[RUST-AXUM] fix generator not handling application/x-www-form-urlencoded request content

[denisbog]

to fix #18060

PR checklist

• Read the contribution guidelines.
• Pull Request title clearly describes the work in the pull request and Pull Request description provides details about how to validate the work. Missing information here may result in delayed response from the community.
• Run the following to build the project and update samples:

  ./mvnw clean package 
  ./bin/generate-samples.sh ./bin/configs/*.yaml
  ./bin/utils/export_docs_generators.sh
  

  (For Windows users, please run the script in Git BASH)
  Commit all changed files.
  This is important, as CI jobs will verify all generator outputs of your HEAD commit as it would merge with master.
  These must match the expectations made by your contribution.
  You may regenerate an individual generator by passing the relevant config(s) as an argument to the script, for example ./bin/generate-samples.sh bin/configs/java*.
  IMPORTANT: Do NOT purge/delete any folders/files (e.g. tests) when regenerating the samples as manually written tests may be removed.
• File the PR against the correct branch: master (upcoming 7.1.0 minor release - breaking changes with fallbacks), 8.0.x (breaking changes without fallbacks)
• If your PR is targeting a particular programming language, @mention the technical committee members, so they are more likely to review the pull request.

[wing328]

can you please elaborate more on this change?

[denisbog]

this is a new flag to disable the logic on how the form params are being handled, currently the body is being consumed and all identified form params extracted, in this branch bodyParam is not being set which is required by the axum template:

openapi-generator/modules/openapi-generator/src/main/resources/rust-axum/server-operation.mustache

  {{#bodyParam}}
    {{#vendorExtensions}}
      {{#x-consumes-json}}
          Json(body): Json<{{^required}}Option<{{/required}}{{{dataType}}}{{^required}}>{{/required}}>,
      {{/x-consumes-json}}
      {{#x-consumes-form-urlencoded}}
          Form(body): Form<{{^required}}Option<{{/required}}{{{dataType}}}{{^required}}>{{/required}}>,
      {{/x-consumes-form-urlencoded}}

axum can deserialize form params from the body

https://docs.rs/axum/latest/axum/struct.Form.html

[wing328]

I prefer using !(this instanceof RustAxumServerCodegen) to make it much easier to understand this logic is tailor-made for the RustAxumServerCodegen instead of adding another option/flag

[denisbog]

it does work, however this to me looks that we create a dependency to more specialized class inside the generic one (since we have to import RustAxumServerCodegen)

but I see that similar was done before.

import org.openapitools.codegen.languages.PhpNextgenClientCodegen;
import org.openapitools.codegen.languages.RustAxumServerCodegen; // new import
import org.openapitools.codegen.languages.RustServerCodegen;

[wing328]

cc @linxGnu

[wing328]

https://github.com/OpenAPITools/openapi-generator/actions/runs/8215440138/job/22492223594?pr=18061

that's fixed in the latest master so it can be ignored

[wing328]

@linxGnu are you happy with this change?

[linxGnu]

@wing328 LGTM for the changes