nexarch/dms/internal/modulecall/modulecall.go

package modulecall

import (
	"errors"
	"net/http"
	"strings"
)

const (
	HeaderTenant = "X-Nexarch-Tenant"
	HeaderUser   = "X-Nexarch-User"
	maxLen       = 128
)

var (
	ErrTenantRequired = errors.New("modulecall: tenant-kontext fehlt")
	ErrTenantMismatch = errors.New("modulecall: tenant-kontext passt nicht zur instanz")
)

type Context struct {
	Tenant string
	User   string
}

func valid(s string) bool {
	if s == "" || len(s) > maxLen {
		return false
	}
	for _, r := range s {
		if r < 0x21 || r == 0x7f {
			return false
		}
	}
	return true
}

func Apply(req *http.Request, tc Context, instanceTenant string) error {
	if !valid(instanceTenant) || !valid(tc.Tenant) {
		return ErrTenantRequired
	}
	if tc.Tenant != instanceTenant {
		return ErrTenantMismatch
	}
	if tc.User != "" && !valid(tc.User) {
		return ErrTenantRequired
	}
	req.Header.Set(HeaderTenant, tc.Tenant)
	if tc.User != "" {
		req.Header.Set(HeaderUser, tc.User)
	}
	return nil
}

func FromRequest(r *http.Request, instanceTenant string) (Context, error) {
	if !valid(instanceTenant) {
		return Context{}, ErrTenantRequired
	}
	tenant := strings.TrimSpace(r.Header.Get(HeaderTenant))
	if !valid(tenant) {
		return Context{}, ErrTenantRequired
	}
	if tenant != instanceTenant {
		return Context{Tenant: tenant}, ErrTenantMismatch
	}
	return Context{Tenant: tenant, User: strings.TrimSpace(r.Header.Get(HeaderUser))}, nil
}