shrty/short/shrt.go

package shrt

import (
	"bytes"
	"crypto/sha256"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/url"
	"os"
	"time"
)

type Storage struct {
	Token map[string]*Shrt  `json:"token"`
	Url   map[string]string `json:"url"`
}

type Shrt struct {
	URL   string `json:"url"`
	Date string `json:"datum"`
	Clicks int64  `json:"clicks"`
}

var (
	ErrNotFound    = errors.New("Url not Found")
	ErrCreateToken = errors.New("There are some problems while creating Token")
	ErrNoUrl       = errors.New("String is no Url!")
)

// Open up
func Open(path string) (*Storage, error) {
	s := Storage{Token: make(map[string]*Shrt), Url: make(map[string]string)}
	// Open db ore create if not exist!
	if db, err := os.OpenFile(path, os.O_RDWR|os.O_CREATE, 0644); err == nil {
		json.Unmarshal(StreamToByte(db), &s)
		db.Close()
		return &s, nil
	} else {
		return &s, err
	}
}

func (s *Storage) Short(URL string, value *string) error {
	// Check if it is a valide Url found on:
	// http://stackoverflow.com/questions/31480710/validate-url-with-standard-package-in-go
	_, err := url.ParseRequestURI(URL)
	if err != nil {
		return ErrNoUrl
	}

	// Create a sha256 Hash from the URL
	hash := fmt.Sprintf("%x", sha256.Sum256([]byte(URL)))

	// Test if the URL alraedy exist and return the key
	if val, ok := s.Url[hash]; ok {
                value = &val
		return nil
	}
	// Iterate to the length of hash to get the shortest output
	for hashShortestLen := 1; hashShortestLen <= 32; hashShortestLen++ {
		// Test if the Token not exist and return the new generated token
		if _, ok := s.Token[hash[:hashShortestLen]]; !ok {
			token := hash[:hashShortestLen]
			t := time.Now()
			s.Token[token] = &Shrt{
				URL:   URL,
				Date: t.String(),
			}
			s.Url[hash] = token
			*value = s.Url[hash]
			s.Save()
			return nil
		}
	}

	return ErrCreateToken
}

func (s *Storage) Add(URL string, value *string) (string, error) {
	// Check if it is a valide Url found on:
	// http://stackoverflow.com/questions/31480710/validate-url-with-standard-package-in-go
	_, err := url.ParseRequestURI(URL)
	if err != nil {
		return "", ErrNoUrl
	}

	// Create a sha256 Hash from the URL
	hash := fmt.Sprintf("%x", sha256.Sum256([]byte(URL)))

	// Test if the URL alraedy exist and return the key
	if val, ok := s.Url[hash]; ok {
		return val, nil
	}
	// Iterate to the length of hash to get the shortest output
	for hashShortestLen := 1; hashShortestLen <= 32; hashShortestLen++ {
		// Test if the Token not exist and return the new generated token
		if _, ok := s.Token[hash[:hashShortestLen]]; !ok {
			token := hash[:hashShortestLen]
			t := time.Now()
			s.Token[token] = &Shrt{
				URL:   URL,
				Date: t.String(),
			}
			s.Url[hash] = token
			*value = s.Url[hash]
			s.Save()
			return token, nil
		}
	}

	return "", ErrCreateToken
}

func (s *Storage) Remove(URL string) error {
	return nil
}

// Get returns the URL for the given token
func (s *Storage) Get(token string) (string, bool) {
	if shrt, ok := s.Token[token]; ok {
		fmt.Printf("Url mit dem Token %s gefunden: %s \n", token, shrt.URL)
		s.Token[token].Clicks += 1
		s.Save()
		return shrt.URL, true
	}
	return "", false
}

// Get returns the URL for the given token
func (s *Storage) GetAPI(token string, value *Shrt) bool {
  if shrt, ok := s.Token[token]; ok {
    *value = *shrt
    return true
  }
  return false
}

// Get all entries
func (s *Storage) All() string {
	b, err := json.Marshal(&s)
	if err != nil {
		return ""
	}
	return string(b)
}

func (s *Storage) Save() error {
	if db, err := os.OpenFile("./test.db", os.O_RDWR|os.O_CREATE, 0644); err == nil {
		b, err := json.Marshal(&s)
		db.Write(b)
		db.Close()
		return err
	} else {
		return err
	}
}

func StreamToByte(stream io.Reader) []byte {
	buf := new(bytes.Buffer)
	buf.ReadFrom(stream)
	return buf.Bytes()
}