Package com.linecorp.armeria.client

Class Clients

java.lang.Object

com.linecorp.armeria.client.Clients

public final class Clients
extends Object

Creates a new client that connects to a specified URI. If you are creating a WebClient, it is recommended to use the factory methods in WebClient.

Method Summary

Modifier and Type	Method	Description
static ClientBuilder	builder(Scheme scheme, EndpointGroup endpointGroup)	Returns a new ClientBuilder that builds the client that connects to the specified EndpointGroup with the specified Scheme.
static ClientBuilder	builder(Scheme scheme, EndpointGroup endpointGroup, String path)	Returns a new ClientBuilder that builds the client that connects to the specified EndpointGroup with the specified Scheme and path.
static ClientBuilder	builder(SessionProtocol protocol, EndpointGroup endpointGroup)	Returns a new ClientBuilder that builds the client that connects to the specified EndpointGroup with the specified SessionProtocol.
static ClientBuilder	builder(SessionProtocol protocol, EndpointGroup endpointGroup, String path)	Returns a new ClientBuilder that builds the client that connects to the specified EndpointGroup with the specified SessionProtocol and path.
static ClientBuilder	builder(String uri)	Returns a new ClientBuilder that builds the client that connects to the specified uri.
static ClientBuilder	builder(String scheme, EndpointGroup endpointGroup)	Returns a new ClientBuilder that builds the client that connects to the specified EndpointGroup with the specified scheme.
static ClientBuilder	builder(String scheme, EndpointGroup endpointGroup, String path)	Returns a new ClientBuilder that builds the client that connects to the specified EndpointGroup with the specified scheme and path.
static ClientBuilder	builder(URI uri)	Returns a new ClientBuilder that builds the client that connects to the specified URI.
static boolean	isUndefinedUri(URI uri)	Returns true if the specified uri is an undefined URI, which signifies that a Client, was created without a URI or EndpointGroup.
static <T> T	newClient(Scheme scheme, EndpointGroup endpointGroup, Class<T> clientType)	Creates a new client that connects to the specified EndpointGroup with the specified Scheme using the default ClientFactory.
static <T> T	newClient(Scheme scheme, EndpointGroup endpointGroup, String path, Class<T> clientType)	Creates a new client that connects to the specified EndpointGroup with the specified Scheme and path using the default ClientFactory.
static <T> T	newClient(SessionProtocol protocol, EndpointGroup endpointGroup, Class<T> clientType)	Creates a new client that connects to the specified EndpointGroup with the specified SessionProtocol using the default ClientFactory.
static <T> T	newClient(SessionProtocol protocol, EndpointGroup endpointGroup, String path, Class<T> clientType)	Creates a new client that connects to the specified EndpointGroup with the specified SessionProtocol and path using the default ClientFactory.
static <T> T	newClient(String scheme, EndpointGroup endpointGroup, Class<T> clientType)	Creates a new client that connects to the specified EndpointGroup with the specified scheme using the default ClientFactory.
static <T> T	newClient(String scheme, EndpointGroup endpointGroup, String path, Class<T> clientType)	Creates a new client that connects to the specified EndpointGroup with the specified scheme and path using the default ClientFactory.
static <T> T	newClient(String uri, Class<T> clientType)	Creates a new client that connects to the specified uri using the default ClientFactory.
static <T> T	newClient(URI uri, Class<T> clientType)	Creates a new client that connects to the specified URI using the default ClientFactory.
static ClientRequestContextCaptor	newContextCaptor()	Prepare to capture the ClientRequestContext of the next request sent from the current thread.
static <T> T	newDerivedClient(T client, ClientOptionValue<?>... additionalOptions)	Creates a new derived client that connects to the same URI with the specified client and the specified additionalOptions.
static <T> T	newDerivedClient(T client, Iterable<ClientOptionValue<?>> additionalOptions)	Creates a new derived client that connects to the same URI with the specified client and the specified additionalOptions.
static <T> T	newDerivedClient(T client, Function<? super ClientOptions,ClientOptions> configurator)	Creates a new derived client that connects to the same URI with the specified client but with different ClientOptions.
static <T> T	unwrap(Object client, Class<T> type)	Unwraps the specified client into the object of the specified type.
static SafeCloseable	withContextCustomizer(Consumer<? super ClientRequestContext> contextCustomizer)	Sets the specified ClientRequestContext customizer function in a thread-local variable so that the customized context is used when the client invokes a request from the current thread.
static SafeCloseable	withHeader(CharSequence name, Object value)	Sets the specified HTTP header in a thread-local variable so that the header is sent by the client call made from the current thread.
static SafeCloseable	withHeader(CharSequence name, String value)	Sets the specified HTTP header in a thread-local variable so that the header is sent by the client call made from the current thread.
static SafeCloseable	withHeaders(Consumer<HttpHeadersBuilder> headerMutator)	Sets the specified Consumer, which mutates HTTP headers, in a thread-local variable so that the mutated headers are sent by the client call made from the current thread.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

