selfcare init

proxy_go/public/go-telnet@v0.0.0-20180421082511-9ff0b2ab096e/standard_caller.go

@@ -0,0 +1,93 @@
+package telnet
+
+
+import (
+	"github.com/reiver/go-oi"
+
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"os"
+
+	"time"
+)
+
+
+// StandardCaller is a simple TELNET client which sends to the server any data it gets from os.Stdin
+// as TELNET (and TELNETS) data, and writes any TELNET (or TELNETS) data it receives from
+// the server to os.Stdout, and writes any error it has to os.Stderr.
+var StandardCaller Caller = internalStandardCaller{}
+
+
+type internalStandardCaller struct{}
+
+
+func (caller internalStandardCaller) CallTELNET(ctx Context, w Writer, r Reader) {
+	standardCallerCallTELNET(os.Stdin, os.Stdout, os.Stderr, ctx, w, r)
+}
+
+
+func standardCallerCallTELNET(stdin io.ReadCloser, stdout io.WriteCloser, stderr io.WriteCloser, ctx Context, w Writer, r Reader) {
+
+	go func(writer io.Writer, reader io.Reader) {
+
+		var buffer [1]byte // Seems like the length of the buffer needs to be small, otherwise will have to wait for buffer to fill up.
+		p := buffer[:]
+
+		for {
+			// Read 1 byte.
+			n, err := reader.Read(p)
+			if n <= 0 && nil == err {
+				continue
+			} else if n <= 0 && nil != err {
+				break
+			}
+
+			oi.LongWrite(writer, p)
+		}
+	}(stdout, r)
+
+
+
+	var buffer bytes.Buffer
+	var p []byte
+
+	var crlfBuffer [2]byte = [2]byte{'\r','\n'}
+	crlf := crlfBuffer[:]
+
+	scanner := bufio.NewScanner(stdin)
+	scanner.Split(scannerSplitFunc)
+
+	for scanner.Scan() {
+		buffer.Write(scanner.Bytes())
+		buffer.Write(crlf)
+
+		p = buffer.Bytes()
+
+		n, err := oi.LongWrite(w, p)
+		if nil != err {
+			break
+		}
+		if expected, actual := int64(len(p)), n; expected != actual {
+			err := fmt.Errorf("Transmission problem: tried sending %d bytes, but actually only sent %d bytes.", expected, actual)
+			fmt.Fprint(stderr, err.Error())
+			return
+		}
+
+
+		buffer.Reset()
+	}
+
+	// Wait a bit to receive data from the server (that we would send to io.Stdout).
+	time.Sleep(3 * time.Millisecond)
+}
+
+
+func scannerSplitFunc(data []byte, atEOF bool) (advance int, token []byte, err error) {
+	if atEOF {
+		return 0, nil, nil
+	}
+
+	return bufio.ScanLines(data, atEOF)
+}