paregis.me

Creating templates

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Recap

We have set up our development environment on our own computer, now it's time to build something useful. In this post, we will build our first static page using python, an html template, and we will also serve the website locally.

Create a template

To start, let's create a file in the /templates folder and call it hello.html. Now let's put some very basic html:

<html>
    <body>
        Hello world!
    </body>
</html>

That's it. Nothing fancy here!

Updating the build script

At this point, it's worth mentioning that the workflow that we are about to create will not change. So even though these first examples will look super simplistic, the way that you will make your pages will feel very similar.

Now let's go to the build.py script. In the build script, the first thing we need to do is import the jinja engine so add the import to the top. We will also use the pathlib library that should already be available to you with python 3:

from jinja2 import Environment, FileSystemLoader
from pathlib import Path

We will use the FileSystemLoader to point to a folder that contains all the template files. It makes our life easier so we don't have to open the files and parse them ourselves. The Environment class will let us load the templates by passing the filename of the template, that of course is inside the /templates folder:

file_loader = FileSystemLoader('templates')
env = Environment(loader=file_loader)
template = env.get_template('hello.html')   # tell jinja to load the template "hello.html"
output = template.render()                  # generates the html code as a string
o = Path.cwd()                              # get the current directory of the build script
o = o / Path('index.html')                  # append the output filename to the path
with o.open(mode='w') as fh:                # open de output file represented by the Path object 'o'
    fh.write(output)                        # write the generated html code into the file

Save the build script. Now go to the terminal and run it (don't forget you have to CD to the folder of your project):

cd /path/to/project/folder
python build.py

If everything goes smoothly, you should see a new file in your project folder, named **index**.html! If you open the file, you will notice that it looks exactly like the template **hello**.html, and that's not fun at all. Let's change that!

Edit the template hello.html to look like this:

<html>
    <body>
        Hello **{{ name }}**!
    </body>
</html>

And in the build script you only edit one line, the render() method that Jinja uses to generate the html markup:

output = template.render(name="Harry Potter")

Now run the build command again: python build.py

Wow! Now if you open the index.html file you will see Harry's name there! That's pretty cool if you ask me.

But it's a little annoying that the built index.html is mixed in the project folder, let's instead, write to our build directory /_site. You can name it whatever you want, but I'm used to this underscore site pattern so I'll stick to it.

In the build script edit so the o variable looks like this:

o = o / Path('_site/index.html')

This will create a path the points to the build dir /_site. Run the build command. Now the file is generated in the subfolder. Awesome, this way we don't have to worry trying to figure out which html files are used as a template and which are generated pages. All files in the /_site subfolder will be considered the final product!

Serve the website with a proper webserver

As of now we haven't really SERVED our website, we were simply opening the html files with whatever program we wanted like a text editor or a browser. Now that our build files are all centralized in a single folder, we can spin up an HTTP server that points to the /_site folder.

Luckily, python comes with a very simple server that gets the job done, very useful in development mode. In your terminal, after generating the html files in the build directory, run this command:

python -m http.server --directory ./_site/

Note python 2 has a similar command: python -m SimpleHTTPServer but you will need to cd /_site/ first.

This command will start python's built-in http server pointing to the /_site folder. Now move to your browser and enter 127.0.0.1:8000 in the address bar, that's your localhost address. And the server by default uses port 8000, so we need that too.

Ta-Da! Now we have a fully functional website. How exciting! Even though the end product is very minimalist, to be polite, it helps to figure out the development workflow of building and serving. We will build upon this process to personalize the website further.

Summary

In this post, we saw how to create a simple jinja2 template. We also use the built-in python http server to serve the website locally.

  • Summarizing, in this video we:
  • Created a template file
  • Loaded the template engine in the build script
  • Used the template file to create a static page
  • Served the website using an http server