AEM中Sling Servlet调用方式选型建议：AJAX vs Sightly

Great question! Let’s break down each approach, their strengths, and the scenarios where each shines:

1. AJAX via JavaScript #

This method uses client-side JavaScript to send asynchronous requests to your Servlet (like the example you mentioned: type: 'POST', url:'/bin/calculatorServlet'). Here’s why you’d reach for this:

• Asynchronous, non-disruptive experience: Users don’t have to wait for a full page reload. You can update just a specific section of the page (say, a calculator result) without breaking their workflow.
• Granular data control: You can send targeted payloads (JSON, form data) and handle the response directly in JS—perfect for dynamic UIs like auto-completes or real-time calculations.
• Flexible response handling: As you noted, you can parse JSON responses, show inline success/error messages, or manipulate the DOM based on the Servlet’s output. This is a game-changer for interactive features.
• No page navigation: Ideal for single-page-like interactions within AEM, where you want to keep users on the same page while processing actions.

Quick example to illustrate:

fetch('/bin/calculatorServlet', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/x-www-form-urlencoded',
  },
  body: 'num1=5&num2=3'
})
.then(response => response.json())
.then(data => {
  document.getElementById('result').textContent = `Result: ${data.sum}`;
})
.catch(error => console.error('Error:', error));

2. Sightly Form Action #

This involves setting the action attribute of a Sightly form directly to your Servlet path (e.g., <form action="/bin/myservlet" method="POST">). Its key advantages are:

• Simplicity for server-side workflows: No need to write client-side JS—great for straightforward actions like form submissions that require a full page redirect (e.g., sending users to a "thank you" page after submitting a contact form).
• Better accessibility: Forms work natively with browser features (like enter-key submission, screen reader support) without relying on JS, making your site more inclusive for all users.
• Easier security setup: You can leverage AEM’s built-in CSRF protection more seamlessly (AJAX can handle this too, but it requires extra JS configuration).
• JS-independent functionality: If users have JavaScript disabled, this approach still works—critical for scenarios where you can’t assume JS is enabled.

Example Sightly form snippet:

<form action="/bin/myservlet" method="POST" data-sly-use.form="com.example.FormHelper">
  <input type="hidden" name="${form.csrfTokenName}" value="${form.csrfToken}">
  <input type="text" name="username" required>
  <button type="submit">Submit</button>
</form>

How to Pick the Right Approach? #

• Go with AJAX if you need:
  • Interactive, real-time updates without page reloads
  • Dynamic UI elements (like loading spinners, inline error messages)
  • To handle JSON responses and manipulate the DOM post-request
• Go with Sightly Form Action if you need:
  • A simple, JS-free workflow for form submissions
  • Full page redirects after processing
  • Maximum accessibility and compatibility with non-JS environments

内容的提问来源于stack exchange，提问作者vipin gupta