Extension: File to String. String to File. Base64.

[Juan Antonio]

Hi friends,

this extension convert image, sound, doc,... file to String in Base64, and String Base64 in file.

Usefulness: 

- convert a image, sound, doc,.. to String Base64 and then save this String in TinyDB. Then recovery String B64 from TinyDB and convert to File.

- convert a file to String and send this String by Bluetooth.

[MiuMiu]

great！very useful extension！than you！

[Abraham Getzler]

(added to Files section of FAQ)

https://groups.google.com/forum/?utm_medium=email&utm_source=footer#!msg/mitappinventortest/2cd6Uz__xA0/cPQSiZpcDAAJ

ABG

[TimAI2]

Note: needs full path if using files in assets e.g.

when in development

/mnt/sdcard/AppInventor/assets/

when in production

/android_asset/

[TimAI2]

Also a problem when trying to decode in my Google web app.

If I encode an image to base64 using bash the output works, if I encode using the extension I get a different output and the webapp cannot decode the base64 string

From Ai2

iVBORw0KGgoAAAANSUhEUgAAAA4AAABnCAYAAAAws3NDAAAABHNCSVQICAgIfAhkiAAAAAlwSFlz

AAAHXgAAB14BODEn8gAAABl0RVh0U29mdHdhcmUAd3d3Lmlua3NjYXBlLm9yZ5vuPBoAAAAwSURB

VFiF7cuxDQAACAMg9f-f6w8mbrDTSVIHc0miKIqiKIqiKIqiKIqiKIqi-BIXrUIEyqlMIQQAAAAA

SUVORK5CYII

From bash

iVBORw0KGgoAAAANSUhEUgAAAA4AAABnCAYAAAAws3NDAAAABHNCSVQICAgIfAhkiAAAAAlwSFlz

AAAHXgAAB14BODEn8gAAABl0RVh0U29mdHdhcmUAd3d3Lmlua3NjYXBlLm9yZ5vuPBoAAAAwSURB

VFiF7cuxDQAACAMg9f+f6w8mbrDTSVIHc0miKIqiKIqiKIqiKIqiKIqi+BIXrUIEyqlMIQQAAAAA

SUVORK5CYII=

You will see that the encodes are slightly different (+'s and -'s, and no = at the end) 

Code in web app:

var data = Utilities.base64Decode(e.parameters.file, Utilities.Charset.UTF_8);

 

[Juan Antonio]

Hi Tim, the idea of this extension is get an external file, perhaps with an Explorer, and upload to web o save to TinyDB, or other file.

https://groups.google.com/forum/#!category-topic/mitappinventortest/apps-tips--tricks/jtxmB-TT92Q

https://groups.google.com/forum/#!category-topic/mitappinventortest/apps-tips--tricks/NGaVDbjFihE

This extension use Web Safe, change +-=  so they do not have a problem when traveling on the internet.

When they arrive at the server, change those characters again.

<?php
// Juan A. Villalpando
// kio4.com

$datos=$_POST;
$contenido=$datos['contenido'];

$archivo = 'imagen.txt';
$auxi = fopen($archivo, 'w');
fwrite($auxi, $contenido); 
fclose($auxi);

echo $contenido;

$foto = 'foto.png';
$auxi = fopen($foto, 'w');
$contenido2 = strtr($contenido, '-_,', '+/=');
$contenido2 = base64_decode($contenido2);
fwrite($auxi, $contenido2); 
fclose($auxi);

?>

http://kio4.com/appinventor/277_extension_imagen_string.htm

https://stackoverflow.com/questions/24460422/how-to-send-a-message-successfully-using-the-new-gmail-rest-api/24461102#24461102

[TimAI2]

OK Juan, I understand, but thought you should know it doesn't work in some circumstances where the receiving end is not expecting "Web Safe"!

If I get a chance, I will add some find/replace code to my web app and try your extension again :)

I found ghostfox's similar extension on thunkable that does work so no worries :)

[Juan Antonio]

Hi Tim, 

I am testing this new version of the Base64 extension.

In this example the extension gets a file from the Assets, converts it to StringBase64 and presents it in Label1.

Then take that text and save it in a file.

Then read that file and present it in Label2.

Can you try it please?

http://kio4.com/appinventor/aplicaciones/Stringtobase64_Assets.aia

I think the conversion to Base64 is different from others, but it works.

Regards.

[TimAI2]

Hi Juan

Yes, I can see this works inside AI2. I tested my image on it as well (the one that generated the base64 above) and your new version appears to encode it in the same way - with +'s and ='s  :)

If you wish, private email me the aix file and I will test out on my google drive upload example app.

Regards

Tim