Soenneker.Deduplication.SlidingWindow 4.0.99

Prefix Reserved
.NET 10.0 This package targets .NET 10.0. The package is compatible with this framework or higher. 
dotnet add package Soenneker.Deduplication.SlidingWindow --version 4.0.99
                    


                    

                
NuGet\Install-Package Soenneker.Deduplication.SlidingWindow -Version 4.0.99
This command is intended to be used within the Package Manager Console in Visual Studio, as it uses the NuGet module's version of Install-Package. 
<PackageReference Include="Soenneker.Deduplication.SlidingWindow" Version="4.0.99" />
For projects that support PackageReference, copy this XML node into the project file to reference the package. 
<PackageVersion Include="Soenneker.Deduplication.SlidingWindow" Version="4.0.99" />
                    


                            Directory.Packages.props
                        

                    

                
<PackageReference Include="Soenneker.Deduplication.SlidingWindow" />
                    


                            Project file
For projects that support Central Package Management (CPM), copy this XML node into the solution Directory.Packages.props file to version the package. 
paket add Soenneker.Deduplication.SlidingWindow --version 4.0.99
                    


                    

                
#r "nuget: Soenneker.Deduplication.SlidingWindow, 4.0.99"
#r directive can be used in F# Interactive and Polyglot Notebooks. Copy this into the interactive tool or source code of the script to reference the package. 
#:package Soenneker.Deduplication.SlidingWindow@4.0.99
#:package directive can be used in C# file-based apps starting in .NET 10 preview 4. Copy this into a .cs file before any lines of code to reference the package. 
#addin nuget:?package=Soenneker.Deduplication.SlidingWindow&version=4.0.99
                    


                            Install as a Cake Addin
                        

                    

                
#tool nuget:?package=Soenneker.Deduplication.SlidingWindow&version=4.0.99
                    


                            Install as a Cake Tool

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Soenneker.Deduplication.SlidingWindow

A thread-safe, in-memory “seen recently” set with bucketed expiration and compact XXH3-64 keys.

Installation

dotnet add package Soenneker.Deduplication.SlidingWindow

Usage

using Soenneker.Deduplication.SlidingWindow;

await using var dedupe = new SlidingWindowXxHashDedupe(
    window: TimeSpan.FromMinutes(5),
    rotationInterval: TimeSpan.FromSeconds(10),
    capacityHint: 100_000);

if (dedupe.TryMarkSeen("event:01J..."))
{
    // First observation inside the active window.
}

TryMarkSeen returns true when the hash was absent and adds it. A repeat returns false and refreshes that hash into the current time bucket, so it remains present until a full window passes without another observation.

Use Contains for a non-refreshing lookup and TryRemove to make a value immediately eligible again:

bool recentlySeen = dedupe.Contains(eventId);
bool removed = dedupe.TryRemove(eventId);

Window precision

Expiration is bucketed rather than per-item. The bucket count is Ceiling(window / rotationInterval), with a minimum of two buckets. A key therefore expires on a rotation near the configured window boundary, not at an exact timestamp.

Choose a shorter rotation interval for finer expiry precision, at the cost of more buckets and more frequent cleanup. capacityHint sizes the internal dictionary initially; it is not a hard memory limit.

Repeated observations are queued so the implementation can preserve the latest bucket safely. Memory use therefore depends on both unique keys and observation rate; it is not simply eight bytes per unique hash.

Hash representation

Original values are not retained. The string and ReadOnlySpan<char> APIs hash UTF-16 characters, while the Utf8 APIs hash the supplied bytes. Use one representation consistently for mark, lookup, and removal.

Different inputs can theoretically share a 64-bit hash. Use exact keys when collision tolerance is unacceptable.

Lifetime and scope

The instance owns a background rotation task and must be disposed. It is process-local: restarts lose history, and separate application instances do not share it. It is useful for best-effort suppression and reducing repeated work, but it is not an exactly-once or durable idempotency boundary.

Product Compatible and additional computed target framework versions.
.NET net10.0 is compatible.  net10.0-android was computed.  net10.0-browser was computed.  net10.0-ios was computed.  net10.0-maccatalyst was computed.  net10.0-macos was computed.  net10.0-tvos was computed.  net10.0-windows was computed. 
Compatible target framework(s)
Included target framework(s) (in package)
Learn more about Target Frameworks and .NET Standard.

NuGet packages (1)

Showing the top 1 NuGet packages that depend on Soenneker.Deduplication.SlidingWindow:

Package Downloads
Soenneker.Deduplication.SlidingWindow.Registry

A keyed registry of sliding window dedupe instances.

GitHub repositories

This package is not used by any popular GitHub repositories.

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Update dependency Soenneker.Hashing.XxHash to 4.0.87 (#218)