137 lines
6.6 KiB
Plaintext
137 lines
6.6 KiB
Plaintext
=== Common configuration
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The `RestClientBuilder` supports providing both a `RequestConfigCallback` and
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an `HttpClientConfigCallback` which allow for any customization that the Apache
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Async Http Client exposes. Those callbacks make it possible to modify some
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specific behaviour of the client without overriding every other default
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configuration that the `RestClient` is initialized with. This section
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describes some common scenarios that require additional configuration for the
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low-level Java REST Client.
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==== Timeouts
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Configuring requests timeouts can be done by providing an instance of
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`RequestConfigCallback` while building the `RestClient` through its builder.
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The interface has one method that receives an instance of
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https://hc.apache.org/httpcomponents-client-ga/httpclient/apidocs/org/apache/http/client/config/RequestConfig.Builder.html[`org.apache.http.client.config.RequestConfig.Builder`]
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as an argument and has the same return type. The request config builder can
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be modified and then returned. In the following example we increase the
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connect timeout (defaults to 1 second) and the socket timeout (defaults to 30
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seconds). Also we adjust the max retry timeout accordingly (defaults to 30
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seconds too).
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[source,java]
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--------------------------------------------------
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RestClient restClient = RestClient.builder(new HttpHost("localhost", 9200))
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.setRequestConfigCallback(new RestClientBuilder.RequestConfigCallback() {
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@Override
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public RequestConfig.Builder customizeRequestConfig(RequestConfig.Builder requestConfigBuilder) {
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return requestConfigBuilder.setConnectTimeout(5000)
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.setSocketTimeout(60000);
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}
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})
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.setMaxRetryTimeoutMillis(60000)
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.build();
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--------------------------------------------------
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==== Number of threads
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The Apache Http Async Client starts by default one dispatcher thread, and a
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number of worker threads used by the connection manager, as many as the number
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of locally detected processors (depending on what
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`Runtime.getRuntime().availableProcessors()` returns). The number of threads
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can be modified as follows:
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[source,java]
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--------------------------------------------------
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RestClient restClient = RestClient.builder(new HttpHost("localhost", 9200))
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.setHttpClientConfigCallback(new RestClientBuilder.HttpClientConfigCallback() {
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@Override
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public HttpAsyncClientBuilder customizeHttpClient(HttpAsyncClientBuilder httpClientBuilder) {
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return httpClientBuilder.setDefaultIOReactorConfig(
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IOReactorConfig.custom().setIoThreadCount(1).build());
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}
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})
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.build();
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--------------------------------------------------
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==== Basic authentication
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Configuring basic authentication can be done by providing an
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`HttpClientConfigCallback` while building the `RestClient` through its builder.
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The interface has one method that receives an instance of
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https://hc.apache.org/httpcomponents-asyncclient-dev/httpasyncclient/apidocs/org/apache/http/impl/nio/client/HttpAsyncClientBuilder.html[`org.apache.http.impl.nio.client.HttpAsyncClientBuilder`]
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as an argument and has the same return type. The http client builder can be
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modified and then returned. In the following example we set a default
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credentials provider that requires basic authentication.
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[source,java]
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--------------------------------------------------
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final CredentialsProvider credentialsProvider = new BasicCredentialsProvider();
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credentialsProvider.setCredentials(AuthScope.ANY,
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new UsernamePasswordCredentials("user", "password"));
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RestClient restClient = RestClient.builder(new HttpHost("localhost", 9200))
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.setHttpClientConfigCallback(new RestClientBuilder.HttpClientConfigCallback() {
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@Override
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public HttpAsyncClientBuilder customizeHttpClient(HttpAsyncClientBuilder httpClientBuilder) {
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return httpClientBuilder.setDefaultCredentialsProvider(credentialsProvider);
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}
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})
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.build();
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--------------------------------------------------
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You can disable Preemptive Authentication, which means that every request will be sent without
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authorization headers to see if it is accepted and, upon receiving a HTTP 401 response, it will
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resend the exact same request with the basic authentication header. If you wish to do this, then
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you can do so by disabling it via the `HttpAsyncClientBuilder`:
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[source,java]
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--------------------------------------------------
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final CredentialsProvider credentialsProvider = new BasicCredentialsProvider();
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credentialsProvider.setCredentials(AuthScope.ANY,
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new UsernamePasswordCredentials("user", "password"));
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RestClient restClient = RestClient.builder(new HttpHost("localhost", 9200))
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.setHttpClientConfigCallback(new RestClientBuilder.HttpClientConfigCallback() {
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@Override
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public HttpAsyncClientBuilder customizeHttpClient(HttpAsyncClientBuilder httpClientBuilder) {
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// disable preemptive authentication
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httpClientBuilder.disableAuthCaching();
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return httpClientBuilder.setDefaultCredentialsProvider(credentialsProvider);
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}
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})
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.build();
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--------------------------------------------------
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==== Encrypted communication
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Encrypted communication can also be configured through the
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`HttpClientConfigCallback`. The
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https://hc.apache.org/httpcomponents-asyncclient-dev/httpasyncclient/apidocs/org/apache/http/impl/nio/client/HttpAsyncClientBuilder.html[`org.apache.http.impl.nio.client.HttpAsyncClientBuilder`]
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received as an argument exposes multiple methods to configure encrypted
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communication: `setSSLContext`, `setSSLSessionStrategy` and
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`setConnectionManager`, in order of precedence from the least important.
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The following is an example:
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[source,java]
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--------------------------------------------------
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KeyStore keystore = KeyStore.getInstance("jks");
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try (InputStream is = Files.newInputStream(keyStorePath)) {
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keystore.load(is, keyStorePass.toCharArray());
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}
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RestClient restClient = RestClient.builder(new HttpHost("localhost", 9200))
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.setHttpClientConfigCallback(new RestClientBuilder.HttpClientConfigCallback() {
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@Override
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public HttpAsyncClientBuilder customizeHttpClient(HttpAsyncClientBuilder httpClientBuilder) {
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return httpClientBuilder.setSSLContext(sslcontext);
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}
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})
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.build();
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--------------------------------------------------
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==== Others
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For any other required configuration needed, the Apache HttpAsyncClient docs
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should be consulted: https://hc.apache.org/httpcomponents-asyncclient-4.1.x/ .
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