fix url check wrong detection of absolute windows path

cmd/root.go

@@ -9,6 +9,7 @@ import (
 	"github.com/nothub/mrpack-install/server"
 	"github.com/nothub/mrpack-install/update"
 	"github.com/nothub/mrpack-install/util"
+	"github.com/nothub/mrpack-install/web"
 	"github.com/spf13/cobra"
 	"log"
 	"os"
@@ -106,7 +107,7 @@ var rootCmd = &cobra.Command{
 		}
 
 		archivePath := ""
-		if util.IsValidUrl(input) {
+		if web.IsValidHttpUrl(input) {
 			fmt.Println("Downloading mrpack file from", args)
 			file, err := requester.DefaultHttpClient.DownloadFile(input, serverDir, "")
 			if err != nil {

cmd/update.go

@@ -6,6 +6,7 @@ import (
 	"github.com/nothub/mrpack-install/requester"
 	"github.com/nothub/mrpack-install/update"
 	"github.com/nothub/mrpack-install/util"
+	"github.com/nothub/mrpack-install/web"
 	"github.com/spf13/cobra"
 	"log"
 	"os"
@@ -74,7 +75,7 @@ var updateCmd = &cobra.Command{
 		if util.PathIsFile(input) {
 			archivePath = input
 
-		} else if util.IsValidUrl(input) {
+		} else if web.IsValidHttpUrl(input) {
 			fmt.Println("Downloading mrpack file from", args)
 			file, err := requester.DefaultHttpClient.DownloadFile(input, serverDir, "")
 			if err != nil {

web/url.go

@@ -0,0 +1,11 @@
+package web
+
+import "net/url"
+
+func IsValidHttpUrl(s string) bool {
+	u, err := url.Parse(s)
+	if err != nil {
+		return false
+	}
+	return u.Scheme == "http" || u.Scheme == "https"
+}

web/url_test.go

@@ -0,0 +1,28 @@
+package web
+
+import "testing"
+
+func TestIsValidHttpUrl(t *testing.T) {
+	type testCase struct {
+		url  string
+		want bool
+	}
+
+	cases := []testCase{
+		{url: "C:\\Foo\\Bar", want: false},
+		{url: "C://Foo//Bar", want: false},
+		{url: "http://example.org", want: true},
+		{url: "https://example.org", want: true},
+		{url: "https://example.org\n", want: false},
+		{url: "https://example.org/foo/bar", want: true},
+		{url: "https://example.org/foo/bar?x=y", want: true},
+	}
+
+	for _, c := range cases {
+		t.Run(c.url, func(t *testing.T) {
+			if got := IsValidHttpUrl(c.url); got != c.want {
+				t.Errorf("IsValidUrl() = %v, want %v", got, c.want)
+			}
+		})
+	}
+}