front/home: add version and build time

scripts/build-frontend.js

@@ -4,6 +4,11 @@ const fs = require('fs');
 const glob = require('glob');
 const path = require('path');
 const util = require('util');
+const execSync = require('child_process').execSync;
+
+function getVersion() {
+    return execSync('git describe --always --dirty --long --tags').toString();
+}
 
 function getConfig() {
     const ini = require('ini');
@@ -34,6 +39,10 @@ function getConfig() {
     delete config.database;
     config.service.userRanks = config.service.userRanks.split(/,\s*/);
     config.service.tagCategories = config.service.tagCategories.split(/,\s*/);
+    config.meta = {
+        version: getVersion(),
+        buildDate: new Date().toUTCString(),
+    };
 
     return config;
 }

static/html/home.tpl

@@ -1,4 +1,5 @@
 <div class='content-wrapper transparent' id='home'>
     <div class='messages'></div>
     <h1>{{name}}</h1>
+    <footer>Version: <span class="version">{{version}}</span> (built {{buildDate}})</footer>
 </div>

static/js/util.js

@@ -0,0 +1,44 @@
+'use strict';
+
+function formatRelativeTime(timeString) {
+    if (!timeString) {
+        return 'never';
+    }
+
+    const then = Date.parse(timeString);
+    const now = Date.now();
+    const difference = Math.abs(now - then) / 1000.0;
+    const future = now < then;
+
+    const descriptions = [
+        [60,                        'a few seconds',    null],
+        [60*2,                      'a minute',         null],
+        [60*60,                     '% minutes',        60],
+        [60*60*2,                   'an hour',          null],
+        [60*60*24,                  '% hours',          60*60],
+        [60*60*24*2,                'a day',            null],
+        [60*60*24*30.42,            '% days',           60*60*24],
+        [60*60*24*30.42*2,          'a month',          null],
+        [60*60*24*30.42*12,         '% months',         60*60*24*30.42],
+        [60*60*24*30.42*12*2,       'a year',           null],
+        [8640000000000000/*max*/,   '% years',          60*60*24*30.42*12],
+    ];
+
+    let text = null;
+    for (let kv of descriptions) {
+        const multiplier = kv[0];
+        const template = kv[1];
+        const divider = kv[2];
+        if (difference < multiplier) {
+            text = template.replace(/%/, Math.round(difference / divider));
+            break;
+        }
+    }
+
+    if (text === 'a day') {
+        return future ? 'tomorrow' : 'yesterday';
+    }
+    return future ? 'in ' + text : text + ' ago';
+}
+
+module.exports = {formatRelativeTime: formatRelativeTime};

static/js/views/home_view.js

@@ -1,5 +1,6 @@
 'use strict';
 
+const util = require('../util.js');
 const config = require('../config.js');
 const BaseView = require('./base_view.js');
 
@@ -11,7 +12,9 @@ class HomeView extends BaseView {
 
     render(section) {
         this.showView(this.template({
-            'name': config.basic.name,
+            name: config.basic.name,
+            version: config.meta.version,
+            buildDate: util.formatRelativeTime(config.meta.buildDate),
         }));
     }
 }