/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch licenses this file to you 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.elasticsearch.common.xcontent;
import com.fasterxml.jackson.dataformat.cbor.CBORConstants;
import com.fasterxml.jackson.dataformat.smile.SmileConstants;
import org.elasticsearch.ElasticsearchParseException;
import org.elasticsearch.common.bytes.BytesArray;
import org.elasticsearch.common.bytes.BytesReference;
import org.elasticsearch.common.io.Streams;
import org.elasticsearch.common.xcontent.cbor.CborXContent;
import org.elasticsearch.common.xcontent.json.JsonXContent;
import org.elasticsearch.common.xcontent.smile.SmileXContent;
import org.elasticsearch.common.xcontent.yaml.YamlXContent;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
/**
* A one stop to use {@link org.elasticsearch.common.xcontent.XContent} and {@link XContentBuilder}.
*/
public class XContentFactory {
private static final int GUESS_HEADER_LENGTH = 20;
/**
* Returns a content builder using JSON format ({@link org.elasticsearch.common.xcontent.XContentType#JSON}.
*/
public static XContentBuilder jsonBuilder() throws IOException {
return contentBuilder(XContentType.JSON);
}
/**
* Constructs a new json builder that will output the result into the provided output stream.
*/
public static XContentBuilder jsonBuilder(OutputStream os) throws IOException {
return new XContentBuilder(JsonXContent.jsonXContent, os);
}
/**
* Returns a content builder using SMILE format ({@link org.elasticsearch.common.xcontent.XContentType#SMILE}.
*/
public static XContentBuilder smileBuilder() throws IOException {
return contentBuilder(XContentType.SMILE);
}
/**
* Constructs a new json builder that will output the result into the provided output stream.
*/
public static XContentBuilder smileBuilder(OutputStream os) throws IOException {
return new XContentBuilder(SmileXContent.smileXContent, os);
}
/**
* Returns a content builder using YAML format ({@link org.elasticsearch.common.xcontent.XContentType#YAML}.
*/
public static XContentBuilder yamlBuilder() throws IOException {
return contentBuilder(XContentType.YAML);
}
/**
* Constructs a new yaml builder that will output the result into the provided output stream.
*/
public static XContentBuilder yamlBuilder(OutputStream os) throws IOException {
return new XContentBuilder(YamlXContent.yamlXContent, os);
}
/**
* Returns a content builder using CBOR format ({@link org.elasticsearch.common.xcontent.XContentType#CBOR}.
*/
public static XContentBuilder cborBuilder() throws IOException {
return contentBuilder(XContentType.CBOR);
}
/**
* Constructs a new cbor builder that will output the result into the provided output stream.
*/
public static XContentBuilder cborBuilder(OutputStream os) throws IOException {
return new XContentBuilder(CborXContent.cborXContent, os);
}
/**
* Constructs a xcontent builder that will output the result into the provided output stream.
*/
public static XContentBuilder contentBuilder(XContentType type, OutputStream outputStream) throws IOException {
if (type == XContentType.JSON) {
return jsonBuilder(outputStream);
} else if (type == XContentType.SMILE) {
return smileBuilder(outputStream);
} else if (type == XContentType.YAML) {
return yamlBuilder(outputStream);
} else if (type == XContentType.CBOR) {
return cborBuilder(outputStream);
}
throw new IllegalArgumentException("No matching content type for " + type);
}
/**
* Returns a binary content builder for the provided content type.
*/
public static XContentBuilder contentBuilder(XContentType type) throws IOException {
if (type == XContentType.JSON) {
return JsonXContent.contentBuilder();
} else if (type == XContentType.SMILE) {
return SmileXContent.contentBuilder();
} else if (type == XContentType.YAML) {
return YamlXContent.contentBuilder();
} else if (type == XContentType.CBOR) {
return CborXContent.contentBuilder();
}
throw new IllegalArgumentException("No matching content type for " + type);
}
/**
* Returns the {@link org.elasticsearch.common.xcontent.XContent} for the provided content type.
