JDK14/Java14源码在线阅读
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* particular file as subject to the "Classpath" exception as provided
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*
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* accompanied this code).
*
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package java.net.http;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import java.nio.ByteBuffer;
import java.nio.charset.Charset;
import java.nio.channels.FileChannel;
import java.nio.charset.StandardCharsets;
import java.nio.file.OpenOption;
import java.nio.file.Path;
import java.util.List;
import java.util.Objects;
import java.util.Optional;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.CompletionStage;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.Flow;
import java.util.concurrent.Flow.Subscriber;
import java.util.concurrent.Flow.Publisher;
import java.util.concurrent.Flow.Subscription;
import java.util.function.Consumer;
import java.util.function.Function;
import java.util.function.Supplier;
import java.util.stream.Stream;
import javax.net.ssl.SSLSession;
import jdk.internal.net.http.BufferingSubscriber;
import jdk.internal.net.http.LineSubscriberAdapter;
import jdk.internal.net.http.ResponseBodyHandlers.FileDownloadBodyHandler;
import jdk.internal.net.http.ResponseBodyHandlers.PathBodyHandler;
import jdk.internal.net.http.ResponseBodyHandlers.PushPromisesHandlerWithMap;
import jdk.internal.net.http.ResponseSubscribers;
import jdk.internal.net.http.ResponseSubscribers.PathSubscriber;
import static java.nio.file.StandardOpenOption.*;
import static jdk.internal.net.http.common.Utils.charsetFrom;
/**
* An HTTP response.
*
* <p> An {@code HttpResponse} is not created directly, but rather returned as
* a result of sending an {@link HttpRequest}. An {@code HttpResponse} is
* made available when the response status code and headers have been received,
* and typically after the response body has also been completely received.
* Whether or not the {@code HttpResponse} is made available before the response
* body has been completely received depends on the {@link BodyHandler
* BodyHandler} provided when sending the {@code HttpRequest}.
*
* <p> This class provides methods for accessing the response status code,
* headers, the response body, and the {@code HttpRequest} corresponding
* to this response.
*
* <p> The following is an example of retrieving a response as a String:
*
* <pre>{@code HttpResponse<String> response = client
* .send(request, BodyHandlers.ofString()); }</pre>
*
* <p> The class {@link BodyHandlers BodyHandlers} provides implementations
* of many common response handlers. Alternatively, a custom {@code BodyHandler}
* implementation can be used.
*
* @param <T> the response body type
* @since 11
*/
public interface HttpResponse<T> {
/**
* Returns the status code for this response.
*
* @return the response code
*/
public int statusCode();
/**
* Returns the {@link HttpRequest} corresponding to this response.
*
* <p> The returned {@code HttpRequest} may not be the initiating request
* provided when {@linkplain HttpClient#send(HttpRequest, BodyHandler)
* sending}. For example, if the initiating request was redirected, then the
* request returned by this method will have the redirected URI, which will
* be different from the initiating request URI.
*
* @see #previousResponse()
*
* @return the request
*/
public HttpRequest request();
/**
* Returns an {@code Optional} containing the previous intermediate response
* if one was received. An intermediate response is one that is received
* as a result of redirection or authentication. If no previous response
* was received then an empty {@code Optional} is returned.
*
* @return an Optional containing the HttpResponse, if any.
*/
public Optional<HttpResponse<T>> previousResponse();
/**
* Returns the received response headers.
*
* @return the response headers
*/
public HttpHeaders headers();
/**
* Returns the body. Depending on the type of {@code T}, the returned body
* may represent the body after it was read (such as {@code byte[]}, or
* {@code String}, or {@code Path}) or it may represent an object with
* which the body is read, such as an {@link java.io.InputStream}.
*
* <p> If this {@code HttpResponse} was returned from an invocation of
* {@link #previousResponse()} then this method returns {@code null}
*
* @return the body
*/
public T body();
/**
* Returns an {@link Optional} containing the {@link SSLSession} in effect
* for this response. Returns an empty {@code Optional} if this is not a
* <i>HTTPS</i> response.
*
* @return an {@code Optional} containing the {@code SSLSession} associated
* with the response
*/
public Optional<SSLSession> sslSession();
/**
* Returns the {@code URI} that the response was received from. This may be
* different from the request {@code URI} if redirection occurred.
*
* @return the URI of the response
*/
public URI uri();
/**
* Returns the HTTP protocol version that was used for this response.
*
* @return HTTP protocol version
*/
public HttpClient.Version version();
/**
* Initial response information supplied to a {@link BodyHandler BodyHandler}
* when a response is initially received and before the body is processed.
*/
public interface ResponseInfo {
/**
* Provides the response status code.
* @return the response status code
*/
public int statusCode();
/**
* Provides the response headers.
* @return the response headers
*/
public HttpHeaders headers();
/**
* Provides the response protocol version.
* @return the response protocol version
*/
public HttpClient.Version version();
}
/**
* A handler for response bodies. The class {@link BodyHandlers BodyHandlers}
* provides implementations of many common body handlers.
*
* <p> The {@code BodyHandler} interface allows inspection of the response
* code and headers, before the actual response body is received, and is
* responsible for creating the response {@link BodySubscriber
* BodySubscriber}. The {@code BodySubscriber} consumes the actual response
* body bytes and, typically, converts them into a higher-level Java type.
*
* <p> A {@code BodyHandler} is a function that takes a {@link ResponseInfo
* ResponseInfo} object; and which returns a {@code BodySubscriber}. The
* {@code BodyHandler} is invoked when the response status code and headers
* are available, but before the response body bytes are received.
