CODEWITHSUNDEEP
gowebsocketgorilla
user12574700
user12574700

Reputation:

gorilla/websocket send and read bytes data

i'm trying to send bytes of image data via gorilla/websocket, my current code is : 

var b bytes.Buffer
empty := bufio.NewWriter(&b)
png.Encode(empty, img)

err = c.WriteMessage(websocket.TextMessage, b.Bytes())

my code for receiving message : 

_, message, err := c.ReadMessage()
if err != nil {
    log.Println("read:", err)
    return
}
// log.Printf("recv: %s", message)
ioutil.WriteFile("./nani.png", []byte(message), 0644)

then the saved file are corrupted, how do i write/read message as binary/bytes

Upvotes: 1

Views: 2899

Answers (1)

Thundercat
Thundercat

Reputation: 120960

The bufio.Writer must be flushed to write any buffered data to the underlying writer (the bytes.Buffer in this case). If the bufio.Writer is not flushed, then some of the image data may be lost and the image will appear to be corrupted.

See the bufio.Writer documentation for more information on flushing the writer.

Here's the fix:

var b bytes.Buffer
empty := bufio.NewWriter(&b)
png.Encode(empty, img)
empty.Flush()    // <-- add this call

Because there's no need to buffer data when writing to a byte.Buffer, the code can be improved by eliminating the bufio.Writer:

var b bytes.Buffer
png.Encode(&b, img)

Use websocket.BinaryMessage to send binary messages. See the Data Message section of the documentation for more information on message types.

Upvotes: 1

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