From 27467fa2c8a533cad7da1b0210a0a8d5c1f04757 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Sven=20Sch=C3=B6ling?= <sven.schoeling@opendynamic.de>
Date: Fri, 12 Apr 2019 18:13:39 +0200
Subject: [PATCH] kivi.js: kivi.save_file und client_js binding

(cherry picked from commit f68ea953a6a563172f12991d2ca3f9f17ad89dd2)
---
 SL/ClientJS.pm  |  1 +
 js/client_js.js |  1 +
 js/kivi.js      | 33 +++++++++++++++++++++++++++++++++
 3 files changed, 35 insertions(+)

diff --git a/SL/ClientJS.pm b/SL/ClientJS.pm
index a134cad9b..336f97144 100644
--- a/SL/ClientJS.pm
+++ b/SL/ClientJS.pm
@@ -113,6 +113,7 @@ my %supported_methods = (
 
   # ## other stuff ##
   redirect_to            => 1,  # window.location.href = <TARGET>
+  save_file              => 4,  # kivi.save_file(<TARGET>, <ARGS>)
 
   flash                  => 2,  # kivi.display_flash(<TARGET>, <ARGS>)
   flash_detail           => 2,  # kivi.display_flash_detail(<TARGET>, <ARGS>)
diff --git a/js/client_js.js b/js/client_js.js
index 8be5676e4..9fc14b6c6 100644
--- a/js/client_js.js
+++ b/js/client_js.js
@@ -151,6 +151,7 @@ ns.eval_json_result = function(data) {
 
       // ## other stuff ##
       else if (action[0] == 'redirect_to')          window.location.href = action[1];
+      else if (action[0] == 'save_file')            kivi.save_file(action[1], action[2], action[3], action[4]);
       else if (action[0] == 'flash')                kivi.display_flash(action[1], action[2]);
       else if (action[0] == 'flash_detail')         kivi.display_flash_detail(action[1], action[2]);
       else if (action[0] == 'clear_flash')          kivi.clear_flash(action[1], action[2]);
diff --git a/js/kivi.js b/js/kivi.js
index 444892117..a76ad8a99 100644
--- a/js/kivi.js
+++ b/js/kivi.js
@@ -558,6 +558,39 @@ namespace("kivi", function(ns) {
     return undefined;
   };
 
+  ns.save_file = function(base64_data, content_type, size, attachment_name) {
+    // atob returns a unicode string with one codepoint per octet. revert this
+    const b64toBlob = (b64Data, contentType='', sliceSize=512) => {
+      const byteCharacters = atob(b64Data);
+      const byteArrays = [];
+
+      for (let offset = 0; offset < byteCharacters.length; offset += sliceSize) {
+        const slice = byteCharacters.slice(offset, offset + sliceSize);
+
+        const byteNumbers = new Array(slice.length);
+        for (let i = 0; i < slice.length; i++) {
+          byteNumbers[i] = slice.charCodeAt(i);
+        }
+
+        const byteArray = new Uint8Array(byteNumbers);
+        byteArrays.push(byteArray);
+      }
+
+      const blob = new Blob(byteArrays, {type: contentType});
+      return blob;
+    }
+
+    var blob = b64toBlob(base64_data, content_type);
+    var a = $("<a style='display: none;'/>");
+    var url = window.URL.createObjectURL(blob);
+    a.attr("href", url);
+    a.attr("download", attachment_name);
+    $("body").append(a);
+    a[0].click();
+    window.URL.revokeObjectURL(url);
+    a.remove();
+  }
+
   ns.detect_duplicate_ids_in_dom = function() {
     var ids   = {},
         found = false;
-- 
2.20.1