newClient

public static <T> T newClient(String uri,
 Class<T> clientType)

Creates a new client that connects to the specified uri using the default ClientFactory.

Parameters:

uri - the URI of the server endpoint

clientType - the type of the new client

Throws:

IllegalArgumentException - if the specified uri is invalid, or the specified clientType is unsupported for the uri's scheme

newClient

public static <T> T newClient(URI uri,
 Class<T> clientType)

Creates a new client that connects to the specified URI using the default ClientFactory.

Parameters:

uri - the URI of the server endpoint

clientType - the type of the new client

Throws:

IllegalArgumentException - if the specified URI is invalid, or the specified clientType is unsupported for the URI's scheme

newClient

public static <T> T newClient(String scheme,
 EndpointGroup endpointGroup,
 Class<T> clientType)

Creates a new client that connects to the specified EndpointGroup with the specified scheme using the default ClientFactory.

Parameters:

scheme - the Scheme represented as a String

endpointGroup - the server EndpointGroup

clientType - the type of the new client

Throws:

IllegalArgumentException - if the specified scheme is invalid or the specified clientType is unsupported for the specified scheme.

newClient

public static <T> T newClient(String scheme,
 EndpointGroup endpointGroup,
 String path,
 Class<T> clientType)

Creates a new client that connects to the specified EndpointGroup with the specified scheme and path using the default ClientFactory.

Parameters:

scheme - the Scheme represented as a String

endpointGroup - the server EndpointGroup

path - the path to the endpoint

clientType - the type of the new client

Throws:

IllegalArgumentException - if the specified scheme is invalid or the specified clientType is unsupported for the specified scheme.

newClient

public static <T> T newClient(Scheme scheme,
 EndpointGroup endpointGroup,
 Class<T> clientType)

Creates a new client that connects to the specified EndpointGroup with the specified Scheme using the default ClientFactory.

Parameters:

scheme - the Scheme

endpointGroup - the server EndpointGroup

clientType - the type of the new client

Throws:

IllegalArgumentException - if the specified clientType is unsupported for the specified Scheme.

newClient

public static <T> T newClient(Scheme scheme,
 EndpointGroup endpointGroup,
 String path,
 Class<T> clientType)

Creates a new client that connects to the specified EndpointGroup with the specified Scheme and path using the default ClientFactory.

Parameters:

scheme - the Scheme

endpointGroup - the server EndpointGroup

path - the path to the endpoint

clientType - the type of the new client

Throws:

IllegalArgumentException - if the specified clientType is unsupported for the specified Scheme.

newClient

public static <T> T newClient(SessionProtocol protocol,
 EndpointGroup endpointGroup,
 Class<T> clientType)

Creates a new client that connects to the specified EndpointGroup with the specified SessionProtocol using the default ClientFactory.

