wow, what a journey we've really been on today. From
truly understanding flasks, micro framework philosophy and its core dependencies
like ver seige, ginga to and click through bringing web
pages to life with that elegant URL routing and diemic
templates all the way to building robust applications with database integration,
secure user management, and then organizing for scale with these
(19:08):
modular blueprints and those crucial contexts.
Speaker 2 (19:11):
Yeah, it's truly fascinating. Here is how Flask, despite starting
with that minimalist core, it leverages this really rich ecosystem
of extensions and intelligent design patterns like blueprints and context
to become an incredibly powerful and flexible tool for web development.
It genuinely scales with your needs. It allows you to
focus on your application's unique logic rather than constantly reinventing
(19:32):
those foundational web components. It really embodies that Pythonic ideal,
doesn't it. Simplicity leading to profound capability, and.
Speaker 1 (19:38):
That really is the beauty of it. It's not just
about learning a framework. It feels like it's about understanding
of philosophy, a philosophy that empowers you to build sophisticated
web solutions efficiently, whether that's a small personal project or
you know, a large scale enterprise application supporting multiple teams, which.
Speaker 2 (19:55):
I think raises an important question for you, the listener.
Knowing Flask's philosoph now empowering choice, simplifying complex interactions, scaling
with intelligent modularity, what kind of ambitious problem maybe one
you previously thought was too complex for a micro framework.
Could you now envision tackling with flask
Popular Podcasts
Stuff You Should Know
If you've ever wanted to know about champagne, satanism, the Stonewall Uprising, chaos theory, LSD, El Nino, true crime and Rosa Parks, then look no further. Josh and Chuck have you covered.
Dateline NBC
Current and classic episodes, featuring compelling true-crime mysteries, powerful documentaries and in-depth investigations. Follow now to get the latest episodes of Dateline NBC completely free, or subscribe to Dateline Premium for ad-free listening and exclusive bonus content: DatelinePremium.com
The Burden
The Burden is a documentary series that takes listeners into the hidden places where justice is done (and undone). It dives deep into the lives of heroes and villains. And it focuses a spotlight on those who triumph even when the odds are against them. Season 5 - The Burden: Death & Deceit in Alliance On April Fools Day 1999, 26-year-old Yvonne Layne was found murdered in her Alliance, Ohio home. David Thorne, her ex-boyfriend and father of one of her children, was instantly a suspect. Another young man admitted to the murder, and David breathed a sigh of relief, until the confessed murderer fingered David; “He paid me to do it.” David was sentenced to life without parole. Two decades later, Pulitzer winner and podcast host, Maggie Freleng (Bone Valley Season 3: Graves County, Wrongful Conviction, Suave) launched a “live” investigation into David's conviction alongside Jason Baldwin (himself wrongfully convicted as a member of the West Memphis Three). Maggie had come to believe that the entire investigation of David was botched by the tiny local police department, or worse, covered up the real killer. Was Maggie correct? Was David’s claim of innocence credible? In Death and Deceit in Alliance, Maggie recounts the case that launched her career, and ultimately, “broke” her.” The results will shock the listener and reduce Maggie to tears and self-doubt. This is not your typical wrongful conviction story. In fact, it turns the genre on its head. It asks the question: What if our champions are foolish? Season 4 - The Burden: Get the Money and Run “Trying to murder my father, this was the thing that put me on the path.” That’s Joe Loya and that path was bank robbery. Bank, bank, bank, bank, bank. In season 4 of The Burden: Get the Money and Run, we hear from Joe who was once the most prolific bank robber in Southern California, and beyond. He used disguises, body doubles, proxies. He leaped over counters, grabbed the money and ran. Even as the FBI was closing in. It was a showdown between a daring bank robber, and a patient FBI agent. Joe was no ordinary bank robber. He was bright, articulate, charismatic, and driven by a dark rage that he summoned up at will. In seven episodes, Joe tells all: the what, the how… and the why. Including why he tried to murder his father. Season 3 - The Burden: Avenger Miriam Lewin is one of Argentina’s leading journalists today. At 19 years old, she was kidnapped off the streets of Buenos Aires for her political activism and thrown into a concentration camp. Thousands of her fellow inmates were executed, tossed alive from a cargo plane into the ocean. Miriam, along with a handful of others, will survive the camp. Then as a journalist, she will wage a decades long campaign to bring her tormentors to justice. Avenger is about one woman’s triumphant battle against unbelievable odds to survive torture, claim justice for the crimes done against her and others like her, and change the future of her country. Season 2 - The Burden: Empire on Blood Empire on Blood is set in the Bronx, NY, in the early 90s, when two young drug dealers ruled an intersection known as “The Corner on Blood.” The boss, Calvin Buari, lived large. He and a protege swore they would build an empire on blood. Then the relationship frayed and the protege accused Calvin of a double homicide which he claimed he didn’t do. But did he? Award-winning journalist Steve Fishman spent seven years to answer that question. This is the story of one man’s last chance to overturn his life sentence. He may prevail, but someone’s gotta pay. The Burden: Empire on Blood is the director’s cut of the true crime classic which reached #1 on the charts when it was first released half a dozen years ago. Season 1 - The Burden In the 1990s, Detective Louis N. Scarcella was legendary. In a city overrun by violent crime, he cracked the toughest cases and put away the worst criminals. “The Hulk” was his nickname. Then the story changed. Scarcella ran into a group of convicted murderers who all say they are innocent. They turned themselves into jailhouse-lawyers and in prison founded a lway firm. When they realized Scarcella helped put many of them away, they set their sights on taking him down. And with the help of a NY Times reporter they have a chance. For years, Scarcella insisted he did nothing wrong. But that’s all he’d say. Until we tracked Scarcella to a sauna in a Russian bathhouse, where he started to talk..and talk and talk. “The guilty have gone free,” he whispered. And then agreed to take us into the belly of the beast. Welcome to The Burden.