Question

On http://83.150.87.220/HelsinkiViSe/helsinki-map-application/ajax_test.php you can send a very simple async HTTP request when pushing the button on top of the page.
Bellow is the code for it:

var xmlString = "<request><session></session><target_id>20</target_id></request>";

// Build the URL to connect to
var url = "http://83.150.87.220/HelsinkiViSe.dll/load";

$.ajax({ 
    type: "POST", 
    url: url,
    dataType: 'application/xml',
    data: xmlString, 
    success: function(msg) { 
        //var data = JSON.parse(msg); 
        $("#text").html(msg); 
    },
    error: function(jqXHR, textStatus, errorThrown) {
        $("#text").html(jqXHR+'<br>'+textStatus+'<br>'+errorThrown); 
    }
});

As you can see, the request data block is a simple piece of XML:

var xmlString = "<request><session></session><target_id>20</target_id></request>";

The back-end script is supposed to respond with an XML block as well, which it does (monitoring communication using Firebug and Chrome’s “code inspector”). This block is:

<?xml version="1.0" encoding="UTF-8"?>
<response>
  <target>
    <target_id>20</target_id>
    <plot>20803/3</plot>
    <builder>(makasiini L3)</builder>
    <housing_form>avoin</housing_form>
    <block_name>JätkäHieta</block_name>
    <finnish_year></finnish_year>
    <target_name></target_name>
    <target_address></target_address>
    <office_space></office_space>
    <purpose></purpose>
    <reservations></reservations>
    <contacts></contacts>
  </target>
  <status>OK</status>
  <errormsg></errormsg>
</response>

The problem is that the error handler launches nevertheless, and the success handler doesn’t. And this is giving me white hairs. Do you know what might the cause for this be and how to fix it?

Thanks in advance.

Andrei

Answer 1

There are at least two and possibly three problems, one of which I’m sure is just debug code:

1. You’ve told jQuery to use dataType: "application/xml". The dataType argument isn’t a MIME type, it’s a jQuery-specific thing. You want dataType: "xml".

2. (This is probably the debug thing.) In your success function, you’re passing the XML document into the html function, which will raise an error. If you change it to text instead, it’ll show "[object Document]" instead, which makes sense — jQuery has deserialized the XML into an XML Document object for you.

3. You’re sending the XML string without encoding it. When you specify a string for the data argument, you are responsible for ensuring it’s properly encoded for transit (reference). I’m fairly sure you need to change the line

   data: xmlString
   

   …to

   data: encodeURIComponent(xmlString)
   

   I say “fairly sure” because I don’t remember the last time I tried to post XML to a server. But anything you’re sending via POST should typically be URL-encoded.

Live working example | source