Http.post a zip file

Hi,
I would like to make use of the following webservice to convert a zip file containing .shp files to GeoJSON:
http://ogre.adc4gis.com/

That page says it can be done by HTTP post.
I have done a ‘meteor add http’. Below is my code.
I get a result in my HTTP.post callback which says: {“error”:true,“msg”:“Cannot read property ‘path’ of undefined”}
I think the arguments in my POST request is not correct.
Any advice?

Html (added | to opening brackets so that html shows in this post):
<|template name=“test”>
<|input class=‘dataURL’ type=‘file’ name=‘upload’>
<|/template>

Client event handler:
‘change .dataURL’: function(event, template){
event.preventDefault();
var file = event.target.files[0];
HTTP.post(‘http://ogre.adc4gis.com/convert’, {params:{upload:file}}, function(error, result){
if(error){
console.log(“error”, error);
} else {
console.log("result: ",result);
}
});
}

If the requested endpoint is expecting a content-type of application/json by default, use “data” instead of “params”:

HTTP.post('http://ogre.adc4gis.com/convert', {data:{upload:file}}, ...

Hi,
The following raw html works:
<|form action=“http://ogre.adc4gis.com/convert” method=“post” enctype=“multipart/form-data”>
<|input name=“upload” type=“file”>
<|button>Convert to GeoJSON
<|/form>

My meteor javascript code (which does not work) is:
‘change .dataURL’: function(event, template){
event.preventDefault();
var file = event.target.files[0];
console.log("file: ",file);
HTTP.post(‘http://ogre.adc4gis.com/convert’, {data:{“upload”:file},headers:{“Content-Type”:“multipart/form-data”}}, function(error, result){
if(error){
console.log(“error”, error);
} else {
console.log("result: ",result);
}
});
}

I get the error:
09:37:35.744 error Error: network
Stack trace:
HTTP.call/xhr.onreadystatechange@http://localhost:3000/packages/http.js?40d307fefc00445c189ac03f4ba12bc9ccf50635:262:20
1 leaflettest.js:413:9