*
* <p> The following example uses one of the {@linkplain BodyHandlers
* predefined body handlers} that always process the response body in the
* same way ( streams the response body to a file ).
*
* <pre>{@code HttpRequest request = HttpRequest.newBuilder()
* .uri(URI.create("http://www.foo.com/"))
* .build();
* client.sendAsync(request, BodyHandlers.ofFile(Paths.get("/tmp/f")))
* .thenApply(HttpResponse::body)
* .thenAccept(System.out::println); }</pre>
*
* Note, that even though the pre-defined handlers do not examine the
* response code, the response code and headers are always retrievable from
* the {@link HttpResponse}, when it is returned.
*
* <p> In the second example, the function returns a different subscriber
* depending on the status code.
* <pre>{@code HttpRequest request = HttpRequest.newBuilder()
* .uri(URI.create("http://www.foo.com/"))
* .build();
* BodyHandler<Path> bodyHandler = (rspInfo) -> rspInfo.statusCode() == 200
* ? BodySubscribers.ofFile(Paths.get("/tmp/f"))
* : BodySubscribers.replacing(Paths.get("/NULL"));
* client.sendAsync(request, bodyHandler)
* .thenApply(HttpResponse::body)
* .thenAccept(System.out::println); }</pre>
*
* @param <T> the response body type
* @see BodyHandlers
* @since 11
*/
@FunctionalInterface
public interface BodyHandler<T> {
/**
* Returns a {@link BodySubscriber BodySubscriber} considering the
* given response status code and headers. This method is invoked before
* the actual response body bytes are read and its implementation must
* return a {@link BodySubscriber BodySubscriber} to consume the response
* body bytes.
*
* <p> The response body can be discarded using one of {@link
* BodyHandlers#discarding() discarding} or {@link
* BodyHandlers#replacing(Object) replacing}.
*
* @param responseInfo the response info
* @return a body subscriber
*/
public BodySubscriber<T> apply(ResponseInfo responseInfo);
}
/**
* Implementations of {@link BodyHandler BodyHandler} that implement various
* useful handlers, such as handling the response body as a String, or
* streaming the response body to a file.
*
* <p> These implementations do not examine the status code, meaning the
* body is always accepted. They typically return an equivalently named
* {@code BodySubscriber}. Alternatively, a custom handler can be used to
* examine the status code and headers, and return a different body
* subscriber, of the same type, as appropriate.
*
* <p>The following are examples of using the predefined body handlers to
* convert a flow of response body data into common high-level Java objects:
*
* <pre>{@code // Receives the response body as a String
* HttpResponse<String> response = client
* .send(request, BodyHandlers.ofString());
*
* // Receives the response body as a file
* HttpResponse<Path> response = client
* .send(request, BodyHandlers.ofFile(Paths.get("example.html")));
*
* // Receives the response body as an InputStream
* HttpResponse<InputStream> response = client
* .send(request, BodyHandlers.ofInputStream());
*
* // Discards the response body
* HttpResponse<Void> response = client
* .send(request, BodyHandlers.discarding()); }</pre>
*
* @since 11
*/
public static class BodyHandlers {
private BodyHandlers() { }
/**
* Returns a response body handler that returns a {@link BodySubscriber
* BodySubscriber}{@code <Void>} obtained from {@link
* BodySubscribers#fromSubscriber(Subscriber)}, with the given
* {@code subscriber}.
*
* <p> The response body is not available through this, or the {@code
* HttpResponse} API, but instead all response body is forwarded to the
* given {@code subscriber}, which should make it available, if
* appropriate, through some other mechanism, e.g. an entry in a
* database, etc.
*
* @apiNote This method can be used as an adapter between {@code
* BodySubscriber} and {@code Flow.Subscriber}.
*
* <p> For example:
* <pre> {@code TextSubscriber subscriber = new TextSubscriber();
* HttpResponse<Void> response = client.sendAsync(request,
* BodyHandlers.fromSubscriber(subscriber)).join();
* System.out.println(response.statusCode()); }</pre>
*
* @param subscriber the subscriber
* @return a response body handler
*/
public static BodyHandler<Void>
fromSubscriber(Subscriber<? super List<ByteBuffer>> subscriber) {
Objects.requireNonNull(subscriber);
return (responseInfo) -> BodySubscribers.fromSubscriber(subscriber,
s -> null);
}
/**
* Returns a response body handler that returns a {@link BodySubscriber
* BodySubscriber}{@code <T>} obtained from {@link
* BodySubscribers#fromSubscriber(Subscriber, Function)}, with the
* given {@code subscriber} and {@code finisher} function.
*
* <p> The given {@code finisher} function is applied after the given
* subscriber's {@code onComplete} has been invoked. The {@code finisher}
* function is invoked with the given subscriber, and returns a value
* that is set as the response's body.
*
* @apiNote This method can be used as an adapter between {@code
* BodySubscriber} and {@code Flow.Subscriber}.
