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Malar's DevNotes

Creating a RESTful CRUD application using GoLang and MongoDB

Malarvizhi_Kandasamy Tags: database crud language mongo rest api db go nosql ‎ 593 Views

In this article, I will show you how to create a RESTful CRUD(Create, Read, Update, Delete) application using Go language and MongoDB as database.

Pr-Requisites:

-------------------

a) Install go in your system(mac).

brew install go

brew upgrade go

b) Edit ~/.bash_profile and set the below:

export GOPATH=/Users/malark/work
export GOBIN=$GOPATH/binå
export GOROOT=/usr/local/Cellar/go/1.13.1/libexec
export PATH=$GOPATH/bin:$GOROOT/bin:$PATH

c) Install mongodb as a docker container:

Please see the article, "Getting Started With MongoDB As A Docker Container Deployment"

https://www.thepolyglotdeveloper.com/2019/01/getting-started-mongodb-docker-container-deployment/

Run the command "docker ps", you should see the output as below :

Malars-MacBook-Pro:~ malark$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
a6173fcf6fcd mongo:latest "docker-entrypoint.s…" 11 hours ago Up 11 hours 0.0.0.0:27017-27019->27017-27019/tcp mongodb

Now, lets create a RESTful application that performs CRUD operation using mongodb as database.

d) Create directory structure:

/Users/malark/work/src/
Install Mongodb driver for go:

go get github.com/gorilla/mux
go get go.mongodb.org/mongo-driver/mongo

e) Create a source code directory for your program:

github.com/makandas/restapi

f) List all directories under /Users/malark/work/src/ directory:

malars-mbp:src malark$ ls
github.com go.mongodb.org google.golang.org k8s.io sigs.k8s.io
github.ibm.com golang.org gopkg.in

Now lets, see the code:

Here is the code that connects to Mongodb:

-----------------------------------------------------------------------------

func main() {
        fmt.Println("Starting the application...")
        ctx, _ := context.WithTimeout(context.Background(), 10*time.Second)
        clientOptions := options.Client().ApplyURI("mongodb://localhost:27017")
        client, _ = mongo.Connect(ctx, clientOptions)
        router := mux.NewRouter()
        router.HandleFunc("/people", GetPeopleEndpoint).Methods("GET")
        router.HandleFunc("/people/{id}", GetPersonEndpoint).Methods("GET")
        router.HandleFunc("/person", CreatePersonEndpoint).Methods("POST")
        router.HandleFunc("/people/{firstname}", UpdatePersonEndpoint).Methods("PUT")
        router.HandleFunc("/people/{firstname}", DeletePersonEndpoint).Methods("DELETE")
        log.Fatal(http.ListenAndServe(":8080", router))
}

----------------------------------------------------------------------------

You can find the complete code here: https://github.com/MalarvizhiK/restapi/mongo_restproject.go

Run the project:
--------------------------------------------------------------------------------

malars-mbp:restapi malark$ go run mongo_restproject.go
Starting the application...

.........

--------------------------------------------------------------------------------

a) Create a Person:

Use Postman to create a Person:

URL : http://localhost:8080/person

Method: POST

Body:

{
"firstname": "Vasant",
"lastname": "Sivashanmugam"
}

Status:200, Output:

{
"InsertedID": "5db7aa24bee4d4e3ded6359b"
}

b) Update a Person:

URL : http://localhost:8080/person/Vasant

Method: PUT

Body:

{
"lastname": "Siva"
}

Status: 200, Output:

{
"MatchedCount": 1,
"ModifiedCount": 1,
"UpsertedCount": 0,
"UpsertedID": null
}

c) Get a specific Person using id:

URL : http://localhost:8080/people/5db6fb9e561a9b24a04e5dd3

Method: GET

Status: 200, Output:

{
"_id": "5db6fb9e561a9b24a04e5dd3",
"firstname": "Vasant",
"lastname": "Siva"
}
d) Delete a Person:
URL : http://localhost:8080/people/Malar
Method: DELETE
Status: 200, Output:
{
"DeletedCount": 1
}
e) Get all Person:
URL : http://localhost:8080/people
Method: GET
Status: 200, Output:
[
{
"_id": "5db6529f2cd9bd4720cbb0e7",
"firstname": "Mahathi",
"lastname": "Vasant"
},
{
"_id": "5db6fb4b561a9b24a04e5dd1"
},
{
"_id": "5db6fb80561a9b24a04e5dd2",
"firstname": "Ishani",
"lastname": "Vasant"
},
{
"_id": "5db6fb9e561a9b24a04e5dd3",
"firstname": "Vasant",
"lastname": "Siva"
},
{
"_id": "5db7aa24bee4d4e3ded6359b",
"firstname": "Vasant",
"lastname": "Sivashanmugam"
}
]
 