How can I read custom Response Headers

[Nick]

Hello!

The Rails service I connecting to, sends certain important data in the HTTP headers . I' can't figure out how to access that

Here is what I'm trying to do  - See schema {total } below in bold

01.productsDataSource = new kendo.data.DataSource({
02.  autoSync: true,
03.  pageSize: 10,
04.  serverPaging: true,
05.  serverSorting: true,
06.  serverFiltering: true,
07.  //serverGrouping: true,
08.  schema: {
09.    data: "data",
10.    total: "count", // THIS needs to be read from X-Total:31067  - line 9 in the code block below.
11.    model: {
12.      fields: {
13.        name:            {type: "string"},
14.        description:     {type: "string"},
15.        id:              {type: "number"}
16.      }
17.    }
18.  }
19.});

Response Headers

01.Server:nginx/1.6.0 + Phusion Passenger 4.0.42
02.Status:200 OK
03.X-Meta-Request-Version:0.3.4
04.X-Next-Page:2
05.X-Page:1
06.X-Powered-By:Phusion Passenger 4.0.42
07.X-Request-Id:1fd5e3b7541e7c0fee888b3799a26990
08.X-Runtime:0.238255
09.X-Total:31067
10.X-Total-Pages:1243
11.X-UA-Compatible:IE=Edge,chrome=1

Thank you!

[Nikolay Rusev]

Hello Nick,

DataSource uses jQuery.ajax to request remote resource. That said you should be able to handle complete event of and inspect the headers available in the jqXHR object. Sample code snippet:

transport: {
 read: {
  url: "some url",
  complete: function(jqXHR, textStatus) {
   // inspect the content in the jqXHR object
   // jqXHR.getAllResponseHeaders() for example or related methods
  }
 }
}

Regards,
Nikolay Rusev
Telerik

 

 

[Bengt]

Hello Nikolay,

I'm having the same problem, need to get total-count from header response.
I tried hooking up the complete event as you recommended and I was able to extract the total count from the header data just fine.
The problem I run into is that it's fired after the schema.total function.
So I can't get the paging of the grid to work correct.

Regards
Bengt

[Nick]

Hi Bengt. 
I don't know if it's an option for you but if you have any control over the api / backend  see if you can include that info in the jason rather than headers. It will make your life easier. I ran into the same problem you did, and since I was upgrading the server app from rails 3.2 to rails 4.2 I changed the api response to include meta info like pagination and some other stuff about the object.

[Bengt]

Thanks for your reply Nick!
In this particular case I have control over the backend, but that is for sure not true all the time, and it requires to rewrite our web api due to "client" demands, not the way you would like it in a perfect world I believe.. :-)

[Nikolay Rusev]

Hello,

Indeed data, total etc. field must be part of the response body. Otherwise the will no be picked from the DataSource.

Regards,
Nikolay Rusev
Telerik

 

 

[Nick]

@Nikolay Rusev

Hi. 

As bengt mentioned sometimes we have no control over api we consume, and it would helpful if there was a way to access the whole raw response for cases like this. Something along the lines of dataSource.raw() or dataSource.fullResponse() - this way Telerik doesn't need to account for all the edge cases, and the same time we would be able to accommodate api's we don't have control over.

[Petur Subev]

Hello Everyone,

In case you want to take full control over the logic that performs the XHR request you can define the read operation as function:

http://docs.telerik.com/kendo-ui/api/javascript/data/datasource#configuration-transport.read

e.g.

http://dojo.telerik.com/@pesho/IQOKo

Kind Regards,
Petur Subev
Telerik