URL Shortening Service (Go)

Create short URLs, resolve shortened URLs, and fetch all shortened URLs.

• Development
• Short URL API
  • Base Config
  • Resolve URL
  • API: Create URL | Get URL | Get all URLs | Update URL | Delete URL

Development

• Create .env file from .env.example and populate with correct development variables
• go run cmd

Loosely based on Nic Jackson's microservice tutorials

Packages:

shorty

• Definitions of the business data, Link, used in the application

type Link struct {
  // Shortened URL result. Ex: https://ospk.org/bas12d21dc.
  ShortURL string `json:"shortUrl" bson:"shortUrl"`
  // Short Code used as the path of the short URL. Ex: bas12d21dc.
  Code string `json:"code" bson:"code"`
  // Optional custom short code passed when creating or updating the short URL.
  CustomCode string `json:"customCode" bson:"customCode"`
  // The URL where the short URL redirects.
  OriginalUrl string `json:"originalUrl" bson:"originalUrl"`
  // Count of times the short URL has been used.
  TotalClicks int `json:"totalClicks" bson:"totalClicks"`
  // Identifier of the entity that created the short URL.
  CreatedBy string `json:"createdBy" bson:"createdBy"`
  // DateTime the URL was created.
  CreatedAt time.Time `json:"createdAt" bson:"createdAt"`
  // DateTime the URL was last updated.
  UpdatedAt time.Time `json:"updatedAt" bson:"updatedAt"`
}

handlers

• HTTP route handlers that call the CRUD methods on the given store implementation.

func (s *ShortyService) createLink(w http.ResponseWriter, r *http.Request) {
  // Parse JSON body into a link
  linkInput.FromJSON(r.Body)

  // Error handling omitted for brevity...

	// Create and save the short link to the DB
	newLink, err := s.store.SaveLink(r.Context(), linkInput)

	// Send new link JSON
	if err = newLink.ToJSON(w); err != nil {
		http.Error(w, "Problem marshaling your short link", http.StatusInternalServerError)
	}
}

• Contains LinkStore interface to be implemented in data access layer(s).

type LinkStore interface {
  SaveLink(ctx context.Context, newLink shorty.Link) (shorty.Link, error)
  FindLink(ctx context.Context, code string) (shorty.Link, error)
  FindAllLinks(ctx context.Context) (shorty.Links, error)
  UpdateLink(ctx context.Context, code string, toUpdate shorty.Link) (shorty.Link, error)
  DeleteLink(ctx context.Context, code string) (int, error)
  CheckCodeInUse(ctx context.Context, code string) (bool, error)
  IncrementTotalClicks(ctx context.Context, code string) (int, error)
}

mongodb

• Data access layer, implemented for MongoDB

func (i *Store) SaveLink(ctx context.Context, newLink shorty.Link) (shorty.Link, error) {
	coll := i.Client.Database(i.DBName).Collection(i.LinksCollName)
	_, err := coll.InsertOne(ctx, newLink)
	if err != nil {
		return shorty.Link{}, fmt.Errorf("insertOne: %v", err)
	}
	return newLink, nil
}

inmem

• Data access layer implemented for an in-memory store for simpler API testing

func (i *Store) SaveLink(ctx context.Context, newLink shorty.Link) (shorty.Link, error) {
	i.lock.Lock()
	defer i.lock.Unlock()

	i.Store[newLink.Code] = newLink
	return newLink, nil
}

function

• Entrypoint in to the Cloud function
• All packages tied together here:

func init() {
	functions.HTTP("ServeShorty", NewMux().ServeHTTP)
}

var store shorty.ShortyStore

func NewMux() *http.ServeMux {
  mongoURI := os.Getenv("MONGO_URI")
	store, err := mongodb.NewStore(mongodb.StoreOpts{URI: mongoURI})
	if err != nil {
		panic(err)
	}

	baseURL := os.Getenv("HOST_BASE_URL")
	apiKey := os.Getenv("API_KEY")

	service := handlers.NewAPIService(store, baseURL, apiKey)
	return handlers.NewServer(service)
}

Tests

If you already have a local MongoDB server running, you can use it for the tests.

$ go test

The tests can alternatively use docker to build and start a MongoDB service for you. Note: This will take a bit longer (30-60s).

$ go test --tags=integration

You can view your test coverage in a browser:

$ go-acc --covermode=count -o=coverage.out $(go list ./...)
$ go tool cover -html=coverage.out

---

API

Base config

API key is required on all requests, not including GET /:code to resolve the short URL.

• Base URL: https://ospk.org
• Headers: { "key": "API_KEY" }

Resolve short URL

GET /:code
Response: 301 permanent redirect

Create short URL (authenticated)

POST      /api/urls
Headers:   key=$API_KEY
Body:     { "originalUrl": "https://..." }
Response: "https://ospk.org/:code"

Request body properties

Key	Type	Required	Description
originalUrl	string	true	Original URL
customCode	string		Custom endpoint - Defaults to code
createdBy	string		User or bot that created the link

---

Fetch URL (authenticated)

Fetch short URL object

GET /api/urls/:code
Headers:   key=$API_KEY

Example Response:

• See Short URL Properties for more details

{
  "code": "a1b2c3d4e5",
  "customCode": "a1b2c3d4e5",
  "shortUrl": "https://ospk.org/a1b2c3d4e5",
  "originalUrl": "https://oparationspark.org/infoSession",
  "totalClicks": 0,
  "createdBy": "user name",
  "createdAt": "2022-10-21T03:17:15.400Z",
  "updatedAt": "2022-10-21T03:17:15.400Z"
}

---

Fetch all URLs (authenticated)

GET /api/urls
Headers:   key=$API_KEY

Example Response:

• See Short URL Properties for more details

[
  {"..."},

  {
    "code": "a1b2c3d4e5",
    "customCode": "signup",
    "shortUrl": "https://ospk.org/signup",
    "originalUrl": "https://oparationspark.org/infoSession",
    "totalClicks": 0,
    "createdBy": "user name",
    "createdAt": "2022-10-21T03:17:15.400Z",
    "updatedAt": "2022-10-21T03:17:15.400Z"
  },

  {"..."}
]

Update URL (authenticated)

PUT /api/urls/:code

Request body properties

Key	Type	Description
originalUrl	string	Original URL
customCode	string	Custom endpoint - Defaults to code
createdBy	string	User or bot that created the link

Example Request Body:

• See Short URL Properties for more details

{
  "customCode": "info",
  "originalUrl": "https://oparationspark.org/info-session",
  "createdBy": "User Name"
}

Example Response:

• See Short URL Properties for more details

{
  "code": "a1b2c3d4e5",
  "customCode": "a1b2c3d4e5",
  "shortUrl": "https://ospk.org/a1b2c3d4e5",
  "originalUrl": "https://oparationspark.org/info-session",
  "totalClicks": 0,
  "createdBy": "User Name",
  "createdAt": "2022-10-21T03:17:15.400Z",
  "updatedAt": "2022-10-21T03:17:15.400Z"
}

Delete URL (authenticated)

DELETE /api/urls/:code
Headers:   key=$API_KEY
Response Status: 200 | 404

Short URL Properties

Key	Type	Edit	Description
code	string		randomized 10 character code
customCode	string	true	custom endpoint - Defaults to code
shortUrl	string		short url
originalUrl	string	true	Full URL originally provided
createdBy	string	true	User or bot that created the link
totalClicks	number		Total clicks (Allows duplicates)
createdAt	Date		Date created
updatedAt	Date		Date last modified