如何将Golang中的[] []字节发送到浏览器以将其解码为图像

Question

In my back-end golang web server I have converted and processed a directory of images that i have read in using os.ReadDir

These images are stored as a [][]byte. I want to be able to send these images through a GET request to be displayed in the browser using Javascript.

I am having trouble figuring out how to begin the process to send the data from the Golang web server. The resources I am currently using are the typical net/http package, and Gorilla Mux/Websockets.

Here is some sample code that shows how I am currently doing a get request which return some json. How can I similarly send a [][]byte array instead of rendering a template or JSON?

import (
    "html/template"
    "log"
    "net/http"
    "encoding/json"
    "github.com/gorilla/mux"
)

func ViewSample(rw http.ResponseWriter, req *http.Request) {
    type Sample struct {
        Id        int    `json:"id"`
        Name      string `json:"name"`
        User      string `json:"user
    }

    params := mux.Vars(req)
    sampleId := params["id"]

    sample := Sample{
        Id:        3,
        Name:      "test",
        User:      "testuser" 
    }

    json.NewEncoder(rw).Encode(sample)
}

Answer 1

If your image is stored in a []byte, you can write that directly to the http.ResponseWriter

func GetImage(w http.ResponseWriter, r *http.Request) {
    image, err := getImage() // getImage example returns ([]byte, error)
    if err != {
        http.Error(w, err.Error(), http.StatusInternalServerError)
        return
    }

    w.Write(image)
}

There's no way to send multiple images in a single response which is natively understood by clients. One method you could use is to return a json document on the first call, which contains a list of links to fetch each image individually.