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Hello everybody,

i like to read an json from a web api.

The following json show my example for a json for a car object:
{
    "brand": "Audi",
    "model": null,
    "generation": null,
    "yearOfProduction": "1991"
}​
If i got the json, the values of 'model' and 'generation' are null.

But if I transform the json to a struct with "jsonToStruct" method
jsonToStruct sCarAsStruct, sCarAsJson​

the values "model" and "generation" are empty strings

[]
  [brand] = "Audi"
  [model] = ""
  [generation] = ""
  [yearOfProduction] = "1991"


My question: Is it possible to get values "model" and "generation" from the struct object as null values?

Info: I like to save the car object in my database and want to difference between an empty string and a null value.



------------------------------
Viktor Kuenstler
Abrechnungszentrum Emmendingen
Emmendingen DE
------------------------------
Hello everybody,

i like to read an json from a web api.

The following json show my example for a json for a car object:
{
    "brand": "Audi",
    "model": null,
    "generation": null,
    "yearOfProduction": "1991"
}​
If i got the json, the values of 'model' and 'generation' are null.

But if I transform the json to a struct with "jsonToStruct" method
jsonToStruct sCarAsStruct, sCarAsJson​

the values "model" and "generation" are empty strings

[]
  [brand] = "Audi"
  [model] = ""
  [generation] = ""
  [yearOfProduction] = "1991"


My question: Is it possible to get values "model" and "generation" from the struct object as null values?

Info: I like to save the car object in my database and want to difference between an empty string and a null value.



------------------------------
Viktor Kuenstler
Abrechnungszentrum Emmendingen
Emmendingen DE
------------------------------
Hi  Viktor,

You can test the jsonDataType of the value "model" :
struct->model->$tags->jsonDataType  return null .

you can see  more struct info using struct->$dbgstring:

[]
[$tags]
[jsonClass] = object
[brand] = "Audi"
[$tags]
[jsonDataType] = string
[model] = ""
[$tags]
[jsonDataType] = null
[generation] = ""
[$tags]
[jsonDataType] = null
[yearOfProduction] = "1991"
[$tags]
[jsonDataType] = string


Gilles

------------------------------
Hortion Gilles
Agfa-Gevaert NV
------------------------------
Hello everybody,

i like to read an json from a web api.

The following json show my example for a json for a car object:
{
    "brand": "Audi",
    "model": null,
    "generation": null,
    "yearOfProduction": "1991"
}​
If i got the json, the values of 'model' and 'generation' are null.

But if I transform the json to a struct with "jsonToStruct" method
jsonToStruct sCarAsStruct, sCarAsJson​

the values "model" and "generation" are empty strings

[]
  [brand] = "Audi"
  [model] = ""
  [generation] = ""
  [yearOfProduction] = "1991"


My question: Is it possible to get values "model" and "generation" from the struct object as null values?

Info: I like to save the car object in my database and want to difference between an empty string and a null value.



------------------------------
Viktor Kuenstler
Abrechnungszentrum Emmendingen
Emmendingen DE
------------------------------
Hello Viktor,

You need to check the jsonDataType tag of the "model" and "generation" node. This will return null.

Here's the output of the generated struct using $dbgstring (e.g. putmess sCarAsStruct->$dbgstring):

[]
  [$tags]
    [jsonClass] = object
  [brand] = "Audi"
    [$tags]
      [jsonDataType] = string
  [model] = ""
    [$tags]
      [jsonDataType] = null
  [generation] = ""
    [$tags]
      [jsonDataType] = null
  [yearOfProduction] = "1991"
    [$tags]
      [jsonDataType] = string
Here's an example of how to check if the value is null:

if (sCarAsStruct->model->$tags->jsonDataType = "null")
  message/info "The value of the node model is null"
endif

I hope this helps.

Kind Regards,

------------------------------
Daniel Iseli
Principal Technical Support Engineer
Uniface Services
Rocket Software, Switzerland
------------------------------
Hi  Viktor,

You can test the jsonDataType of the value "model" :
struct->model->$tags->jsonDataType  return null .

you can see  more struct info using struct->$dbgstring:

[]
[$tags]
[jsonClass] = object
[brand] = "Audi"
[$tags]
[jsonDataType] = string
[model] = ""
[$tags]
[jsonDataType] = null
[generation] = ""
[$tags]
[jsonDataType] = null
[yearOfProduction] = "1991"
[$tags]
[jsonDataType] = string


Gilles

------------------------------
Hortion Gilles
Agfa-Gevaert NV
------------------------------
Thank you Gilles, thank you Daniel :)

Best Regards

------------------------------
Viktor Kuenstler
Abrechnungszentrum Emmendingen
Emmendingen DE
------------------------------
Hello everybody,

i like to read an json from a web api.

The following json show my example for a json for a car object:
{
    "brand": "Audi",
    "model": null,
    "generation": null,
    "yearOfProduction": "1991"
}​
If i got the json, the values of 'model' and 'generation' are null.

But if I transform the json to a struct with "jsonToStruct" method
jsonToStruct sCarAsStruct, sCarAsJson​

the values "model" and "generation" are empty strings

[]
  [brand] = "Audi"
  [model] = ""
  [generation] = ""
  [yearOfProduction] = "1991"


My question: Is it possible to get values "model" and "generation" from the struct object as null values?

Info: I like to save the car object in my database and want to difference between an empty string and a null value.



------------------------------
Viktor Kuenstler
Abrechnungszentrum Emmendingen
Emmendingen DE
------------------------------
The problem with round tripping (json->struct->json) is that you can loose metadata information.  I explain this using an xml to json and visa versa example; The example xml->json:  json has only name-value pairs, so every xml node (e.g. attribute, element, processing-instruction, comment) becomes an name-value pair in json. so transforming json back to xml, can be arranged by prefix the name with a _ for example for attribute, __for comment, ___for a processing-instruction and so on. The otherway arround json has arrays in xml there are no array, so transforming to xml you need to add an element arround it called for example array. The same using json to struct and visa versa, meta information is gone.  The solution is simple: add metadata. The question is here what is your single source of truth? modify that and translate. e.g.  in case json, change json before translating.

------------------------------
Dino Seelig
Tcco
Drunen NL
------------------------------
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