Servlet receives parameters as JSON

[OnaBai]

When defining a Grid (using JSP wrapper) my servlet receives the parameters pageSize, take, skip and page as a JSON string in the name part of the parameters. I mean, the servlet receives one single parameters which name is: {"take":10,"skip":0,"page":1,"pageSize":10} and the value is empty.

Equivalent code using JavaScript receives 4 parameters:

1. name: take, value: 10
2. name: skip, value: 0
3. name: page, value: 1
4. name: pageSize, value: 10

Is this difference intentional?
Is correct encoding a JSON string in the name side of the parameter?

[OnaBai]

The problem is in TransportTag.doEndTag that when parameterMap is null (not defined) defines function(options,type){return JSON.stringify(options);} as parameterMap  preventing in JavaScript code RemoteTransport.setup from invoking identity function as happens for other frameworks.

[youssef]

you must do that : give a name to parameters

{paramName1: {"take":10,"skip":0,"page":1,"pageSize":10}}

[OnaBai]

The question is that I don't do it but Kendo UI Java code that implements the taglib.

And, btw, I agree with you that if I decide to send it as JSON I would have transmitted it in the value side of the parameter and not as the name..

[Atanas Korchev]

Hello,

 You need to specify a parameterMap attribute in order to avoid this behavior (or treat the request body as JSON and parse it). We are sending the parameters as JSON by default to make it easier to parse on the server side.

Regards,
Atanas Korchev
the Telerik team

[OnaBai]

Atenas, Two questión: 1. It behaves different than if you use JavaScript for initialized the grid -> annoying 2. JSON is sent as the parameter name and not as the parameter value -> bad practice since before hand you don't know how to retrieve it from the list Regards

[Atanas Korchev]

Hi Emilio,

 As I said in my first reply we are doing this to make parsing the request easier. If you don't like it specify a parameterMap as I said in my first reply:

parameterMap="myParameterMap"

<scirpt>

function myParameterMap(options) {
    return options;
}

</script>

Kendo UI uses jQuery to make ajax requests. Also the result of the parameterMap function is passed as the data setting of jQuery.ajax. This causes the request body to be in JSON format (see attached screenshot). 

Regards,
Atanas Korchev
the Telerik team

[OnaBai]

Hi Atanas,

First of all I'd like to thank you for your fast answer. 

Said so, I'm afraid I did not stated the problem correctly. I'm going to provide a little more information and hopefully now it is going to be easier to understand.

Using KendoUI Web (HTML+JavaScript) I wrote:

$("#grid").kendoGrid({

    columns:   [

        { field:"name", title:"Name" },

        { field:"abv", title:"ABV", format:"{0:n1}", width:"50" },

        { field:"style", title:"Style", format:"{0:n1}" },

        { field:"category", title:"Category", format:"{0:n1}" }

    ],

    pageable:  true,

    sortable:  true,

    filterable:false,

    groupable: false,

    dataSource:{

        pageSize:    10,

        serverPaging:true,

        transport:   {

            read:{

                url:        "/ListBeer",

                type:       "GET",

                contentType:"application/json"

            }

        },

        schema:      {

            data:  "data",

            total: "total",

            groups:"data",

            model: {

                fields:{

                    name:    { type:"string" },

                    abv:     { type:"number" },

                    style:   { type:"string" },

                    category:{ type:"string" }

                }

            }

        }

    }

})

What really matters is only this part:

dataSource:{

    pageSize:    10,

    serverPaging:true,

    transport:   {

        read:{

            url:        "/ListBeer",

            type:       "GET",

            contentType:"application/json"

        }

    },

When I use JSP wrap, I translated it into this:

<kendo:grid name="grid" pageable="true" sortable="true" filterable="false" groupable="false">

    <kendo:grid-columns>

        <kendo:grid-column title="Name" field="name"/>

        <kendo:grid-column title="ABV" field="abv" format="{0:n1}" width="50px"/>

        <kendo:grid-column title="Style" field="style"/>

        <kendo:grid-column title="Category" field="category"/>

    </kendo:grid-columns>

    <kendo:dataSource pageSize="10" serverPaging="true">

        <kendo:dataSource-transport>

            <kendo:dataSource-transport-read url="/ListBeer" type="GET" contentType="application/json"/>

        </kendo:dataSource-transport>

        <kendo:dataSource-schema data="data" total="total" groups="data">

            <kendo:dataSource-schema-model>

                <kendo:dataSource-schema-model-fields>

                    <kendo:dataSource-schema-model-field name="name" type="string"/>

                    <kendo:dataSource-schema-model-field name="abv" type="number"/>

                    <kendo:dataSource-schema-model-field name="style" type="string"/>

                    <kendo:dataSource-schema-model-field name="category" type="string"/>

                </kendo:dataSource-schema-model-fields>

            </kendo:dataSource-schema-model>

        </kendo:dataSource-schema>

    </kendo:dataSource>

</kendo:grid>

And again, what really matters is:

<kendo:dataSource pageSize="10" serverPaging="true">

    <kendo:dataSource-transport>

        <kendo:dataSource-transport-read url="/ListBeer" type="GET" contentType="application/json"/>

    </kendo:dataSource-transport>

As far I as I understand they are equivalent and I expect that my servlet "/ListBeer" might be the same for both.

Then, I use Chrome for checking network traffic and I see in (attached captures) that the parameters "Query String Parameters" are not the same for HTML.png and JSP.png.

I know how to use parameterMap and if KendoUI is not making both products (Web and JSP wrapper) 100% compatible I will have to go that path. BUT since this is a Beta and you want to hear from us, I've decided to share with you that I have to write extra code for making both compatible and migration will imply extra work.

Then, we might enter a philosophical question regarding the fact that json is transmitted as name and not as value but for me the most important question is understand if KendoUI strategy is make both products 100% compatible or just 99.9% :-)

Thanks in advance and my best regards
Emiliano

[Atanas Korchev]

Hi,

 Thank you for your feedback. We will see if other users find this behavior abnormal and decide whether to send parameters as json by default or not.

Regards,
Atanas Korchev
the Telerik team