*/
public static XContent xContent(XContentType type) {
if (type == null) {
throw new IllegalArgumentException("Cannot get xcontent for unknown type");
}
return type.xContent();
}
/**
* Guesses the content type based on the provided char sequence.
*
* @deprecated the content type should not be guessed except for few cases where we effectively don't know the content type.
* The REST layer should move to reading the Content-Type header instead. There are other places where auto-detection may be needed.
* This method is deprecated to prevent usages of it from spreading further without specific reasons.
*/
@Deprecated
public static XContentType xContentType(CharSequence content) {
int length = content.length() < GUESS_HEADER_LENGTH ? content.length() : GUESS_HEADER_LENGTH;
if (length == 0) {
return null;
}
char first = content.charAt(0);
if (first == '{') {
return XContentType.JSON;
}
// Should we throw a failure here? Smile idea is to use it in bytes....
if (length > 2 && first == SmileConstants.HEADER_BYTE_1 && content.charAt(1) == SmileConstants.HEADER_BYTE_2 && content.charAt(2) == SmileConstants.HEADER_BYTE_3) {
return XContentType.SMILE;
}
if (length > 2 && first == '-' && content.charAt(1) == '-' && content.charAt(2) == '-') {
return XContentType.YAML;
}
// CBOR is not supported
for (int i = 0; i < length; i++) {
char c = content.charAt(i);
if (c == '{') {
return XContentType.JSON;
}
if (Character.isWhitespace(c) == false) {
break;
}
}
return null;
}
/**
* Guesses the content (type) based on the provided char sequence and returns the corresponding {@link XContent}
*
* @deprecated the content type should not be guessed except for few cases where we effectively don't know the content type.
* The REST layer should move to reading the Content-Type header instead. There are other places where auto-detection may be needed.
* This method is deprecated to prevent usages of it from spreading further without specific reasons.
*/
@Deprecated
public static XContent xContent(CharSequence content) {
XContentType type = xContentType(content);
if (type == null) {
throw new ElasticsearchParseException("Failed to derive xcontent");
}
return xContent(type);
}
/**
* Guesses the content type based on the provided bytes and returns the corresponding {@link XContent}
*
* @deprecated the content type should not be guessed except for few cases where we effectively don't know the content type.
* The REST layer should move to reading the Content-Type header instead. There are other places where auto-detection may be needed.
* This method is deprecated to prevent usages of it from spreading further without specific reasons.
*/
@Deprecated
public static XContent xContent(byte[] data) {
return xContent(data, 0, data.length);
}
/**
* Guesses the content type based on the provided bytes and returns the corresponding {@link XContent}
*
* @deprecated guessing the content type should not be needed ideally. We should rather know the content type upfront or read it
* from headers. Till we fixed the REST layer to read the Content-Type header, that should be the only place where guessing is needed.
*/
@Deprecated
public static XContent xContent(byte[] data, int offset, int length) {
XContentType type = xContentType(data, offset, length);
if (type == null) {
throw new ElasticsearchParseException("Failed to derive xcontent");
}
return xContent(type);
}
/**
* Guesses the content type based on the provided bytes.
*
* @deprecated the content type should not be guessed except for few cases where we effectively don't know the content type.
* The REST layer should move to reading the Content-Type header instead. There are other places where auto-detection may be needed.
* This method is deprecated to prevent usages of it from spreading further without specific reasons.
*/
@Deprecated
public static XContentType xContentType(byte[] data) {
return xContentType(data, 0, data.length);
}
/**
* Guesses the content type based on the provided input stream without consuming it.
*
* @deprecated the content type should not be guessed except for few cases where we effectively don't know the content type.
* The REST layer should move to reading the Content-Type header instead. There are other places where auto-detection may be needed.
