Go マイクロサービスでのリクエスト、検証、レスポンス処理の改善

package httpsuite

import (
 "bytes"
 "context"
 "encoding/json"
 "errors"
 "fmt"
 "github.com/go-chi/chi/v5"
 "github.com/stretchr/testify/assert"
 "log"
 "net/http"
 "net/http/httptest"
 "strconv"
 "strings"
 "testing"
)

// TestRequest includes custom type annotation for UUID
type TestRequest struct {
 ID   int    `json:"id" validate:"required"`
 Name string `json:"name" validate:"required"`
}

func (r *TestRequest) SetParam(fieldName, value string) error {
 switch strings.ToLower(fieldName) {
 case "id":
  id, err := strconv.Atoi(value)
  if err != nil {
   return errors.New("invalid id")
  }
  r.ID = id
 default:
  log.Printf("Parameter %s cannot be set", fieldName)
 }

 return nil
}

func Test_ParseRequest(t *testing.T) {
 testSetURLParam := func(r *http.Request, fieldName, value string) *http.Request {
  ctx := chi.NewRouteContext()
  ctx.URLParams.Add(fieldName, value)
  return r.WithContext(context.WithValue(r.Context(), chi.RouteCtxKey, ctx))
 }

 type args struct {
  w          http.ResponseWriter
  r          *http.Request
  pathParams []string
 }
 type testCase[T any] struct {
  name    string
  args    args
  want    *TestRequest
  wantErr assert.ErrorAssertionFunc
 }
 tests := []testCase[TestRequest]{
  {
   name: "Successful Request",
   args: args{
    w: httptest.NewRecorder(),
    r: func() *http.Request {
     body, _ := json.Marshal(TestRequest{Name: "Test"})
     req := httptest.NewRequest("POST", "/test/123", bytes.NewBuffer(body))
     req = testSetURLParam(req, "ID", "123")
     req.Header.Set("Content-Type", "application/json")
     return req
    }(),
    pathParams: []string{"ID"},
   },
   want:    &TestRequest{ID: 123, Name: "Test"},
   wantErr: assert.NoError,
  },
  {
   name: "Missing body",
   args: args{
    w: httptest.NewRecorder(),
    r: func() *http.Request {
     req := httptest.NewRequest("POST", "/test/123", nil)
     req = testSetURLParam(req, "ID", "123")
     req.Header.Set("Content-Type", "application/json")
     return req
    }(),
    pathParams: []string{"ID"},
   },
   want:    nil,
   wantErr: assert.Error,
  },
  {
   name: "Missing Path Parameter",
   args: args{
    w: httptest.NewRecorder(),
    r: func() *http.Request {
     req := httptest.NewRequest("POST", "/test", nil)
     req.Header.Set("Content-Type", "application/json")
     return req
    }(),
    pathParams: []string{"ID"},
   },
   want:    nil,
   wantErr: assert.Error,
  },
  {
   name: "Invalid JSON Body",
   args: args{
    w: httptest.NewRecorder(),
    r: func() *http.Request {
     req := httptest.NewRequest("POST", "/test/123", bytes.NewBufferString("{invalid-json}"))
     req = testSetURLParam(req, "ID", "123")
     req.Header.Set("Content-Type", "application/json")
     return req
    }(),
    pathParams: []string{"ID"},
   },
   want:    nil,
   wantErr: assert.Error,
  },
  {
   name: "Validation Error for body",
   args: args{
    w: httptest.NewRecorder(),
    r: func() *http.Request {
     body, _ := json.Marshal(TestRequest{})
     req := httptest.NewRequest("POST", "/test/123", bytes.NewBuffer(body))
     req = testSetURLParam(req, "ID", "123")
     req.Header.Set("Content-Type", "application/json")
     return req
    }(),
    pathParams: []string{"ID"},
   },
   want:    nil,
   wantErr: assert.Error,
  },
  {
   name: "Validation Error for zero ID",
   args: args{
    w: httptest.NewRecorder(),
    r: func() *http.Request {
     body, _ := json.Marshal(TestRequest{Name: "Test"})
     req := httptest.NewRequest("POST", "/test/0", bytes.NewBuffer(body))
     req = testSetURLParam(req, "ID", "0")
     req.Header.Set("Content-Type", "application/json")
     return req
    }(),
    pathParams: []string{"ID"},
   },
   want:    nil,
   wantErr: assert.Error,
  },
 }