Parameters:

protocol - the SessionProtocol

endpointGroup - the server EndpointGroup

clientType - the type of the new client

Throws:

IllegalArgumentException - if the specified clientType is unsupported for the specified SessionProtocol or SerializationFormat is required.

newClient

public static <T> T newClient(SessionProtocol protocol,
 EndpointGroup endpointGroup,
 String path,
 Class<T> clientType)

Creates a new client that connects to the specified EndpointGroup with the specified SessionProtocol and path using the default ClientFactory.

Parameters:

protocol - the SessionProtocol

endpointGroup - the server EndpointGroup

path - the path to the endpoint

clientType - the type of the new client

Throws:

IllegalArgumentException - if the specified clientType is unsupported for the specified SessionProtocol or SerializationFormat is required.

builder

public static ClientBuilder builder(String uri)

Returns a new ClientBuilder that builds the client that connects to the specified uri.

Throws:

IllegalArgumentException - if the specified uri is invalid, or the specified clientType is unsupported for the uri's scheme

builder

public static ClientBuilder builder(URI uri)

Returns a new ClientBuilder that builds the client that connects to the specified URI.

Throws:

IllegalArgumentException - if the specified URI is invalid, or the specified clientType is unsupported for the URI's scheme

builder

public static ClientBuilder builder(String scheme,
 EndpointGroup endpointGroup)

Returns a new ClientBuilder that builds the client that connects to the specified EndpointGroup with the specified scheme.

Throws:

IllegalArgumentException - if the scheme is invalid.

builder

public static ClientBuilder builder(String scheme,
 EndpointGroup endpointGroup,
 String path)

Returns a new ClientBuilder that builds the client that connects to the specified EndpointGroup with the specified scheme and path.

Throws:

IllegalArgumentException - if the scheme is invalid.

builder

public static ClientBuilder builder(SessionProtocol protocol,
 EndpointGroup endpointGroup)

Returns a new ClientBuilder that builds the client that connects to the specified EndpointGroup with the specified SessionProtocol.

builder

public static ClientBuilder builder(SessionProtocol protocol,
 EndpointGroup endpointGroup,
 String path)

Returns a new ClientBuilder that builds the client that connects to the specified EndpointGroup with the specified SessionProtocol and path.

builder

public static ClientBuilder builder(Scheme scheme,
 EndpointGroup endpointGroup)

Returns a new ClientBuilder that builds the client that connects to the specified EndpointGroup with the specified Scheme.

builder

public static ClientBuilder builder(Scheme scheme,
 EndpointGroup endpointGroup,
 String path)

Returns a new ClientBuilder that builds the client that connects to the specified EndpointGroup with the specified Scheme and path.

newDerivedClient

public static <T> T newDerivedClient(T client,
 ClientOptionValue<?>... additionalOptions)

Creates a new derived client that connects to the same URI with the specified client and the specified additionalOptions.

See Also:

• ClientBuilder, for more information about how the base options and additional options are merged when a derived client is created.

newDerivedClient

public static <T> T newDerivedClient(T client,
 Iterable<ClientOptionValue<?>> additionalOptions)

Creates a new derived client that connects to the same URI with the specified client and the specified additionalOptions.

See Also:

• ClientBuilder, for more information about how the base options and additional options are merged when a derived client is created.

newDerivedClient

public static <T> T newDerivedClient(T client,
 Function<? super ClientOptions,ClientOptions> configurator)

Creates a new derived client that connects to the same URI with the specified client but with different ClientOptions. For example:

 WebClient derivedWebClient = Clients.newDerivedClient(webClient, options -> {
     ClientOptionsBuilder builder = options.toBuilder();
     builder.decorator(...); // Add a decorator.
     builder.addHeader(...); // Add an HTTP header.
     return builder.build();
 });
 

Parameters:

configurator - a Function whose input is the original ClientOptions of the client being derived from and whose output is the ClientOptions of the new derived client

See Also:

