Response modification on KrakenD req-resp-modifier plugin

[Evghenii Garbuzneac]

Hi all.

I've written a plugin corresponding to that article. https://www.krakend.io/docs/extending/plugin-modifiers/ 

My plugin converts XML response from API to JSON.

But now I want to add one improvement: I need to convert XML to JSON only if Accept: application/json is set in the request. 

So, the question is: how I can get access to request headers inside responseModifier function? 

Some parts of my code:

func (r registerer) RegisterModifiers(f func(
name string,
factoryFunc func(map[string]interface{}) func(interface{}) (interface{}, error),
appliesToRequest bool,
appliesToResponse bool,
)) {
f(string(r)+"-request", r.requestModifier, true, false)
f(string(r)+"-response", r.responseModifier, false, true)
fmt.Println(string(r), "registered!!!")
}

-------------

func (r registerer) requestModifier(
cfg map[string]interface{},
) func(interface{}) (interface{}, error) {

    return func(input interface{}) (interface{}, error) {

        return input, nil
    }
}

func (r registerer) responseModifier(
cfg map[string]interface{},
) func(interface{}) (interface{}, error) {

        return func(input interface{}) (interface{}, error) {

       // need logic to check request headers

       if !hasAcceptHeder {

           return input, nil

       }

       modifiedResp := ......

       return modifiedResp, nil
    }
}

[Albert Lombarte]

Hi Evghenii,

You don't need any plugin to get this behavior, as KrakenD does it automatically. If you choose an output_encoding = negotiate then KrakenD will honor the conversion.

See: https://www.krakend.io/docs/endpoints/content-types/#working-with-non-json

El dia dijous, 21 de març del 2024 a les 15:20:10 UTC+1, evghe...@optimum-web.com va escriure:

[Evghenii Garbuzneac]

Hi Albert, 

Thank you for your response.

Yes, I know about https://www.krakend.io/docs/endpoints/content-types/#working-with-non-json 

But we also change the structure of the response for JSON, for example, we need to remove some nodes

четверг, 21 марта 2024 г. в 17:11:23 UTC+2, Albert Lombarte:

[Albert Lombarte]

You can use "deny" for this example: https://www.krakend.io/docs/backends/data-manipulation/#deny

El dia dijous, 21 de març del 2024 a les 18:04:24 UTC+1, evghe...@optimum-web.com va escriure:

[Evghenii Garbuzneac]

Yes, it will work if we want to remove any child nodes.

But it will not work if we want to change the structure:

Node1

      Node1.1

          Node1.1.1

          Node1.1.2

     Node1.2

          Node1.2.1

To:

{

      Node1.1.1: "",

      Node1.2.1: ""

}

I didn't find the way to do that in the CE version, on in the EE

     

четверг, 21 марта 2024 г. в 19:11:37 UTC+2, Albert Lombarte:

[Albert Lombarte]

Try https://www.krakend.io/docs/backends/flatmap/ before over complicating your installation

	Albert Lombarte CEO

Missatge de Evghenii Garbuzneac <evghe...@optimum-web.com> del dia dj., 21 de març 2024 a les 18:16:

[Evghenii Garbuzneac]

Hi Albert. 

Thank you, Hope it will work for us in combination with https://www.krakend.io/docs/endpoints/common-expression-language-cel/#adding-logic-in-the-requests-and-responses

четверг, 21 марта 2024 г. в 19:17:30 UTC+2, Albert Lombarte: