feat: collect app download statistics

This adds download statistics collection for Keyman apps hosted on
downloads.keyman.com - specifically Keyman for Windows, Keyman for Mac,
and Keyman Developer. Other platforms are distributed through stores or
other mechanisms, so will not generally be visible here.

For now we collect app, version, and tier data, by day. This can be
expanded as needed in the future.

This is the frontend change; see keymanapp/api.keyman.com#321 for the
api backend and database changes.

This is implemented as a passthrough redirect on keyman.com. Online
updates will not currently appear in these statistics, so the stats
against downloads.keyman.com hits will differ.

Relates-to: keymanapp/api.keyman.com#321
Test-bot: skip

Author: mcdurdin

_includes/includes/ui/downloads.php

@@ -73,9 +73,12 @@ function downloadLargeCTA($product, $platform, $tier, $filepattern) {
     $fileData = $versions->$platform->$tier->files->$file;
     $fileSize = formatSizeUnits($fileData->size);
     $host = KeymanHosts::Instance()->downloads_keyman_com;
+    $downloadSiteUrl = "$host/$platform/$tier/{$versions->$platform->$tier->version}/$file";
+    $downloadUrl = htmlentities("/go/app/download/$platform/{$versions->$platform->$tier->version}/$tier?url=".
+      rawurlencode($downloadSiteUrl));
 
     echo <<<END
-<div class="download-cta-big selected" id="cta-big-Windows" data-url='$host/$platform/$tier/{$versions->$platform->$tier->version}/$file' data-version='{$versions->$platform->$tier->version}'>
+<div class="download-cta-big selected" id="cta-big-Windows" data-url='$downloadUrl' data-version='{$versions->$platform->$tier->version}'>
     <div class="download-stable-email">
     <h3>$product {$versions->$platform->$tier->version}</h3>
     <p>Released: {$fileData->date}</p>

go/.htaccess

@@ -31,6 +31,13 @@ RewriteRule "^package/download/(keyboard/)?([^/]+)$" "package/download.php?type=
 # keyboard/id/share
 RedirectMatch "/go/keyboard/([^/?]+)/share$" "/keyboards/share/$1"
 
+#
+# go/app/download
+#
+
+# download-app?url=...
+RewriteRule "^app/download/([^/?]+)/([^/?]+)/(.*)" "app/download.php?product=$1&version=$2&tier=$3" [END,QSA]
+
 #
 # Non-app-specific endpoints
 #

go/app/download.php

@@ -0,0 +1,99 @@
+<?php
+  declare(strict_types=1);
+
+  namespace Keyman\Site\com\keyman;
+
+  require __DIR__ . '/../../_includes/autoload.php';
+
+  const DEBUG=0;
+
+  use Keyman\Site\com\keyman\KeymanComSentry;
+  use Keyman\Site\com\keyman\Validation;
+  use Keyman\Site\Common\KeymanHosts;
+  use Keyman\Site\Common\JsonApiFailure;
+
+  $env = getenv();
+  KeymanComSentry::init();
+
+  AppDownloadPage::redirect_to_file(
+    isset($_REQUEST['url']) ? $_REQUEST['url'] : null,
+    isset($_REQUEST['product']) ? $_REQUEST['product'] : null,
+    isset($_REQUEST['version']) ? $_REQUEST['version'] : null,
+    isset($_REQUEST['tier']) ? $_REQUEST['tier'] : null,
+    // TODO: should we? or just leave it encoded in URL for now?
+    // isset($_REQUEST['bcp47']) ? $_REQUEST['bcp47'] : null,
+    // isset($_REQUEST['update']) ? $_REQUEST['update'] : null
+  );
+
+  class AppDownloadPage {
+
+    public static function redirect_to_file($url, $product, $version, $tier) {
+      if(empty($url)) {
+        JsonApiFailure::InvalidParameters("url");
+      }
+
+      if(empty($product)) {
+        $product = 'unknown';
+      }
+
+      if(empty($version)) {
+        $version = '0.0';
+      }
+
+      if(empty($tier)) {
+        $tier = 'stable';
+      }
+
+      $tier = Validation::validate_tier($tier, 'stable');
+
+      $url_e = htmlentities($url);
+
+      if(DEBUG) {
+        header('Content-Type: text/plain');
+      }
+
+      if(KeymanHosts::Instance()->Tier() !== KeymanHosts::TIER_TEST) {
+        self::report_app_download_event($product, $version, $tier);
+
+        if(DEBUG) {
+          echo "\n\nLocation: $url\n";
+          exit;
+        }
+
+        // We don't do a redirect for Test tier because a test instance of the
+        // downloads server is not available and so it gives us an error
+        header("HTTP/1.1 302 Found");
+        header("Cache-Control: no-store");
+        header("Location: $url");
+      }
+
+      echo "<a href='$url_e'>Download Link</a>";
+    }
+
+    private static function report_app_download_event($product, $version, $tier) {
+      global $env;
+      $url = KeymanHosts::Instance()->SERVER_api_keyman_com . "/app-downloads-increment/".rawurlencode($product).
+        "/".rawurlencode($version)."/".rawurlencode($tier);
+
+      if(KeymanHosts::Instance()->Tier() !== KeymanHosts::TIER_TEST) {
+        if(KeymanHosts::Instance()->Tier() === KeymanHosts::TIER_DEVELOPMENT)
+          $key = 'local';
+        else
+          $key = $env['API_KEYMAN_COM_INCREMENT_DOWNLOAD_KEY'];
+
+        $c = curl_init($url);
+        curl_setopt($c, CURLOPT_HEADER, 0);
+        curl_setopt($c, CURLOPT_POSTFIELDS, 'key='.rawurlencode($key));
+        curl_setopt($c, CURLOPT_RETURNTRANSFER, TRUE);
+        curl_setopt($c, CURLOPT_USERAGENT , "Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1)");
+        $data = curl_exec($c);
+        curl_close($c);
+
+        if(DEBUG) {
+          var_dump("app-downloads-increment ($url):",$data);
+        }
+      } else
+        $data = TRUE;
+      return $data !== FALSE;
+    }
+  }

go/package/download.php

@@ -117,48 +117,3 @@ private static function report_download_event($id, $platform, $tier, $bcp47, $up
       return $data !== FALSE;
     }
   }
-
-/**
-* Returns a GUIDv4 string
-*
-* Uses the best cryptographically secure method
-* for all supported pltforms with fallback to an older,
-* less secure version.
-* https://www.php.net/manual/en/function.com-create-guid.php#119168
-*
-* @param bool $trim
-* @return string
-*/
-function GUIDv4 ($trim = true)
-{
-    // Windows
-    if (function_exists('com_create_guid') === true) {
-        if ($trim === true)
-            return trim(com_create_guid(), '{}');
-        else
-            return com_create_guid();
-    }
-
-    // OSX/Linux
-    if (function_exists('openssl_random_pseudo_bytes') === true) {
-        $data = openssl_random_pseudo_bytes(16);
-        $data[6] = chr(ord($data[6]) & 0x0f | 0x40);    // set version to 0100
-        $data[8] = chr(ord($data[8]) & 0x3f | 0x80);    // set bits 6-7 to 10
-        return vsprintf('%s%s-%s-%s-%s-%s%s%s', str_split(bin2hex($data), 4));
-    }
-
-    // Fallback (PHP 4.2+)
-    mt_srand((double)microtime() * 10000);
-    $charid = strtolower(md5(uniqid(rand(), true)));
-    $hyphen = chr(45);                  // "-"
-    $lbrace = $trim ? "" : chr(123);    // "{"
-    $rbrace = $trim ? "" : chr(125);    // "}"
-    $guidv4 = $lbrace.
-              substr($charid,  0,  8).$hyphen.
-              substr($charid,  8,  4).$hyphen.
-              substr($charid, 12,  4).$hyphen.
-              substr($charid, 16,  4).$hyphen.
-              substr($charid, 20, 12).
-              $rbrace;
-    return $guidv4;
-}

keyboards/install.php

@@ -122,11 +122,12 @@ protected static function WriteWindowsBoxes() {
 
       // This maps to buildStandardWindowsDownloadUrl in install.js (which we don't use here for those
       // few users who have JS disabled -- although this is not really a tested/supported scenario)
-      $downloadLink = KeymanHosts::Instance()->downloads_keyman_com .
+      $downloadServerLink = KeymanHosts::Instance()->downloads_keyman_com .
         "/windows/{$hu['tier']}/{$hu['version']}/keyman-setup" .
         self::BOOTSTRAP_SEPARATOR . "{$hu['id']}" .
         (empty($hu['bcp47']) ? "" : ".{$hu['bcp47']}") .
         ".exe";
+      $downloadLink = "/go/app/download/windows/{$hu['version']}/{$hu['tier']}?url=".rawurlencode($downloadServerLink);
 
       $helpLink = KeymanHosts::Instance()->help_keyman_com . "/products/windows/current-version/start/download-and-install-keyman";