Error 12869 when reading JSON content with the ABL HTTP Client

When using the ABL HTTP Client to process an HTTP response that contains JSON content, the following error is returned: Invalid cast from OpenEdge.Core.ByteBucket to Progress.Json.ObjectModel.JsonObject. (12869)

Jan 25, 2023
Knowledge

Title

URL Name

Error-12869-when-reading-JSON-content-with-the-ABL-HTTP-Client

Article Number

000228322

Environment

Product: OpenEdge Version: 11.7.3 OS: All supported platforms Other: HTTP Client

Question/Problem Description

When using the ABL HTTP Client to process an HTTP response that contains JSON content, the following error is returned while casting the response object to a JsonObject object:

Invalid cast from OpenEdge.Core.ByteBucket to Progress.Json.ObjectModel.JsonObject. (12869)

Steps to Reproduce

Clarifying Information

The HTTP Content-Type header of the HTTP response contains a JSON value, for example:

application/problem+json
application/json

The response object is cast to a JsonObject object as follows:

oJsonResp = CAST(oResponse:Entity, JsonObject).

While this issue has only been reported in OpenEdge 11.7.3, it may also impact other retired versions.

Error Message

Invalid cast from OpenEdge.Core.ByteBucket to Progress.Json.ObjectModel.JsonObject. (12869)

Defect Number

Enhancement Number

Cause

In OpenEdge 11.7.3, the type of the response's Entity is a ByteBucket instead of a JsonObject.

Resolution

Upgrade to the latest OpenEdge 11.7 release (11.7.15 at the time of this writing). The type of the response's Entity is now correctly seen as JsonObject.
Alternatively, upgrade to OpenEdge 12.2 or later.

Workaround

Check the type of the response's Entity before casting the object. For example, here is a code excerpt that illustrates that:

DEFINE VARIABLE oByteBucket AS OpenEdge.Core.ByteBucket NO-UNDO.
DEFINE VARIABLE oJsonResp AS JsonObject NO-UNDO.
DEFINE VARIABLE JsonString AS LONGCHAR NO-UNDO.

...

/* Check if response is a ByteBucket object */
IF TYPE-OF(oResponse:Entity, ByteBucket) THEN DO:
    oByteBucket = CAST(oResponse:Entity, ByteBucket).
    JsonString = GET-STRING(oByteBucket:GetBytes():VALUE, 1).
    MESSAGE  "Body : " STRING(jsonString) VIEW-AS ALERT-BOX.
END.

/* Check if response is a JSON object */
ELSE IF TYPE-OF(oResponse:Entity, JsonObject) THEN DO:
    oJsonResp = CAST(oResponse:Entity, JsonObject).
    oJsonResp:Write(JsonString, TRUE).    
    MESSAGE  "Body : " STRING(jsonString) VIEW-AS ALERT-BOX.
END.

Notes

Progress Article(s):
How to send and receive a simple JSON document with the ABL HTTP Client

Keyword Phrase

Last Modified Date

1/25/2023 12:13 PM

Error 12869 when reading JSON content with the ABL HTTP Client

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Error 12869 when reading JSON content with the ABL HTTP Client

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