I followed the guide to write the mongodb API here: https://www.thepolyglotdeveloper.com/2019/02/developing-restful-api-golang-mongodb-nosql-database/
The guide's code run perfectly. But when I tried to split the code into small packages to add more cases and easier to read, the server always return as the title. Below is the code, I just split the guide's code into small packages not add anything new or remove anything. What did I do wrong or what am I missing? https://github.com/imperiustx/mongo_golang
You are facing this problem because the client variable in the middleware.go file is nil.
client is a dependency here. It has to be injected from main package to middleware package.
Fix:-
middleware.go
type endpoints struct {
client *mongo.Client
}
func NewEndpoints(client *mongo.Client) *endpoints {
return &endpoints{
client: client,
}
}
func (e *endpoints) CreatePersonEndpoint(response http.ResponseWriter, request *http.Request) {
response.Header().Set("content-type", "application/json")
var person models.Person
_ = json.NewDecoder(request.Body).Decode(&person)
collection := e.client.Database("thepolyglotdeveloper").Collection("people")
ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
defer cancel()
result, _ := collection.InsertOne(ctx, person)
json.NewEncoder(response).Encode(result)
}
func (e *endpoints) GetPeopleEndpoint(response http.ResponseWriter, request *http.Request) {
response.Header().Set("content-type", "application/json")
var people []models.Person
collection := e.client.Database("thepolyglotdeveloper").Collection("people")
ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
defer cancel()
cursor, err := collection.Find(ctx, bson.M{})
if err != nil {
response.WriteHeader(http.StatusInternalServerError)
response.Write([]byte(`{ "message": "` + err.Error() + `" }`))
return
}
defer cursor.Close(ctx)
for cursor.Next(ctx) {
var person models.Person
cursor.Decode(&person)
people = append(people, person)
}
if err := cursor.Err(); err != nil {
response.WriteHeader(http.StatusInternalServerError)
response.Write([]byte(`{ "message": "` + err.Error() + `" }`))
return
}
json.NewEncoder(response).Encode(people)
}
func (e *endpoints) GetPersonEndpoint(response http.ResponseWriter, request *http.Request) {
response.Header().Set("content-type", "application/json")
params := mux.Vars(request)
id, _ := primitive.ObjectIDFromHex(params["id"])
var person models.Person
collection := e.client.Database("thepolyglotdeveloper").Collection("people")
ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
defer cancel()
err := collection.FindOne(ctx, models.Person{ID: id}).Decode(&person)
if err != nil {
response.WriteHeader(http.StatusInternalServerError)
response.Write([]byte(`{ "message": "` + err.Error() + `" }`))
return
}
json.NewEncoder(response).Encode(person)
}
main.go
func main() {
fmt.Println("Starting the application...")
ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
defer cancel()
clientOptions := options.Client().ApplyURI("mongodb://localhost:27017")
client, _ = mongo.Connect(ctx, clientOptions)
endpoints := middleware.NewEndpoints(client) // injecting the dependency
router := mux.NewRouter()
router.HandleFunc("/person", endpoints.CreatePersonEndpoint).Methods("POST")
router.HandleFunc("/people", endpoints.GetPeopleEndpoint).Methods("GET")
router.HandleFunc("/person/{id}", endpoints.GetPersonEndpoint).Methods("GET")
http.ListenAndServe(":12345", router)
}