wiki/content/20201109153159-local_service_binding.md

---
date: 20201109
id: 764a4845-b98c-43f6-9b9c-f5b6cc849e7f
title: Local Service Binding
---

# Introduction

Since [Symfony 4.0](20201109140137-symfony_4_0) autowiring scalar
arguments has been simplified with local binding:

# Syntax

## Pre Symfony 4.0

``` yaml
services:
    _defaults:
        autowire: true
        autoconfigure: true
        public: false

    App\Some\Service1:
        $projectDir: '%kernel.project_dir%'

    App\Some\Service2:
        $projectDir: '%kernel.project_dir%'

    App\Some\Service3:
        $projectDir: '%kernel.project_dir%'

```

## Post Symfony 4.0

``` yaml
services:
    _defaults:
        autowire: true
        autoconfigure: true
        public: false
        bind:
            $projectDir: '%kernel.project_dir%'

```

## Explicitly define injection services

``` yaml
# when services created/defined in this file inject 'BarInterface',
# use the '@normal_bar_service' ...
services:
  _defaults:
    bind:
      BarInterface: "@normal_bar_service"

  # ... except for this particular service, which uses a different service
  Foo:
    bind:
      BarInterface: "@special_bar_service"
```