Serve video file via http and tell your Kodi instance to play the served file

config.toml

Host="192.168.1.100"
Port=8080
User="your-username"
Pass="your-password"

main.go

package main

import (
	"bytes"
	"fmt"
	"io/ioutil"
	"log"
	"net"
	"net/http"
	"net/url"
	"os"
	"path/filepath"
	"strconv"
	"time"

	toml "github.com/pelletier/go-toml"
	kingpin "gopkg.in/alecthomas/kingpin.v2"
)

var (
	file            = kingpin.Arg("file", "Video file to play").Required().ExistingFile()
	localServerPort = kingpin.Flag("local-server-port", "Which port to host the local HTTP server on").Short('l').Default("8080").Int()
	config          = Config{}
)

type Config struct {
	Host string
	Port int
	User string
	Pass string
}

func sendURL(file string) {
	localIP := getOutboundIP()

	url := "http://" + localIP + ":" + strconv.Itoa(*localServerPort) + "/" + url.PathEscape(file)
	remoteUrl := "http://" + config.Host + ":" + strconv.Itoa(config.Port) + "/jsonrpc"

	client := http.Client{
		Timeout: 10 * time.Second,
	}

	reqBody := `
	{
		"params": {
			"item": {
				"file": "` + url + `"
			}
		},
		"jsonrpc": "2.0",
		"method": "Player.Open",
		"id": 1
	}`
	// fmt.Println(reqBody)
	req, err := http.NewRequest("POST", remoteUrl, bytes.NewBuffer([]byte(reqBody)))
	if err != nil {
		log.Fatalln(err)
	}

	req.Header.Add("Content-Type", "application/json")
	req.SetBasicAuth(config.User, config.Pass)

	resp, err := client.Do(req)
	if err != nil {
		log.Fatalln(err)
	}
	defer resp.Body.Close()
	body, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		print(err)
	}
	fmt.Println(string(body))
}

func getOutboundIP() string {
	conn, err := net.Dial("udp", "8.8.8.8:80")
	if err != nil {
		log.Fatal(err)
	}
	defer conn.Close()

	localAddr := conn.LocalAddr().(*net.UDPAddr)

	return localAddr.IP.String()
}

func readConfig() error {
	path := filepath.Join(os.Getenv("HOME"), ".config/send-to-kodi/config.toml")
	configFile, err := ioutil.ReadFile(path)
	if err != nil {
		log.Fatal(err)
	}
	err = toml.Unmarshal(configFile, &config)
	if err != nil {
		log.Fatal(err)
	}
	return nil
}

func main() {
	kingpin.Parse()
	readConfig()

	filePath := (*file)
	fileName := filepath.Base(filePath)
	http.HandleFunc("/"+fileName, func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, filePath)
	})

	go func() {
		sendURL(fileName)
		fmt.Println("serving ...")
	}()

	http.ListenAndServe(":"+strconv.Itoa(*localServerPort), nil)
}