[C++][Pistache-server] Object containing an Array - model file (.h) is not included and generated code is wrong - Compilation failed

[CyrilleBenard]

Description

When the YAML file describes the use of an array inside an object there are two issues :

• One model file is not included (whereas it as been well generated)
  In the current example see the lack of #include "EpsBearerId.h" inside the file AssignEbi.h

• The generated code below is wrong because the ::push_back method can't handle an json object

void AssignEbi::fromJson(const nlohmann::json& val)
{
    {
        m_ReleasedEbiList.clear();
        if(val.find("releasedEbiList") != val.end())
        {
            for( auto& item : val["releasedEbiList"] )
            {
                m_ReleasedEbiList.push_back(item);
                
            }
        }
    }
}

It should generate something like this :

void AssignEbi::fromJson(const nlohmann::json& val)
{
    {
        m_ReleasedEbiList.clear();
        if(val.find("releasedEbiList") != val.end())
        {
            for( auto& item : val["releasedEbiList"] )
            {
                if(item.is_null())
                {
                    m_ReleasedEbiList.push_back(EpsBearerId());
                }
                else
                {
                    EpsBearerId newItem ;
                    newItem.fromJson(item);
                    m_ReleasedEbiList.push_back(newItem);
                }
            }
        }
    }
}

openapi-generator version

Current master 3.3.4-SNAPSHOT

OpenAPI declaration file content or url

openapi: 3.0.0
info:
  version: 1.0.0
  title: Check generation of array inside object
  description: Internal ref filename is check_object_containing_array.yaml 

servers:
  - url: http://localhost:8080

paths:
  /ue-contexts/{ueContextId}/assignEbi:
    post:
      summary: Namf_Communication EBI Assignment service Operation
      tags:
        - EBI Assignment
      operationId: EBIAssignment
      parameters:
        - name: ueContextId
          in: path
          description: UE Context Identifier
          required: true
          schema:
            type: string
      requestBody:
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/AssignEbi'
        required: true
      responses:
        '200':
          description: EBI Assignment successfully performed.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Content'
        default:
          description: Unexpected error

components:
  schemas:
    Content:
      type: string

    AssignEbi:
      type: object
      properties:
        releasedEbiList:
          type: array
          items:
            $ref: '#/components/schemas/EpsBearerId'
          minItems: 0

#
# Generated code is also wrong with this below definition
#
#    AssignEbi:
#      type: array
#      items:
#        $ref: '#/components/schemas/EpsBearerId'
#      minItems: 0


    EpsBearerId:
      $ref: '#/components/schemas/Uinteger'


    Uinteger:
      type: integer
      minimum: 0

Command line used for generation

Generate :

openapi-generator-cli.sh generate -i ./openapi.yaml -g cpp-pistache-server -c ./config.json -o .

Compile :

g++ -c  -I./api -I./model -I./impl -Wall -g -std=c++11 -o obj/model/AssignEbi.o model/AssignEbi.cpp

Steps to reproduce

Generate & compile

Related issues/PRs

N/A

Suggest a fix/enhancement

I wrote a proposal of generated code above.

[CyrilleBenard]

Something remarkable is that I got the exact same issues (lack of include and wrong code) when using the generator cpp-restsdk

[grmcdorman]

This OpenAPI declaration:

{
  "swagger": "2.0",
  "info": {
    "description": "Test API.",
    "title": "Test",
    "version": "1"
  },
  "paths": {
    "/demo": {
      "get": {
        "tags": [
          "demo"
        ],
        "operationId": "demo",
        "summary": "Test C++ code gen",
        "produces": [
          "application/json"
        ],
        "responses": {
          "200": {
            "description": "Successful operation",
            "schema": {
              "$ref": "#/definitions/DemoArray"
            }
          }
        }
      }
    }
  },
  "definitions": {
    "DemoArray": {
      "description": "A list of data",
      "type": "array",
      "items": {
        "type": "string",
        "example": "142aee4a50c03168ffb2d957b158229a"
      }
    }
  }
}

has major problems with cpp-restsdk (uncompilable code generated) as well as appearing to generate the same invalid code as the initial bug report.

For C++, the model header contains this:

class  DemoArray
    : public null<utility::string_t>

which is syntatically invalid.

It appears to be related to this mustache code:

class {{declspec}} {{classname}}
    : public {{#parent}}{{{parent}}}{{/parent}}{{^parent}}ModelBase{{/parent}}

which apparently evaluates #parent to true when it is null instead of the expected false.

EDIT: Fixed code quoting.

[grmcdorman]

Further investigation: It appears that the cpp-restsdk does not support at all:

• As specified above, the base class is incorrect; this is in part because CppRestSdkCodegen.java is missing initialization of the instantiationTypes map
• The code generation also needs the full property type for the array items to generate correct code.
• The model-header.mustache needs to include ModelBase
• The model-source.mustache needs to handle arrays

The attached diff includes these fixes, plus support for binary ("string"/'binary") and byte array ("string"/"byte") body data.
diff1.txt

[etherealjoy]

@grmcdorman @CyrilleBenard
For pistache it is already solved on latest master branch.
Please open a different issue for cpprest-sdk, it is lacking quite a bit in such features.

[grmcdorman]

Will do when I get appropriate details from my manager. Have also made very extensive changes to the C++ code generation:

• Support for developer-provided custom content-type encoding/decoding (e.g. BSON or msgpack)
• Support for reusing the HTTP client connection (current code reopens the connection every time)
• Support for using std::chrono::system_clock::time_point for date/time values instead of utility::datetime
• Support for byte array bodies
• Support for returning API responses with the HTTP response as well as the body (if any)
• Inline doxygen-style documentation for a lot of methods
• Some cleanup of generated code, notably using _XPLATSTR instead of converting from char* to the platform string at runtime

[tnmtechnologies]

@CyrilleBenard This workaround #1050 (comment) should work.