Added an API listener

listeners/http_api.go

@@ -0,0 +1,110 @@
+package listeners
+
+import (
+	"context"
+	"log/slog"
+	"net/http"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"git.savin.nyc/alex/go-receipt-tracker/listeners/handlers"
+	"github.com/gin-contrib/cors"
+	"github.com/gin-gonic/gin"
+	"github.com/uptrace/bun"
+)
+
+const TypeApi = "api"
+
+// HTTPHealthCheck is a listener for providing an HTTP healthcheck endpoint.
+type HttpApi struct {
+	sync.RWMutex
+	id      string       // the internal id of the listener
+	address string       // the network address to bind to
+	config  Config       // configuration values for the listener
+	listen  *http.Server // the http server
+	end     uint32       // ensure the close methods are only called once
+	db      *bun.DB      //
+}
+
+// NewHTTPHealthCheck initializes and returns a new HTTP listener, listening on an address.
+func NewHttpApi(config Config, db *bun.DB) *HttpApi {
+	return &HttpApi{
+		id:      config.ID,
+		address: config.Address,
+		config:  config,
+		db:      db,
+	}
+}
+
+// ID returns the id of the listener.
+func (l *HttpApi) ID() string {
+	return l.id
+}
+
+// Address returns the address of the listener.
+func (l *HttpApi) Address() string {
+	return l.address
+}
+
+// Protocol returns the address of the listener.
+func (l *HttpApi) Protocol() string {
+	if l.listen != nil && l.listen.TLSConfig != nil {
+		return "https"
+	}
+
+	return "http"
+}
+
+// Init initializes the listener.
+func (l *HttpApi) Init(_ *slog.Logger) error {
+
+	handlers.DB = l.db
+	router := gin.Default()
+	router.Use(cors.Default())
+
+	v1 := router.Group("/api/v1")
+	{
+		v1.GET("/", handlers.HomePage)
+		v1.GET("/receipts", handlers.GetReceipts)
+		v1.GET("/receipts/:id", handlers.GetReceipt)
+		v1.DELETE("/receipts/:id", handlers.RemoveReceipt)
+		v1.POST("/receipts", handlers.AddReceipt)
+		v1.PUT("/receipts/:id", handlers.UpdateReceipt)
+		v1.GET("/receipts/:id/items", handlers.GetItems)
+	}
+
+	l.listen = &http.Server{
+		ReadTimeout:  5 * time.Second,
+		WriteTimeout: 5 * time.Second,
+		Addr:         l.address,
+		Handler:      router.Handler(),
+	}
+
+	if l.config.TLSConfig != nil {
+		l.listen.TLSConfig = l.config.TLSConfig
+	}
+
+	return nil
+}
+
+// Serve starts listening for new connections and serving responses.
+func (l *HttpApi) Serve() {
+	if l.listen.TLSConfig != nil {
+		_ = l.listen.ListenAndServeTLS("", "")
+	} else {
+		_ = l.listen.ListenAndServe()
+	}
+}
+
+// Close closes the listener and any client connections.
+func (l *HttpApi) Close() {
+	l.Lock()
+	defer l.Unlock()
+
+	if atomic.CompareAndSwapUint32(&l.end, 0, 1) {
+		ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+		defer cancel()
+		_ = l.listen.Shutdown(ctx)
+	}
+}