Golang : Fix cannot convert buffer (type *bytes.Buffer) to type string error
Encountered these similar error messages while working on the previous tutorials on how to reset buffer and writing to http.ResponseWriter :
cannot convert buffer (type *bytes.Buffer) to type string
and
cannot use buffer (type *bytes.Buffer) as type []byte in argument to w.Write
1. Cannot convert buffer (type *bytes.Buffer) to type string solution
the error message is generated because of attempt to convert the bytes.Buffer directly to string type with string()
function.
fmt.Println(string(buffer))
to fix this error. Use buffer.String()
or string(buffer.Bytes())
package main
import (
"bytes"
"fmt"
)
func main() {
buffer := bytes.NewBuffer([]byte("Hello World!"))
fmt.Println(buffer.String())
// or
// fmt.Println(string(buffer.Bytes())
}
2. Cannot use buffer (type *bytes.Buffer) as type []byte in argument to w.Write solution
Writing buffer directly to http.ResponseWriter will cause error
func SayHelloWorld(w http.ResponseWriter, r *http.Request) {
buffer := bytes.NewBuffer([]byte("Hello World!"))
w.Write(buffer) // <--- wrong!
}
the solution is to use
w.Write(buffer.Bytes())
or use Buffer.WriteTo() function.
func SayHelloWorld(w http.ResponseWriter, r *http.Request) {
buffer := bytes.NewBuffer([]byte("Hello World!"))
buffer.WriteTo(w)
}
By Adam Ng
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