*
* <p> For example:
* <pre> {@code TextSubscriber subscriber = ...; // accumulates bytes and transforms them into a String
* HttpResponse<String> response = client.sendAsync(request,
* BodyHandlers.fromSubscriber(subscriber, TextSubscriber::getTextResult)).join();
* String text = response.body(); }</pre>
*
* @param <S> the type of the Subscriber
* @param <T> the type of the response body
* @param subscriber the subscriber
* @param finisher a function to be applied after the subscriber has completed
* @return a response body handler
*/
public static <S extends Subscriber<? super List<ByteBuffer>>,T> BodyHandler<T>
fromSubscriber(S subscriber, Function<? super S,? extends T> finisher) {
Objects.requireNonNull(subscriber);
Objects.requireNonNull(finisher);
return (responseInfo) -> BodySubscribers.fromSubscriber(subscriber,
finisher);
}
/**
* Returns a response body handler that returns a {@link BodySubscriber
* BodySubscriber}{@code <Void>} obtained from {@link
* BodySubscribers#fromLineSubscriber(Subscriber, Function, Charset, String)
* BodySubscribers.fromLineSubscriber(subscriber, s -> null, charset, null)},
* with the given {@code subscriber}.
* The {@link Charset charset} used to decode the response body bytes is
* obtained from the HTTP response headers as specified by {@link #ofString()},
* and lines are delimited in the manner of {@link BufferedReader#readLine()}.
*
* <p> The response body is not available through this, or the {@code
* HttpResponse} API, but instead all response body is forwarded to the
* given {@code subscriber}, which should make it available, if
* appropriate, through some other mechanism, e.g. an entry in a
* database, etc.
*
* @apiNote This method can be used as an adapter between a {@code
* BodySubscriber} and a text based {@code Flow.Subscriber} that parses
* text line by line.
*
* <p> For example:
* <pre> {@code // A PrintSubscriber that implements Flow.Subscriber<String>
* // and print lines received by onNext() on System.out
* PrintSubscriber subscriber = new PrintSubscriber(System.out);
* client.sendAsync(request, BodyHandlers.fromLineSubscriber(subscriber))
* .thenApply(HttpResponse::statusCode)
* .thenAccept((status) -> {
* if (status != 200) {
* System.err.printf("ERROR: %d status received%n", status);
* }
* }); }</pre>
*
* @param subscriber the subscriber
* @return a response body handler
*/
public static BodyHandler<Void>
fromLineSubscriber(Subscriber<? super String> subscriber) {
Objects.requireNonNull(subscriber);
return (responseInfo) ->
BodySubscribers.fromLineSubscriber(subscriber,
s -> null,
charsetFrom(responseInfo.headers()),
null);
}
/**
* Returns a response body handler that returns a {@link BodySubscriber
* BodySubscriber}{@code <T>} obtained from {@link
* BodySubscribers#fromLineSubscriber(Subscriber, Function, Charset, String)
* BodySubscribers.fromLineSubscriber(subscriber, finisher, charset, lineSeparator)},
* with the given {@code subscriber}, {@code finisher} function, and line separator.
* The {@link Charset charset} used to decode the response body bytes is
* obtained from the HTTP response headers as specified by {@link #ofString()}.
*
* <p> The given {@code finisher} function is applied after the given
* subscriber's {@code onComplete} has been invoked. The {@code finisher}
* function is invoked with the given subscriber, and returns a value
* that is set as the response's body.
*
* @apiNote This method can be used as an adapter between a {@code
* BodySubscriber} and a text based {@code Flow.Subscriber} that parses
* text line by line.
*
* <p> For example:
* <pre> {@code // A LineParserSubscriber that implements Flow.Subscriber<String>
* // and accumulates lines that match a particular pattern
* Pattern pattern = ...;
* LineParserSubscriber subscriber = new LineParserSubscriber(pattern);
* HttpResponse<List<String>> response = client.send(request,
* BodyHandlers.fromLineSubscriber(subscriber, s -> s.getMatchingLines(), "\n"));
* if (response.statusCode() != 200) {
* System.err.printf("ERROR: %d status received%n", response.statusCode());
* } }</pre>
*
*
* @param <S> the type of the Subscriber
* @param <T> the type of the response body
* @param subscriber the subscriber
* @param finisher a function to be applied after the subscriber has completed
* @param lineSeparator an optional line separator: can be {@code null},
* in which case lines will be delimited in the manner of
* {@link BufferedReader#readLine()}.
* @return a response body handler
* @throws IllegalArgumentException if the supplied {@code lineSeparator}
* is the empty string
*/
public static <S extends Subscriber<? super String>,T> BodyHandler<T>
fromLineSubscriber(S subscriber,
Function<? super S,? extends T> finisher,
String lineSeparator) {
Objects.requireNonNull(subscriber);
Objects.requireNonNull(finisher);
// implicit null check
if (lineSeparator != null && lineSeparator.isEmpty())
throw new IllegalArgumentException("empty line separator");
return (responseInfo) ->
BodySubscribers.fromLineSubscriber(subscriber,
finisher,
charsetFrom(responseInfo.headers()),
lineSeparator);
}
/**
* Returns a response body handler that discards the response body.
*
* @return a response body handler
*/
public static BodyHandler<Void> discarding() {
return (responseInfo) -> BodySubscribers.discarding();
}
/**
* Returns a response body handler that returns the given replacement
* value, after discarding the response body.
*
* @param <U> the response body type
* @param value the value of U to return as the body, may be {@code null}
* @return a response body handler
*/
public static <U> BodyHandler<U> replacing(U value) {
return (responseInfo) -> BodySubscribers.replacing(value);
}
/**
* Returns a {@code BodyHandler<String>} that returns a
* {@link BodySubscriber BodySubscriber}{@code <String>} obtained from
* {@link BodySubscribers#ofString(Charset) BodySubscribers.ofString(Charset)}.
* The body is decoded using the given character set.
