co.cask.wrangler.RequestExtractor Maven / Gradle / Ivy
/*
* Copyright © 2017 Cask Data, Inc.
*
* 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 co.cask.wrangler;
import co.cask.cdap.api.service.http.HttpServiceRequest;
import co.cask.wrangler.proto.Request;
import co.cask.wrangler.service.directive.RequestDeserializer;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import java.nio.ByteBuffer;
import java.nio.charset.Charset;
/**
* This class {@link RequestExtractor} provides utility functions for extracting different aspects of the request.
* It provides functionality to extract headers and content.
*/
public final class RequestExtractor {
private final HttpServiceRequest request;
public static final String CONTENT_TYPE_HEADER = PropertyIds.CONTENT_TYPE;
public static final String CHARSET_HEADER = PropertyIds.CHARSET;
public RequestExtractor(HttpServiceRequest request) {
this.request = request;
}
/**
* Checks if the request has a HTTP header.
*
* @param name of the header to be checked.
* @return true if header is found, false otherwise.
*/
public boolean hasHeader(String name) {
String header = request.getHeader(name);
return (header == null ? false : true);
}
/**
* Extracts the HTTP header, if the header is not present, then default value is returned.
*
* @param name of the HTTP header to be extracted.
* @param defaultValue value to returned if header doesn't exist.
* @return value defined for the header.
*/
public T getHeader(String name, String defaultValue) {
String header = request.getHeader(name);
return (T) (header == null ? defaultValue : header);
}
/**
* @return Content as received by the HTTP multipart/form body.
*/
public byte[] getContent() {
ByteBuffer content = request.getContent();
if (content != null && content.hasRemaining()) {
byte[] bytes = new byte[content.remaining()];
content.get(bytes);
return bytes;
}
return null;
}
/**
* Returns the content by converting it to UNICODE from the provided charset.
*
* @param charset of the content being extracted and converted to UNICODE.
* @return UNICODE representation of the content, else null.
*/
public String getContent(Charset charset) {
ByteBuffer content = request.getContent();
if (content != null && content.hasRemaining()) {
return charset.decode(content).toString();
}
return null;
}
public String getContent(String charset) {
return getContent(Charset.forName(charset));
}
/**
* Returns the content transformed into a Class defined.
* It first transforms from the charset into unicode and then applies the transformation.
*
* @param charset source charset of the content.
* @param type class to converted to.
* @return instance of type T as defined by the class.
*/
public T getContent(String charset, Class type) {
String data = getContent(charset);
if (data != null) {
GsonBuilder builder = new GsonBuilder();
builder.registerTypeAdapter(Request.class, new RequestDeserializer());
Gson gson = builder.create();
return (T) gson.fromJson(data, type);
}
return null;
}
/**
* Checks if the 'Content-Type' matches expected.
*
* @param expectedType to be checked for content type.
* @return true if it matches, false if it's not present or doesn't match expected.
*/
public boolean isContentType(String expectedType) {
if (hasHeader(CONTENT_TYPE_HEADER)) {
String header = getHeader(CONTENT_TYPE_HEADER, null);
return (header != null && !header.equalsIgnoreCase(expectedType)) ? false : true;
}
return false;
}
}