In the previous article we started learning how to create RESTful API using golang's gin framework. In this article we are going to see how to create a GET endpoint using golang's gin http framework.

Step 1

Create a file controller.go in a directory with the name content in the project.

Create an endpoint in a controller which can accept query parameters and register it for a GET request in the main.go file.

package content

import (
    "fmt"
    "net/http"

    "github.com/gin-gonic/gin"
)

func GetContents(ctx *gin.Context) {
    name, present := ctx.GetQuery("name")
    if !present {
        ctx.Error(fmt.Errorf("name is required"))
        ctx.AbortWithStatus(http.StatusBadRequest)
        return
    }
    response := make(map[string]string, 0)
    response["name"] = name

    ctx.JSON(http.StatusOK, response)
}

Step 2

Register the above created endpoint to gin server in the main.go file. Similar to what we did in Step 4 of previous article add the below code after the http.Server object creation in the main.go file.

    //gin has the option to group endpoints as shown below
    v1 := engine.Group("/api/v1")
    {
        v1.GET("/contents", content.GetContents)
    }

Step 3

Now run the main.go file.

Access the endpoint localhost:8080/api/v1/contents?name=deepak and you should get a 200 status with response body

{
    "name": "deepak"
}

Now, access the endpoint without the query parameter i.e., localhost:8080/api/v1/contents and you should get a 400 status with no response body

Step 4

Now let us write some tests to test the above created endpoint. Create a file with the name content_test.go in the content directory.

package content

import (
    "encoding/json"
    "net/http"
    "net/http/httptest"
    "testing"

    "github.com/gin-gonic/gin"
    "github.com/stretchr/testify/assert"
)

func TestGetContents_success(t *testing.T) {
    responseRecorder := httptest.NewRecorder()
    ctx, engine := gin.CreateTestContext(responseRecorder)
    engine.GET("/contents", GetContents)
    ctx.Request = httptest.NewRequest(http.MethodGet, "/contents?name=deepak", nil)
    engine.ServeHTTP(responseRecorder, ctx.Request)

    assert.Equal(t, http.StatusOK, responseRecorder.Code)

    expectedBody := map[string]string{
        "name": "deepak",
    }

    var actualBody map[string]string
    err := json.Unmarshal(responseRecorder.Body.Bytes(), &actualBody)
    if err != nil {
        t.FailNow()
    }

    assert.Equal(t, expectedBody, actualBody)
}

func TestGetContents_failure(t *testing.T) {
    responseRecorder := httptest.NewRecorder()
    ctx, engine := gin.CreateTestContext(responseRecorder)
    engine.GET("/contents", GetContents)
    ctx.Request = httptest.NewRequest(http.MethodGet, "/contents", nil)
    engine.ServeHTTP(responseRecorder, ctx.Request)

    assert.Equal(t, http.StatusBadRequest, responseRecorder.Code)
}