*
* @param charset the character set to convert the body with
* @return a response body handler
*/
public static BodyHandler<String> ofString(Charset charset) {
Objects.requireNonNull(charset);
return (responseInfo) -> BodySubscribers.ofString(charset);
}
/**
* Returns a {@code BodyHandler<Path>} that returns a
* {@link BodySubscriber BodySubscriber}{@code <Path>} obtained from
* {@link BodySubscribers#ofFile(Path, OpenOption...)
* BodySubscribers.ofFile(Path,OpenOption...)}.
*
* <p> When the {@code HttpResponse} object is returned, the body has
* been completely written to the file, and {@link #body()} returns a
* reference to its {@link Path}.
*
* <p> Security manager permission checks are performed in this factory
* method, when the {@code BodyHandler} is created. Care must be taken
* that the {@code BodyHandler} is not shared with untrusted code.
*
* @param file the file to store the body in
* @param openOptions any options to use when opening/creating the file
* @return a response body handler
* @throws IllegalArgumentException if an invalid set of open options
* are specified
* @throws SecurityException If a security manager has been installed
* and it denies {@linkplain SecurityManager#checkWrite(String)
* write access} to the file.
*/
public static BodyHandler<Path> ofFile(Path file, OpenOption... openOptions) {
Objects.requireNonNull(file);
List<OpenOption> opts = List.of(openOptions);
if (opts.contains(DELETE_ON_CLOSE) || opts.contains(READ)) {
// these options make no sense, since the FileChannel is not exposed
throw new IllegalArgumentException("invalid openOptions: " + opts);
}
return PathBodyHandler.create(file, opts);
}
/**
* Returns a {@code BodyHandler<Path>} that returns a
* {@link BodySubscriber BodySubscriber}{@code <Path>}.
*
* <p> Equivalent to: {@code ofFile(file, CREATE, WRITE)}
*
* <p> Security manager permission checks are performed in this factory
* method, when the {@code BodyHandler} is created. Care must be taken
* that the {@code BodyHandler} is not shared with untrusted code.
*
* @param file the file to store the body in
* @return a response body handler
* @throws SecurityException If a security manager has been installed
* and it denies {@linkplain SecurityManager#checkWrite(String)
* write access} to the file.
*/
public static BodyHandler<Path> ofFile(Path file) {
return BodyHandlers.ofFile(file, CREATE, WRITE);
}
/**
* Returns a {@code BodyHandler<Path>} that returns a
* {@link BodySubscriber BodySubscriber}<{@link Path}>
* where the download directory is specified, but the filename is
* obtained from the {@code Content-Disposition} response header. The
* {@code Content-Disposition} header must specify the <i>attachment</i>
* type and must also contain a <i>filename</i> parameter. If the
* filename specifies multiple path components only the final component
* is used as the filename (with the given directory name).
*
* <p> When the {@code HttpResponse} object is returned, the body has
* been completely written to the file and {@link #body()} returns a
* {@code Path} object for the file. The returned {@code Path} is the
* combination of the supplied directory name and the file name supplied
* by the server. If the destination directory does not exist or cannot
* be written to, then the response will fail with an {@link IOException}.
*
* <p> Security manager permission checks are performed in this factory
* method, when the {@code BodyHandler} is created. Care must be taken
* that the {@code BodyHandler} is not shared with untrusted code.
*
* @param directory the directory to store the file in
* @param openOptions open options used when opening the file
* @return a response body handler
* @throws IllegalArgumentException if the given path does not exist,
* is not a directory, is not writable, or if an invalid set
* of open options are specified
* @throws SecurityException If a security manager has been installed
* and it denies
* {@linkplain SecurityManager#checkRead(String) read access}
* to the directory, or it denies
* {@linkplain SecurityManager#checkWrite(String) write access}
* to the directory, or it denies
* {@linkplain SecurityManager#checkWrite(String) write access}
* to the files within the directory.
*/
public static BodyHandler<Path> ofFileDownload(Path directory,
OpenOption... openOptions) {
Objects.requireNonNull(directory);
List<OpenOption> opts = List.of(openOptions);
if (opts.contains(DELETE_ON_CLOSE)) {
throw new IllegalArgumentException("invalid option: " + DELETE_ON_CLOSE);
}
return FileDownloadBodyHandler.create(directory, opts);
}
/**
* Returns a {@code BodyHandler<InputStream>} that returns a
* {@link BodySubscriber BodySubscriber}{@code <InputStream>} obtained from
* {@link BodySubscribers#ofInputStream() BodySubscribers.ofInputStream}.
*
* <p> When the {@code HttpResponse} object is returned, the response
* headers will have been completely read, but the body may not have
* been fully received yet. The {@link #body()} method returns an
* {@link InputStream} from which the body can be read as it is received.
*
* @apiNote See {@link BodySubscribers#ofInputStream()} for more
* information.
*
* @return a response body handler
*/
public static BodyHandler<InputStream> ofInputStream() {
return (responseInfo) -> BodySubscribers.ofInputStream();
}
/**
* Returns a {@code BodyHandler<Stream<String>>} that returns a
* {@link BodySubscriber BodySubscriber}{@code <Stream<String>>} obtained
* from {@link BodySubscribers#ofLines(Charset) BodySubscribers.ofLines(charset)}.
* The {@link Charset charset} used to decode the response body bytes is
* obtained from the HTTP response headers as specified by {@link #ofString()},
* and lines are delimited in the manner of {@link BufferedReader#readLine()}.
*
* <p> When the {@code HttpResponse} object is returned, the body may
* not have been completely received.