 for _, tt := range tests {
  t.Run(tt.name, func(t *testing.T) {
   got, err := ParseRequest[*TestRequest](tt.args.w, tt.args.r, tt.args.pathParams...)
   if !tt.wantErr(t, err, fmt.Sprintf("parseRequest(%v, %v, %v)", tt.args.w, tt.args.r, tt.args.pathParams)) {
    return
   }
   assert.Equalf(t, tt.want, got, "parseRequest(%v, %v, %v)", tt.args.w, tt.args.r, tt.args.pathParams)
  })
 }
}

package httpsuite

import (
 "errors"
 "github.com/go-playground/validator/v10"
)

// ValidationErrors represents a collection of validation errors for an HTTP request.
type ValidationErrors struct {
 Errors map[string][]string `json:"errors,omitempty"`
}

// NewValidationErrors creates a new ValidationErrors instance from a given error.
// It extracts field-specific validation errors and maps them for structured output.
func NewValidationErrors(err error) *ValidationErrors {
 var validationErrors validator.ValidationErrors
 errors.As(err, &validationErrors)

 fieldErrors := make(map[string][]string)
 for _, vErr := range validationErrors {
  fieldName := vErr.Field()
  fieldError := fieldName + " " + vErr.Tag()

  fieldErrors[fieldName] = append(fieldErrors[fieldName], fieldError)
 }

 return &ValidationErrors{Errors: fieldErrors}
}

// IsRequestValid validates the provided request struct using the go-playground/validator package.
// It returns a ValidationErrors instance if validation fails, or nil if the request is valid.
func IsRequestValid(request any) *ValidationErrors {
 validate := validator.New(validator.WithRequiredStructEnabled())
 err := validate.Struct(request)
 if err != nil {
  return NewValidationErrors(err)
 }
 return nil
}

package httpsuite

import (
 "github.com/go-playground/validator/v10"
 "testing"

 "github.com/stretchr/testify/assert"
)

type TestValidationRequest struct {
 Name string `validate:"required"`
 Age  int    `validate:"required,min=18"`
}

func TestNewValidationErrors(t *testing.T) {
 validate := validator.New()
 request := TestValidationRequest{} // Missing required fields to trigger validation errors

 err := validate.Struct(request)
 if err == nil {
  t.Fatal("Expected validation errors, but got none")
 }

 validationErrors := NewValidationErrors(err)

 expectedErrors := map[string][]string{
  "Name": {"Name required"},
  "Age":  {"Age required"},
 }

 assert.Equal(t, expectedErrors, validationErrors.Errors)
}

func TestIsRequestValid(t *testing.T) {
 tests := []struct {
  name           string
  request        TestValidationRequest
  expectedErrors *ValidationErrors
 }{
  {
   name:           "Valid request",
   request:        TestValidationRequest{Name: "Alice", Age: 25},
   expectedErrors: nil, // No errors expected for valid input
  },
  {
   name:    "Missing Name and Age below minimum",
   request: TestValidationRequest{Age: 17},
   expectedErrors: &ValidationErrors{
    Errors: map[string][]string{
     "Name": {"Name required"},
     "Age":  {"Age min"},
    },
   },
  },
  {
   name:    "Missing Age",
   request: TestValidationRequest{Name: "Alice"},
   expectedErrors: &ValidationErrors{
    Errors: map[string][]string{
     "Age": {"Age required"},
    },
   },
  },
 }

 for _, tt := range tests {
  t.Run(tt.name, func(t *testing.T) {
   errs := IsRequestValid(tt.request)
   if tt.expectedErrors == nil {
    assert.Nil(t, errs)
   } else {
    assert.NotNil(t, errs)
    assert.Equal(t, tt.expectedErrors.Errors, errs.Errors)
   }
  })
 }
}