RedisGeoHash 2.0.0

RedisGeoHash

A library for creating RedisGeo Hash values within .NET.

Credits

This is a C# port of the Redis Geo Hash code by antirez: https://github.com/antirez/redis

Why?

When I was involved in the writing of the StackExchange.Redis Geo functionality I became interested in how Redis uses geohashes to store information in sorted sets. Behind the scenes a RedisGeo collection is nothing more than a sorted set: Redis uses a numerical representation of geohashes as the member scores. I wanted to do the same thing from within .NET to implement local GEO collections for caching purposes at work.

How?

using GeoHash;

var hash = new RedisGeoHash(39.923422, -86.1078998); // latitude, longitude
Console.WriteLine(hash.GeoHash); // 1782901374540128

Compared to Redis:

127.0.0.1:6379> GEOADD willt -86.1078998 39.923422 1
(integer) 1
127.0.0.1:6379> ZRANGE willt 0 100 WITHSCORES
1) "1"
2) "1782901374540128"

Note that Redis commands take longitude first; this library's constructor takes latitude first. Coordinates outside the supported range (latitude ±85.05112878, longitude ±180) throw ArgumentOutOfRangeException.

Decoding

Decode() returns the bounding box of the geohash cell, and GeohashDecodeToLongLatWgs84 returns its center point:

var area = hash.Decode();
// area.Latitude.Min/Max and area.Longitude.Min/Max bound the original point

var xy = new double[2];
RedisGeoHash.GeohashDecodeToLongLatWgs84(hash.GeoHashBits, xy);
// xy[0] = longitude, xy[1] = latitude of the cell center

Neighbors

Neighbors() returns the eight adjacent cells:

var neighbors = hash.Neighbors();
Console.WriteLine(neighbors.North.Bits);

Building and testing

dotnet build
dotnet test

Mutation testing

Stryker.NET is pinned as a local dotnet tool and configured by stryker-config.json:

dotnet tool restore
dotnet dotnet-stryker

The run fails if the mutation score drops below the break threshold in stryker-config.json. The HTML report lands in StrykerOutput/.

Benchmarks

BenchmarkDotNet benchmarks live in Benchmarks/:

dotnet run -c Release --project Benchmarks -- --filter '*'

CI and releases

.github/workflows/ci.yml runs on every PR and push to master/main:

• Build & Test — dotnet test on the full solution
• Mutation Testing — Stryker, failing below the configured threshold, with the HTML report uploaded as an artifact
• Benchmarks — a short BenchmarkDotNet job, results uploaded as an artifact

On push to master/main, after tests and mutation testing pass, the Publish to NuGet job packs GeoHash/GeoHash.csproj and pushes it to nuget.org with --skip-duplicate — so a merge only publishes when <Version> in the csproj has been bumped; otherwise the push is a no-op.

Publishing uses NuGet Trusted Publishing: the workflow exchanges a GitHub OIDC token for a short-lived API key via NuGet/login, so no stored API-key secret is needed. The nuget.org trusted publishing policy must name this repo with workflow file ci.yml.