Add examples

.gitignore

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+.DS_Store
+.idea

LICENSE

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+MIT License
+
+Copyright (c) 2018 Kat
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

domain-driven-hex/Gopkg.toml

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+[[constraint]]
+  name = "github.com/julienschmidt/httprouter"
+  version = "1.1.0"

domain-driven-hex/cmd/data/main.go

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+package main
+
+import (
+	"fmt"
+
+	"github.com/katzien/structure-examples/domain-driven/storage"
+	"github.com/katzien/structure-examples/domain-driven/adding"
+	"github.com/katzien/structure-examples/domain-driven/reviewing"
+)
+
+func main() {
+
+	// error handling omitted for simplicity
+	beersStorage, _ := storage.NewJSONBeerStorage()
+	reviewsStorage, _ := storage.NewJSONReviewStorage()
+
+	// create the available services
+	adder := adding.NewService(beersStorage)
+	reviewer := reviewing.NewService(reviewsStorage)
+
+	// add some sample data
+	adder.AddSampleBeers()
+	reviewer.AddSampleReviews()
+
+	fmt.Println("Finished adding sample data.")
+}

domain-driven-hex/cmd/server/main.go

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+package main
+
+import (
+	"fmt"
+	"log"
+	"net/http"
+
+	"github.com/julienschmidt/httprouter"
+	"github.com/katzien/structure-examples/domain-driven/beers"
+	"github.com/katzien/structure-examples/domain-driven/reviews"
+	"github.com/katzien/structure-examples/domain-driven/storage"
+	"github.com/katzien/structure-examples/domain-driven/adding"
+	"github.com/katzien/structure-examples/domain-driven/reviewing"
+	"github.com/katzien/structure-examples/domain-driven/listing"
+)
+
+func main() {
+
+	// set up storage
+	storageType := storage.InMemory // this could be a flag; hardcoded here for simplicity
+
+	var beersStorage beers.Repository
+	var reviewsStorage reviews.Repository
+
+	switch storageType {
+	case storage.InMemory:
+		beersStorage = new(storage.MemoryBeerStorage)
+		reviewsStorage = new(storage.MemoryReviewStorage)
+	case storage.JSONFiles:
+		// error handling omitted for simplicity
+		beersStorage, _ = storage.NewJSONBeerStorage();
+		reviewsStorage, _ = storage.NewJSONReviewStorage();
+	}
+
+	// create the available services
+	adder := adding.NewService(beersStorage)
+	reviewer := reviewing.NewService(reviewsStorage)
+	lister := listing.NewService(beersStorage, reviewsStorage)
+
+	// add some sample data
+	adder.AddSampleBeers()
+	reviewer.AddSampleReviews()
+
+	// set up the HTTP server
+	router := httprouter.New()
+
+	router.GET("/beers", listing.MakeGetBeersEndpoint(lister))
+	router.GET("/beers/:id", listing.MakeGetBeerEndpoint(lister))
+	router.GET("/beers/:id/reviews", listing.MakeGetBeerReviewsEndpoint(lister))
+
+	router.POST("/beers", adding.MakeAddBeerEndpoint(adder))
+	router.POST("/beers/:id/reviews", reviewing.MakeAddBeerReviewEndpoint(reviewer))
+
+	fmt.Println("The beer server is on tap now: http://localhost:8080")
+	log.Fatal(http.ListenAndServe(":8080", router))
+}

domain-driven-hex/pkg/adding/endpoint.go

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+package adding
+
+import (
+	"github.com/julienschmidt/httprouter"
+	"net/http"
+	"encoding/json"
+	"github.com/katzien/structure-examples/domain-driven/beers"
+)
+
+// MakeAddBeerEndpoint creates a handler for POST /beers requests
+func MakeAddBeerEndpoint(s Service) func(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
+	return func(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
+		decoder := json.NewDecoder(r.Body)
+
+		var newBeer beers.Beer
+		err := decoder.Decode(&newBeer)
+		if err != nil {
+			http.Error(w, "Bad beer - this will be a HTTP status code soon!", http.StatusBadRequest)
+			return
+		}
+
+		s.AddBeer(newBeer)
+
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode("New beer added.")
+	}
+}

domain-driven-hex/pkg/adding/service.go

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+package adding
+
+import (
+	"github.com/katzien/structure-examples/domain-driven/beers"
+)
+
+// Service provides beer or review adding operations
+type Service interface {
+	AddBeer(b ...beers.Beer)
+	AddSampleBeers()
+}
+
+type service struct {
+	bR beers.Repository
+}
+
+// NewService creates an adding service with the necessary dependencies
+func NewService(bR beers.Repository) Service {
+	return &service{bR}
+}
+
+// AddBeer adds the given beer(s) to the database
+func (s *service) AddBeer(b ...beers.Beer) {
+	for _, beer := range b {
+		_ = s.bR.Add(beer) // error handling omitted for simplicity
+	}
+}
+
+// AddSampleBeers adds some sample beers to the database
+func (s *service) AddSampleBeers() {
+	for _, b := range beers.DefaultBeers {
+		_ = s.bR.Add(b) // error handling omitted for simplicity
+	}
+}

