org.httprpc.kilo.WebServiceProxy Maven / Gradle / Ivy
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/*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.httprpc.kilo;
import org.httprpc.kilo.beans.BeanAdapter;
import org.httprpc.kilo.io.JSONDecoder;
import org.httprpc.kilo.io.JSONEncoder;
import org.httprpc.kilo.io.TextDecoder;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.lang.reflect.Array;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.net.HttpURLConnection;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.net.URLEncoder;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Date;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.UUID;
import static org.httprpc.kilo.util.Collections.*;
import static org.httprpc.kilo.util.Optionals.*;
/**
* Client-side invocation proxy for web services.
*/
public class WebServiceProxy {
/**
* @deprecated This type will be removed in a future release.
*/
@Deprecated
public enum Encoding {
/**
* The "application/x-www-form-urlencoded" encoding.
*/
APPLICATION_X_WWW_FORM_URLENCODED,
/**
* The "multipart/form-data" encoding.
*/
MULTIPART_FORM_DATA
}
/**
* Represents a request handler.
*/
public interface RequestHandler {
/**
* Returns the handler's content type.
*
* @return
* The content type produced by the handler.
*/
String getContentType();
/**
* Encodes a request to an output stream.
*
* @param body
* A value representing the body content.
*
* @param outputStream
* The output stream to write to.
*
* @throws IOException
* If an exception occurs.
*/
void encodeRequest(Object body, OutputStream outputStream) throws IOException;
}
/**
* Represents a response handler.
*/
public interface ResponseHandler {
/**
* Decodes a response from an input stream.
*
* @param inputStream
* The input stream to read from.
*
* @param contentType
* The content type, or {@code null} if the content type is not known.
*
* @return
* The decoded body content.
*
* @throws IOException
* If an exception occurs.
*/
Object decodeResponse(InputStream inputStream, String contentType) throws IOException;
}
/**
* Represents an error handler.
*/
public interface ErrorHandler {
/**
* Handles an error response.
*
* @param errorStream
* The error stream.
*
* @param contentType
* The content type, or {@code null} if the content type is not known.
*
* @param statusCode
* The status code.
*
* @throws IOException
* Representing the error that occurred, or if an exception occurs while
* handling the error.
*/
void handleResponse(InputStream errorStream, String contentType, int statusCode) throws IOException;
}
/**
* Specifies proxy configuration.
*/
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface Configuration {
/**
* The request handler.
*/
Class requestHandler() default RequestHandler.class;
/**
* The response handler.
*/
Class responseHandler() default ResponseHandler.class;
/**
* The error handler.
*/
Class errorHandler() default ErrorHandler.class;
/**
* The connect timeout.
*/
int connectTimeout() default -1;
/**
* The read timeout.
*/
int readTimeout() default -1;
/**
* The chunk size.
*/
int chunkSize() default -1;
}
private static class TypedInvocationHandler implements InvocationHandler {
URI baseURI;
Map headers;
TypedInvocationHandler(URI baseURI, Map headers) {
this.baseURI = baseURI;
this.headers = headers;
}
@Override
public Object invoke(Object proxy, Method method, Object[] arguments) throws Throwable {
if (method.getDeclaringClass() == Object.class) {
try {
return method.invoke(this, arguments);
} catch (IllegalAccessException | InvocationTargetException exception) {
throw new RuntimeException(exception);
}
} else if (method.isDefault()) {
return InvocationHandler.invokeDefault(proxy, method, arguments);
} else {
var requestMethod = method.getAnnotation(RequestMethod.class);
if (requestMethod == null) {
throw new UnsupportedOperationException("Request method is not defined.");
}
var exceptionTypes = method.getExceptionTypes();
if (exceptionTypes.length != 1 || !exceptionTypes[0].isAssignableFrom(IOException.class)) {
throw new UnsupportedOperationException("Missing or invalid exception declaration.");
}
var argumentList = coalesce(map(arguments, Arrays::asList), listOf());
var scheme = baseURI.getScheme();
var userInfo = baseURI.getUserInfo();
var host = baseURI.getHost();
var port = baseURI.getPort();
var pathBuilder = new StringBuilder(baseURI.getPath());
var keyCount = 0;
var resourcePath = method.getAnnotation(ResourcePath.class);
if (resourcePath != null) {
var components = resourcePath.value().split("/");
for (var i = 0; i < components.length; i++) {
if (i > 0) {
pathBuilder.append("/");
}
var component = components[i];
