B4J Question How to convert base64String to Image and save

[Chris Guanzon]

Hello everyone

How can I convert a base64 string to an image and save it? I have a server and a web app. What I want to achieve is that from the web app, the user will send a POST request with a base64 string. The server will then convert the base64 string to an image and save it inside a folder.

 

[Johan Schoeman]

There is an example in the code in this posting

QR Code - "Store" image/bitmap in a QR Code

See attached B4A project: 1. It takes an image (png or jpg) and convert it into a byte array 2. The byte array is converted into a Base64 String 3. The String is then converted into a QR Code (bitmap) 4. Use the QR Code bitmap and decodes it into a string (Base64) 5. Convert the Base64 string...

www.b4x.com

 

[Chris Guanzon]

There is an example in the code in this posting

QR Code - "Store" image/bitmap in a QR Code

See attached B4A project: 1. It takes an image (png or jpg) and convert it into a byte array 2. The byte array is converted into a Base64 String 3. The String is then converted into a QR Code (bitmap) 4. Use the QR Code bitmap and decodes it into a string (Base64) 5. Convert the Base64 string...

www.b4x.com

Is this applicable for b4j? The library used in the sample.

 

[Erel]

Dim su As StringUtils
Dim b() As Byte = su.DecodeBase64(...)
File.WriteBytes(.., .., b)

 

[Chris Guanzon]

Dim su As StringUtils
Dim b() As Byte = su.DecodeBase64(...)
File.WriteBytes(.., .., b)

Thank you Sir @Erel

Dim su As StringUtils
Dim b() As Byte = su.DecodeBase64(b64string)
File.WriteBytes(File.Combine(File.DirApp, "www/assets/images/"), $"filename.png"$, b)

 

[Erel]

This code will fail if multiple clients upload files at one. I don't know whether it is relevant to your user case or not...

 

[Chris Guanzon]

This code will fail if multiple clients upload files at one. I don't know whether it is relevant to your user case or not...

What changes do I need to make in my code? This code is for the server.

 

[Erel]

You need to use a unique file name for each request. Otherwise the file will be overwritten

 

[Chris Guanzon]

You need to use a unique file name for each request. Otherwise the file will be overwritten

dim filename as string = req.getparameter("filename")
Dim su As StringUtils
Dim b() As Byte = su.DecodeBase64(b64string)
File.WriteBytes(File.Combine(File.DirApp, "www/assets/images/"), $"${filename}.png"$, b)