invalid JPEG format: missing SOI marker

Question

Trying to decode an image and write to a file.

This is my code:

package main

import (
        "bytes"
        "fmt"
        "github.com/reteps/gopowerschool"
        "image/jpeg"
)

func main() {
        client := gopowerschool.Client("https://example.com")
        session, userID, err := client.CreateUserSessionAndStudent("username", "password")
        if err != nil {
                panic(err)
        }   
        response, err := client.GetStudentPhoto(&gopowerschool.GetStudentPhoto{UserSessionVO: session, StudentID: userID})
        if err != nil {
                panic(err)
        }   
        fmt.Println(string(response.Return_))
        image, err := jpeg.Decode(bytes.NewReader(response.Return_))
        if err != nil {
                panic(err)
        }   
        fmt.Println(image)

}

The image is:

/9j/4AAQSkZJRg....VNpSP8f6VmE4oopks//Z

It is giving me an error when I try to decode the []byte of the image.

panic: invalid JPEG format: missing SOI marker

Answer 1

The data for the image that you show appears to be base-64 encoded.

Base-64 decoding "/9j/4AAQSkZJRg==" (the "==" pads it to a correct length) gives "???? JFIF". The important hint is the "JFIF", which shows that the image data is indeed base-64 encoded.

To get the image, you need to base-64 decode the string that represents the image data.