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Flask with SQLAlchemy Basics

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Intro to Flask

6:24 with Megan Amendola

Jump into the wonderful world of Flask. Learn what the request-response cycle is and how Python's Flask framework fits into it.

Docs

It is always a good idea to bookmark the documentation for reference.

Local Setup Steps

  • Setting up a local env - Mac

  • Setting up a local env - Windows

  • Create a folder for your project

  • Open your folder in your IDE

  • Open the terminal in your IDE

  • Create a virtual environment

    • Mac: python3 -m venv env
    • Windows: python -m venv env

  • Activate your environment

    • Mac: source ./env/bin/activate
    • Windows: .\env\Scripts\activate

  • Install Flask pip install flask

  • Create requirements file pip freeze > requirements.txt

GitHub Resources

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    [MUSIC] 0:00
    Hi, my name is Megan, and I'm a teacher here at Treehouse. 0:09
    My pronouns are she/her/hers. 0:13
    In this course, I'll teach you how to work with Flask, a popular Python framework for 0:16
    creating websites or web applications. 0:21
    A framework is a collection of code that makes building something easier. 0:25
    Flask will help us to create a website. 0:30
    Because it has written a lot of the code for us, 0:33
    we just need to learn how to use these new tools. 0:36
    Flask helps us work with the request response cycle. 0:40
    Let's take a look at what that means. 0:44
    The application gets requests, which are people on the internet asking for 0:47
    information from our application. 0:52
    Once they get to our application, it looks at all the routes available, 0:55
    and figures out which function to call. 1:00
    A lot of people call these functions controllers, but 1:03
    they can also be called views. 1:07
    The view then sends back a response, which can be HTML, or JSON, or XML. 1:09
    A user requests information from your site. 1:16
    Your site determines how to handle the request and what information to send back. 1:20
    And then a response is sent to the user. 1:25
    So when a user asks for Treehouse's homepage, 1:28
    the site will receive the request and send back the home page's information. 1:32
    Together, we're going to create this pet adoption website using Flask, 1:38
    SQLAlchemy, HTML, and CSS. 1:44
    It will hold a list of pets available for adoptions. 1:46
    Users will also have the ability to add, 1:50
    Edit, and delete. 2:04
    As we go along, feel free to play around with the site's colors and 2:08
    structure to make it your own. 2:12
    For this project, you can follow along in workspaces. 2:15
    It already has Flask installed, and 2:18
    I have attached them to the videos moving forward. 2:20
    If you would like to follow along locally, you will need to install Flask. 2:24
    I would also suggest creating a virtual environment to 2:28
    practice a typical workflow. 2:31
    First, I created a new project folder called adoption-flask-project, 2:34
    and I opened it inside of my IDE. 2:39
    I'm using Visual Studio, but please use whichever IDE or 2:41
    integrated development environment you feel comfortable with. 2:45
    You can find links to two favorites in the teacher's notes. 2:49
    Once I opened it, I can navigate to the terminal and 2:53
    create a virtual environment by running python3 -m venv env. 2:59
    On a Windows computer, you may not need this 3 here at the end of python. 3:08
    I'm on a Mac, so I am going to use it. 3:12
    You can see it created my environment folder, and Visual Studio's like, hey, 3:18
    you created a virtual environment, do you wanna use it? 3:22
    And yes we do, we definitely wanna use it. Awesome, 3:25
    now I need to activate the environment 3:31
    by running, on Windows, 3:37
    you would do .\env\Scripts\activate. 3:41
    If you're on a Mac, like I am, then you do source and 3:49
    then you do forward slashes as opposed to backslashes, ./env/bin/activate. 3:54
    So make sure to use the one that works for your machine. 4:01
    They're also listed in the teacher's notes, just in case. 4:03
    So I'm gonna go ahead and do that. 4:07
    And you can see it's activated now because I have this environment here at 4:08
    the beginning of my command prompt. 4:13
    Okay, so now we have our environment activated, 4:15
    let's install Flask, we'll use pip install flask. 4:20
    Awesome, and to make sure that it got installed, 4:26
    we can do pip freeze > requirements.txt. 4:34
    Hit Enter, and it'll create that requirements.txt file here. 4:40
    And you can see everything that gets downloaded along with Flask. 4:44
    Perfect, now that our project requirements file is ready, if you want to create 4:50
    a repo for this project, and others end up wanting to run your project to check it 4:55
    out, all they'll have to do is download the requirements from this file. 5:00
    If you do wanna post this on GitHub, then let's also create a gitignore file. 5:05
    Do new file, .gitignore, and then inside, 5:11
    we don't want this env file to be sent up, so I'm gonna do env. 5:15
    VS Code also creates this folder, we don't need that either. 5:21
    And another good one is /__pycache__, 5:26
    you might have seen it already when working with Python. 5:29
    It's a file that gets created sometimes, and we don't need that either. 5:34
    And if you're on a Mac, 5:38
    there's also this .DS_Store file that pops up from time to time. 5:39
    And it's specific to Macs, so if you're on a Windows, 5:44
    you don't need to worry about that one, but it's always a good one to ignore. 5:47
    Cool, make sure you save, and then we don't need that file anymore right now, 5:51
    and you're all set to work on this locally. 5:55
    I also posted these steps in the teacher's notes below for reference, along 5:58
    with a resource on virtual environments in case you decide to work locally later on. 6:02
    Again, choose the path that works best for you. 6:09
    I'll have the resources available throughout the course for 6:12
    both local and workspaces-based projects. 6:16
    I'm excited to work on this project with you, so let's get started. 6:19

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