Okay, this is starting to look like something.

functions/fibonacci.go

@@ -0,0 +1,57 @@
+package functions
+
+import (
+	"fmt"
+	"net/http"
+	"strconv"
+)
+
+func HttpAbort(w http.ResponseWriter, code int, message string) {
+	w.WriteHeader(code)
+	fmt.Fprint(w, message)
+}
+
+func MyFibonacci(count int) (fibonaccivalue int) {
+	fibonaccivalue = 1
+	var prev_fibonacci int = 0
+
+	for i := 1; i < count; i++ {
+		fibonaccivalue += prev_fibonacci
+		prev_fibonacci = fibonaccivalue - prev_fibonacci
+	}
+	return
+}
+
+func HttFibonacci(w http.ResponseWriter, request *http.Request) {
+	switch request.Method {
+	case "POST":
+		error := request.ParseForm()
+		if error != nil {
+			fmt.Printf("Error parsing POST request: %s\n", error)
+			HttpAbort(w, http.StatusUnprocessableEntity,
+				"Unable to parse your POST request.\n")
+		} else {
+			s_seq := request.Form.Get("seq")
+			seq, error := strconv.Atoi(s_seq)
+			if error != nil {
+				fmt.Printf("Error parsing integer value out of %s: %s\n",
+					s_seq,
+					error)
+				HttpAbort(w, http.StatusExpectationFailed,
+					fmt.Sprintf("[%s] is not a number.\n", s_seq))
+			} else if seq < 1 {
+				fmt.Printf("Invalid sequence number: %d\n", seq)
+				HttpAbort(w, http.StatusBadRequest,
+					"Please provide a positive integer as the sequence number.\n")
+			} else {
+				fmt.Printf("Received request for Fibonacci Sequence Number %d\n",
+					seq)
+				fmt.Fprintf(w, "Fibonacci sequence index [%d]: %d\n",
+					seq, MyFibonacci(seq))
+			}
+		}
+	default:
+		HttpAbort(w, http.StatusMethodNotAllowed,
+			fmt.Sprintf("Operation %s not implemented for this URL", request.Method))
+	}
+}

go.mod

@@ -0,0 +1,3 @@
+module darjeeling.systemec.nl/rhouben/fibonacci
+
+go 1.24.4

main.go

@@ -0,0 +1,45 @@
+package main
+
+import (
+	"fmt"
+	"net/http"
+	"os"
+	"strconv"
+
+	"darjeeling.systemec.nl/rhouben/fibonacci/functions"
+)
+
+func MyFibonacci(count int) (fibonaccivalue int) {
+	fibonaccivalue = 1
+	var prev_fibonacci int = 0
+
+	for i := 1; i < count; i++ {
+		fibonaccivalue += prev_fibonacci
+		prev_fibonacci = fibonaccivalue - prev_fibonacci
+	}
+	return
+}
+
+func main() {
+	var port_number int
+	var error error
+	var bind_socket string
+	fmt.Println("Hello, world. I'm teaching myself Go.")
+
+	if len(os.Args) <= 1 {
+		port_number = 8088
+	} else {
+		port_number, error = strconv.Atoi(os.Args[1])
+
+		if error != nil {
+			fmt.Printf("I had an error trying to parse %s into a number: %s\n",
+				os.Args[1],
+				error)
+			os.Exit(0)
+		}
+	}
+	bind_socket = fmt.Sprintf(":%d", port_number)
+	http.HandleFunc("/fibonacci", functions.HttFibonacci)
+	fmt.Printf("Listening on port %d...", port_number)
+	http.ListenAndServe(bind_socket, nil)
+}