feature(session): add session middleware

[BarryThePenguin]

I've been replacing an authentication library in a Next.js application, and thought it would be a good contribution to make. This PR is only focusing on the session middleware.

It started out as a library to bridge the gap between the previous authentication library and a new library. It runs on Cloudflare Workers, so the library gradually evolved into a standalone worker. This latest iteration is now middleware for a Hono app. It's been in progress for a while now.

I've done a lot of reading and research along the way. Some key resources that I've used include:

• The Copenhagen Book
• Session Management Cheat Sheet
• openid-client
• jose
• express-session

I also looked at using other similar libraries and frameworks including..

• OpenAuth
• Better Auth
• @hono/oidc-auth

..all of which do a lot more than I need, like account and database management, or don't expose the functionality I'm after. Specifically, an OIDC-client service to manage sessions and access/id/refresh tokens, while acting as an auth middleware proxying requests to upstream services.

What I'm essentially after is OAuth2 Proxy that I can run in Cloudflare Workers 😅

There are a few other's out there with similar needs, so I thought I'd share the end result.

[changeset-bot]

🦋 Changeset detected

Latest commit: 9281235

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@hono/session	Minor

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[codecov-commenter]

Codecov Report

Attention: Patch coverage is 99.25373% with 2 lines in your changes missing coverage. Please review.

Project coverage is 63.45%. Comparing base (86a4ca4) to head (9281235).
Report is 43 commits behind head on main.

Files with missing lines	Patch %	Lines
packages/session/src/helper/testing/index.ts	95.34%	2 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #1188       +/-   ##
===========================================
- Coverage   79.32%   63.45%   -15.88%     
===========================================
  Files          81      100       +19     
  Lines        2443     3467     +1024     
  Branches      633      911      +278     
===========================================
+ Hits         1938     2200      +262     
- Misses        419     1029      +610     
- Partials       86      238      +152     

Flag	Coverage Δ
session	8.35% <99.25%> (?)

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[yusukebe]

I updated the examples to the "not chained" style. It's common for users. If you pass SessionEnv to Hono as a generic, you can write it like this.

[BarryThePenguin]

Makes sense, thank you!

[yusukebe]

LGTM!

[yusukebe]

Hi @BarryThePenguin

Looks good to me! I like this middleware. I'll create some examples using it later. Thank you!