if (component.isEmpty()) {
throw new UnsupportedOperationException("Invalid resource path.");
}
if (component.equals("?")) {
var parameterValue = getParameterValue(argumentList.get(keyCount));
if (parameterValue == null) {
throw new IllegalArgumentException("Path variable is required.");
}
component = parameterValue.toString();
keyCount++;
}
pathBuilder.append(component);
}
}
URI uri;
try {
uri = new URI(scheme, userInfo, host, port, pathBuilder.toString(), null, null);
} catch (URISyntaxException exception) {
throw new UnsupportedOperationException(exception);
}
var webServiceProxy = new WebServiceProxy(requestMethod.value(), uri);
webServiceProxy.setHeaders(headers);
var empty = switch (webServiceProxy.method) {
case "POST", "PUT" -> {
@SuppressWarnings("deprecation")
var formData = method.getAnnotation(FormData.class);
if (formData == null) {
yield argumentList.size() == keyCount;
} else {
if (formData.multipart()) {
webServiceProxy.setEncoding(Encoding.MULTIPART_FORM_DATA);
} else {
webServiceProxy.setEncoding(Encoding.APPLICATION_X_WWW_FORM_URLENCODED);
}
yield true;
}
}
default -> true;
};
var parameters = method.getParameters();
var n = parameters.length;
if (!empty) {
n--;
}
var argumentMap = new LinkedHashMap();
for (var i = keyCount; i < n; i++) {
var parameter = parameters[i];
var value = argumentList.get(i);
if (parameter.getAnnotation(Required.class) != null && value == null) {
throw new IllegalArgumentException("Required argument is not defined.");
}
var name = coalesce(map(parameter.getAnnotation(Name.class), Name::value), parameter.getName());
argumentMap.put(name, value);
}
webServiceProxy.setArguments(argumentMap);
if (n < parameters.length) {
var body = argumentList.get(n);
if (body == null && parameters[n].getType() != Void.class) {
throw new IllegalArgumentException("Body is required.");
}
webServiceProxy.setBody(body);
}
var configuration = method.getAnnotation(Configuration.class);
if (configuration != null) {
configure(webServiceProxy, configuration);
}
return BeanAdapter.toGenericType(webServiceProxy.invoke(), method.getGenericReturnType());
}
}
private static void configure(WebServiceProxy webServiceProxy, Configuration configuration) {
var requestHandler = configuration.requestHandler();
if (requestHandler != RequestHandler.class) {
webServiceProxy.setRequestHandler(instantiate(requestHandler));
}
var responseHandler = configuration.responseHandler();
if (responseHandler != ResponseHandler.class) {
webServiceProxy.setResponseHandler(instantiate(responseHandler));
}
var errorHandler = configuration.errorHandler();
if (errorHandler != ErrorHandler.class) {
webServiceProxy.setErrorHandler(instantiate(errorHandler));
}
var connectTimeout = configuration.connectTimeout();
if (connectTimeout >= 0) {
webServiceProxy.setConnectTimeout(connectTimeout);
}
var readTimeout = configuration.readTimeout();
if (readTimeout >= 0) {
webServiceProxy.setReadTimeout(readTimeout);
}
var chunkSize = configuration.chunkSize();
if (chunkSize >= 0) {
webServiceProxy.setChunkSize(chunkSize);
}
}
private static T instantiate(Class type) {
try {
return type.getDeclaredConstructor().newInstance();
} catch (NoSuchMethodException | InstantiationException | IllegalAccessException | InvocationTargetException exception) {
throw new UnsupportedOperationException(exception);
}
}
}
private String method;
private URI uri;
private Encoding encoding = null;
private Map headers = mapOf();
private Map arguments = mapOf();
private Object body = null;
private RequestHandler requestHandler = new RequestHandler() {
@Override
public String getContentType() {
return "application/json";
}
@Override
public void encodeRequest(Object body, OutputStream outputStream) throws IOException {
var jsonEncoder = new JSONEncoder();
jsonEncoder.write(BeanAdapter.adapt(body), outputStream);
}
};
private ResponseHandler responseHandler = (inputStream, contentType) -> {
var jsonDecoder = new JSONDecoder();
return jsonDecoder.read(inputStream);
};
private ErrorHandler errorHandler = (errorStream, contentType, statusCode) -> {
String message;
if (errorStream != null && contentType != null && contentType.toLowerCase().startsWith("text/plain")) {
var textDecoder = new TextDecoder();
message = textDecoder.read(errorStream);
} else {
message = String.format("HTTP %d", statusCode);
}
throw new WebServiceException(message, statusCode);
};
private int connectTimeout = 15000;
private int readTimeout = 60000;
private int chunkSize = 0;
private String multipartBoundary = UUID.randomUUID().toString();
private int statusCode = -1;
private static final int EOF = -1;
/**
* Constructs a new web service proxy.
