ARTX.XPathReader 1.0.1

About XPathReader

XPathReader is a .NET/C# library that simplifies the process of reading and extracting data from XML documents using XPath expressions. It uses Source Generators to create a custom reader class based on provided XPath expressions, allowing for memory efficient and fast access to XML data. The name and idea were inspired by Microsoft's XPathReader from early .Net days.

Features

• Source Generators: Automatically generates a reader class based on specified XPath expressions.
• Memory Efficient: Uses XmlReader for low memory consumption when processing large XML files.
• Multiple XPath Support: Reads the document once and extracts data for multiple XPath expressions in a single pass.

Usage example

using ARTX.XPath;

public partial class Program
{
    [GeneratedXPathReader("/bookstore/books/book/title|/bookstore/journals/journal/publisher")]
    public static partial XPathReader BookStoreReader { get; }

    static void Main(string[] args)
    {
        FileStream stream = File.OpenRead("bookstore.xml");

        // There is also an async implementation.
        // await foreach (ReadResult item in BookStoreReader.ReadAsync(stream, cancellationToken))
        foreach (ReadResult item in BookStoreReader.Read(stream))
        {
            Console.WriteLine(item.NodeReader.ReadOuterXml());
        }

        // Output:
        //<title>GFG</title>
        //<title>GFG 2</title >
        //<publisher>Publisher 1</publisher>
        //<publisher>Publisher 2</publisher>
    }
}

Installation

You can install the XPathReader library via NuGet Package Manager:

dotenet add package ARTX.XPathReader

Requirements

• .NET Framework 4.8 or later (requires Language Version 9.0 or later)
• Any .NET version that supports Source Generators

Usage

1. Add the GeneratedXPathReader attribute to a partial method or property, specifying the XPath expressions.
   • You can provide multiple XPath expressions separated by | or new line.
2. Call the generated Read or ReadAsync method, passing in a Stream containing the XML data.
3. These methods return an IEnumerable<ReadResult> or IAsyncEnumerable<ReadResult>, where each ReadResult contains an XmlReader positioned at the matching node, expected XPath from the attribute that, was encountered, and actual XPath of the returned node.

Limitations

• Only simple XPath expressions are supported (e.g., no predicates, functions, or axes).
• Only absolute paths starting from the root are supported.
• When XPath contains an axis, the error is thrown during compilation.
• When XPath contains predicates, they are ignored, and only the node name is considered.
• Please note that the generator adds a field (static or not) into the declared class. Therefore, interfaces and read-only structs only supported in a static context.

Predicates support is planned for future releases.