Middleware

function createI18nMiddleware(
  config: LocaleConfig
): (context: APIContext, next: MiddlewareNext) => Promise<Response>

Creates an Astro middleware that detects the locale from the URL and sets it on Astro.locals.locale.

Usage

src/middleware.ts

import { createI18nMiddleware } from '@otrodigital/astro-i18n-next';
import { config } from 'virtual:i18n';

export const onRequest = createI18nMiddleware(config);

Parameters

Parameter	Type	Description
config	LocaleConfig	Locale configuration (available from virtual:i18n as config)

Behavior

The middleware:

1. Reads the URL pathname from the request
2. Checks if the first path segment matches a configured locale
3. Sets Astro.locals.locale to the detected locale (or defaultLocale if no prefix found)
4. Calls next() to continue the request

Examples:

Request URL	Astro.locals.locale
/about/	'en' (default)
/es/sobre/	'es'
/es/saunas/modelo-165/	'es'

Composing with other middleware

If you have existing middleware, compose them using Astro’s sequence:

src/middleware.ts

import { sequence } from 'astro:middleware';
import { createI18nMiddleware } from '@otrodigital/astro-i18n-next';
import { config } from 'virtual:i18n';

const i18n = createI18nMiddleware(config);

async function myMiddleware(context, next) {
  // Your custom logic here
  return next();
}

export const onRequest = sequence(i18n, myMiddleware);