Prefer user language from request header v1 PROPOSED

Суспільне Надбання: 1
 Prefer user language from request header

 1 files changed, 28 insertions(+), 9 deletions(-)

[PATCH] Prefer user language from request header Export this patch

Another internationalization tweak on my instance:
taking the Accept-Language header the user sends
and defaulting to the first language present in
the Bibliogram backing translation map, if any.
---
 src/site/api/utils/getsettings.js | 37 +++++++++++++++++++++++--------
 1 file changed, 28 insertions(+), 9 deletions(-)

diff --git a/src/site/api/utils/getsettings.js b/src/site/api/utils/getsettings.js
index 65d1fe6..ffd486e 100644
--- a/src/site/api/utils/getsettings.js
+++ b/src/site/api/utils/getsettings.js
@@ -3,20 +3,39 @@ const {parse: parseCookie} = require("cookie")
 
 const constants = require("../../../lib/constants")
 const db = require("../../../lib/db")
+const lang = require("../../../lang")
 
-function addDefaults(input = {}) {
+function addDefaults(req, input = {}) {
 	const result = {}
 	for (const setting of constants.user_settings) {
 		if (input[setting.name] !== undefined) {
 			result[setting.name] = input[setting.name]
-		} else {
-			if (setting.boolean) {
-				result[setting.name] = +(setting.default !== "")
-			} else if (setting.name in constants.default_user_settings) {
+		} else if (setting.boolean) {
+			result[setting.name] = +(setting.default !== "")
+		} else if (setting.name in constants.default_user_settings) {
+			if (setting.name === "language" &&
+					typeof req.headers["accept-language"] === "string") {
+				/* Example: uk-UA,uk;q=0.8,en-US;q=0.5,en;q=0.3
+				 *
+				 * Valid too: fr-CH, fr;q=0.9, en;q=0.8, de;q=0.7, *;q=0.5
+				 *
+				 * Browsers let users set the order. Quality values are usually
+				 * automatic and match it. However, rfc7231 warns that it is
+				 * only the status quo, not a requirement. */
+				for (let want of
+						req.headers["accept-language"].split(/\s*,\s*/)) {
+					want = want.split(/\s*;\s*/)[0].toLowerCase()
+					if (lang.backing.has(want)) {
+						result[setting.name] = want
+						break
+					}
+				}
+			}
+			if (result[setting.name] === undefined) {
 				result[setting.name] = constants.default_user_settings[setting.name]
-			} else {
-				result[setting.name] = setting.default
 			}
+		} else {
+			result[setting.name] = setting.default
 		}
 	}
 	return result
@@ -35,10 +54,10 @@ function getSettings(req) {
 	if (token) {
 		const row = db.prepare("SELECT * FROM UserSettings WHERE token = ?").get(token)
 		if (row) {
-			return addDefaults(row)
+			return addDefaults(req, row)
 		}
 	}
-	return addDefaults()
+	return addDefaults(req)
 }
 
 /*
-- 
2.36.0