FileUploadServer.go

package main

import (
	"bufio"
	"encoding/json"
	"errors"
	"fmt"
	"mime/multipart"
	"net/http"
	"os"
	"path"

	"github.com/gorilla/mux"
)

type FileInfo struct {
	Name      string `json:"name"`
	Extension string `json:"extension"`
}

type FileUploadRoute struct {
}

var scanner bufio.Scanner

func (t *FileUploadRoute) ServeHTTP(w http.ResponseWriter, r *http.Request) {

	err := r.ParseMultipartForm(r.ContentLength)

	if err != nil {
		w.WriteHeader(http.StatusBadGateway)
		w.Write([]byte("error pasing form"))
		return
	}

	var fileInfo FileInfo
	strJson := r.PostFormValue("fileinfo")
	file, header, filerr := r.FormFile("file")
	err = json.Unmarshal([]byte(strJson), &fileInfo)
	defer file.Close()

	if err != nil || filerr != nil {

		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	err = saveFile(file, header)

	if err != nil {
		fmt.Println(err)
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
}

func saveFile(file multipart.File, fileHeader *multipart.FileHeader) error {

	var saveFile *os.File
	reader := bufio.NewReader(file)
	scanner = *bufio.NewScanner(reader)
	scanner.Split(bufio.ScanBytes)
	fileNameStr := path.Join(".", "files", fileHeader.Filename)
	os.MkdirAll("./files", os.ModeDir)

	if _, fileError := os.Stat(fileNameStr); errors.Is(fileError, os.ErrNotExist) {
		saveFile, createError := os.Create(fileNameStr)

		if createError != nil {
			return createError
		}

		for scanner.Scan() {
			bytes := scanner.Bytes()
			saveFile.Write(bytes)
		}

	} else {

		//recreate or replace file? option

	}

	saveFile.Close()

	if scanErr := scanner.Err(); scanErr != nil {
		return scanErr
	} else {
		return nil
	}
}

func main() {

	router := mux.NewRouter()
	router.Handle("/uploadFile", &FileUploadRoute{}).Methods(http.MethodPost)
	http.ListenAndServe(":8000", router)
}