Pass the locale through to Express pages

This change avoids duplicating reading the cookie on the legacy pages by passing through the already-read value. This requires a change to our Express usage to allow for request-specific arguments. As we're not using Express to listen for requests, we've favoured this type-safe way (as opposed to Express's standard of modifying the request object).

Refs #2044

src/Context.ts

@@ -15,7 +15,7 @@ export class DeprecatedLoggerEnv extends Context.Tag('DeprecatedLoggerEnv')<Depr
 
 export class DeprecatedSleepEnv extends Context.Tag('DeprecatedSleepEnv')<DeprecatedSleepEnv, SleepEnv>() {}
 
-export class Express extends Context.Tag('Express')<Express, ExpressServer>() {}
+export class Express extends Context.Tag('Express')<Express, (locale: SupportedLocale) => ExpressServer>() {}
 
 export class ExpressConfig extends Context.Tag('ExpressConfig')<
   ExpressConfig,

src/ExpressHttpApp.ts

@@ -2,21 +2,22 @@ import { type HttpApp, HttpMiddleware, HttpServerRequest, HttpServerResponse } f
 import { NodeHttpServerRequest } from '@effect/platform-node'
 import { Effect } from 'effect'
 import express, { type ErrorRequestHandler } from 'express'
-import { Express } from './Context.js'
+import { Express, Locale } from './Context.js'
 
-export const ExpressHttpApp: HttpApp.Default<never, Express | HttpServerRequest.HttpServerRequest> = Effect.gen(
-  function* () {
+export const ExpressHttpApp: HttpApp.Default<never, Express | HttpServerRequest.HttpServerRequest | Locale> =
+  Effect.gen(function* () {
     const expressApp = yield* Express
     const request = yield* HttpServerRequest.HttpServerRequest
 
     const nodeRequest = NodeHttpServerRequest.toIncomingMessage(request)
     const nodeResponse = NodeHttpServerRequest.toServerResponse(request)
+    const locale = yield* Locale
 
     return yield* Effect.async<HttpServerResponse.HttpServerResponse>(resume => {
       nodeResponse.once('close', () => resume(Effect.succeed(HttpServerResponse.empty())))
 
       express()
-        .use(expressApp)
+        .use(expressApp(locale))
         .use(((error, req, res, next) => {
           if (error instanceof Error && 'code' in error && error.code === 'ERR_HTTP_HEADERS_SENT') {
             return next()
@@ -25,5 +26,4 @@ export const ExpressHttpApp: HttpApp.Default<never, Express | HttpServerRequest.
           next(error)
         }) satisfies ErrorRequestHandler)(nodeRequest, nodeResponse)
     }).pipe(HttpMiddleware.withLoggerDisabled)
-  },
-)
+  })

src/app.ts

@@ -23,7 +23,7 @@ import { pageNotFound } from './http-error.js'
 import { getUserOnboarding } from './keyv.js'
 import { getPreprintIdFromLegacyPreviewUuid, getProfileIdFromLegacyPreviewUuid } from './legacy-prereview.js'
 import { type LegacyEnv, legacyRoutes } from './legacy-routes/index.js'
-import { DefaultLocale } from './locales/index.js'
+import type { SupportedLocale } from './locales/index.js'
 import { type MailjetApiEnv, sendEmailWithMailjet } from './mailjet.js'
 import { type NodemailerEnv, sendEmailWithNodemailer } from './nodemailer.js'
 import { page } from './page.js'
@@ -85,7 +85,7 @@ const withEnv =
   (...a: A) =>
     f(...a)(env)
 
-export const app = (config: ConfigEnv) =>
+export const app = (config: ConfigEnv) => (locale: SupportedLocale) =>
   express()
     .disable('x-powered-by')
     .use((req, res, next) => {
@@ -232,7 +232,7 @@ export const app = (config: ConfigEnv) =>
             getUserOnboarding: withEnv(getUserOnboarding, env),
             getPreprint: withEnv(getPreprint, env),
             getPreprintTitle: withEnv(getPreprintTitle, env),
-            locale: DefaultLocale,
+            locale,
             templatePage: withEnv(page, env),
             getPreprintIdFromUuid: withEnv(getPreprintIdFromLegacyPreviewUuid, env),
             getProfileIdFromUuid: withEnv(getProfileIdFromLegacyPreviewUuid, env),