Tutorial: Criar um Aplicativo da Web com o Driver Go e o Gi

package main
import (	"context"	"log"
	"github.com/gin-gonic/gin"	"go.mongodb.org/mongo-driver/v2/mongo"	"go.mongodb.org/mongo-driver/v2/mongo/options")
// Replace with your MongoDB connection stringconst uri = "<connection-string>"
func main() {	// Connects to MongoDB	serverAPI := options.ServerAPI(options.ServerAPIVersion1)	opts := options.Client().ApplyURI(uri).SetServerAPIOptions(serverAPI)
	client, err := mongo.Connect(opts)	if err != nil {		log.Fatal("Could not connect to MongoDB:", err)	}
	// Ensures the client disconnects when main exits	defer func() {		if err := client.Disconnect(context.TODO()); err != nil {			log.Fatal("Error disconnecting from MongoDB:", err)		}	}()
	// Pings the database to verify connection	if err := client.Ping(context.TODO(), nil); err != nil {		log.Fatal("Could not ping MongoDB:", err)	}
	r := gin.Default()	r.GET("/", func(c *gin.Context) {		c.JSON(200, gin.H{			"message": "Hello World",		})	})
	if err := r.Run(); err != nil {		log.Fatal("Failed to start server:", err)	}}

package main
import (	"context"	"log"	"net/http"
	"github.com/gin-gonic/gin"	"go.mongodb.org/mongo-driver/v2/bson"	"go.mongodb.org/mongo-driver/v2/mongo"	"go.mongodb.org/mongo-driver/v2/mongo/options")
// Replace with your MongoDB connection stringconst uri = "YOUR-CONNECTION-STRING-HERE"
func main() {	// Connects to MongoDB	serverAPI := options.ServerAPI(options.ServerAPIVersion1)	opts := options.Client().ApplyURI(uri).SetServerAPIOptions(serverAPI)
	client, err := mongo.Connect(opts)	if err != nil {		log.Fatal("Could not connect to MongoDB:", err)	}
	// Ensures the client disconnects when main exits	defer func() {		if err := client.Disconnect(context.TODO()); err != nil {			log.Fatal("Error disconnecting from MongoDB:", err)		}	}()
	// Pings the database to verify connection	if err := client.Ping(context.TODO(), nil); err != nil {		log.Fatal("Could not ping MongoDB:", err)	}
	r := gin.Default()
	r.GET("/", func(c *gin.Context) {		c.JSON(200, gin.H{			"message": "Hello World",		})	})
	// Registers movie endpoints	r.GET("/movies", func(c *gin.Context) {		getMovies(c, client)	})	r.GET("/movies/:id", func(c *gin.Context) {		getMovieByID(c, client)	})	r.POST("/movies/aggregations", func(c *gin.Context) {		aggregateMovies(c, client)	})
	if err := r.Run(); err != nil {		log.Fatal("Failed to start server:", err)	}}
// GET /movies - Retrieves all moviesfunc getMovies(c *gin.Context, client *mongo.Client) {	// Find all movies in the collection	cursor, err := client.Database("sample_mflix").Collection("movies").Find(c.Request.Context(), bson.D{})	if err != nil {		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})		return	}	defer cursor.Close(c.Request.Context())
	// Decodes all results	var movies []bson.D	if err = cursor.All(c.Request.Context(), &movies); err != nil {		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})		return	}
	// Returns the movies	c.JSON(http.StatusOK, movies)}
// GET /movies/:id - Retrieves a movie by IDfunc getMovieByID(c *gin.Context, client *mongo.Client) {	// Gets the movie ID from the URL parameter as a string	idStr := c.Param("id")
	// Converts string ID to MongoDB ObjectID	id, err := bson.ObjectIDFromHex(idStr)	if err != nil {		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid movie ID format"})		return	}
	// Finds the movie by ObjectID	var movie bson.D	err = client.Database("sample_mflix").Collection("movies").FindOne(c.Request.Context(), bson.D{{"_id", id}}).Decode(&movie)	if err != nil {		if err == mongo.ErrNoDocuments {			c.JSON(http.StatusNotFound, gin.H{"error": "Movie not found"})			return		}		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})		return	}
	// Returns the movie	c.JSON(http.StatusOK, movie)}
// POST /movies/aggregations - Runs aggregation pipelinefunc aggregateMovies(c *gin.Context, client *mongo.Client) {	// Gets aggregation pipeline from request body	var pipeline interface{}	if err := c.ShouldBindJSON(&pipeline); err != nil {		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid aggregation pipeline"})		return	}
	// Executes the aggregation pipeline	cursor, err := client.Database("sample_mflix").Collection("movies").Aggregate(c.Request.Context(), pipeline)	if err != nil {		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})		return	}	defer cursor.Close(c.Request.Context())
	// Decodes the results	var result []bson.D	if err = cursor.All(c.Request.Context(), &result); err != nil {		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})		return	}
	// Returns the aggregation result	c.JSON(http.StatusOK, result)}