*
* @return a response body handler
*/
public static BodyHandler<Stream<String>> ofLines() {
return (responseInfo) ->
BodySubscribers.ofLines(charsetFrom(responseInfo.headers()));
}
/**
* Returns a {@code BodyHandler<Void>} that returns a
* {@link BodySubscriber BodySubscriber}{@code <Void>} obtained from
* {@link BodySubscribers#ofByteArrayConsumer(Consumer)
* BodySubscribers.ofByteArrayConsumer(Consumer)}.
*
* <p> When the {@code HttpResponse} object is returned, the body has
* been completely written to the consumer.
*
* @apiNote
* The subscriber returned by this handler is not flow controlled.
* Therefore, the supplied consumer must be able to process whatever
* amount of data is delivered in a timely fashion.
*
* @param consumer a Consumer to accept the response body
* @return a response body handler
*/
public static BodyHandler<Void>
ofByteArrayConsumer(Consumer<Optional<byte[]>> consumer) {
Objects.requireNonNull(consumer);
return (responseInfo) -> BodySubscribers.ofByteArrayConsumer(consumer);
}
/**
* Returns a {@code BodyHandler<byte[]>} that returns a
* {@link BodySubscriber BodySubscriber}{@code <byte[]>} obtained
* from {@link BodySubscribers#ofByteArray() BodySubscribers.ofByteArray()}.
*
* <p> When the {@code HttpResponse} object is returned, the body has
* been completely written to the byte array.
*
* @return a response body handler
*/
public static BodyHandler<byte[]> ofByteArray() {
return (responseInfo) -> BodySubscribers.ofByteArray();
}
/**
* Returns a {@code BodyHandler<String>} that returns a
* {@link BodySubscriber BodySubscriber}{@code <String>} obtained from
* {@link BodySubscribers#ofString(Charset) BodySubscribers.ofString(Charset)}.
* The body is decoded using the character set specified in
* the {@code Content-Type} response header. If there is no such
* header, or the character set is not supported, then
* {@link StandardCharsets#UTF_8 UTF_8} is used.
*
* <p> When the {@code HttpResponse} object is returned, the body has
* been completely written to the string.
*
* @return a response body handler
*/
public static BodyHandler<String> ofString() {
return (responseInfo) -> BodySubscribers.ofString(charsetFrom(responseInfo.headers()));
}
/**
* Returns a {@code BodyHandler<Publisher<List<ByteBuffer>>>} that creates a
* {@link BodySubscriber BodySubscriber}{@code <Publisher<List<ByteBuffer>>>}
* obtained from {@link BodySubscribers#ofPublisher()
* BodySubscribers.ofPublisher()}.
*
* <p> When the {@code HttpResponse} object is returned, the response
* headers will have been completely read, but the body may not have
* been fully received yet. The {@link #body()} method returns a
* {@link Publisher Publisher}{@code <List<ByteBuffer>>} from which the body
* response bytes can be obtained as they are received. The publisher
* can and must be subscribed to only once.
*
* @apiNote See {@link BodySubscribers#ofPublisher()} for more
* information.
*
* @return a response body handler
*/
public static BodyHandler<Publisher<List<ByteBuffer>>> ofPublisher() {
return (responseInfo) -> BodySubscribers.ofPublisher();
}
/**
* Returns a {@code BodyHandler} which, when invoked, returns a {@linkplain
* BodySubscribers#buffering(BodySubscriber,int) buffering BodySubscriber}
* that buffers data before delivering it to the downstream subscriber.
* These {@code BodySubscriber} instances are created by calling
* {@link BodySubscribers#buffering(BodySubscriber,int)
* BodySubscribers.buffering} with a subscriber obtained from the given
* downstream handler and the {@code bufferSize} parameter.
*
* @param <T> the response body type
* @param downstreamHandler the downstream handler
* @param bufferSize the buffer size parameter passed to {@link
* BodySubscribers#buffering(BodySubscriber,int) BodySubscribers.buffering}
* @return a body handler
* @throws IllegalArgumentException if {@code bufferSize <= 0}
*/
public static <T> BodyHandler<T> buffering(BodyHandler<T> downstreamHandler,
int bufferSize) {
Objects.requireNonNull(downstreamHandler);
if (bufferSize <= 0)
throw new IllegalArgumentException("must be greater than 0");
return (responseInfo) -> BodySubscribers
.buffering(downstreamHandler.apply(responseInfo),
bufferSize);
}
}
/**
* A handler for push promises.
*
* <p> A <i>push promise</i> is a synthetic request sent by an HTTP/2 server
* when retrieving an initiating client-sent request. The server has
* determined, possibly through inspection of the initiating request, that
* the client will likely need the promised resource, and hence pushes a
* synthetic push request, in the form of a push promise, to the client. The
* client can choose to accept or reject the push promise request.
*
* <p> A push promise request may be received up to the point where the
* response body of the initiating client-sent request has been fully
* received. The delivery of a push promise response, however, is not
* coordinated with the delivery of the response to the initiating
* client-sent request.
*
* @param <T> the push promise response body type
* @since 11
*/
public interface PushPromiseHandler<T> {
/**
* Notification of an incoming push promise.
*
* <p> This method is invoked once for each push promise received, up
* to the point where the response body of the initiating client-sent
* request has been fully received.
*
* <p> A push promise is accepted by invoking the given {@code acceptor}
* function. The {@code acceptor} function must be passed a non-null
* {@code BodyHandler}, that is to be used to handle the promise's
* response body. The acceptor function will return a {@code
* CompletableFuture} that completes with the promise's response.
