Java/RestTemplate - Allow flexible options in generated client when a file is needed

[MosheElisha]

Hi,

I have an API that requires a org.springframework.web.multipart.MultipartFile parameter (Swagger 2.0 API spec is below).

I am using generatorName=java and library=resttemplate to generate the client.

The generated Api client looks like:

public ResponseEntity<Template> createTemplateWithHttpInfo(File file, com.example.model.CreateTemplateRequest request) throws RestClientException {
...
    if (file != null)
            formParams.add("file", new FileSystemResource(file));
...

I would like to have the option to generate a client that takes an org.springframework.core.io.AbstractResource instead of a File.
The user will be able to pass a new FileSystemResource(file) to have same behavior as now but if the user does not have the file on disk, he/she can use an InputStreamResource or a ByteArrayResource or ... For example:

    api.createTemplateWithHttpInfo(
        new ByteArrayResource(byteArray) {
          @Override
          public String getFilename() {
            return "memoryBytes";
          }
        },
        ...
    );

From the source code it seems that there is no such option:

openapi-generator/modules/openapi-generator/src/main/resources/Java/libraries/resttemplate/api.mustache

Line 133 in 5cdc9e9

formParams.{{^collectionFormat}}add{{/collectionFormat}}{{#collectionFormat}}put{{/collectionFormat}}("{{baseName}}", {{#isFile}}new FileSystemResource({{paramName}}){{/isFile}}{{^isFile}}{{paramName}}{{/isFile}});{{#hasMore}}

I'm proposing a new configOption (something like "useAbstractionForFiles") and every library can try to support as possible (My first priority is to have the resttemplate library support this).

Swagger 2.0 API spec:

      "post" : {
        "operationId" : "createTemplate",
        "consumes" : [ "multipart/form-data" ],
        "produces" : [ "application/json" ],
        "parameters" : [ {
          "name" : "file",
          "in" : "formData",
          "required" : true,
          "type" : "ref"
        }, {
          "name" : "request",
          "in" : "formData",
          "required" : true,
          "type" : "ref"
        } ],
        "responses" : {
          "200" : {
            "description" : "successful operation",
            "schema" : {
              "$ref" : "#/definitions/Template"
            }
          },
          "201" : {
            "description" : ""
          }
        }
      }
    }

[MosheElisha]

@wing328 Can you please start the discussion or assign to / tag relevant engineers? Thanks.

[wing328]

As discussed, it looks reasonable to me to add another option to meet the requirement. Please go ahead to submit a PR and we'll review the change accordingly.

[nrgraham23]

Hello,

Is there documentation on how this is used?

I am using gradle and have done the following:

Added this to my dependencies:

compile group: 'org.springframework.android', name: 'spring-android-rest-template', version: '1.0.1.RELEASE'

Updated our generator:

id "org.openapi.generator" version "5.0.0-beta"

And added this option to the configOptions:

configOptions = [ dateLibrary: "java8", serializationLibrary: "jackson", useAbstractionForFiles: "true" ]

However, the method signature still returns a File:

public File dooFoo(String foo) throws ApiException

Thanks for adding this feature!

[MosheElisha]

Hi,

The feature is not included in 5.0.0-beta and will be included in 5.0.0-beta2 that is expected to be released in 30.07.2020.
If you would like to test this feature earlier, you should use the latest 5.0.0-SNAPSHOT.

[ogerardin]

This is a good idea, but is there a reason for not using the interface Resource instead of AbstractResource ?

PS: just tried with a custom template using Resource and it works as expected. Always prefer interfaces :)

[MosheElisha]

This is a good idea, but is there a reason for not using the interface Resource instead of AbstractResource ?

Good question :-). No good reason except it was just missed. I will change it to Resource soon. Thanks!

[iyzana]

It seems like this option should be present for the webclient generator as well.
It is very similar to the resttemplate generator.

[sblumenstock-doubleSlash]

How can I use this with the command line?
openapi-generator-cli generate -i petstore.yaml -g java --library=resttemplate --useAbstractionForFiles=true -o ./Desktop/OpenApi/test1

This is not working: [error] Found unexpected parameters: [--useAbstractionForFiles=true]

[MosheElisha]

@sblumenstock-doubleSlash Because this is a config option, I believe you should use the additional-properties flag:

--additional-properties=useAbstractionForFiles=true

More details here: https://openapi-generator.tech/docs/usage/#additional-properties

[sblumenstock-doubleSlash]

Ahh thank you! :)
I missed that.

[sblumenstock-doubleSlash]

Is this only implemented when uploading a file?
When I generate a client, the downloads are still files.
Doesn't it also make sense to implement this in the downloads?

[MosheElisha]

It is currently implemented for uploading files. That was my immediate need. Agree that it will be useful to get an InputStream (or similar) when downloading as well.

I don't have time to do it now but maybe in the future. If it is important for you, please feel free.

[sblumenstock-doubleSlash]

I tried to solve it by myself, but I got an issue.
public {{#returnType}}{{#isFile}}{{#useAbstractionForFiles}}...
IsFile cannot be used for returnType. How do I implement this?

[sblumenstock-doubleSlash]

I tried to solve it by myself, but I got an issue.
public {{#returnType}}{{#isFile}}{{#useAbstractionForFiles}}...
IsFile cannot be used for returnType. How do I implement this?

How can I check if the returnType is a file?
Is there a boolean that checks this?