Provide TypeScript typings for dnsconfig.js (#1830)

Co-authored-by: Jeffrey Cafferata <jeffrey@jcid.nl>
Co-authored-by: Tom Limoncelli <tlimoncelli@stackoverflow.com>

commands/writeTypes.go

@@ -0,0 +1,70 @@
+package commands
+
+import (
+	"io"
+	"net/http"
+	"os"
+	"strings"
+
+	versionInfo "github.com/StackExchange/dnscontrol/v3/pkg/version"
+	"github.com/urfave/cli/v2"
+)
+
+var _ = cmd(catUtils, func() *cli.Command {
+	var args TypesArgs
+	return &cli.Command{
+		Name:  "write-types",
+		Usage: "[BETA] Write a TypeScript declaration file in the current directory",
+		Action: func(c *cli.Context) error {
+			return exit(WriteTypes(args))
+		},
+		Flags: args.flags(),
+	}
+}())
+
+// TypesArgs stores arguments related to the types subcommand.
+type TypesArgs struct {
+	DTSFile string
+}
+
+func (args *TypesArgs) flags() []cli.Flag {
+	var flags []cli.Flag
+	flags = append(flags, &cli.StringFlag{
+		Name:        "dts-file",
+		Aliases:     []string{"o"},
+		Value:       "types-dnscontrol.d.ts",
+		Usage:       "Path to the .d.ts file to create",
+		Destination: &args.DTSFile,
+	})
+	return flags
+}
+
+func WriteTypes(args TypesArgs) error {
+	url := "https://raw.githubusercontent.com/StackExchange/dnscontrol/" + strings.Replace(versionInfo.SHA, "[dirty]", "", 1) + "/types/dnscontrol.d.ts"
+	print("Downloading " + url + " to " + args.DTSFile + "...")
+	defer print("\n")
+
+	resp, err := http.Get(url)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+
+	file, err := os.Create(args.DTSFile)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	file.WriteString("// This file was automatically generated by DNSControl. Do not edit it directly.\n")
+	file.WriteString("// To update it, run `dnscontrol write-types`.\n\n")
+	file.WriteString("// DNSControl version: " + versionInfo.Banner() + "\n")
+	file.WriteString("// Source: " + url + "\n\n")
+	_, err = io.Copy(file, resp.Body)
+	if err != nil {
+		return err
+	}
+
+	print(" done.")
+	return nil
+}