github.com/lovung/GoCleanArchitecture@v0.0.0-20210302152432-50d91fd29f9f/app/internal/interface/restful/middleware/json_writer_middleware.go (about)

     1  package middleware
     2  
     3  import (
     4  	"net/http"
     5  
     6  	"github.com/lovung/GoCleanArchitecture/app/internal/appctx"
     7  	"github.com/lovung/GoCleanArchitecture/app/internal/interface/restful/presenter"
     8  
     9  	"github.com/gin-gonic/gin"
    10  	"github.com/go-playground/validator/v10"
    11  )
    12  
    13  // JSONWriterMiddleware follow jsonapi.org
    14  // Respond check errors, prepare meta and respond data
    15  func JSONWriterMiddleware(ctx *gin.Context) {
    16  	ctx.Next()
    17  
    18  	// Check error if exists
    19  	// Base on error/success to return meta object
    20  	var (
    21  		res      presenter.Response
    22  		httpCode int
    23  	)
    24  	appErr := appctx.GetValue(ctx.Request.Context(), appctx.ErrorContextKey)
    25  	if appErr != nil {
    26  		_processAppError(&res, appErr)
    27  		httpCode = res.Meta.Code
    28  	}
    29  
    30  	// Respond the data object/array
    31  	data := appctx.GetValue(ctx.Request.Context(), appctx.DataContextKey)
    32  	if data != nil {
    33  		res.Data = data
    34  	}
    35  	meta := appctx.GetValue(ctx.Request.Context(), appctx.MetaContextKey)
    36  	if meta != nil {
    37  		metaRes, ok1 := meta.(presenter.MetaResponse)
    38  		if ok1 {
    39  			res.Meta = metaRes
    40  			httpCode = metaRes.Code
    41  		}
    42  	}
    43  	if res.IsEmpty() {
    44  		ctx.JSON(http.StatusNoContent, nil)
    45  	} else {
    46  		ctx.JSON(httpCode, res)
    47  	}
    48  }
    49  
    50  func _processAppError(res *presenter.Response, appErr interface{}) {
    51  	bindingErr := _catchBindingError(appErr.(error))
    52  	if bindingErr != nil {
    53  		res.Errors = bindingErr.(presenter.ErrorResponses)
    54  		res.Meta = presenter.MetaResponse{
    55  			Code:    http.StatusBadRequest,
    56  			Message: "error when binding the request",
    57  		}
    58  	}
    59  }
    60  
    61  func _catchBindingError(appErr error) error {
    62  	var errs presenter.ErrorResponses
    63  	if _, ok := appErr.(*validator.InvalidValidationError); ok {
    64  		errs.Append(presenter.ErrorResponse{
    65  			Code:   http.StatusInternalServerError,
    66  			Detail: "invalid validation error",
    67  		})
    68  		return errs
    69  	}
    70  
    71  	if vldrErr, ok := appErr.(validator.ValidationErrors); ok {
    72  		errs.FromValidationErrors(vldrErr)
    73  		return errs
    74  	}
    75  
    76  	return nil
    77  }