JSON to ABAP transformation issue

[johnm16]

Hi Folks,

after having problems with the serialize/deserialize methods, I took Sandra Rossi's advice and created some simple JSON-ABAP-JSON transformations. My first ABAP to JSON transformation worked perfectly.

However, I'm having an issue with a very simple JSON to ABAP transformation: it takes a very basic JSON string (3 fields) and converts them to an ABAP flat structure, or tries to.

Here is the JSON string:

{<br>"access_token":"67118f6bfaa1efedba09c90f9b2bc578e70f8468",<br>"expires_in":21600,<br>"token_type":"bearer"<br>}

Here is the target ABAP structure ZSTY_IN_JSON_TOKEN_RESPONSE:

ACCESS_TOKEN     Type ZDE_ACCESS_TOKEN  STRING	0<br>EXPIRES_IN       Type ZDE_EXPIRES_IN    STRING	0<br>TOKEN_TYPE       Type ZDE_TOKEN_TYPE    STRING	0

Here is the transformation:

  <tt:root name="ACCESS_RESPONSE" type="ddic:ZSTY_IN_JSON_TOKEN_RESPONSE"/><br>  <tt:template><br>    <object><br>      <str name="access_token"><br>        <tt:value ref="access_response.access_token"/><br>      </str><br>      <str name="expires_in"><br>        <tt:value ref="access_response.expires_in"/><br>      </str><br>      <str name="token_type"><br>        <tt:value ref="access_response.token_type"/><br>      </str><br>    </object><br>  </tt:template>

And here's the transformation call (lr_reader TYPE REF TO if_sxml_reader):

      CALL TRANSFORMATION zca_in_json_token_response<br>               SOURCE XML lr_reader<br>                   RESULT access_response = ls_response.

Now here's the thing: when I call the transformation, the first field ("access_token") is initialised in the ABAP structure perfectly. The second field ("expires_in") fails every time with the exception CX_ST_MATCH_ELEMENT. The exception error message is "System expected element 'str'".

Maybe it's because the incoming JSON value is numeric, and my structure has a string field as the target? But I have also tried NUMC type (my original choice), integer, decimal and character text for the "expires_in" field. All options fail with the same error.

I suspect the problem lies in this part of the transformation:

      <str name="expires_in"><br>        <tt:value ref="access_response.expires_in"/><br>      </str>

The debugger catches the exception at the first of these three lines, so I expect there's something wrong with it; but I've no idea what.

Thank you for reading, all advice gratefully received.

Cheers

John Moulding.

[johnm16]

PS Please ignore the attachment!

[Sandra_Rossi]

Press menu Actions > Edit and delete your attachment (cross button in the attachment).

All your codes have <br> inside them.

To paste code without <br>, use Ctrl+Shift+V (unformatted paste).

Here is the JSON string:

{
"access_token":"67118f6bfaa1efedba09c90f9b2bc578e70f8468",
"expires_in":21600,
"token_type":"bearer"
}

Here is the target ABAP structure ZSTY_IN_JSON_TOKEN_RESPONSE:

ACCESS_TOKEN   Type ZDE_ACCESS_TOKEN  STRING
EXPIRES_IN     Type ZDE_EXPIRES_IN    STRING
TOKEN_TYPE     Type ZDE_TOKEN_TYPE    STRING

Here is the transformation:

  <tt:root name="ACCESS_RESPONSE" type="ddic:ZSTY_IN_JSON_TOKEN_RESPONSE"/>
  <tt:template>
    <object>
      <str name="access_token">
        <tt:value ref="access_response.access_token"/>
      </str>
      <str name="expires_in">
        <tt:value ref="access_response.expires_in"/>
      </str>
      <str name="token_type">
        <tt:value ref="access_response.token_type"/>
      </str>
    </object>
  </tt:template>

And here's the transformation call (lr_reader TYPE REF TO if_sxml_reader):

      CALL TRANSFORMATION zca_in_json_token_response
               SOURCE XML lr_reader
               RESULT access_response = ls_response.

[johnm16]

Thank you Sandra!

Any ideas for a solution?

JM

[Sandra_Rossi]

You need to understand how SAP converts JSON into JSON XML before it's passed to the XML transformation.

{
"access_token":"67118f6bfaa1efedba09c90f9b2bc578e70f8468",
"expires_in":21600,
"token_type":"bearer"
}

is automatically converted into:

<object>
  <str name="access_token">67118f6bfaa1efedba09c90f9b2bc578e70f8468</str>
  <num name="expires_in">21600</num>
  <str name="token_type">bearer</str>
</object>

THE PROBLEM: your transformation fails because it expects <str name="expires_in"> --- In your below code, use <num ...> instead of <str ...>:

      <num name="expires_in">
        <tt:value ref="access_response.expires_in"/>
      </num>

In case it's not obvious, you may ask ABAP to obtain JSON-XML automatically with this kind of code (ASSERT is just present to show what is obtained):

call transformation id source xml `{"a":1}` result xml data(json_xml) options xml_header = 'no'.
assert cl_abap_codepage=>convert_from( json_xml ) = `<object><num name="a">1</num></object>`.

[johnm16]

Thank you very much!

Cheers

John