Скачать или смотреть How to Use XSL Dynamic XPath Evaluation for Effective XML Data Extraction

Learn how to utilize XSL 3.0's dynamic XPath evaluation with `xsl:evaluate` to extract semantic information from XML files and convert it to a JSON format effectively.
---
This video is based on the question https://stackoverflow.com/q/68551776/ asked by the user 'DerMannMitDerMaske' ( https://stackoverflow.com/u/16060813/ ) and on the answer https://stackoverflow.com/a/68552072/ provided by the user 'Martin Honnen' ( https://stackoverflow.com/u/252228/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: XSL Dynamic XPath evaluation

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Mastering XSL Dynamic XPath Evaluation

When it comes to handling XML data, efficiently extracting the desired elements can sometimes feel like a daunting task. If you have multiple XML documents and need to retrieve semantically similar information, you may have encountered the limitations of static XPath expressions. This is where XSL Dynamic XPath evaluation steps in to save the day.

The Problem

Suppose you have a structure just like this:

[[See Video to Reveal this Text or Code Snippet]]

And you want to extract information from XML documents that contain details about books. For example, one of your XML files might look like this:

[[See Video to Reveal this Text or Code Snippet]]

Your goal is to produce a JSON output like:

[[See Video to Reveal this Text or Code Snippet]]

However, when you tried using XSLT to dynamically evaluate XPath, you ended up with concatenated strings instead of the desired output.

The Solution

To resolve this issue, follow the steps outlined below. Utilizing the xsl:evaluate function effectively can streamline your XML data extraction process.

Step 1: Initial Template Setup

Start simple with a basic template that matches the root node:

[[See Video to Reveal this Text or Code Snippet]]

Implementing the above code snippet for your initial XML will yield the following output:

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Store Outputs in a Variable

To get individual descriptions and compile them into a meaningful array, store the sequence in an xsl:variable. This way, you can control how the data gets captured and displayed:

[[See Video to Reveal this Text or Code Snippet]]

Step 3: Finalizing Your Output

By applying these insights, you will effectively gather the individual descriptions, which allows you to create a structured output resembling:

[[See Video to Reveal this Text or Code Snippet]]

Additional Tips

Testing different XPath expressions: Always check the validity of your XPath queries to ensure they correctly point to the desired elements.

Running in Saxon XSL HE: For those using Saxon, ensure your version supports XSLT 3.0 features, particularly xsl:evaluate, as it may vary based on the version.

Conclusion

Handling XML data extraction can be complex, especially when dealing with various files and structures. With XSL Dynamic XPath evaluation, you not only gain flexibility but also enhance your XML processing capabilities. No more concatenated strings, just precise, structured data ready for conversion into formats like JSON!

By following these organized steps and keeping your XPath queries dynamic, you’ll find that extracting and utilizing your XML data becomes a straightforward and efficient task.