Returning a Buffered Image in Spring boot

[arctic vale]

Hey friends, I keep getting an error when I try to return a buffered image with spring. Here is the error below:
2023-03-14T13:45:04.645-04:00 WARN 81359 --- [nio-8080-exec-8] .w.s.m.s.DefaultHandlerExceptionResolver : Resolved [org.springframework.http.converter.HttpMessageNotWritableException: No converter for [class java.awt.image.BufferedImage] with preset Content-Type 'null']

Here is the GetMapping code.

@GetMapping(path = "/long", produces = "image/png")
    public BufferedImage createLong() {
        try {
            return ImageIO.read(new File("/Users/ntdi/Documents/planium/src/main/resources/static/Ntdi_world_1200px-01.png"));
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
}```

[viscid narwhal]

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[arctic vale]

Im just unsure of how to return a buffered image, I did some research and it could be a content header thing? This seems silly.. 😦

[forest anchor]

Try returning a byte array:

ByteArrayOutputStream baos = new ByteArrayOutputStream();
  ImageIO.write(bi, "jpg", baos);
  byte[] bytes = baos.toByteArray();

Eh sorry, if you're just reading a file you can just return its bytes directly without involving buffered image: https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/nio/file/Files.html#readAllBytes(java.nio.file.Path)

[arctic vale]

I've come up with a new solution,

instead of returning a buffered image, I am returning a link to where the image would be located

I am storing it in a dir inside of the resources/static folder

but now I cannot access the image live until the spring boot app restarts bc the images there arent updated live

[forest anchor]

You'll have to put it somewhere else. The resources dir gets compiled into the jar root on run/restart

[arctic vale]

I've found this, spring.web.resources.static-locations[0]=file:src/main/resources/static/ spring.web.resources.static-locations[1]=classpath:/static/

this allows spring web to constantly reload, so maybe it'll work?

[forest anchor]

This is not a great solution. I would recommend putting it in a regular directory like /tmp/myapp or whatever

Or /opt/myapp or what have you (or the windows equivalent)

[arctic vale]

I know it isn't great, but I just tested it and it works.

¯_(ツ)_/¯

[forest anchor]

Well if it's good enough for you who am I to criticise

[arctic vale]

haha, Thanks a lot!

[viscid narwhal]

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