bookmarkService.go

package main

import (
	"encoding/json"
	"io/ioutil"
	"net/http"
	"os"
)

type SaveResponse struct {
	Status, Msg string
}

type Entry struct {
	Title, Url string
}

type EntryList struct {
	Entries map[string](Entry)
}

type ListStorageReader interface {
	Read() EntryList
}

type ListStorageWriter interface {
	Write(e Entry)
}

type ListStorageDeleter interface {
	DeleteEntry(title string)
}

type FileStorage struct {
	FileName string
}

func (f FileStorage) Read() EntryList {
	data, err := ioutil.ReadFile(f.FileName)
	if err != nil {
		emptyMap := make(map[string]Entry)
		return EntryList{emptyMap}
	}
	var entryList EntryList
	json.Unmarshal(data, &entryList)

	return entryList
}

func (f FileStorage) Write(e Entry) {
	existing := f.Read()
	existing.Entries[e.Title] = e
	data, _ := json.Marshal(existing)
	ioutil.WriteFile(f.FileName, data, os.ModePerm)
}

func (f FileStorage) DeleteEntry(title string) {
	existing := f.Read()
	if _, ok := existing.Entries[title]; ok == true {
		delete(existing.Entries, title)
		data, _ := json.Marshal(existing)
		ioutil.WriteFile(f.FileName, data, os.ModePerm)
	}
}

var storage = FileStorage{FileName: "data.json"}

func main() {
	http.HandleFunc("/save", save)
	http.HandleFunc("/list", list)
	http.HandleFunc("/delete", deleteEntry)
	http.ListenAndServe(":8080", nil)
}

func deleteEntry(w http.ResponseWriter, req *http.Request) {
	title := req.FormValue("title")
	if "" == title {
		w.Write(getFormattedSaveResponse("1", "No title given"))
		return
	}
	storage.DeleteEntry(title)
	w.Write(getFormattedSaveResponse("0", "Entry deleted"))
}

func list(w http.ResponseWriter, req *http.Request) {
	resp := storage.Read()
	jsonResp, _ := json.MarshalIndent(resp, "", "    ")
	w.Write([]byte(jsonResp))
}

func save(w http.ResponseWriter, req *http.Request) {
	title := req.FormValue("title")
	if "" == title {
		w.Write(getFormattedSaveResponse("1", "No title given"))
		return
	}
	url := req.FormValue("url")
	if "" == url {
		w.Write(getFormattedSaveResponse("1", "No url given"))
		return
	}
	storage.Write(Entry{Title: title, Url: url})
	w.Write(getFormattedSaveResponse("0", "Link Saved"))
}

func getFormattedSaveResponse(status, msg string) []byte {
	resp, _ := json.MarshalIndent(SaveResponse{Status: status, Msg: msg}, "", "    ")
	return []byte(resp)
}