如何使用错误响应进行JSON API调用？

Question

I use Javascript to retrieve through a JSON api call the amount of active products pasted in a certain filter. My typicall response would be

{"total":34,"product_ids":["PRODUCT1","PRODUCT2",....."]}

My script is working fine when products are present but when none of the products are active the response will be:

{"error":"No products found, please check request settings"}

In this case the script will crash.

What I tried to do is to set the var NumEdPicks to 0 when I get an error but I don't really know how as the script is crashing when it doesn't find "total".

This is what the retrieve part of the script looks like

// Retrieve
var url = 'http://api.jetlore.com/products/products_by_filter.json?jl_cid=' + clientID + '&filter=' + filterName + '&per_page=' + maxCount + '&page=1';
var response = HTTP.Get(url);
var responseObj = Platform.Function.ParseJSON(response["Content"]);
var NumEditorsPick = responseObj.total;
if(NumEditorsPick>maxCount){ var NumEditorsPick = maxCount;}

I would like to set NumEditorsPick to 0 when I get the error response. Some things I was thinking about but which isn't working:

var NumEditorsPick = responseObj.total || 0

or

var NumEditorsPick = ‘total’ in responseObj ? responseObj.total : 0

How to define NumEditorsPick when there is no total?

I've tried so far:

if (responseObj.hasOwnProperty('total')){
  var NumEditorsPick = responseObj.total;
}else{
  var NumEditorsPick = 0;
}

And

  if (responseObj.has("total")){var NumEditorsPick = responseObj.total;
}
  if (responseObj.has("error")){var NumEditorsPick = 0;
}

Both are crashing the execution of my script, so I'm starting to think that when there is an error response it just stops the script and ignores the rest, would that be possible? In that case, how to ignore this error response?

EDIT: After using the try/catch method as suggested in the comments, I managed to finally make it work:

var NumEditorsPick;

  try {
    var response = HTTP.Get(url);
    var responseObj = Platform.Function.ParseJSON(response["Content"]);
    NumEditorsPick = responseObj.total;
  } catch (error) {
    NumEditorsPick = 0;
  }

Answer 1

You can use Javascript's hasOwnProperty() to check if the parse JSON has the key you're looking for.

In this case, I'd be something like:

var responseObj = Platform.Function.ParseJSON(response["Content"]);
if (responseObj.hasOwnProperty('error')){
    // handle error msg
}else{
    // do something else
}

Here's a simple example using the JSON input you've provided.

---

Update

Ok, so my initial answer was based on what you said here:

My script is working fine when products are present but when none of the products are active the response will be:

{"error":"No products found, please check request settings"}

But the service you're calling does not return a JSON string containing the error. Instead it returns a 404 and therefore, any attempt to parse or use the response content is not valid.

So, to start, you could try wrapping your HTTP.Get(url) in a try/catch method and on the catch clause set the NumEdPicks to zero.

Another option would be to check HTTP.Get() method documentation to see if the response object has a status (eg: response.Status ) or if you can pass a callback function for response and error, like this example in AJAX:

$.ajax({
    url: 'yourUrl',
    type: 'GET',
    success: function(data){ 
        // Set NumEdPicks to total and do other stuff 
    },
    error: function(data) {
        // Set NumEdPicks to zero
    }
});