Introduction
Welcome to this comprehensive developer-centric guide on dynamic page rendering using Jinja templating language in Empress. This feature carries significant importance for developers working with Empress, a powerful platform for software development and customization.
Introduction to Jinja Templating Language
At the core of Empress, we have the Jinja Templating Language. Jinja is a high-level, easy-to-learn and powerful templating engine for Python. It is used to dynamically generate HTML from Python code and allows developers to seamlessly integrate backend logic with frontend presentation.
The primary advantage of Jinja is its robustness and flexibility. It supports a wide array of operations including variable assignment, mathematical calculations, conditional statements, loops, and more, all within your HTML files. This makes it an excellent tool for creating dynamic web content.
Integrating Jinja Templating with Empress
To integrate Jinja Templating with Empress, we utilize the context object. This object is passed to the template for rendering and can be updated to query data. This update happens inside a .py file with the same filename as the .html file (e.g., index.py for index.html).
This process is facilitated by a method named get_context, which is added to the .py file. It’s within this method that you can write the logic for querying data and updating the context object.
Example: Creating a User List Page
Let’s consider an example where we want to create a page to display a list of users. To do this, we need to create two main files: users.html and users.py, both residing in the www/ folder.
users.py
Below is the Python code for users.py:
import frappe
def get_context(context):
context.users = frappe.get_list("User", fields=["first_name", "last_name"])
In the code above, we import the frappe module and define the get_context function. Inside this function, we query the list of users and their respective first and last names using the get_list method from the frappe module. This list is then assigned to context.users.
users.html
For the HTML file, users.html, we implement the following Jinja Templating code:
<h3>List of Users</h3>
<ol>
{% for user in users %}
<li>{{ user.first_name }} {{ user.get("last_name", "") }}</li>
{% endfor %}
</ol>
In the code above, we use a for loop to iterate through the users object in the context (which we populated in users.py). For each user, we display their first and last name, with the get method providing a default value of an empty string for any user who may not have a last name.
Conclusion
Dynamic page rendering using Jinja Templating Language significantly enhances the development and customization of business solutions in Empress. It provides developers with a powerful, flexible tool to generate dynamic web content, bridging the gap between backend functionalities and frontend presentation. By understanding and effectively utilizing this feature, developers can create responsive, data-driven applications that cater to complex business needs.