*
* <p> If the {@code acceptor} function is not successfully invoked,
* then the push promise is rejected. The {@code acceptor} function will
* throw an {@code IllegalStateException} if invoked more than once.
*
* @param initiatingRequest the initiating client-send request
* @param pushPromiseRequest the synthetic push request
* @param acceptor the acceptor function that must be successfully
* invoked to accept the push promise
*/
public void applyPushPromise(
HttpRequest initiatingRequest,
HttpRequest pushPromiseRequest,
Function<HttpResponse.BodyHandler<T>,CompletableFuture<HttpResponse<T>>> acceptor
);
/**
* Returns a push promise handler that accumulates push promises, and
* their responses, into the given map.
*
* <p> Entries are added to the given map for each push promise accepted.
* The entry's key is the push request, and the entry's value is a
* {@code CompletableFuture} that completes with the response
* corresponding to the key's push request. A push request is rejected /
* cancelled if there is already an entry in the map whose key is
* {@linkplain HttpRequest#equals equal} to it. A push request is
* rejected / cancelled if it does not have the same origin as its
* initiating request.
*
* <p> Entries are added to the given map as soon as practically
* possible when a push promise is received and accepted. That way code,
* using such a map like a cache, can determine if a push promise has
* been issued by the server and avoid making, possibly, unnecessary
* requests.
*
* <p> The delivery of a push promise response is not coordinated with
* the delivery of the response to the initiating client-sent request.
* However, when the response body for the initiating client-sent
* request has been fully received, the map is guaranteed to be fully
* populated, that is, no more entries will be added. The individual
* {@code CompletableFutures} contained in the map may or may not
* already be completed at this point.
*
* @param <T> the push promise response body type
* @param pushPromiseHandler t he body handler to use for push promises
* @param pushPromisesMap a map to accumulate push promises into
* @return a push promise handler
*/
public static <T> PushPromiseHandler<T>
of(Function<HttpRequest,BodyHandler<T>> pushPromiseHandler,
ConcurrentMap<HttpRequest,CompletableFuture<HttpResponse<T>>> pushPromisesMap) {
return new PushPromisesHandlerWithMap<>(pushPromiseHandler, pushPromisesMap);
}
}
/**
* A {@code BodySubscriber} consumes response body bytes and converts them
* into a higher-level Java type. The class {@link BodySubscribers
* BodySubscribers} provides implementations of many common body subscribers.
*
* <p> The object acts as a {@link Flow.Subscriber}<{@link List}<{@link
* ByteBuffer}>> to the HTTP Client implementation, which publishes
* lists of ByteBuffers containing the response body. The Flow of data, as
* well as the order of ByteBuffers in the Flow lists, is a strictly ordered
* representation of the response body. Both the Lists and the ByteBuffers,
* once passed to the subscriber, are no longer used by the HTTP Client. The
* subscriber converts the incoming buffers of data to some higher-level
* Java type {@code T}.
*
* <p> The {@link #getBody()} method returns a
* {@link CompletionStage}{@code <T>} that provides the response body
* object. The {@code CompletionStage} must be obtainable at any time. When
* it completes depends on the nature of type {@code T}. In many cases,
* when {@code T} represents the entire body after being consumed then
* the {@code CompletionStage} completes after the body has been consumed.
* If {@code T} is a streaming type, such as {@link java.io.InputStream
* InputStream}, then it completes before the body has been read, because
* the calling code uses the {@code InputStream} to consume the data.
*
* @apiNote To ensure that all resources associated with the corresponding
* HTTP exchange are properly released, an implementation of {@code
* BodySubscriber} should ensure to {@linkplain Flow.Subscription#request
* request} more data until one of {@link #onComplete() onComplete} or
* {@link #onError(Throwable) onError} are signalled, or {@link
* Flow.Subscription#request cancel} its {@linkplain
* #onSubscribe(Flow.Subscription) subscription} if unable or unwilling to
* do so. Calling {@code cancel} before exhausting the response body data
* may cause the underlying HTTP connection to be closed and prevent it
* from being reused for subsequent operations.
*
* @implNote The flow of data containing the response body is immutable.
* Specifically, it is a flow of unmodifiable lists of read-only ByteBuffers.
*
* @param <T> the response body type
* @see BodySubscribers
* @since 11
*/
public interface BodySubscriber<T>
extends Flow.Subscriber<List<ByteBuffer>> {
/**
* Returns a {@code CompletionStage} which when completed will return
* the response body object. This method can be called at any time
* relative to the other {@link Flow.Subscriber} methods and is invoked
* using the client's {@link HttpClient#executor() executor}.
*
* @return a CompletionStage for the response body
*/
public CompletionStage<T> getBody();
}
/**
* Implementations of {@link BodySubscriber BodySubscriber} that implement
* various useful subscribers, such as converting the response body bytes
* into a String, or streaming the bytes to a file.
*
* <p>The following are examples of using the predefined body subscribers
* to convert a flow of response body data into common high-level Java
* objects:
*
* <pre>{@code // Streams the response body to a File
* HttpResponse<byte[]> response = client
* .send(request, responseInfo -> BodySubscribers.ofByteArray());
*
* // Accumulates the response body and returns it as a byte[]
* HttpResponse<byte[]> response = client
* .send(request, responseInfo -> BodySubscribers.ofByteArray());
*
* // Discards the response body
* HttpResponse<Void> response = client
* .send(request, responseInfo -> BodySubscribers.discarding());
*
* // Accumulates the response body as a String then maps it to its bytes
* HttpResponse<byte[]> response = client
* .send(request, responseInfo ->
* BodySubscribers.mapping(BodySubscribers.ofString(UTF_8), String::getBytes));
* }</pre>
*
* @since 11
*/
public static class BodySubscribers {
private BodySubscribers() { }
/**
* Returns a body subscriber that forwards all response body to the
* given {@code Flow.Subscriber}. The {@linkplain BodySubscriber#getBody()
* completion stage} of the returned body subscriber completes after one
* of the given subscribers {@code onComplete} or {@code onError} has
* been invoked.
