[REQ] proposal: rust/reqwest changes

@frol / @farcaller / @richardwhiuk / @paladinzh

In order to make the rust/reqwest api/models more flexible for use with an arbitrary/external client
I would propose the following changes...

1. Add extensions to alter generation :
   new extension attributes: vendorExtensions.*
   x-add-dependencies Cargo dependency additions
   x-add-dependencies-dev Cargo dependency-dev additions
   x-add-use Use statements for all files (could be added to partial header
   x-add-derive-enum Added before all enum definitions
   x-add-derive-struct Added before all struct definitions

It would be used with something like this:

generatorName: rust
outputDir: xxxxx
library: reqwest
inputSpec: xxxxx/yyy.yaml
additionalProperties:
  supportAsync: true
  packageName: my_xxxx
  vendorExtensions.x-group-parameters: true
  vendorExtensions.x-add-dependencies: >
    strum = "*"

    strum_macros = "*"

    builder_macro = "*"

    derive-getters = "*"

    derive_builder = "*"

    getset    = "*"

    rand = "*"
  vendorExtensions.x-add-dependencies-dev: >
    # added dev dependencies
  vendorExtensions.x-add-use: >
    #[allow(unused_imports)]
    pub use serde::{
        Serialize, Deserialize, 
        ser::{SerializeStruct},
        de::{Visitor, MapAccess},
    };

    #[allow(unused_imports)]

    pub use derive_builder::{Builder};

    #[allow(unused_imports)]

    pub use getset::{CopyGetters, Getters, MutGetters, Setters};

    #[allow(unused_imports)]

    pub use strum_macros::{  Display, EnumMessage, EnumIter, EnumString,  AsRefStr, AsStaticStr, };
  vendorExtensions.x-add-derive-enum: >
    #[derive(Display, AsRefStr, AsStaticStr, EnumString, EnumMessage, EnumIter)]
  vendorExtensions.x-add-derive-struct: >
    #[derive(Builder, Getters, Setters, MutGetters, CopyGetters)]

    #[builder(try_setter, setter(into))]
  vendorExtensions.x-other: false

2. Split the API methods into:

   • {{{operationId}}}_setparameters(builder, ...)
     -- Set all parameters
   • {{{operationId}}}(config, ...)
     • create builder
     • call {{{operationId}}}_setparameters(builder, ...)
     • execute
       This change would make the integration into an external library with existing client generator easier.

3. Generate #[tests] based on examples in spec file

4. Create a trait definition that all API methods implement
   To make it easier to have a map of traits and call them generically

I have implemented some of this already in my branch...

Comments thoughts ?
Thanks
JR

Start by reviewing the rust/reqwest generator and the proposer’s branch, jrz_v500_add_extensions. The proposal covers vendor-extension support, API method splitting, generated tests, and traits; done would require agreeing on scope and implementing and validating the selected changes.