domain-driven-hex/pkg/beers/beer.go

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+package beers
+
+import (
+	"time"
+	"errors"
+)
+
+// Beer defines the properties of a reviewable beer
+type Beer struct {
+	ID        int       `json:"id"`
+	Name      string    `json:"name"`
+	Brewery   string    `json:"brewery"`
+	Abv       float32   `json:"abv"`
+	ShortDesc string    `json:"short_description"`
+	Created   time.Time `json:"created"`
+}
+
+// ErrUnknown is used when a beer could not be found.
+var ErrUnknown = errors.New("unknown beer")
+var ErrDuplicate = errors.New("beer already exists")
+
+// Repository provides access to the list of beers.
+type Repository interface {
+	GetAll() []Beer
+	Get(id int) (Beer, error)
+	Add(Beer) error
+}

domain-driven-hex/pkg/beers/sample_beers.go

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+package beers
+
+import "time"
+
+var DefaultBeers = []Beer{
+	{
+		ID:      1,
+		Name:    "Pliny the Elder",
+		Brewery: "Russian River Brewing Company",
+		Abv:     8,
+		ShortDesc: "Pliny the Elder is brewed with Amarillo, " +
+			"Centennial, CTZ, and Simcoe hops. It is well-balanced with " +
+			"malt, hops, and alcohol, slightly bitter with a fresh hop " +
+			"aroma of floral, citrus, and pine.",
+		Created: time.Date(2017, time.October, 24, 22, 6, 0, 0, time.UTC),
+	},
+	{
+		ID:      2,
+		Name:    "Oatmeal Stout",
+		Brewery: "Samuel Smith",
+		Abv:     5,
+		ShortDesc: "Brewed with well water (the original well at the " +
+			"Old Brewery, sunk in 1758, is still in use, with the hard well " +
+			"water being drawn from 85 feet underground); fermented in " +
+			"‘stone Yorkshire squares’ to create an almost opaque, " +
+			"wonderfully silky and smooth textured ale with a complex " +
+			"medium dry palate and bittersweet finish.",
+		Created: time.Date(2017, time.October, 24, 22, 12, 0, 0, time.UTC),
+	},
+	{
+		ID:      3,
+		Name:    "Märzen",
+		Brewery: "Schlenkerla",
+		Abv:     5,
+		ShortDesc: "Bamberg's speciality, a dark, bottom fermented " +
+			"smokebeer, brewed with Original Schlenkerla Smokemalt from " +
+			"the Schlenkerla maltings and tapped according to old tradition " +
+			"directly from the gravity-fed oakwood cask in the historical " +
+			"brewery tavern.",
+		Created: time.Date(2017, time.October, 24, 22, 17, 0, 0, time.UTC),
+	},
+	{
+		ID:      4,
+		Name:    "Duvel",
+		Brewery: "Duvel Moortgat",
+		Abv:     9,
+		ShortDesc: "A Duvel is still seen as the reference among strong " +
+			"golden ales. Its bouquet is lively and tickles the nose with an " +
+			"element of citrus which even tends towards grapefruit thanks to " +
+			"the use of only the highest-quality hop varieties.",
+		Created: time.Date(2017, time.October, 24, 22, 24, 0, 0, time.UTC),
+	},
+	{
+		ID:      5,
+		Name:    "Negra",
+		Brewery: "Modelo",
+		Abv:     5,
+		ShortDesc: "Brewed longer to enhance the flavors, this Munich " +
+			"Dunkel-style Lager gives way to a rich flavor and remarkably " +
+			"smooth taste.",
+		Created: time.Date(2017, time.October, 24, 22, 27, 0, 0, time.UTC),
+	},
+	{
+		ID:      6,
+		Name:    "Guinness Draught",
+		Brewery: "Guinness Ltd.",
+		Abv:     4,
+		ShortDesc: "Pours dark brown, almost black with solid lasting light brown head. " +
+			"Aroma of bitter cocoa, light coffee and roasted malt. " +
+			"Body is light sweet, medium bitter. " +
+			"Body is light to medium, texture almost thin and carbonation average. " +
+			"Finish is medium bitter cocoa with more pronounced roast flavor. Smooth drinker.",
+		Created: time.Date(2017, time.October, 24, 22, 27, 0, 0, time.UTC),
+	},
+	{
+		ID:      7,
+		Name:    "XX Lager",
+		Brewery: "Cuahutemoc Moctezuma",
+		Abv:     4.2,
+		ShortDesc: "A crisp, refreshing, light-bodied malt-flavored beer with a well-balanced finish. " +
+			"A Lager that drinks like a Pilsner. A liquid embodiment of living life to the fullest. " +
+			"A beverage made from pure spring water and the choicest hops. A beer with such good taste, it’s chosen you to drink it.",
+		Created: time.Date(2017, time.October, 28, 15, 02, 0, 0, time.UTC),
+	},
+	{
+		ID:      8,
+		Name:    "Tecate",
+		Brewery: "Cuahutemoc Moctezuma",
+		Abv:     5,
+		ShortDesc: "Very smooth, medium bodied brew. Malt sweetness is thin, and can be likened to diluted sugar water. " +
+			"Touch of fructose-like sweetness. Light citric hop flavours gently prick the palate with tea-like notes that follow and fade quickly. " +
+			"Finishes a bit dry with husk tannins and a pasty mouthfeel.",
+		Created: time.Date(2017, time.October, 28, 15, 07, 0, 0, time.UTC),
+	},
+	{
+		ID:      9,
+		Name:    "Sol",
+		Brewery: "Cuahutemoc Moctezuma",
+		Abv:     5,
+		ShortDesc: "While Corona wins the marketing wars in the U.S., Sol is the winning brand in much of Mexico, despite not being a standout in any respect. " +
+			"You see the logo plastered everywhere and it’s seemingly on every restaurant and bar menu. Like Corona, it’s simple and inoffensive, " +
+			"but still slightly more flavorful than your typical American macrobrew. At its best ice cold, and progressively worse as it gets warmer.",
+		Created: time.Date(2017, time.October, 28, 15, 12, 0, 0, time.UTC),
+	},
+	{
+		ID:      10,
+		Name:    "Corona",
+		Brewery: "Cuahutemoc Moctezuma",
+		Abv:     5,
+		ShortDesc: "One of the five best-selling beers in the world, but it usually tastes better in Mexico, " +
+			"where the bottles don’t have so much time in transit and on shelves. (Sunlight coming through clear bottles is never a good thing for beer.) " +
+			"This is the typical “drink all afternoon” beer, working well on its own or with a plate of tacos. Refreshing with a lime.",
+		Created: time.Date(2017, time.October, 28, 15, 14, 0, 0, time.UTC),
+	},
+}

