Add a Windows specific function to scrape the route table for the IP address from the default route.

1 files changed, 76 insertions, 0 deletions

diff --git a/cmd/web/windows.go b/cmd/web/windows.go
index 76491f1..d7e32d2 100644
--- a/cmd/web/windows.go
+++ b/cmd/web/windows.go
@@ -2,6 +2,16 @@
 
 package main
 
+import (
+	"bufio"
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
+	"os/exec"
+	"regexp"
+)
+
 // DefaultLib path for the operating system in question
 var DefaultLib string = `C:\Program Files (x86)\Steam\steamapps`
 
@@ -10,3 +20,69 @@ var DefaultLib string = `C:\Program Files (x86)\Steam\steamapps`
 func BrowserCommand(url string) []string {
 	return []string{"cmd", "/c", "start", url}
 }
+
+func GetHostIP() string {
+	s, err := GetHostIPFromRoutes()
+	if err != nil {
+		panic(err)
+	}
+	return s
+}
+
+// GetHostIPFromRoutes is a terrible little function to scrape up the
+// information about the route table and return the IP address associated with
+// the default route
+func GetHostIPFromRoutes() (string, error) {
+	spaceRe := regexp.MustCompile("  *")
+
+	c := exec.Command("route", "print", "-4")
+
+	b, err := c.Output()
+	if err != nil {
+		return "", err
+	}
+
+	rdr := bufio.NewReader(bytes.NewBuffer(b))
+
+	net := false
+	for {
+		l, err := rdr.ReadBytes('\n')
+		if err == io.EOF {
+			break
+		} else if err != nil {
+			return "", err
+		}
+
+		fmt.Println(string(l))
+
+		if bytes.HasPrefix(l, []byte("Network Destination")) && !net {
+			net = true
+			continue
+		}
+
+		if net && bytes.HasPrefix(l, []byte("=")) {
+			break
+		}
+
+		if net == false {
+			continue
+		}
+
+		fmt.Println("Before: ", string(l))
+
+		l = spaceRe.ReplaceAll(l, []byte{' '})
+		l = bytes.TrimPrefix(l, []byte{' '})
+
+		fields := bytes.Split(l, []byte(" "))
+
+		if len(fields) < 5 {
+			return "", errors.New("Less than five fields")
+		}
+
+		if bytes.Equal(fields[0], []byte("0.0.0.0")) {
+			return string(fields[3]), nil
+		}
+	}
+
+	return "", errors.New("Unable to parse IP from route table")
+}