*
* @apiNote This method can be used as an adapter between {@code
* BodySubscriber} and {@code Flow.Subscriber}.
*
* @param subscriber the subscriber
* @return a body subscriber
*/
public static BodySubscriber<Void>
fromSubscriber(Subscriber<? super List<ByteBuffer>> subscriber) {
return new ResponseSubscribers.SubscriberAdapter<>(subscriber, s -> null);
}
/**
* Returns a body subscriber that forwards all response body to the
* given {@code Flow.Subscriber}. The {@linkplain BodySubscriber#getBody()
* completion stage} of the returned body subscriber completes after one
* of the given subscribers {@code onComplete} or {@code onError} has
* been invoked.
*
* <p> The given {@code finisher} function is applied after the given
* subscriber's {@code onComplete} has been invoked. The {@code finisher}
* function is invoked with the given subscriber, and returns a value
* that is set as the response's body.
*
* @apiNote This method can be used as an adapter between {@code
* BodySubscriber} and {@code Flow.Subscriber}.
*
* @param <S> the type of the Subscriber
* @param <T> the type of the response body
* @param subscriber the subscriber
* @param finisher a function to be applied after the subscriber has
* completed
* @return a body subscriber
*/
public static <S extends Subscriber<? super List<ByteBuffer>>,T> BodySubscriber<T>
fromSubscriber(S subscriber,
Function<? super S,? extends T> finisher) {
return new ResponseSubscribers.SubscriberAdapter<>(subscriber, finisher);
}
/**
* Returns a body subscriber that forwards all response body to the
* given {@code Flow.Subscriber}, line by line.
* The {@linkplain BodySubscriber#getBody() completion
* stage} of the returned body subscriber completes after one of the
* given subscribers {@code onComplete} or {@code onError} has been
* invoked.
* Bytes are decoded using the {@link StandardCharsets#UTF_8
* UTF-8} charset, and lines are delimited in the manner of
* {@link BufferedReader#readLine()}.
*
* @apiNote This method can be used as an adapter between {@code
* BodySubscriber} and {@code Flow.Subscriber}.
*
* @implNote This is equivalent to calling <pre>{@code
* fromLineSubscriber(subscriber, s -> null, StandardCharsets.UTF_8, null)
* }</pre>
*
* @param subscriber the subscriber
* @return a body subscriber
*/
public static BodySubscriber<Void>
fromLineSubscriber(Subscriber<? super String> subscriber) {
return fromLineSubscriber(subscriber, s -> null,
StandardCharsets.UTF_8, null);
}
/**
* Returns a body subscriber that forwards all response body to the
* given {@code Flow.Subscriber}, line by line. The {@linkplain
* BodySubscriber#getBody() completion stage} of the returned body
* subscriber completes after one of the given subscribers
* {@code onComplete} or {@code onError} has been invoked.
*
* <p> The given {@code finisher} function is applied after the given
* subscriber's {@code onComplete} has been invoked. The {@code finisher}
* function is invoked with the given subscriber, and returns a value
* that is set as the response's body.
*
* @apiNote This method can be used as an adapter between {@code
* BodySubscriber} and {@code Flow.Subscriber}.
*
* @param <S> the type of the Subscriber
* @param <T> the type of the response body
* @param subscriber the subscriber
* @param finisher a function to be applied after the subscriber has
* completed
* @param charset a {@link Charset} to decode the bytes
* @param lineSeparator an optional line separator: can be {@code null},
* in which case lines will be delimited in the manner of
* {@link BufferedReader#readLine()}.
* @return a body subscriber
* @throws IllegalArgumentException if the supplied {@code lineSeparator}
* is the empty string
*/
public static <S extends Subscriber<? super String>,T> BodySubscriber<T>
fromLineSubscriber(S subscriber,
Function<? super S,? extends T> finisher,
Charset charset,
String lineSeparator) {
return LineSubscriberAdapter.create(subscriber,
finisher, charset, lineSeparator);
}
/**
* Returns a body subscriber which stores the response body as a {@code
* String} converted using the given {@code Charset}.
*
* <p> The {@link HttpResponse} using this subscriber is available after
* the entire response has been read.
*
* @param charset the character set to convert the String with
* @return a body subscriber
*/
public static BodySubscriber<String> ofString(Charset charset) {
Objects.requireNonNull(charset);
return new ResponseSubscribers.ByteArraySubscriber<>(
bytes -> new String(bytes, charset)
);
}
/**
* Returns a {@code BodySubscriber} which stores the response body as a
* byte array.
*
* <p> The {@link HttpResponse} using this subscriber is available after
* the entire response has been read.
*
* @return a body subscriber
*/
public static BodySubscriber<byte[]> ofByteArray() {
return new ResponseSubscribers.ByteArraySubscriber<>(
Function.identity() // no conversion
);
}
/**
* Returns a {@code BodySubscriber} which stores the response body in a
* file opened with the given options and name. The file will be opened
* with the given options using {@link FileChannel#open(Path,OpenOption...)
