Initial implementation

ifconfig.go

@@ -0,0 +1,44 @@
+package main
+
+import (
+    "fmt"
+    "io"
+    "log"
+    "net"
+    "net/http"
+    "regexp"
+)
+
+func isCli(userAgent string) bool {
+    match, _ := regexp.MatchString("^(?i)(curl|wget|fetch\\slibfetch)\\/.*$",
+        userAgent)
+    return match
+}
+
+func handler(w http.ResponseWriter, req *http.Request) {
+    if req.Method != "GET" {
+        http.Error(w, "Invalid request method", 405)
+        return
+    }
+
+    host, _, err := net.SplitHostPort(req.RemoteAddr)
+    if err != nil {
+        log.Printf("Failed to parse remote address: %s\n", req.RemoteAddr)
+        http.Error(w, "Failed to parse remote address", 500)
+        return
+    }
+
+    if isCli(req.UserAgent()) {
+        io.WriteString(w, fmt.Sprintf("%s\n", host))
+    } else {
+        // XXX: Render HTML
+    }
+}
+
+func main() {
+    http.HandleFunc("/", handler)
+    err := http.ListenAndServe(":8080", nil)
+    if err != nil {
+        log.Fatal("ListenAndServe: ", err)
+    }
+}