Overview
本教程向您展示如何使用MongoDB Go驱动程序和 Gin Web框架构建Web应用程序。
Gin 是一个快速、轻量级的Go Web框架。其极简主义和模块化设计使其成为构建 Web 服务器、API 和微服务的理想选择。
在本教程中，您可以学习；了解如何创建具有以下连接到MongoDB 数据库的端点的 Web应用程序：
用于从集合中检索所有电影的端点
按ID检索单部电影的端点
用于在
movies集合上运行聚合操作的端点
样本数据
moviessample_mflix本教程使用Atlas示例数据集的 数据库中的 集合。要学习；了解如何创建免费的MongoDB Atlas 群集并加载示例数据集，请参阅Atlas入门指南。
先决条件
在开始本教程之前，请确保您具备以下条件：
设置您的项目
创建应用程序结构
1
连接至 MongoDB
更新 main.go文件以连接到MongoDB。将现有代码替换为以下代码以连接到MongoDB 部署：
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 string const 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) } }
将<connection-string> 占位符替换为实际的MongoDB连接字符串。要学习；了解有关如何获取连接字符串的更多信息，请参阅连接到集群指南。
实施API端点
现在，您可以添加三个端点来与电影数据交互。更新 main.go文件以包含必要的导入和端点实现。
1
2
添加路由处理程序
在 connectToMongoDB 函数之后添加以下路由处理程序：
// GET /movies - Retrieves all movies func 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 ID func 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 pipeline func 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) }
3
注册路由
更新 main 函数以注册新路由：
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) } }
测试您的应用程序
您可以测试创建的端点，确保它们按预期工作。
测试获取所有电影
重新启动服务器并在网络浏览器中导航至 http://localhost:8080/movies。您应该会看到一个JSON响应，其中包含示例数据集中的电影大量。
测试通过ID获取电影
要测试单个电影端点，请从电影响应中复制 _id 值并导航到 http://localhost:8080/movies/{id}。
示例，如果导航到 http://localhost:8080/movies/573a1390f29313caabcd42e8，浏览器中的响应将类似于以下内容：
{ "_id": "573a1390f29313caabcd42e8", "awards": { "wins": 1, "nominations": 0, "text": "1 win." }, "cast": [ "A.C. Abadie", "Gilbert M. 'Broncho Billy' Anderson", "George Barnes", "Justus D. Barnes" ], "countries": [ "USA" ], "directors": [ "Edwin S. Porter" ], "fullplot": "Among the earliest existing films in American cinema - notable as the first film that presented a narrative story to tell - it depicts a group of cowboy outlaws who hold up a train and rob the passengers. They are then pursued by a Sheriff's posse. Several scenes have color included - all hand tinted.", "genres": [ "Short", "Western" ]," .... }
测试聚合端点
要测试聚合端点，您需要发出 POST请求。您可以使用 curl 或 Postman 等工具发送在请求正文中包含聚合管道的请求。
以下示例聚合按年份对喜剧电影进行计数：
[ {"$match": {"genres": "Comedy"}}, {"$group": { "_id": "$year", "count": {"$sum": 1} }}, {"$sort": {"count": -1}} ]
在终端中运行以下代码以使用 curl 测试此端点：
curl -X POST http://localhost:8080/movies/aggregations \ -H "Content-Type: application/json" \ -d '[ {"$match": {"genres": "Comedy"}}, {"$group": {"_id": "$year", "count": {"$sum": 1}}}, {"$sort": {"count": -1}} ]'
[ { "_id": 2014, "count": 287 }, { "_id": 2013, "count": 286 }, { "_id": 2009, "count": 268 }, { "_id": 2011, "count": 263 }, { "_id": 2006, "count": 260 }, ... ]
警告
本教程中的聚合端点允许用户运行任何聚合管道。在生产环境中，应限制操作类型并验证输入，以防止潜在的安全问题或性能问题。
完整代码
以下文件显示了 Web应用程序的完整代码：
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 string const 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 movies func 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 ID func 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 pipeline func 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) }
总结
您现在拥有一个基本应用程序，可演示以下内容：
使用 Gin Web框架和Go驾驶员设置Go项目。
使用Go驾驶员连接到MongoDB 数据库。
实现执行MongoDB操作以查找文档、查找单个文档和运行聚合管道的REST API端点。
处理常见场景，例如将字符串 ID 转换为 ObjectID。
为数据库操作实施正确的错误处理。
后续步骤
要进一步开发您的应用程序，请考虑以下后续步骤：
其他资源
要详细学习；了解本教程中的概念，请参阅以下资源：