Gopher Api created for respective article on the blog

Author: aperezg

README.md

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+# Gopher API
+The Gopher API, is a simple CRUD API for formative purpose, we're building it while writing the posts of the [blog](https://blog.friendsofgo.tech).
+
+## How can I use it?
+
+**Install**
+
+```sh
+$ go get -u github.com/friendsofgo/gopherapi/cmd/gopherapi
+```
+
+**Usage**
+Launch server with predefined data
+
+```sh
+$ gopherapi --withData
+The gopher server is on tap now: http://localhost:8080
+```
+
+## Endpoints
+
+Fetch all gophers
+
+```
+GET /gophers
+```
+
+Fetch a gopher by ID
+
+```
+GET /gophers/{gopher_id}
+```
+
+## Contributing
+If you think that you can improve with new endpoints, and functionallities the API feel free to contribute with this project with fork this repo and send your Pull Request.
+
+## License
+MIT License, see [LICENSE](https://github.com/friendsofgo/gopherapi/blob/master/LICENSE)
+

cmd/gopherapi/main.go

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+package main
+
+import (
+	"flag"
+	"fmt"
+	"log"
+	"net/http"
+
+	"github.com/friendsofgo/gopher-api/pkg/storage/inmem"
+
+	sample "github.com/friendsofgo/gopher-api/cmd/sample-data"
+	gopher "github.com/friendsofgo/gopher-api/pkg"
+
+	"github.com/friendsofgo/gopher-api/pkg/server"
+)
+
+func main() {
+	withData := flag.Bool("withData", false, "initialize the api with some gophers")
+	flag.Parse()
+
+	var gophers map[string]*gopher.Gopher
+	if *withData {
+		gophers = sample.Gophers
+	}
+
+	repo := inmem.NewGopherRepository(gophers)
+	s := server.New(repo)
+
+	fmt.Println("The gopher server is on tap now: http://localhost:8080")
+	log.Fatal(http.ListenAndServe(":8080", s.Router()))
+}

cmd/sample-data/data.go

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+package sample
+
+import (
+	gopher "github.com/friendsofgo/gopher-api/pkg"
+)
+
+var Gophers = map[string]*gopher.Gopher{
+	"01D3XZ3ZHCP3KG9VT4FGAD8KDR": &gopher.Gopher{
+		ID:    "01D3XZ3ZHCP3KG9VT4FGAD8KDR",
+		Name:  "Jenny",
+		Age:   18,
+		Image: "https://storage.googleapis.com/gopherizeme.appspot.com/gophers/0ceb2c10fc0c30575c18ff1defa1ffd41501bc62.png",
+	},
+	"01D3XZ7CN92AKS9HAPSZ4D5DP9": &gopher.Gopher{
+		ID:    "01D3XZ7CN92AKS9HAPSZ4D5DP9",
+		Name:  "Billy",
+		Age:   24,
+		Image: "https://storage.googleapis.com/gopherizeme.appspot.com/gophers/13c7d425111a501600db8587b52bb292836c5bee.png",
+	},
+	"01D3XZ89NFJZ9QT2DHVD462AC2": &gopher.Gopher{
+		ID:    "01D3XZ89NFJZ9QT2DHVD462AC2",
+		Name:  "Rainbow",
+		Age:   48,
+		Image: "https://storage.googleapis.com/gopherizeme.appspot.com/gophers/b9e8d637c91c089fd56d7b159825fc9089377118.png",
+	},
+	"01D3XZ8JXHTDA6XY05EVJVE9Z2": &gopher.Gopher{
+		ID:    "01D3XZ8JXHTDA6XY05EVJVE9Z2",
+		Name:  "Bjorn",
+		Age:   32,
+		Image: "https://storage.googleapis.com/gopherizeme.appspot.com/gophers/fd01b36091560c2a128b8fddfb2c627d8bb7417c.png",
+	},
+}

go.mod

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+module github.com/friendsofgo/gopher-api
+
+require (
+	github.com/aperezg/monster v0.0.0-20190201085025-648ece19f831
+	github.com/gorilla/mux v1.7.0
+)

go.sum

@@ -0,0 +1,7 @@
+github.com/aperezg/monster v0.0.0-20190201085025-648ece19f831 h1:zcVrTQ22nmJ1+0sp9Lc7OuAMkNqqbEy/3OKXiWB2ods=
+github.com/aperezg/monster v0.0.0-20190201085025-648ece19f831/go.mod h1:59SPFI3k23yeORvJqB1py+ZSdAgQKVaPAMZ0ZUWvZyo=
+github.com/google/jsonapi v0.0.0-20181016150055-d0428f63eb51/go.mod h1:XSx4m2SziAqk9DXY9nz659easTq4q6TyrpYd9tHSm0g=
+github.com/gorilla/mux v1.7.0 h1:tOSd0UKHQd6urX6ApfOn4XdBMY6Sh1MfxV3kmaazO+U=
+github.com/gorilla/mux v1.7.0/go.mod h1:1lud6UwP+6orDFRuTfBEV8e9/aOM/c4fVVCaMa2zaAs=
+github.com/oklog/ulid v1.3.1 h1:EGfNDEx6MqHz8B3uNV6QAib1UR2Lm97sHi3ocA6ESJ4=
+github.com/oklog/ulid v1.3.1/go.mod h1:CirwcVhetQ6Lv90oh/F+FBtV6XMibvdAFo93nm5qn4U=