• ClientBuilder, for more information about how the base options and additional options are merged when a derived client is created.
• ClientOptionsBuilder

unwrap

@Nullable
public static <T> T unwrap(Object client,
 Class<T> type)

Unwraps the specified client into the object of the specified type. Use this method instead of an explicit downcast. For example:

 WebClient client = WebClient.builder(...)
                             .decorator(LoggingClient.newDecorator())
                             .build();

 LoggingClient unwrapped = Clients.unwrap(client, LoggingClient.class);

 // If the client implements Unwrappable, you can just use the 'as()' method.
 LoggingClient unwrapped2 = client.as(LoggingClient.class);
 

Parameters:

type - the type of the object to return

Returns:

the object of the specified type if found, or null if not found.

See Also:

• Client.as(Class)
• ClientFactory.unwrap(Object, Class)
• Unwrappable

withHeader

@MustBeClosed
public static SafeCloseable withHeader(CharSequence name,
 String value)

Sets the specified HTTP header in a thread-local variable so that the header is sent by the client call made from the current thread. Use the try-with-resources block with the returned SafeCloseable to unset the thread-local variable automatically:

 import static com.linecorp.armeria.common.HttpHeaderNames.AUTHORIZATION;

 try (SafeCloseable ignored = withHeader(AUTHORIZATION, myCredential)) {
     client.executeSomething(..);
 }
 

You can also nest the header manipulation:

 import static com.linecorp.armeria.common.HttpHeaderNames.AUTHORIZATION;
 import static com.linecorp.armeria.common.HttpHeaderNames.USER_AGENT;

 try (SafeCloseable ignored = withHeader(USER_AGENT, myAgent)) {
     for (String secret : secrets) {
         try (SafeCloseable ignored2 = withHeader(AUTHORIZATION, secret)) {
             // Both USER_AGENT and AUTHORIZATION will be set.
             client.executeSomething(..);
         }
     }
 }
 

See Also:

• withHeaders(Consumer)

withHeader

@MustBeClosed
public static SafeCloseable withHeader(CharSequence name,
 Object value)

Sets the specified HTTP header in a thread-local variable so that the header is sent by the client call made from the current thread. Use the try-with-resources block with the returned SafeCloseable to unset the thread-local variable automatically:

 import static com.linecorp.armeria.common.HttpHeaderNames.CONTENT_TYPE;
 import static com.linecorp.armeria.common.MediaType.JSON_UTF_8;

 try (SafeCloseable ignored = withHeader(CONTENT_TYPE, JSON_UTF_8)) {
     client.executeSomething(..);
 }
 

You can also nest the header manipulation:

 import static com.linecorp.armeria.common.HttpHeaderNames.AUTHORIZATION;
 import static com.linecorp.armeria.common.HttpHeaderNames.CONTENT_TYPE;
 import static com.linecorp.armeria.common.MediaType.JSON_UTF_8;

 try (SafeCloseable ignored = withHeader(CONTENT_TYPE, JSON_UTF_8)) {
     for (String secret : secrets) {
         try (SafeCloseable ignored2 = withHeader(AUTHORIZATION, secret)) {
             // Both CONTENT_TYPE and AUTHORIZATION will be set.
             client.executeSomething(..);
         }
     }
 }
 

See Also:

• withHeaders(Consumer)

withHeaders

@MustBeClosed
public static SafeCloseable withHeaders(Consumer<HttpHeadersBuilder> headerMutator)

Sets the specified Consumer, which mutates HTTP headers, in a thread-local variable so that the mutated headers are sent by the client call made from the current thread. Use the try-with-resources block with the returned SafeCloseable to unset the thread-local variable automatically:

 import static com.linecorp.armeria.common.HttpHeaderNames.AUTHORIZATION;
 import static com.linecorp.armeria.common.HttpHeaderNames.USER_AGENT;

 try (SafeCloseable ignored = withHeaders(builder -> {
     builder.set(HttpHeaders.AUTHORIZATION, myCredential)
            .set(HttpHeaders.USER_AGENT, myAgent);
 })) {
     client.executeSomething(..);
 }
 