* This method is deprecated to prevent usages of it from spreading further without specific reasons.
*/
@Deprecated
public static XContentType xContentType(InputStream si) throws IOException {
if (si.markSupported() == false) {
throw new IllegalArgumentException("Cannot guess the xcontent type without mark/reset support on " + si.getClass());
}
si.mark(GUESS_HEADER_LENGTH);
try {
final byte[] firstBytes = new byte[GUESS_HEADER_LENGTH];
final int read = Streams.readFully(si, firstBytes);
return xContentType(new BytesArray(firstBytes, 0, read));
} finally {
si.reset();
}
}
/**
* Guesses the content type based on the provided bytes.
*
* @deprecated the content type should not be guessed except for few cases where we effectively don't know the content type.
* The REST layer should move to reading the Content-Type header instead. There are other places where auto-detection may be needed.
* This method is deprecated to prevent usages of it from spreading further without specific reasons.
*/
@Deprecated
public static XContentType xContentType(byte[] data, int offset, int length) {
return xContentType(new BytesArray(data, offset, length));
}
/**
* Guesses the content type based on the provided bytes and returns the corresponding {@link XContent}
*
* @deprecated the content type should not be guessed except for few cases where we effectively don't know the content type.
* The REST layer should move to reading the Content-Type header instead. There are other places where auto-detection may be needed.
* This method is deprecated to prevent usages of it from spreading further without specific reasons.
*/
@Deprecated
public static XContent xContent(BytesReference bytes) {
XContentType type = xContentType(bytes);
if (type == null) {
throw new ElasticsearchParseException("Failed to derive xcontent");
}
return xContent(type);
}
/**
* Guesses the content type based on the provided bytes.
*
* @deprecated the content type should not be guessed except for few cases where we effectively don't know the content type.
* The REST layer should move to reading the Content-Type header instead. There are other places where auto-detection may be needed.
* This method is deprecated to prevent usages of it from spreading further without specific reasons.
*/
@Deprecated
public static XContentType xContentType(BytesReference bytes) {
int length = bytes.length();
if (length == 0) {
return null;
}
byte first = bytes.get(0);
if (first == '{') {
return XContentType.JSON;
}
if (length > 2 && first == SmileConstants.HEADER_BYTE_1 && bytes.get(1) == SmileConstants.HEADER_BYTE_2 && bytes.get(2) == SmileConstants.HEADER_BYTE_3) {
return XContentType.SMILE;
}
if (length > 2 && first == '-' && bytes.get(1) == '-' && bytes.get(2) == '-') {
return XContentType.YAML;
}
// CBOR logic similar to CBORFactory#hasCBORFormat
if (first == CBORConstants.BYTE_OBJECT_INDEFINITE && length > 1){
return XContentType.CBOR;
}
if (CBORConstants.hasMajorType(CBORConstants.MAJOR_TYPE_TAG, first) && length > 2) {
// Actually, specific "self-describe tag" is a very good indicator
if (first == (byte) 0xD9 && bytes.get(1) == (byte) 0xD9 && bytes.get(2) == (byte) 0xF7) {
return XContentType.CBOR;
}
}
// for small objects, some encoders just encode as major type object, we can safely
// say its CBOR since it doesn't contradict SMILE or JSON, and its a last resort
if (CBORConstants.hasMajorType(CBORConstants.MAJOR_TYPE_OBJECT, first)) {
return XContentType.CBOR;
}
int jsonStart = 0;
// JSON may be preceded by UTF-8 BOM
if (length > 3 && first == (byte) 0xEF && bytes.get(1) == (byte) 0xBB && bytes.get(2) == (byte) 0xBF) {
jsonStart = 3;
}
// a last chance for JSON
for (int i = jsonStart; i < length; i++) {
byte b = bytes.get(i);
if (b == '{') {
return XContentType.JSON;
}
if (Character.isWhitespace(b) == false) {
break;
}
}
return null;
}
}