Learning Flask from Scratch: Template Inheritance and Variable Rendering
This article introduces the core of the Flask template system, which uses the Jinja2 engine to implement dynamic HTML rendering. Key skills include: 1. **Variable Rendering**: Embed Python variables (supporting strings, numbers, lists, dictionaries) in HTML using the `{{ variable }}` syntax. Variables are passed via `render_template` in view functions, with support for loops (`{% for %}`) and conditional checks (`{% if %}`). 2. **Template Inheritance**: Define a base template (base.html) with `{% block %}` placeholders. Child templates inherit from the base via `{% extends %}` and override content blocks to reuse common structures like navigation bars and footers, avoiding code duplication. The project structure includes app.py (main program) and a templates folder for storing templates. The article also addresses common issues and solutions, summarizing that variable rendering and template inheritance are fundamental to Flask development.
Read MoreFlask Template Engine Jinja2: From Basic Syntax to Page Rendering
Jinja2 is the default templating engine for Flask, used for dynamically rendering HTML by combining data with static pages. Core features include variables, conditional statements, loops, template inheritance and inclusion, as well as filters for variable processing. In terms of syntax, variables are embedded using `{{ }}`, conditions with `{% if %}`, and loops with `{% for %}` (supporting the loop state variable and empty list handling); templates inherit from parent templates via `extend` (defining blocks) and reuse fragments with `include`; filters use `|` (e.g., `truncate` to truncate text). In Flask, templates are stored in the `templates` folder and rendered by passing data through the `render_template` function. Mastering these core syntaxes can enhance web development efficiency, and it is recommended to consolidate through practice with template inheritance and data processing.
Read MoreJinja2 Template Engine: Dynamically Rendering Data in Web Pages with Flask (with Examples)
This article introduces the role of template engines in web development and the application of Jinja2 in Flask. Template engines solve the cumbersome problem of splicing backend data with frontend HTML, allowing developers to focus on separating data logic from page structure. Jinja2 is Flask's default template engine, with a concise syntax that supports variable substitution, conditional judgment, loops, filters, and other features. The basic process of using Jinja2 involves: first installing Flask, creating an application and defining routes, preparing backend data (such as user information and article lists), and rendering the template through render_template. Template files should be placed in the 'templates' folder, where data is embedded using {{ variables }}, conditional logic and loops are implemented with {% if %} and {% for %}, and filters are applied using the | operator to process data. Template inheritance, through base.html and child templates, promotes code reusability by reusing page structures. The core syntax of Jinja2 includes variable substitution, conditional judgment, loop traversal, and filters, while template inheritance further optimizes project structure. Mastering Jinja2 enables efficient implementation of dynamic page rendering and is a key tool for connecting data and interfaces in web development.
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