How can I use a payload instead of form-data for log4javascript

Question

I am bound to the restrictions of my webservice: It expects a json-payload!

So, doing something like

var ajaxAppender = new log4javascript.AjaxAppender("clientLogger");
var jsonLayout = new log4javascript.JsonLayout();
ajaxAppender.setLayout(jsonLayout);
log.addAppender(ajaxAppender);

won't work, as it creates two keys in the forms-collection (data and layout).

How can I, with built-in options, get a json-payload?

Answer 1

I've created a JsonAppender

function JsonAppender(url) {
    var isSupported = true;
    var successCallback = function(data, textStatus, jqXHR) { return; };
    if (!url) {
        isSupported = false;
    }
    this.setSuccessCallback = function(successCallbackParam) {
        successCallback = successCallbackParam;
    };
    this.append = function (loggingEvent) {
        if (!isSupported) {
            return;
        }
        $.post(url, {
            'logger': loggingEvent.logger.name,
            'timestamp': loggingEvent.timeStampInMilliseconds,
            'level': loggingEvent.level.name,
            'url': window.location.href,
            'message': loggingEvent.getCombinedMessages(),
            'exception': loggingEvent.getThrowableStrRep()
        }, successCallback, 'json');
    };
}

JsonAppender.prototype = new log4javascript.Appender();
JsonAppender.prototype.toString = function() {
    return 'JsonAppender';
};
log4javascript.JsonAppender = JsonAppender;

used like so

var logger = log4javascript.getLogger('clientLogger');
var jsonAppender = new JsonAppender(url);
logger.addAppender(jsonAppender);

Answer 2

According to log4javascript's change log, with version 1.4.5, there is no longer the need to write a custom appender, if the details sent by Log4Javascript suffice.

1.4.5 (20/2/2013) - Changed AjaxAppender to send raw data rather than URL-encoded form data when content-type is not "application/x-www-form-urlencoded" https://github.com/DECK36/log4javascript/blob/master/changelog.txt

Simply adding the 'Content-Type' header to the AjaxAppender and setting it to 'application/json' is enough

ajaxAppender.addHeader("Content-Type", "application/json;charset=utf-8");

A quick test using fiddler shows that log4javascipt sends a collection of objects. Here's a sample of the payload:

[{
    "logger": "myLogger",
    "timestamp": 1441881152618,
    "level": "DEBUG",
    "url": "http://localhost:5117/Test.Html",
    "message": "Testing message"
}]