# Configure the Apache-based HTTP client
<a name="http-configuration-apache"></a>

**Note**  
`ApacheHttpClient` is deprecated because Apache HttpClient 4.x is in maintenance mode. Use the Apache HttpClient 5.x based [Apache5HttpClient](http-configuration-apache5.md).

The SDK's `ApacheHttpClient` is based on the Apache [HttpClient 4.x](https://hc.apache.org/httpcomponents-client-4.5.x/index.html).

The SDK also offers the [UrlConnectionHttpClient](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/http/urlconnection/UrlConnectionHttpClient.html), which loads more quickly, but has fewer features. For information about configuring the `UrlConnectionHttpClient`, see [Configure the URLConnection-based HTTP client](http-configuration-url.md). 

To see the full set of configuration options available to you for the `ApacheHttpClient`, see [ApacheHttpClient.Builder](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/http/apache/ApacheHttpClient.Builder.html) and [ProxyConfiguration.Builder](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/http/apache/ProxyConfiguration.Builder.html).

## Access the `ApacheHttpClient`
<a name="http-apache-dependency"></a>

### Configuration needed
<a name="http-config-apache-yes-config"></a>

To use the `ApacheHttpClient`, you need to add a dependency on the `apache-client` library at *compile* time. 

Refer to the following example of a Maven `pom.xml` file to configure the `ApacheHttpClient`.

```
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>software.amazon.awssdk</groupId>
                <artifactId>bom</artifactId>
                <version>2.54.0</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>software.amazon.awssdk</groupId>
            <artifactId>s3</artifactId>
        </dependency>
        <!-- By adding the apache-client dependency, ApacheHttpClient will be added to 
             the compile classpath so you can configure it. -->
        <dependency>
            <groupId>software.amazon.awssdk</groupId>
            <artifactId>apache-client</artifactId>
        </dependency>
    </dependencies>
```

## Use and configure the `ApacheHttpClient`
<a name="http-apache-config"></a>

You can configure an instance of `ApacheHttpClient` along with building a service client, or you can configure a single instance to share across multiple service clients. 

With either approach, you use the `[ApacheHttpClient.Builder](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/http/apache/ApacheHttpClient.Builder.html)` to configure the properties for the Apache-based HTTP client.

### Best practice: dedicate an `ApacheHttpClient` instance to a service client
<a name="http-config-apache-recomm"></a>

If you need to configure an instance of the `ApacheHttpClient`, we recommend that you build the dedicated `ApacheHttpClient` instance. You can do so by using the `httpClientBuilder` method of the service client's builder. This way, the lifecycle of the HTTP client is managed by the SDK, which helps avoid potential memory leaks if the `ApacheHttpClient` instance is not closed down when it's no longer needed.

The following example creates an `S3Client` and configures the embedded instance of `ApacheHttpClient` with `maxConnections` and `connectionTimeout` values. The HTTP instance is created using the `httpClientBuilder` method of `S3Client.Builder`.

 **Imports** 

```
import software.amazon.awssdk.http.apache.ApacheHttpClient;
import software.amazon.awssdk.services.s3.S3Client;
import java.time.Duration;
```

 **Code** 

```
S3Client s3Client = S3Client   // Singleton: Use the s3Client for all requests.
    .builder()
    .httpClientBuilder(ApacheHttpClient.builder()
        .maxConnections(100)
        .connectionTimeout(Duration.ofSeconds(5))
    ).build();

// Perform work with the s3Client.

s3Client.close();   // Requests completed: Close all service clients.
```

### Alternative approach: share an `ApacheHttpClient` instance
<a name="http-config-apache-alt"></a>

To help keep resource and memory usage lower for your application, you can configure an `ApacheHttpClient` and share it across multiple service clients. The HTTP connection pool will be shared, which lowers resource usage.

**Note**  
When an `ApacheHttpClient` instance is shared, you must close it when it is ready to be disposed. The SDK will not close the instance when the service client is closed.

The following example configures an Apache-based HTTP client that is used by two service clients. The configured `ApacheHttpClient` instance is passed to the `httpClient` method of each builder. When the service clients and the HTTP client are no longer needed, the code explicitly closes them. The code closes the HTTP client last.

**Imports**

```
import software.amazon.awssdk.http.SdkHttpClient;
import software.amazon.awssdk.http.apache.ApacheHttpClient;
import software.amazon.awssdk.services.dynamodb.DynamoDbClient;
import software.amazon.awssdk.services.s3.S3Client;
```

 **Code** 

```
SdkHttpClient apacheHttpClient = ApacheHttpClient.builder()
        .maxConnections(100).build();

// Singletons: Use the s3Client and dynamoDbClient for all requests.
S3Client s3Client = 
    S3Client.builder()
            .httpClient(apacheHttpClient).build();

DynamoDbClient dynamoDbClient = 
    DynamoDbClient.builder()
                  .httpClient(apacheHttpClient).build();

// Perform work with the s3Client and dynamoDbClient.

// Requests completed: Close all service clients.
s3Client.close();
dynamoDbClient.close();
apacheHttpClient.close();  // Explicitly close apacheHttpClient.
```

## Proxy configuration example
<a name="http-configuration-apache-proxy-conf-ex"></a>

The following code snippet uses the [proxy configuration builder for the Apache HTTP client](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/http/apache/ProxyConfiguration.Builder.html).

```
SdkHttpClient apacheHttpClient = ApacheHttpClient.builder()
                .proxyConfiguration(ProxyConfiguration.builder()
                        .endpoint(URI.create("http://example.com:1234"))
                        .username("username")
                        .password("password")
                        .addNonProxyHost("localhost")
                        .addNonProxyHost("host.example.com")
                        .build())
                .build();
```

The equivalent Java system properties for the proxy configuration are shown in the following command line snippet.

```
$ java -Dhttp.proxyHost=example.com -Dhttp.proxyPort=1234 -Dhttp.proxyUser=username \
-Dhttp.proxyPassword=password -Dhttp.nonProxyHosts=localhost|host.example.com -cp ... App
```

The equivalent setup that uses environment variables is:

```
// Set the following environment variables.
// $ export HTTP_PROXY="http://username:password@example.com:1234"
// $ export NO_PROXY="localhost|host.example.com"

// Set the 'useSystemPropertyValues' to false on the proxy configuration.
SdkHttpClient apacheHttpClient = ApacheHttpClient.builder()
                .proxyConfiguration(ProxyConfiguration.builder()
                        .useSystemPropertyValues(Boolean.FALSE)
                        .build())
                .build();

// Run the application.
// $ java -cp ... App
```

**Note**  
The Apache HTTP client does not currently support HTTPS proxy system properties or the HTTPS\_PROXY environment variable.