*
* @param method
* The HTTP method.
*
* @param uri
* The resource URI.
*/
public WebServiceProxy(String method, URI uri) {
if (method == null || uri == null) {
throw new IllegalArgumentException();
}
this.method = method.toUpperCase();
this.uri = uri;
}
/**
* @deprecated Use {@link #WebServiceProxy(String, URI)} instead.
*/
@Deprecated
public WebServiceProxy(String method, URI baseURI, String path, Object... arguments) {
this(method, baseURI.resolve(String.format(path, arguments)));
}
/**
* @deprecated This method will be removed in a future release.
*/
@Deprecated
public Encoding getEncoding() {
return encoding;
}
/**
* @deprecated This method will be removed in a future release.
*/
@Deprecated
public void setEncoding(Encoding encoding) {
this.encoding = encoding;
}
/**
* Returns the header map.
*
* @return
* The header map.
*/
public Map getHeaders() {
return headers;
}
/**
* Sets the header map.
*
* @param headers
* The header map.
*/
public void setHeaders(Map headers) {
if (headers == null) {
throw new IllegalArgumentException();
}
this.headers = headers;
}
/**
* Returns the argument map.
*
* @return
* The argument map.
*/
public Map getArguments() {
return arguments;
}
/**
* Sets the argument map.
*
* @param arguments
* The argument map.
*/
public void setArguments(Map arguments) {
if (arguments == null) {
throw new IllegalArgumentException();
}
this.arguments = arguments;
}
/**
* Returns the request body.
*
* @return
* A value representing the body content, or {@code null} if no body has
* been set.
*/
public Object getBody() {
return body;
}
/**
* Sets the request body.
*
* @param body
* A value representing the body content, or {@code null} for no body.
*/
public void setBody(Object body) {
this.body = body;
}
/**
* Returns the request handler.
*
* @return
* The request handler.
*/
public RequestHandler getRequestHandler() {
return requestHandler;
}
/**
* Sets the request handler.
*
* @param requestHandler
* The request handler.
*/
public void setRequestHandler(RequestHandler requestHandler) {
if (requestHandler == null) {
throw new IllegalArgumentException();
}
this.requestHandler = requestHandler;
}
/**
* Returns the response handler.
*
* @return
* The response handler.
*/
public ResponseHandler getResponseHandler() {
return responseHandler;
}
/**
* Sets the response handler.
*
* @param responseHandler
* The response handler.
*/
public void setResponseHandler(ResponseHandler responseHandler) {
if (responseHandler == null) {
throw new IllegalArgumentException();
}
this.responseHandler = responseHandler;
}
/**
* Returns the error handler.
*
* @return
* The error handler.
*/
public ErrorHandler getErrorHandler() {
return errorHandler;
}
/**
* Sets the error handler.
*
* @param errorHandler
* The error handler.
*/
public void setErrorHandler(ErrorHandler errorHandler) {
if (errorHandler == null) {
throw new IllegalArgumentException();
}
this.errorHandler = errorHandler;
}
/**
* Returns the connect timeout.
*
* @return
* The connect timeout, in milliseconds.
*/
public int getConnectTimeout() {
return connectTimeout;
}
/**
* Sets the connect timeout.
*
* @param connectTimeout
* The connect timeout, in milliseconds, or 0 for no timeout.
*/
public void setConnectTimeout(int connectTimeout) {
if (connectTimeout < 0) {
throw new IllegalArgumentException();
}
this.connectTimeout = connectTimeout;
}
/**
* Returns the read timeout.
*
* @return
* The read timeout, in milliseconds.
*/
public int getReadTimeout() {
return readTimeout;
}
/**
* Sets the read timeout.
*
* @param readTimeout
* The read timeout, in milliseconds, or 0 for no timeout.
*/
public void setReadTimeout(int readTimeout) {
if (readTimeout < 0) {
throw new IllegalArgumentException();
}
this.readTimeout = readTimeout;
}
/**
* Returns the chunk size.
*
* @return
* The chunk size.
*/
public int getChunkSize() {
return chunkSize;
}
/**
* Sets the chunk size.
*
* @param chunkSize
* The chunk size, or 0 to disable chunked streaming.
*/
public void setChunkSize(int chunkSize) {
if (chunkSize < 0) {
throw new IllegalArgumentException();
}
this.chunkSize = chunkSize;
}
/**
* Invokes the service operation.
*
* @return
* The result of the operation.
*
* @throws IOException
* If an exception occurs while executing the operation.
