friendlyid

friendly-id — go-ruby-friendly-id

Pure-Go (CGO=0), MRI-faithful reimplementation of the Ruby friendly_id gem's slug engine — the computation behind pretty, human-readable URL slugs — to be bound into rbgo, the pure-Go embeddable Ruby interpreter, as a native require "friendly_id" module.

It reproduces the pieces of FriendlyId that are pure logic: slug normalization (the ActiveSupport parameterize semantics — accent transliteration, downcasing, non-alphanumeric collapsing), candidate generation with sequential collision-suffixing, an optional slug history, and the friendly finder that resolves a current slug — or an old historical slug — back to a record id, falling back to the numeric primary key.

What it is — and isn't. Everything host-specific — the base attribute to slugify, uniqueness lookups, and history persistence — is left as an injectable seam, so the engine runs with no database. A rbgo binding wires the seams to ActiveRecord; the reference MemStore backs tests and standalone use.

Features

Faithful port of the friendly_id slug core:

• Parameterize(s, sep) — ActiveSupport-compatible slug generation: NFD accent transliteration (Åccénts → accents, straße → strasse, œuvre → oeuvre), downcase, collapse every run of non-[a-z0-9] to one separator, trim ends.
• Config.Normalize / Candidates / Resolve — reserved-words rejection, MaxLength truncation, the slug_candidates sequence, and collision resolution by sequential suffixing (post, post-2, post-3, …) with a configurable sequence separator.
• History (MemStore) — records each record's current slug plus every slug it ever held, so an old slug keeps resolving to the record (the :history module).
• Finder — Model.friendly.find(input): current slug → historical slug → numeric id, returning ErrNotFound when none match. Each lookup is a seam.

Usage

import "github.com/go-ruby-friendly-id/friendly-id"

cfg := friendlyid.Config{Reserved: []string{"new", "edit"}}
store := friendlyid.NewMemStore("Post")

// Generate a unique slug, resolving collisions sequentially.
slug, _ := cfg.Resolve("My First Post!", store.Exists) // "my-first-post"
_ = store.Assign("1", slug)

// A second post with the same title gets a suffixed slug.
slug2, _ := cfg.Resolve("My First Post!", store.Exists) // "my-first-post-2"
_ = store.Assign("2", slug2)

// The friendly finder resolves current + historical slugs, then the id.
id, _ := store.Finder(func(id string) bool { return id == "99" }).Find("my-first-post")
// id == "1"

Intended Ruby surface (via rbgo)

class Post < ApplicationRecord
  extend FriendlyId
  friendly_id :title, use: [:slugged, :history]
end

Post.friendly.find("my-first-post")   # resolves current or historical slug
post.slug                             # "my-first-post"
post.to_param                         # the slug, for URLs

Quality bar

100% test coverage (including every error branch); builds and tests green on all six 64-bit Go architectures (amd64, arm64, riscv64, loong64, ppc64le, s390x) plus js/wasm and wasip1/wasm; CGO=0; Go 1.26.4 floor.

License

BSD-3-Clause © the go-ruby-friendly-id/friendly-id authors.