Soenneker.AngleSharp.Parser 4.0.59

Soenneker.AngleSharp.Parser

A DI-friendly cache of configured AngleSharp HtmlParser instances.

Instead of constructing parser configuration throughout an application, request one of three named parser contexts. The service creates each context on first use and returns the cached instance on later calls.

Installation

dotnet add package Soenneker.AngleSharp.Parser

Registration

Use singleton registration when the parser cache should be shared by the application:

using Soenneker.AngleSharp.Parser.Registrars;

builder.Services.AddAngleSharpParserAsSingleton();

Scoped registration creates an independent cache for each dependency-injection scope:

builder.Services.AddAngleSharpParserAsScoped();

Both registrars use TryAdd, so an existing IAngleSharpParser registration is not replaced.

Parse HTML

Inject IAngleSharpParser, retrieve the appropriate configuration, and use the returned AngleSharp parser normally:

using AngleSharp.Dom;
using AngleSharp.Html.Parser;
using Soenneker.AngleSharp.Parser.Abstract;
using Soenneker.AngleSharp.Parser.Enums;

public sealed class PageTitleReader
{
    private readonly IAngleSharpParser _parsers;

    public PageTitleReader(IAngleSharpParser parsers)
    {
        _parsers = parsers;
    }

    public async ValueTask<string?> Read(
        string html,
        CancellationToken cancellationToken)
    {
        HtmlParser parser = await _parsers.Get(
            AngleSharpContextType.Fast,
            cancellationToken);

        using IDocument document = await parser.ParseDocumentAsync(
            html,
            cancellationToken);

        return document.QuerySelector("title")?.TextContent.Trim();
    }
}

Get() without a context argument is equivalent to Get(AngleSharpContextType.Default).

Parser contexts

Choose the context deliberately. WithLoader permits resource loading through its browsing context, so do not use it with untrusted input in environments where outbound requests must be restricted.

Cache and lifetime behavior

The cache is keyed by AngleSharpContextType. Within one IAngleSharpParser service instance:

• the first request for a context creates its HtmlParser;
• subsequent requests for that context return the same parser instance;
• requests for different contexts return independently configured instances;
• concurrent cache initialization is coordinated by the underlying singleton-key dictionary.

The thread-safety guarantee applies to creating and retrieving cached entries. Because callers receive the same mutable HtmlParser object for a context, avoid changing its configuration after retrieval and validate concurrent parsing behavior against the AngleSharp version used by your application.

The service implements both IDisposable and IAsyncDisposable. Let the dependency-injection container dispose registered instances. If you construct AngleSharpParser yourself, dispose that service when its cache is no longer needed.

API