domain-driven-hex/pkg/listing/endpoint.go

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+package listing
+
+import (
+	"github.com/julienschmidt/httprouter"
+	"net/http"
+	"encoding/json"
+	"strconv"
+	"fmt"
+	"github.com/katzien/structure-examples/domain-driven/beers"
+)
+
+type Handler func(http.ResponseWriter, *http.Request, httprouter.Params)
+
+// MakeAddBeerEndpoint creates a handler for GET /beers requests
+func MakeGetBeersEndpoint(s Service) func(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
+	return func(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
+		w.Header().Set("Content-Type", "application/json")
+		list := s.GetBeers()
+		json.NewEncoder(w).Encode(list)
+	}
+}
+
+// MakeAddBeeEndpoint creates a handler for GET /beers/:id requests
+func MakeGetBeerEndpoint(s Service) func(w http.ResponseWriter, r *http.Request, p httprouter.Params) {
+	return func(w http.ResponseWriter, r *http.Request, p httprouter.Params) {
+		ID, err := strconv.Atoi(p.ByName("id"))
+		if err != nil {
+			http.Error(w, fmt.Sprintf("%s is not a valid beer ID, it must be a number.", p.ByName("id")), http.StatusBadRequest)
+			return
+		}
+
+		beer, err := s.GetBeer(ID)
+		if err == beers.ErrUnknown {
+			http.Error(w, "The beer you requested does not exist.", http.StatusNotFound)
+			return
+		}
+
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(beer)
+	}
+}
+
+// MakeGetBeerReviewsEndpoint creates a handler for GET /beers/:id/reviews requests
+func MakeGetBeerReviewsEndpoint(s Service) func(w http.ResponseWriter, r *http.Request, p httprouter.Params) {
+	return func(w http.ResponseWriter, r *http.Request, p httprouter.Params) {
+		ID, err := strconv.Atoi(p.ByName("id"))
+		if err != nil {
+			http.Error(w, fmt.Sprintf("%s is not a valid beer ID, it must be a number.", p.ByName("id")), http.StatusBadRequest)
+			return
+		}
+
+		reviews, err := s.GetBeerReviews(ID)
+		if err != nil {
+			http.Error(w, fmt.Sprintf("%s is not a valid beer ID.", p.ByName("id")), http.StatusBadRequest)
+			return
+		}
+
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(reviews)
+	}
+}