pkg/gopher.go

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+package gopher
+
+// Gopher defines the properties of a gopher to be listed
+type Gopher struct {
+	ID    string `json:"ID"`
+	Name  string `json:"name,omitempty"`
+	Image string `json:"image,omitempty"`
+	Age   int    `json:"age,omitempty"`
+}
+
+// Repository provides access to the gopher storage
+type GopherRepository interface {
+	// CreateGopher saves a given gopher
+	CreateGopher(g *Gopher) error
+	// FetchGophers return all gophers saved in storage
+	FetchGophers() ([]*Gopher, error)
+	// DeleteGopher remove gopher with given ID
+	DeleteGopher(ID string) error
+	// UpdateGopher modify gopher with given ID and given new data
+	UpdateGopher(ID string, g *Gopher) error
+	// FetchGopherByID returns the gopher with given ID
+	FetchGopherByID(ID string) (*Gopher, error)
+}

pkg/server/api.go

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+package server
+
+import (
+	"encoding/json"
+	"net/http"
+
+	gopher "github.com/friendsofgo/gopher-api/pkg"
+
+	"github.com/gorilla/mux"
+)
+
+type api struct {
+	router     http.Handler
+	repository gopher.GopherRepository
+}
+
+type Server interface {
+	Router() http.Handler
+}
+
+func New(repo gopher.GopherRepository) Server {
+	a := &api{repository: repo}
+
+	r := mux.NewRouter()
+	r.HandleFunc("/gophers", a.fetchGophers).Methods(http.MethodGet)
+	r.HandleFunc("/gophers/{ID:[a-zA-Z0-9_]+}", a.fetchGopher).Methods(http.MethodGet)
+
+	a.router = r
+	return a
+}
+
+func (a *api) Router() http.Handler {
+	return a.router
+}
+
+func (a *api) fetchGophers(w http.ResponseWriter, r *http.Request) {
+	gophers, _ := a.repository.FetchGophers()
+
+	w.Header().Set("Content-Type", "application/json")
+	json.NewEncoder(w).Encode(gophers)
+}
+
+func (a *api) fetchGopher(w http.ResponseWriter, r *http.Request) {
+	vars := mux.Vars(r)
+	gopher, err := a.repository.FetchGopherByID(vars["ID"])
+	w.Header().Set("Content-Type", "application/json")
+	if err != nil {
+		w.WriteHeader(http.StatusNotFound) // We use not found for simplicity
+		json.NewEncoder(w).Encode("Gopher Not found")
+		return
+	}
+
+	json.NewEncoder(w).Encode(gopher)
+}

pkg/storage/inmem/repository.go

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+package inmem
+
+import (
+	"fmt"
+	"sync"
+
+	gopher "github.com/friendsofgo/gopher-api/pkg"
+)
+
+type gopherRepository struct {
+	mtx     sync.RWMutex
+	gophers map[string]*gopher.Gopher
+}
+
+func NewGopherRepository(gophers map[string]*gopher.Gopher) gopher.GopherRepository {
+	if gophers == nil {
+		gophers = make(map[string]*gopher.Gopher)
+	}
+
+	return &gopherRepository{
+		gophers: gophers,
+	}
+}
+
+func (r *gopherRepository) CreateGopher(g *gopher.Gopher) error {
+	r.mtx.Lock()
+	defer r.mtx.Unlock()
+	if err := r.checkIfExists(g.ID); err != nil {
+		return err
+	}
+	r.gophers[g.ID] = g
+	return nil
+}
+
+func (r *gopherRepository) FetchGophers() ([]*gopher.Gopher, error) {
+	r.mtx.Lock()
+	defer r.mtx.Unlock()
+	values := make([]*gopher.Gopher, 0, len(r.gophers))
+	for _, value := range r.gophers {
+		values = append(values, value)
+	}
+	return values, nil
+}
+
+func (r *gopherRepository) DeleteGopher(ID string) error {
+	r.mtx.Lock()
+	defer r.mtx.Unlock()
+	delete(r.gophers, ID)
+
+	return nil
+}
+
+func (r *gopherRepository) UpdateGopher(ID string, g *gopher.Gopher) error {
+	r.mtx.Lock()
+	defer r.mtx.Unlock()
+	r.gophers[ID] = g
+	return nil
+}
+
+func (r *gopherRepository) FetchGopherByID(ID string) (*gopher.Gopher, error) {
+	r.mtx.Lock()
+	defer r.mtx.Unlock()
+
+	for _, v := range r.gophers {
+		if v.ID == ID {
+			return v, nil
+		}
+	}
+
+	return nil, fmt.Errorf("The ID %s doesn't exist", ID)
+}
+
+func (r *gopherRepository) checkIfExists(ID string) error {
+	for _, v := range r.gophers {
+		if v.ID == ID {
+			return fmt.Errorf("The gopher %s is already exist", ID)
+		}
+	}
+
+	return nil
+}