How to ensure that the custom content obtained by the `{% diy %}` tag is safely output in the front-end template?

As an experienced website operations expert, I know that the flexibility of a content management system (CMS) is both an advantage and may bring potential security challenges.AnQiCMS, with its concise, efficient, and powerful customization capabilities, is widely popular among many enterprises and content operators.Its core function is one of the ways through which{% diy %}Label fetches custom content from the backend, which greatly enriches the dynamicity of the template.However, how to ensure that these custom contents are safely output in the front-end template, avoiding potential risks, is a problem that every operator must seriously consider.

Get to know{% diy %}Nature and potential risks

{% diy %}The tag plays a role in AnQiCMS in obtaining the background custom configuration.Imagine that you can define some less frequently used parameters in the background "Global Settings" or "Contact Information Settings", such as special announcement text, slogans for a promotional campaign, or even dynamic customer service QQ numbers, etc.These parameters' values are through{% diy with name="参数名" %}Extracted and displayed in the front-end template.

This custom capability brings great convenience, as it allows operators to adjust certain dynamic information on the website without modifying the code.However, behind the convenience there are also risks. Since this content is directly entered into the background text box, if the operator is not careful, or if a malicious user gains background permissions and enters a string containing JavaScript code (for example<script>alert('XSS');</script>), and if this content is directly output on the front end without processing, then these malicious scripts will be executed in the user's browser that accesses the website, which is known as cross-site scripting (XSS).XSS attacks can lead to session hijacking, data leaks, even website tampering, and serious damage to the trust of users and websites.

The default security mechanism of AnQiCMS: automatic escaping is the first line of defense.

Fortunately, AnQiCMS took full consideration of content security during design.Its template engine (similar to Django template engine) takes a security mechanism called 'autoescape' when processing default output.

This means, when you use double curly braces in the template.{{ 变量 }}When outputting content, the template engine will automatically convert special HTML characters in the content. For example:

• <Will be escaped to<
• >Will be escaped to>
• &Will be escaped to&
• "Will be escaped to"
• 'Will be escaped to'

This default behavior greatly enhances security. Even if someone is in the background's{% diy %}Entered in the custom content<script>alert('XSS');</script>It will also become when output on the front end<script>alert('XSS');</script>The browser treats it as plain text rather than executable JavaScript code, thereby effectively preventing XSS attacks. Therefore, in most cases, you do not need to worry about it extra.{% diy %}The default output security issues.

When do you need to pay extra attention?|safeThe double-edged sword of filters

However, automatic escaping is not always the result we expect. Sometimes, we indeed need{% diy %}The content retrieved is displayed in rich text format with HTML tags, such as a custom announcement that includes bold, links, and even images.In this case, simply outputting the escaped HTML code will not achieve the expected visual effect.

To solve this problem, the AnQiCMS template engine provides|safea filter. When you are sure that the content of a variable is pure and harmless HTML, you can go through{{ 变量|safe }}This content is safe, please do not escape, and output it directly as HTML code.

This is|safeThe reason it is called a 'double-edged sword'. It gives you greater control, allowing you to customize the output of HTML, but it also means you take on the responsibility of content safety review.Once you have used|safeThis template engine will completely trust this content and will not perform any escaping. If at this time{% diy %}The content contains malicious scripts that will execute smoothly in the user's browser, putting the website at serious risk of XSS attacks.

Ensure{% diy %}Content security **practice

Understood the security mechanism of AnQiCMS and|safecharacteristics, we can then formulate a set to ensure{% diy %}a strategy for secure content output:

1. Never use unless necessary|safefilter.This is the core principle. If{% diy %}The content obtained is just plain text (such as contact information, website names, etc.), then the default automatic escaping behavior is **selected, no need to add|safe. Only when the content truly needs to be displayed in HTML format (such as containing<b>/<a>/<img>etc.), should it be considered for use.

2. Strictly control the source of background content input.Even if you need to use|safemake sure that{% diy %}Highly trusted source of custom content. This usually means:

   • Limit modification permissions:Only core administrators (with a basic understanding of Web security) can modify potentially used|safeCustom label parameters.
   • Manual review:For custom content that needs to be output as HTML, there must be a strict manual review process. Before saving the content in the background, it should be carefully checked for any suspicious tags or scripts.
   • Minimize HTML:If HTML is indeed needed, allow only the most basic tags (such as<b>,<i>,<a>,<strong>,<em>). Avoid allowing<script>,<iframe>,<style>tags that may pose security risks.

3. Make good use of other filters for content purification.AnQiCMS provides a rich set of filters, even if you decide to use|safeThey can also be used to refine and control content more finely:

   • |striptags:If you only want to display plain text, no matter how much HTML code is input in the background, you can use{{ diy_content|striptags|safe }}Remove all HTML tags.
   • |removetags:"tag1,tag2":If you want to retain some safe tags while removing other potentially dangerous tags, you can use this filter. For example,{{ diy_content|removetags:"script,iframe,style"|safe }}Can be removedscript/iframeandstyleTags, while retaining other tags that have not been removed.
   • |truncatechars_html:长度:If custom content is long and you want to display only a part of it on the page while maintaining the integrity of the HTML structure, this filter is very useful. For example,{{ diy_content|truncatechars_html:100|safe }}Can extract the first 100 characters while maintaining the HTML structure.

4. Regular audits and tests.No matter how完善 the security measures, there may be loopholes. As an operator, one should regularly review the HTML source code of the website front-end page, check{% diy %}Does the output meet expectations, without any unexpected HTML structure or suspicious scripts.Try entering some test XSS code in the background to see if the front-end output is correctly escaped.

Summary

Of Security CMS{% diy %}The label brings unprecedented flexibility to content operation, but also requires that we remain highly vigilant about content security.Fortunately, AnQiCMS's default automatic escaping mechanism provides us with a solid first line of defense.As long as we follow the principle of 'not using when not necessary'|safeThe principle of combining with strict backstage management processes and flexible filters for content purification can ensure the safety and stability of the front-end output while enjoying highly customized content.

Frequently Asked Questions (FAQ)

Q1:{% diy %}The content obtained by the tag and common{{ 变量 }}What are the differences in security processing of the output content?A1: At the AnQiCMS template engine level, whether it is `{% diy %