dotnet-openapi refresh does not truncate json documents.

[chrisbecke]

Describe the bug

When dotnet-openapi is used to refresh a swagger.json document, if the new document is shorter than the old document, the file is not truncated to the new size leaving invalid trailing bytes that render it un-parsable, causing build errors.

To Reproduce

1. Create a new webapi project and add 2 [HttpXXX] methods to the controller.
2. Run dotnet-openapi add url https://localhost:5001/swagger/v1/swagger.json --output-file MyApi.json from a terminal.
3. Rebuild to verify the MyApiClient is accessible and works.
4. Remove a method from the controller and rebuild and rerun.
5. Run dotnet-openapi refresh https://localhost:5001/swagger/v1/swagger.json
6. Verify that the MyApi.json file retains its original file and has garbage data trailing the new, shorter, swagger definition.

Further technical details

user@mac % dotnet tool list --global
Package Id                       Version      Commands                   
-------------------------------------------------------------------------
dotnet-aspnet-codegenerator      2.2.3        dotnet-aspnet-codegenerator
dotnet-ef                        5.0.9        dotnet-ef                  
dotnet-svcutil                   2.0.2        dotnet-svcutil             
microsoft.dotnet-openapi         5.0.9        dotnet-openapi             

[bradygaster]

cc @darrelmiller do you have an associated issue related to this in Microsoft.OpenAPI? If not, @dougbu do you know if this is a downstream issue unrelated to Microsoft.OpenAPI?

[darrelmiller]

I am not aware of such an issue with Microsoft.OpenAPI.NET , although I'd need to see how the tool uses OpenAPI.NET to see if it is something that it is doing wrong or the calling code is doing wrong.

[bradygaster]

@dougbu your assistance on this would be helpful as you're our resident expert on dotnet-openapi afaik.

[dougbu]

I'm confused because the dotnet-openapi refresh command should never download from more than a single URI and shouldn't use either dotnet-aspnet-codegenerator or cache anything from previous dotnet-openapi executions. But, it's possible there's something wonky with how we open an existing file or close the FileStream.

I would appreciate a test project if one already exists. Could you please upload yours to GitHub @chrisbecke❔

[dougbu]

do you know if this is a downstream issue unrelated to Microsoft.OpenAPI?

…

I'd need to see how the tool uses OpenAPI.NET to see if it is something that it is doing wrong or the calling code is doing wrong.

The tool isn't using OpenAPI.NET as far as I know. It's just downloading OpenAPI docs from the network (loopback network in this case) and writing them out.

[dougbu]

By the way @chrisbecke, does your step 5 include --output-file MyApi.json i.e. reuse the same output file as step 2❔

[chrisbecke]

This is exactly what I did:

mkdir dotnet-openid-bug
cd dotnet-openid-bug
dotnet new sln
dotnet new webapi -o webapi
dotnet sln add webapi
open dotnet-openid-bug.sln

Visual Studio opened the project. I right clicked the project and added a new class picking ApiController template to get a ValuesController.cs
I then clicked run, and it opened in the browser as https://localhost:5001/swagger/index.html
While its running

cd webapi
dotnet-openapi add url https://localhost:5001/swagger/v1/swagger.json --output-file WebApi.json

Now we stop the project, and delete the existing WeatherController.cs and related model file from the root as the scaffolded file will conflict. And its convenient to make the next swagger.json smaller.
Rebuild and run.

dotnet-openapi refresh https://localhost:5001/swagger/v1/swagger.json

Now examine the WebApi.json file.

{
  "openapi": "3.0.1",
  "info": {
    "title": "webapi",
    "version": "v1"
  },
  "paths": {
    "/api/Values": {
      "get": {
        "tags": [
          "Values"
        ],
        "responses": {
          "200": {
            "description": "Success",
            "content": {
              "text/plain": {
                "schema": {
                  "type": "array",
                  "items": {
                    "type": "string"
                  }
                }
              },
              "application/json": {
                "schema": {
                  "type": "array",
                  "items": {
                    "type": "string"
                  }
                }
              },
              "text/json": {
                "schema": {
                  "type": "array",
                  "items": {
                    "type": "string"
                  }
                }
              }
            }
          }
        }
      },
      "post": {
        "tags": [
          "Values"
        ],
        "requestBody": {
          "content": {
            "application/json": {
              "schema": {
                "type": "string",
                "nullable": true
              }
            },
            "text/json": {
              "schema": {
                "type": "string",
                "nullable": true
              }
            },
            "application/*+json": {
              "schema": {
                "type": "string",
                "nullable": true
              }
            }
          }
        },
        "responses": {
          "200": {
            "description": "Success"
          }
        }
      }
    },
    "/api/Values/{id}": {
      "get": {
        "tags": [
          "Values"
        ],
        "parameters": [
          {
            "name": "id",
            "in": "path",
            "required": true,
            "schema": {
              "type": "integer",
              "format": "int32"
            }
          }
        ],
        "responses": {
          "200": {
            "description": "Success",
            "content": {
              "text/plain": {
                "schema": {
                  "type": "string"
                }
              },
              "application/json": {
                "schema": {
                  "type": "string"
                }
              },
              "text/json": {
                "schema": {
                  "type": "string"
                }
              }
            }
          }
        }
      },
      "put": {
        "tags": [
          "Values"
        ],
        "parameters": [
          {
            "name": "id",
            "in": "path",
            "required": true,
            "schema": {
              "type": "integer",
              "format": "int32"
            }
          }
        ],
        "requestBody": {
          "content": {
            "application/json": {
              "schema": {
                "type": "string",
                "nullable": true
              }
            },
            "text/json": {
              "schema": {
                "type": "string",
                "nullable": true
              }
            },
            "application/*+json": {
              "schema": {
                "type": "string",
                "nullable": true
              }
            }
          }
        },
        "responses": {
          "200": {
            "description": "Success"
          }
        }
      },
      "delete": {
        "tags": [
          "Values"
        ],
        "parameters": [
          {
            "name": "id",
            "in": "path",
            "required": true,
            "schema": {
              "type": "integer",
              "format": "int32"
            }
          }
        ],
        "responses": {
          "200": {
            "description": "Success"
          }
        }
      }
    }
  },
  "components": { }
}
      "get": {
        "tags": [
          "WeatherForecast"
        ],
        "responses": {
          "200": {
            "description": "Success",
            "content": {
              "text/plain": {
                "schema": {
                  "type": "array",
                  "items": {
                    "$ref": "#/components/schemas/WeatherForecast"
                  }
                }
              },
              "application/json": {
                "schema": {
                  "type": "array",
                  "items": {
                    "$ref": "#/components/schemas/WeatherForecast"
                  }
                }
              },
              "text/json": {
                "schema": {
                  "type": "array",
                  "items": {
                    "$ref": "#/components/schemas/WeatherForecast"
                  }
                }
              }
            }
          }
        }
      }
    }
  },
  "components": {
    "schemas": {
      "WeatherForecast": {
        "type": "object",
        "properties": {
          "date": {
            "type": "string",
            "format": "date-time"
          },
          "temperatureC": {
            "type": "integer",
            "format": "int32"
          },
          "temperatureF": {
            "type": "integer",
            "format": "int32",
            "readOnly": true
          },
          "summary": {
            "type": "string",
            "nullable": true
          }
        },
        "additionalProperties": false
      }
    }
  }
}

[dougbu]

Thanks @chrisbecke I'll likely not get to this today but appreciate the extra information

[chrisbecke]

Would uploading the project to github still be helpful?