*/
public Object invoke() throws IOException {
var uri = this.uri;
RequestHandler requestHandler;
if (method.equals("POST") && encoding != null) {
requestHandler = new RequestHandler() {
@Override
public String getContentType() {
return switch (encoding) {
case APPLICATION_X_WWW_FORM_URLENCODED -> "application/x-www-form-urlencoded";
case MULTIPART_FORM_DATA -> String.format("multipart/form-data; boundary=%s", multipartBoundary);
};
}
@Override
public void encodeRequest(Object body, OutputStream outputStream) throws IOException {
switch (encoding) {
case APPLICATION_X_WWW_FORM_URLENCODED -> encodeApplicationXWWWFormURLEncodedRequest(outputStream);
case MULTIPART_FORM_DATA -> encodeMultipartFormDataRequest(outputStream);
}
}
};
} else {
if (!arguments.isEmpty()) {
try {
uri = new URI(String.format("%s?%s", uri, encodeQuery()));
} catch (URISyntaxException exception) {
throw new IllegalStateException(exception.getMessage());
}
}
requestHandler = this.requestHandler;
}
// Open URL connection
var connection = (HttpURLConnection)uri.toURL().openConnection();
connection.setRequestMethod(method);
connection.setConnectTimeout(connectTimeout);
connection.setReadTimeout(readTimeout);
var locale = Locale.getDefault();
connection.setRequestProperty("Accept-Language", String.format("%s-%s",
locale.getLanguage().toLowerCase(),
locale.getCountry().toLowerCase()));
// Apply custom headers
for (Map.Entry entry : headers.entrySet()) {
var key = entry.getKey();
var value = entry.getValue();
if (key == null || value == null) {
continue;
}
connection.setRequestProperty(key, value.toString());
}
// Write request body
if (body != null || encoding != null) {
connection.setDoOutput(true);
if (chunkSize > 0) {
connection.setChunkedStreamingMode(chunkSize);
}
connection.setRequestProperty("Content-Type", requestHandler.getContentType());
try (var outputStream = connection.getOutputStream()) {
requestHandler.encodeRequest(body, outputStream);
}
}
// Read response
statusCode = connection.getResponseCode();
var contentType = connection.getContentType();
Object result;
if (statusCode / 100 == 2) {
if (statusCode % 100 < 4) {
try (var inputStream = connection.getInputStream()) {
result = responseHandler.decodeResponse(inputStream, contentType);
}
} else {
result = null;
}
} else {
try (var errorStream = connection.getErrorStream()) {
errorHandler.handleResponse(errorStream, contentType, statusCode);
}
return null;
}
return result;
}
private String encodeQuery() {
var queryBuilder = new StringBuilder(256);
var i = 0;
for (Map.Entry entry : arguments.entrySet()) {
var key = entry.getKey();
if (key == null || key.isEmpty()) {
throw new IllegalStateException();
}
for (var value : getParameterValues(entry.getValue())) {
if (value == null) {
continue;
}
if (i > 0) {
queryBuilder.append("&");
}
queryBuilder.append(URLEncoder.encode(key, StandardCharsets.UTF_8));
queryBuilder.append("=");
queryBuilder.append(URLEncoder.encode(value.toString(), StandardCharsets.UTF_8));
i++;
}
}
return queryBuilder.toString();
}
private void encodeApplicationXWWWFormURLEncodedRequest(OutputStream outputStream) throws IOException {
var writer = new OutputStreamWriter(outputStream, StandardCharsets.UTF_8);
writer.append(encodeQuery());
writer.flush();
}
private void encodeMultipartFormDataRequest(OutputStream outputStream) throws IOException {
var writer = new OutputStreamWriter(outputStream, StandardCharsets.UTF_8);
for (Map.Entry entry : arguments.entrySet()) {
var name = entry.getKey();
if (name == null) {
continue;
}
for (var value : getParameterValues(entry.getValue())) {
if (value == null) {
continue;
}
writer.append(String.format("--%s\r\n", multipartBoundary));
writer.append(String.format("Content-Disposition: form-data; name=\"%s\"", name));
if (value instanceof URL url) {
var path = url.getPath();
var filename = path.substring(path.lastIndexOf('/') + 1);
writer.append(String.format("; filename=\"%s\"\r\n", filename));
writer.append("Content-Type: application/octet-stream\r\n\r\n");
writer.flush();
try (var inputStream = ((URL)value).openStream()) {
int b;
while ((b = inputStream.read()) != EOF) {
outputStream.write(b);
}
}
} else {
writer.append("\r\n\r\n");
writer.append(value.toString());
}
writer.append("\r\n");
}
}
writer.append(String.format("--%s--\r\n", multipartBoundary));
writer.flush();
}
private static List