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index.js

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+/**!
+ * koa-locales - index.js
+ *
+ * Copyright(c) koajs and other contributors.
+ * MIT Licensed
+ *
+ * Authors:
+ *   fengmk2 <m@fengmk2.com> (http://fengmk2.com)
+ */
+
+"use strict";
+
+/**
+ * Module dependencies.
+ */
+
+var debug = require('debug')('koa-locales');
+var util = require('util');
+var fs = require('fs');
+var path = require('path');
+var ms = require('humanize-ms');
+
+module.exports = function (app, options) {
+  options = options || {};
+  var defaultLocale = formatLocale(options.defaultLocale || 'en-US');
+  var queryField = options.queryField || 'locale';
+  var cookieField = options.cookieField || 'locale';
+  var cookieMaxAge = ms(options.cookieMaxAge || '1y');
+  var localeDir = options.dir || path.join(process.cwd(), 'locales');
+  var functionName = options.functionName || '__';
+  var resources = {};
+
+  if (fs.existsSync(localeDir)) {
+    var names = fs.readdirSync(localeDir);
+    for (var i = 0; i < names.length; i++) {
+      var name = names[i];
+      if (!/\.(js|json)$/.test(name)) {
+        continue;
+      }
+      var filepath = path.join(localeDir, name);
+      // support en_US.js => en-US.js
+      var locale = formatLocale(name.split('.')[0]);
+      resources[locale] = require(filepath);
+    }
+  }
+
+  debug('init locales with %j, got %j resources', options, Object.keys(resources));
+
+  var ARRAY_INDEX_RE = /\{(\d+)\}/g;
+  function formatWithArray(text, values) {
+    return text.replace(ARRAY_INDEX_RE, function (orignal, matched) {
+      var index = parseInt(matched);
+      if (index < values.length) {
+        return values[index];
+      }
+      // not match index, return orignal text
+      return orignal;
+    });
+  }
+
+  app.context[functionName] = function (key, value, value2, value3, value4) {
+    if (arguments.length === 0) {
+      // __()
+      return '';
+    }
+
+    var locale = this.__getLocale();
+    var resource = resources[locale] || {};
+    var text = resource[key] || key;
+    debug('%s: %j => %j', locale, key, text);
+    if (!text) {
+      return '';
+    }
+
+    // for performance reason
+    if (arguments.length === 1) {
+      // __(key)
+      return text;
+    }
+    if (arguments.length === 2) {
+      if (Array.isArray(value)) {
+        // __(key, array)
+        // __('{0} {1} {1} {0}', ['foo', 'bar'])
+        // =>
+        // foo bar bar foo
+        return formatWithArray(text, value);
+      }
+
+      // __(key, value)
+      return util.format(text, value);
+    }
+    if (arguments.length === 3) {
+      // __(key, value1, value2)
+      return util.format(text, value, value2);
+    }
+    if (arguments.length === 4) {
+      // __(key, value1, value2, value3)
+      return util.format(text, value, value2, value3);
+    }
+    if (arguments.length === 5) {
+      // __(key, value1, value2, value3, value4)
+      return util.format(text, value, value2, value3, value4);
+    }
+
+    // __(key, value1, value2, value3, value4, value5, ...)
+    var args = Array.prototype.slice.call(arguments, 1);
+    args.unshift(text);
+    return util.format.apply(util, args);
+  };
+
+  // 1. query: /?locale=en-US
+  // 2. cookie: locale=zh-TW
+  // 3. header: Accept-Language: zh-CN,zh;q=0.5
+  app.context.__getLocale = function () {
+    if (this.__locale) {
+      return this.__locale;
+    }
+
+    var cookieLocale = this.cookies.get(cookieField);
+    var locale = this.query[queryField] || cookieLocale;
+    if (!locale) {
+      // Accept-Language: zh-CN,zh;q=0.5
+      // Accept-Language: zh-CN
+      var languages = this.acceptsLanguages();
+      if (languages) {
+        if (Array.isArray(languages)) {
+          if (languages[0] === '*') {
+            languages = languages.slice(1);
+          }
+          if (languages.length > 0) {
+            for (var i = 0; i < languages.length; i++) {
+              var lang = formatLocale(languages[i]);
+              if (resources[lang]) {
+                locale = lang;
+                break;
+              }
+            }
+            if (!locale) {
+              // set the first one
+              locale = languages[0];
+            }
+          }
+        } else {
+          locale = languages;
+        }
+      }
+
+      // all missing, set it to defaultLocale
+      if (!locale) {
+        locale = defaultLocale;
+      }
+    }
+
+    locale = formatLocale(locale);
+
+    // validate locale
+    if (!resources[locale]) {
+      locale = defaultLocale;
+    }
+
+    if (cookieLocale !== locale) {
+      // locale change, need to set cookie
+      this.cookies.set(cookieField, locale, {
+        // make sure brower javascript can read the cookie
+        httpOnly: false,
+        maxAge: cookieMaxAge,
+      });
+    }
+    this.__locale = locale;
+    return locale;
+  };
+
+  function formatLocale(locale) {
+    // support zh_CN, en_US => zh-CN, en-US
+    return locale.replace('_', '-').toLowerCase();
+  }
+};