Overview of Redirector Component

When your URL map changes, every millisecond spent in a 404 costs rankings, revenue, and trust. The Harper Redirector lets you manage millions of redirects with 1 millisecond P95 lookups—without bolting on a separate database, cache, or edge worker. Below is a quick technical tour so you can clone the repo and start stress‑testing it today.

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Why a Dedicated Redirect Engine?

Scale

• Legacy approach: Apache/Nginx conf files grow linearly and reload slowly.
• Harper Redirector: Horizontally sharded tables; handling hundreds of millions of rules is routine. 

Latency

• Legacy approach: Database lookups or client‑side JavaScript add extra round‑trips.
• Harper Redirector: In‑memory index inside the Harper runtime delivers sub‑millisecond lookups

Ops

• Legacy Approach: Redirects scattered across YAML files, CDN rules, and spreadsheets.
• Harper Redirector: One CSV/JSON import or REST write—fully versioned and promotable in bulk. 

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Under the Hood

• Smart matching – Host‑aware lookups, optional regex paths, and query‑string operations (qs:preserve, qs:filter) so one rule can handle thousands of permutations
• Versioning – Flip activeVersion in the version table to atomically swap an entire redirect set—perfect for re‑platform launches. 

Metrics out of the box – Every hit is written to a metrics stream; drop it into Grafana or the Harper Analytics API for real‑time insight.

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3‑Step Local Spin‑Up

git clone https://github.com/HarperDB/template-redirector.git
cd template-redirector
harperdb dev .           # Hot‑reloads while you edit

Requires the Harper CLI (npm i -g harperdb).

The harperdb dev . command will automatically watch for file changes within the component directory and restart the Harper threads when changes are detected.

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Importing Rules

curl http://localhost:9926/redirect \
  --header "Content-Type: text/csv" \
  --data-binary @redirects.csv

Fields include path, redirectURL, optional utcStartTime/EndTime, and regex flag. JSON is equally accepted.

Need a blue‑green cut‑over? Add version=1 to your CSV and promote it later:

PUT /version
{ "activeVersion": 1 }

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Fast Lookup API

GET /checkredirect?path=/shoe-sale&h=www.shop.com&ho=1

Returns {statusCode:301, redirectURL:"/sneakers"} from server in ~ 1ms. Parameters let you override host, version, or testing time, and you can push paths via the Path header to preserve query strings exactly.

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Edge or Origin? You Choose

Because Harper runs identically on a single VM, a Kubernetes cluster, or geo‑distributed edge nodes, you can:

1. Centralize at the origin for simple architectures.
2. Fan‑out to edge instances (or have your CDN call the /checkredirect API) for single‑digit‑ms global round‑trips.

Either way, scaling up is literally adding another Harper node—no extra services to wire.

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Deploying to Dev, Staging, Prod

harperdb deploy_component \
  project=redirector \
  package=https://github.com/HarperDB/template-redirector \
  target=prod.mydomain.io \
  username=$USER password=$PASS \
  restart=true replicated=true

The CLI packages the repo (or pulls from npm/GitHub), ships it to the remote instance with rolling restarts for zero downtime.

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Ready to Test It Yourself?

• Star & fork: https://github.com/HarperDB/template-redirector
• Browse the docs: https://docs.harperdb.io/docs/developers/components/managing 
• Join us on Slack: https://harperdbcommunity.slack.com/join/shared_invite/zt-1qr24rcth-29fwBYzHPXpgJdb9e~o24A#/shared-invite/email 

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The redirect problem is solved; now you can get back to building features. Happy routing!

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