# Advanced Middleware

In the main tutorial you read how to add [Custom Middleware](../tutorial/middleware.md){.internal-link target=_blank} to your application.

And then you also read how to handle [CORS with the `CORSMiddleware`](../tutorial/cors.md){.internal-link target=_blank}.

In this section we'll see how to use other middlewares.

## Adding ASGI middlewares

package clause_test

import (
	"fmt"
	"testing"

	"gorm.io/gorm/clause"
)

func TestUpdate(t *testing.T) {
	results := []struct {
		Clauses []clause.Interface
		Result  string
		Vars    []interface{}
	}{
		{
			[]clause.Interface{clause.Update{}},
			"UPDATE `users`", nil,
		},
		{
			[]clause.Interface{clause.Update{Modifier: "LOW_PRIORITY"}},
			"UPDATE LOW_PRIORITY `users`", nil,
		},
		{

But if you have custom headers that you want a client in a browser to be able to see, you need to add them to your CORS configurations ([CORS (Cross-Origin Resource Sharing)](cors.md){.internal-link target=_blank}) using the parameter `expose_headers` documented in <a href="https://www.starlette.io/middleware/#corsmiddleware" class="external-link" target="_blank">Starlette's CORS docs</a>.

///

/// note | "Technical Details"

        map sigbuild-r2.12-python3.9 2.12-python3.9
        map sigbuild-r2.12-python3.10 2.12-python3.10
        map sigbuild-r2.12-python3.11 2.12-python3.11
        # TF 2.12 + Clang (containers are the same, but env vars in configs.bzl are different)
        map sigbuild-r2.12-clang 2.12-python3.9
        map sigbuild-r2.12-clang-python3.8 2.12-python3.8
        map sigbuild-r2.12-clang-python3.9 2.12-python3.9

	stmt := dryRunDB.Create(&user).Statement
	if stmt.SQL.String() == "" || len(stmt.Vars) != 9 {
		t.Errorf("Failed to generate sql, got %v", stmt.SQL.String())
	}

	stmt2 := dryRunDB.Find(&user, "id = ?", user.ID).Statement
	if stmt2.SQL.String() == "" || len(stmt2.Vars) != 1 {
		t.Errorf("Failed to generate sql, got %v", stmt2.SQL.String())
	}
}

type ageInt int8

			Queries("cors", "")
		// PutBucketCors - this is a dummy call.
		router.Methods(http.MethodPut).
			HandlerFunc(s3APIMiddleware(api.PutBucketCorsHandler)).
			Queries("cors", "")
		// DeleteBucketCors - this is a dummy call.
		router.Methods(http.MethodDelete).
			HandlerFunc(s3APIMiddleware(api.DeleteBucketCorsHandler)).
			Queries("cors", "")
		// GetBucketWebsiteHandler - this is a dummy call.

	"gorm.io/gorm/clause"
)

func TestLimit(t *testing.T) {
	limit0 := 0
	limit10 := 10
	limit50 := 50
	limitNeg10 := -10
	results := []struct {
		Clauses []clause.Interface
		Result  string
		Vars    []interface{}
	}{
		{
			[]clause.Interface{clause.Select{}, clause.From{}, clause.Limit{
				Limit:  &limit10,
				Offset: 20,
			}},
			"SELECT * FROM `users` LIMIT ? OFFSET ?",
			[]interface{}{limit10, 20},

y deseas que un cliente pueda verlos en el navegador, es necesario que los añadas a tus configuraciones de CORS (puedes leer más en [CORS (Cross-Origin Resource Sharing)](../tutorial/cors.md){.internal-link target=_blank}), usando el parámetro `expose_headers` documentado en <a href="https://www.starlette.io/middleware/#corsmiddleware" class="external-link" target="_blank">Starlette's CORS docs</a>....

///

/// توجه | "جزئیات فنی"

شما همچنین می‌توانید از `from starlette.requests import Request` استفاده کنید.

	objectAPI := api.ObjectAPI()
	if objectAPI == nil {
		writeErrorResponse(ctx, w, errorCodes.ToAPIErr(ErrServerNotInitialized), r.URL)
		return
	}

	vars := mux.Vars(r)
	bucket := vars["bucket"]
	object, err := unescapePath(vars["object"])
	if err != nil {
		writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
		return
	}