Repository
What Will I Learn?
- Templating jinja2
- Pass the parameter to the template
- POST data on the routing system
Requirements
- Basic Python
- Install Python 3
- Install Flask
Resources
- Python - https://www.python.org/
- Flask - http://flask.pocoo.org/
- Jinja2 -http://jinja.pocoo.org/docs/2.10/
Difficulty
Basic
Tutorial Content
This tutorial is a continuation of the previous tutorial series, in previous tutorials, we have learned how to install and routing systems on the flask. well in this tutorial we will learn new things, we will learn how to use the templating system on the flask. Well, the flask has a templating system, jinja2 and not only that we will also learn how to use the post method on the flask. for those of you who don't know the flask, I suggest you follow my tutorial before, let's just start our tutorial.
Templating jinja2
When we install the flask, we can automatically use the templating system of the jinja2, with this templating system we can easily render HTML templates. Not only can you render HTML later in the template, but we can also use the logic of the program logic in our templates, such as looping, if else etc.
-Create templates directory
We will start by creating a folder directory to save our templates. so we can more easily access it. I will create a folder with the name templates.
so we will save all of our templates in the templates folder
- Use template in route
We have created our template directory. now we will use it in our routing system. We can render our HTML template with use function render_template().for more details, you can see the code like this:
app.py
// import module
from flask import Flask, render_template
//defined flask
app = Flask(__name__)
//route
@app.route('/welcome')
def myFunction():
return render_template('index.html');
Because we will use the
render_template()function we must import it first like thisfrom flask import Flask, render_templateto use it we can pass the name of our HTML file in the render_template function like this
render_template('index.html')index.html is the file that we created in the templates folder. the contents are as follows.
index.html
<!DOCTYPE html>
<html>
<head>
<title>Template Jinja2</title>
</head>
<body>
<h1 style="color:red;">Hi all member of utopian , I'm new</h1>
</body>
</html>
to see the results we can run our code and the results will be as shown below:
We can see in the picture above we have successfully rendered the HTML file on our application. now we will learn how to pass data on our template
- Passing data to templates
We are still learning about the template, in the previous section, we have successfully rendered the template in our routing system, but the template is still dynamic. well in this section we will learn how to pass dynamic data to our templates. for more details, we can see the code below:
app.py
// import module
from flask import Flask, render_template
//defined flask
app = Flask(__name__)
//routing
@app.route('/welcome/')
def paramFunc(user):
return render_template('profile.html', userData = user);
We have learned how to pass a parameter to routing in the previous tutorial, now we will pass the parameter to the data that will be received in our template.
to pass parameters to the template we can put them in the second parameter and we can give a new name to throw in the template like the following
render_template('profile.html', userData = user);.useris data that we get from routing parameters anduserData is a new name that will be used in the profile.html template, you can use the same or different names. No problem...We can create a new template, namely profile.html. The contents are like the following:
profile.html
<!DOCTYPE html>
<html>
<head>
<title>Template Jinja2</title>
</head>
<body>
<h1>This is the profile page</h1>
<h2 style="color:blue;">Hai my name is {{userData}}</h1>
</body>
</html>
We can print the data we get from routing with {{nameOfdata}}. to see the results we can see in the picture below:
We can see in the picture above we have successfully rendered the data that we pass in the template.
Post method
In web applications, of course, we will use methods such as get, post, put, delete. in this section we will learn how to use these methods in our routing system. but before we use these methods, for example, I will create a login form. I will make a new routing on our application, That is /login. I will create a login page with the name login.html, you can see the contents like this:
login.html
<!DOCTYPE html>
<html>
<head>
<title>Login page</title>
</head>
<body>
<h1>Form Login</h1>
<form action="/login" method="post">
<label for="">Email</label><br>
<input type="text" name="email"><br><br>
<label for="">Password</label><br>
<input type="password" name="password"><br>
<input type="submit" name="" value="login">
</form>
</body>
</html>
We make a simple login using the post method. We make a simple login using the post method and will do an action to the '/login' URL <form action="/login" method="post">.
- Create routing
'/login'
We have created the form section to log in, now we will move to the routing system. In our routing system, we will create a new routing, namely '/login'.For more details, you can see at the code below:
from flask import Flask, render_template, request
app = Flask(__name__)
@app.route('/welcome')
def myFunction():
return render_template('index.html');
@app.route('/welcome/')
def paramFunc(user):
return render_template('profile.html', userData = user)
@app.route('/login', methods=["GET", "POST"])
def login():
if request.method == "POST":
return " Your method is POST"
return render_template('login.html')
Import function request: in the flask we can use the
requestmethod to retrieve all request data, to use it we must import it first as followsfrom flask import Flask, render_template, request.Defined the method in route: in the routing flask system we can define what method we will use in the routing in the following way
@app.route('/login', methods=["GET", "POST"]). We can define the routing method in the second parameter with keymethods = ["GET", "POST"]. Because the method we use more than one we can have to be defined in the form of anarray[].Handle multiple methods: We can use several methods in the same routing, to distinguish it we can use
request.methodand use if else to distinguish the action that will be used. We will make an example like the following:
if request.method == "POST":
return " Your method is POST"
return render_template('login.html')
If the method used is POST we will do return " Your method is POST". If the method is not POST which means the method is GET, then we will render the login.html template. We can see an example like the picture below:
We can see in the image above, the routing that we access the same. but have two different conditions when we access different methods. when the GET method, we will render return render_template('login.html'). but if we use the POST method we will return " Your method is POST"
- Get value from POST data
Now we will learn how to get the data we POST. we can use the request function that we have seen before. because the data we post on our form can use the request.form method. for more details, we can see the code below:
app.py
@app.route('/login', methods=["GET", "POST"]) // the method we used
def login():
if request.method == "POST":
return "Your email is "+ request.form['email']
return render_template('login.html')
- to get the data we post we can use
request.form['nameOfinput']. in this tutorial, we will try to retrieve data that is post through<input type="text" name="email">. the name of input is 'email', so we can get the value like thisrequest.form['email']. to see the results we can see in the picture below:
We see in the picture above we have successfully retrieved the post data, this is something very important when we want to interact with user data, we have learned new things in this tutorial, I hope you can this tutorial can be the basis for you to know the flask to be developed into better. thank you for following this tutorial...
Curriculum
Web developement with python #1 : Flask initialization and Routing system