basic-read

Basics

Many ways to read.

The Read Method

Go provides the io.Reader interface for input operations.

type Reader interface {
    Read(p []byte) (n int, err error)
}

When we call Read, the method expects a []byte argument. So we pass it a literal byte slice but the slice needs to be of right size so that we can read and hold the content.

str := "hello wold"
reader := bytes.NewBufferString(str)
buf := make([]byte, len(str))
reader.Read(buf)
fmt.Println(string(buf))

There are cases where a variable size buffer that grows as needed is useful. For that, we use bytes.Buffer as a utility for reading streams.

reader = bytes.NewBufferString(str)
buffer := new(bytes.Buffer)
buffer.ReadFrom(reader)
fmt.Println(buffer.String())

Pass by io.Reader and io.Writer

Go provides the io.Reader and io.Writer interfaces for I/O operations. As a best practice, pass any I/O stream as io.Reader or io.Writer instead of string, []bytes, etc. This makes the code cleaner and more extensible.

Reference and Credits

• Go Package io