org.apache.flume.source.http

Class JSONHandler

java.lang.Object

org.apache.flume.source.http.JSONHandler

All Implemented Interfaces:

Configurable, HTTPSourceHandler

public class JSONHandler
extends Object
implements HTTPSourceHandler

JSONHandler for HTTPSource that accepts an array of events. This handler throws exception if the deserialization fails because of bad format or any other reason. Each event must be encoded as a map with two key-value pairs.

1. headers - the key for this key-value pair is "headers". The value for this key is another map, which represent the event headers. These headers are inserted into the Flume event as is.

2. body - The body is a string which represents the body of the event. The key for this key-value pair is "body". All key-value pairs are considered to be headers. An example:

[{"headers" : {"a":"b", "c":"d"},"body": "random_body"}, {"headers" : {"e": "f"},"body": "random_body2"}]

would be interpreted as the following two flume events:

* Event with body: "random_body" (in UTF-8/UTF-16/UTF-32 encoded bytes) and headers : (a:b, c:d)

* Event with body: "random_body2" (in UTF-8/UTF-16/UTF-32 encoded bytes) and headers : (e:f)

The charset of the body is read from the request and used. If no charset is set in the request, then the charset is assumed to be JSON's default - UTF-8. The JSON handler supports UTF-8, UTF-16 and UTF-32. To set the charset, the request must have content type specified as "application/json; charset=UTF-8" (replace UTF-8 with UTF-16 or UTF-32 as required). One way to create an event in the format expected by this handler, is to use JSONEvent and use Gson to create the JSON string using the Gson.toJson(java.lang.Object, java.lang.reflect.Type) method. The type token to pass as the 2nd argument of this method for list of events can be created by:

Type type = new TypeToken<List<JSONEvent>>() {}.getType();

Constructor Summary

Constructors

Constructor and Description
JSONHandler()

Method Summary

Modifier and Type	Method and Description
void	configure(Context context) Request the implementing class to (re)configure itself.
List<Event>	getEvents(javax.servlet.http.HttpServletRequest request) Takes an HttpServletRequest and returns a list of Flume Events.

Methods inherited from class java.lang.Object

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

Constructor Detail

JSONHandler

public JSONHandler()

Method Detail

getEvents

public List<Event> getEvents(javax.servlet.http.HttpServletRequest request)
                      throws Exception

Takes an HttpServletRequest and returns a list of Flume Events. If this request cannot be parsed into Flume events based on the format this method will throw an exception. This method may also throw an exception if there is some sort of other error.

Specified by:

getEvents in interface HTTPSourceHandler

Parameters:

request - The request to be parsed into Flume events.

Returns:

List of Flume events generated from the request.

Throws:

HTTPBadRequestException - If the was not parsed correctly into an event because the request was not in the expected format.

Exception - If there was an unexpected error.

configure

public void configure(Context context)

Description copied from interface: Configurable

Request the implementing class to (re)configure itself.

When configuration parameters are changed, they must be reflected by the component asap.

There are no thread safety guarantees on when configure might be called.

Specified by:

configure in interface Configurable