You can also nest the header mutation:

 import static com.linecorp.armeria.common.HttpHeaderNames.AUTHORIZATION;
 import static com.linecorp.armeria.common.HttpHeaderNames.USER_AGENT;

 try (SafeCloseable ignored = withHeaders(builder -> {
          builder.set(USER_AGENT, myAgent);
      })) {
     for (String secret : secrets) {
         try (SafeCloseable ignored2 = withHeaders(builder -> {
                  builder.set(AUTHORIZATION, secret);
              })) {
             // Both USER_AGENT and AUTHORIZATION will be set.
             client.executeSomething(..);
         }
     }
 }
 

See Also:

• withHeader(CharSequence, String)

withContextCustomizer

@MustBeClosed
public static SafeCloseable withContextCustomizer(Consumer<? super ClientRequestContext> contextCustomizer)

Sets the specified ClientRequestContext customizer function in a thread-local variable so that the customized context is used when the client invokes a request from the current thread. The given customizer function is evaluated after the customizer function specified with ClientBuilder.contextCustomizer(Consumer).

Use the try-with-resources block with the returned SafeCloseable to unset the thread-local variable automatically:

 // Good:
 try (SafeCloseable ignored = withContextCustomizer(ctx -> {
     ctx.setAttr(USER_ID, userId);
     ctx.setAttr(USER_SECRET, secret);
 })) {
     client.executeSomething(..);
 }

 // Bad:
 try (SafeCloseable ignored = withContextCustomizer(ctx -> {
     ctx.setAttr(USER_ID, userId);
     ctx.setAttr(USER_SECRET, secret);
 })) {
     executor.execute(() -> {
         // The variables in USER_ID and USER_SECRET will not be propagated to the context.
         // client.executeSomething() must be invoked by the same thread
         // that called withContextCustomizer().
         client.executeSomething(..);
     });
 }
 

You can also nest the request context customization:

 try (SafeCloseable ignored = withContextCustomizer(ctx -> ctx.setAttr(USER_ID, userId))) {
     String secret = client.getSecret();
     try (SafeCloseable ignored2 = withContextCustomizer(ctx -> ctx.setAttr(USER_SECRET, secret))) {
         // Both USER_ID and USER_SECRET will be set.
         client.executeSomething(..);
     }
 }
 

Note that certain properties of ClientRequestContext, such as:

• ClientRequestContext.endpoint()
• RequestContext.localAddress()
• RequestContext.remoteAddress()

may be null while the customizer function runs, because the target host of the Request is not determined yet.

See Also:

• withHeaders(Consumer)
• ClientBuilder.contextCustomizer(Consumer)

newContextCaptor

public static ClientRequestContextCaptor newContextCaptor()

Prepare to capture the ClientRequestContext of the next request sent from the current thread. Use the try-with-resources block with the returned ClientRequestContextCaptor to retrieve the captured ClientRequestContext and to unset the thread-local variable automatically.

 try (ClientRequestContextCaptor captor = Clients.newContextCaptor()) {
     WebClient.of().get("https://www.example.com/hello");
     ClientRequestContext ctx = captor.get();
     assert ctx.path().equals("/hello");
 }

Note that you can also capture more than one ClientRequestContext:

 try (ClientRequestContextCaptor captor = Clients.newContextCaptor()) {
     WebClient.of().get("https://www.example.com/foo");
     WebClient.of().get("https://www.example.com/bar");
     List<ClientRequestContext> contexts = captor.getAll();
     assert contexts.get(0).path().equals("/foo");
     assert contexts.get(1).path().equals("/bar");
 }

isUndefinedUri

public static boolean isUndefinedUri(URI uri)

Returns true if the specified uri is an undefined URI, which signifies that a Client, was created without a URI or EndpointGroup. For example, isUndefinedUri(WebClient.of().uri()) will return true.