* FileChannel.open} just before the body is read. Any exception thrown
* will be returned or thrown from {@link HttpClient#send(HttpRequest,
* BodyHandler) HttpClient::send} or {@link HttpClient#sendAsync(HttpRequest,
* BodyHandler) HttpClient::sendAsync} as appropriate.
*
* <p> The {@link HttpResponse} using this subscriber is available after
* the entire response has been read.
*
* <p> Security manager permission checks are performed in this factory
* method, when the {@code BodySubscriber} is created. Care must be taken
* that the {@code BodyHandler} is not shared with untrusted code.
*
* @param file the file to store the body in
* @param openOptions the list of options to open the file with
* @return a body subscriber
* @throws IllegalArgumentException if an invalid set of open options
* are specified
* @throws SecurityException if a security manager has been installed
* and it denies {@linkplain SecurityManager#checkWrite(String)
* write access} to the file
*/
public static BodySubscriber<Path> ofFile(Path file, OpenOption... openOptions) {
Objects.requireNonNull(file);
List<OpenOption> opts = List.of(openOptions);
if (opts.contains(DELETE_ON_CLOSE) || opts.contains(READ)) {
// these options make no sense, since the FileChannel is not exposed
throw new IllegalArgumentException("invalid openOptions: " + opts);
}
return PathSubscriber.create(file, opts);
}
/**
* Returns a {@code BodySubscriber} which stores the response body in a
* file opened with the given name.
*
* <p> Equivalent to: {@code ofFile(file, CREATE, WRITE)}
*
* <p> Security manager permission checks are performed in this factory
* method, when the {@code BodySubscriber} is created. Care must be taken
* that the {@code BodyHandler} is not shared with untrusted code.
*
* @param file the file to store the body in
* @return a body subscriber
* @throws SecurityException if a security manager has been installed
* and it denies {@linkplain SecurityManager#checkWrite(String)
* write access} to the file
*/
public static BodySubscriber<Path> ofFile(Path file) {
return ofFile(file, CREATE, WRITE);
}
/**
* Returns a {@code BodySubscriber} which provides the incoming body
* data to the provided Consumer of {@code Optional<byte[]>}. Each
* call to {@link Consumer#accept(java.lang.Object) Consumer.accept()}
* will contain a non empty {@code Optional}, except for the final
* invocation after all body data has been read, when the {@code
* Optional} will be empty.
*
* <p> The {@link HttpResponse} using this subscriber is available after
* the entire response has been read.
*
* @apiNote
* This subscriber is not flow controlled.
* Therefore, the supplied consumer must be able to process whatever
* amount of data is delivered in a timely fashion.
*
* @param consumer a Consumer of byte arrays
* @return a BodySubscriber
*/
public static BodySubscriber<Void>
ofByteArrayConsumer(Consumer<Optional<byte[]>> consumer) {
return new ResponseSubscribers.ConsumerSubscriber(consumer);
}
/**
* Returns a {@code BodySubscriber} which streams the response body as
* an {@link InputStream}.
*
* <p> The {@link HttpResponse} using this subscriber is available
* immediately after the response headers have been read, without
* requiring to wait for the entire body to be processed. The response
* body can then be read directly from the {@link InputStream}.
*
* @apiNote To ensure that all resources associated with the
* corresponding exchange are properly released the caller must
* ensure to either read all bytes until EOF is reached, or call
* {@link InputStream#close} if it is unable or unwilling to do so.
* Calling {@code close} before exhausting the stream may cause
* the underlying HTTP connection to be closed and prevent it
* from being reused for subsequent operations.
*
* @return a body subscriber that streams the response body as an
* {@link InputStream}.
*/
public static BodySubscriber<InputStream> ofInputStream() {
return new ResponseSubscribers.HttpResponseInputStream();
}
/**
* Returns a {@code BodySubscriber} which streams the response body as
* a {@link Stream Stream}{@code <String>}, where each string in the stream
* corresponds to a line as defined by {@link BufferedReader#lines()}.
*
* <p> The {@link HttpResponse} using this subscriber is available
* immediately after the response headers have been read, without
* requiring to wait for the entire body to be processed. The response
* body can then be read directly from the {@link Stream}.
*
* @apiNote To ensure that all resources associated with the
* corresponding exchange are properly released the caller must
* ensure to either read all lines until the stream is exhausted,
* or call {@link Stream#close} if it is unable or unwilling to do so.
* Calling {@code close} before exhausting the stream may cause
* the underlying HTTP connection to be closed and prevent it
* from being reused for subsequent operations.
*
* @param charset the character set to use when converting bytes to characters
* @return a body subscriber that streams the response body as a
* {@link Stream Stream}{@code <String>}.
*
* @see BufferedReader#lines()
*/
public static BodySubscriber<Stream<String>> ofLines(Charset charset) {
return ResponseSubscribers.createLineStream(charset);
}
/**
* Returns a response subscriber which publishes the response body
* through a {@code Publisher<List<ByteBuffer>>}.
*
* <p> The {@link HttpResponse} using this subscriber is available
* immediately after the response headers have been read, without
* requiring to wait for the entire body to be processed. The response
* body bytes can then be obtained by subscribing to the publisher
* returned by the {@code HttpResponse} {@link HttpResponse#body() body}
* method.
*
* <p>The publisher returned by the {@link HttpResponse#body() body}
* method can be subscribed to only once. The first subscriber will
* receive the body response bytes if successfully subscribed, or will
* cause the subscription to be cancelled otherwise.
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