Provide ElementTagProcessor to handle element tag in plugin

[JohnNiang]

What type of PR is this?

/kind feature
/area plugin

What this PR does / why we need it:

This PR provides an interface ElementTagProcessor to make plugin handle element tag easily. e.g.:

public class ImgTagProcessor implements ElementTagPostProcessor {

    @Override
    public Mono<Void> process(ITemplateContext context, IProcessableElementTag tag,
        IElementTagStructureHandler structureHandler) {
        var elementName = tag.getElementDefinition().getElementName();
        if (!Objects.equals("img", elementName.getElementName())) {
            return Mono.empty();
        }
        var srcAttr = tag.getAttribute("src");
        if (srcAttr == null) {
            return Mono.empty();
        }
        var newSrc = srcAttr.getValue();
        // TODO rewrite src
        structureHandler.setAttribute("src", newSrc);
        return Mono.empty();
    }
    
}

After PR merged, plugins https://github.com/webp-sh/halo-plugin-webp-cloud and https://github.com/guqing/plugin-cloudinary can be refined with new method.

Does this PR introduce a user-facing change?

支持在插件中操作渲染结果

[guqing]

单元测试没过需要修复一下

[codecov]

Codecov Report

Attention: Patch coverage is 97.05882% with 1 line in your changes missing coverage. Please review.

Project coverage is 58.08%. Comparing base (6cd8dc8) to head (33a3230).
Report is 75 commits behind head on main.

Files with missing lines	Patch %	Lines
...n/halo/app/theme/dialect/HaloProcessorDialect.java	50.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #6670      +/-   ##
============================================
- Coverage     58.18%   58.08%   -0.10%     
- Complexity     3774     3935     +161     
============================================
  Files           651      675      +24     
  Lines         22125    23113     +988     
  Branches       1538     1578      +40     
============================================
+ Hits          12873    13426     +553     
- Misses         8641     9067     +426     
- Partials        611      620       +9     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[JohnNiang]

/hold

This processor cannot handle element tag in th:utext.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[JohnNiang]

/unhold

Now, the post-processor supports to handle element tags evaluated in th:utext.

[guqing]

/lgtm

[f2c-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: guqing

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[JohnNiang]

Current API has been published into Maven publicationrun.halo.tools.platform:plugin:2.20.0-SNAPSHOT.

[wenjing-xin]

请问一下，ElementTagPostProcessor只能获取到文章元素标签，单页面的标签有没有新的处理方或者还是以前的ReactiveSinglePageContentHandler。 IProcessableElementTag 这个thymleaf 提供的对象可以处理主题里边所有的标签吗

IElementTagStructureHandler structureHandler 2.20.0提供的ElementTagPostProcessor接口中的方法没有这个对象呀，无法设置一些标签属性呀

[guqing]

/ping @JohnNiang

[JohnNiang]

Hi @wenjing-xin , please refer to webp-sh/halo-plugin-webp-cloud#15.

[wenjing-xin]

Hi @wenjing-xin , please refer to webp-sh/halo-plugin-webp-cloud#15.
好的，谢谢，还有个问题请教一下佬大，这个对象是单例还是多例的？文档上没有声明