Adding httprouter dependency to manage endpoints. Adding our routes to routes.go file facilitating endpoints management and adding POST /v1/movies and GET /v1/movies/:id endpoints. Updating main.go file removing ServeMux and add httprouter instead in app structure. Creating movies.go file to manage create and show movie endpoint.

cmd/api/movies.go

@@ -0,0 +1,40 @@
+package main
+
+import (
+	"fmt"
+	"github.com/julienschmidt/httprouter"
+	"net/http"
+	"strconv"
+)
+
+// "POST /v1/movies" endpoint.
+func (app *application) createMovieHandler(w http.ResponseWriter, r *http.Request) {
+	fmt.Fprintln(w, "create a new movie")
+}
+
+// "GET /v1/movies/:id"
+func (app *application) showMovieHandler(w http.ResponseWriter, r *http.Request) {
+	/*
+		When httprouter is parsing a request, any interpolated URL parameters will be
+		stored in the request context. We can use the ParamsFromContext() function to
+		retrieve a slice containing these parameter names and values.
+	*/
+	params := httprouter.ParamsFromContext(r.Context())
+
+	/*
+		We can then use the ByName() method to get the value of the "id" parameter from
+		the slice. In our project all movies will have a unique positive integer ID, but
+		the value returned by ByName() is always a string. So we try to convert it to a
+		base 1° integer (with a bit size of 64). If the parameter couldn't be converted,
+		or is less than 1, we know the ID is invalid so we use the http.NotFound()
+		func to return a 404 Not Found Response.
+	*/
+	id, err := strconv.ParseInt(params.ByName("id"), 10, 64)
+	if err != nil || id < 1 {
+		http.NotFound(w, r)
+		return
+	}
+
+	// Otherwise, interpolate the movie ID in a placeholder response.
+	fmt.Fprintf(w, "show the details of movie %d\n", id)
+}