[IMP] web, *: add utils to get dataURL (base64) from file/blob

* = partner_autocomplete, point_of_sale, web_editor,
website_forum, website_slides

This can be used for example to preview an image from a file input field.

It can also be used to send the base64 content of the input by RPC instead of
having to rely on form submit as POST with multipart/form-data.

Technically wrap FileReader.readAsDataURL in a Promise.

This will also be used in task-1930726

PR: #33508

Signed-off-by: Quentin Smetz (qsm) <qsm@odoo.com>

3 files changed, 28 insertions, 10 deletions

diff --git a/addons/web/static/src/js/core/utils.js b/addons/web/static/src/js/core/utils.js
index 44e09933a25..44e17324b85 100644
--- a/addons/web/static/src/js/core/utils.js
+++ b/addons/web/static/src/js/core/utils.js
@@ -279,6 +279,28 @@ var utils = {
         return "";
     },
     /**
+     * Gets dataURL (base64 data) from the given file or blob.
+     * Technically wraps FileReader.readAsDataURL in Promise.
+     *
+     * @param {Blob|File} file
+     * @returns {Promise} resolved with the dataURL, or rejected if the file is
+     *  empty or if an error occurs.
+     */
+    getDataURLFromFile: function (file) {
+        if (!file) {
+            return Promise.reject();
+        }
+        return new Promise(function (resolve, reject) {
+            var reader = new FileReader();
+            reader.addEventListener('load', function () {
+                resolve(reader.result);
+            });
+            reader.addEventListener('abort', reject);
+            reader.addEventListener('error', reject);
+            reader.readAsDataURL(file);
+        });
+    },
+    /**
      * Returns a human readable number (e.g. 34000 -> 34k).
      *
      * @param {number} number
diff --git a/addons/web/static/src/js/fields/basic_fields.js b/addons/web/static/src/js/fields/basic_fields.js
index 713ade2a989..f4a518e28ea 100644
--- a/addons/web/static/src/js/fields/basic_fields.js
+++ b/addons/web/static/src/js/fields/basic_fields.js
@@ -1465,13 +1465,10 @@ var AbstractFieldBinary = AbstractField.extend({
                     this.do_warn(_t("File upload"), _.str.sprintf(msg, utils.human_size(this.max_upload_size)));
                     return false;
                 }
-                var filereader = new FileReader();
-                filereader.readAsDataURL(file);
-                filereader.onloadend = function (upload) {
-                    var data = upload.target.result;
+                utils.getDataURLFromFile(file).then(function (data) {
                     data = data.split(',')[1];
                     self.on_file_uploaded(file.size, file.name, file.type, data);
-                };
+                });
             } else {
                 this.$('form.o_form_binary_form').submit();
             }
diff --git a/addons/web/static/src/js/widgets/name_and_signature.js b/addons/web/static/src/js/widgets/name_and_signature.js
index 7c3f05a7148..57a9a697494 100644
--- a/addons/web/static/src/js/widgets/name_and_signature.js
+++ b/addons/web/static/src/js/widgets/name_and_signature.js
@@ -2,6 +2,7 @@ odoo.define('web.name_and_signature', function (require) {
 'use strict';
 
 var core = require('web.core');
+var utils = require('web.utils');
 var Widget = require('web.Widget');
 
 var _t = core._t;
@@ -597,11 +598,9 @@ var NameAndSignature = Widget.extend({
         }
         this.$loadInvalid.addClass('d-none');
 
-        var reader = new FileReader();
-        reader.onload = function (ev) {
-            self._printImage(reader.result);
-        };
-        reader.readAsDataURL(f);
+        utils.getDataURLFromFile(f).then(function (result) {
+            self._printImage(result);
+        });
     },
     /**
      * Handles input on name field: if the @see mode is 'auto', redraws the