Group multiple parameter definitions for better maintainability

[cansik]

Idea

Sometimes you have some parameters you want to provide on every path. At the moment it is possible to reference them with the $ref tag. This works great if you have a lot of different parameter combination for each route.

But we now have a complex api with a lot of optional get parameters for every path. Now the problem we encounter is, that if we have to add new parameters to this get parameters, it is very cumbersome and inconvenient to set the reference to them on each path. Often it happens that you forget one.

It would be great if we could group parameter definitions for a better maintainability and usability.

Example

As already presented on stackoverflow here an example of the definition (how it could look like):

parameters:
  MetaDataParameters:
    # Meta Data Properties
    - name: id
      in: query
      description: Entry identification number
      required: false
      type: integer

    - name: time_start
      in: query
      description: Start time of flare
      required: false
      type: string

    - name: nar
      in: query
      description: Active region number
      required: false
      type: string

And here is how I would like to reference it:

/test/:
  get:
    tags:
      - TEST
    operationId: routes.test
    parameters:
      - $ref: "#/parameters/MetaDataParameters"
    responses:
        200:
          description: OK

To get more on the user experience, this definition is much more readable than 20 parameters for each route.

Other Ideas?

Have you already thought about something like this or do you want us swagger users to go another way to deal with this problem?

Regards
Florian

[webron]

Thanks for opening the issue, there's just one thing that's not clear. On one hand, you're saying that you want to provide them for 'every path' which implies a global definition that won't require you to reference it, and on other hand, you go ahead and reference from a specific method to the group of parameters. So which of the two are you looking for? or is it both?

[cansik]

Ok the formulation every path is maybe wrong (too open). We still have paths which do not need this parameter. We would like to use it as described in the example to reference a group of parameter with one reference. Otherwise it would look like this:

/test/:
  get:
    tags:
      - TEST
    operationId: routes.test
    parameters:
      # In path parameter
      - $ref: "#/parameters/event_type"
      - $ref: "#/parameters/appearance_date"

      # Meta Data Properties
      - $ref: "#/parameters/param1"
      - $ref: "#/parameters/param2"
      - $ref: "#/parameters/param3"
      - $ref: "#/parameters/param4"
      - $ref: "#/parameters/param5"
      - $ref: "#/parameters/param6"

      # Data Properties
      - $ref: "#/parameters/param7"
      - $ref: "#/parameters/param8"
      - $ref: "#/parameters/param9"
      - $ref: "#/parameters/param10"

      # Specific Properties
      - $ref: "#/parameters/param11"
      - $ref: "#/parameters/param12"
      - $ref: "#/parameters/param13"
      - $ref: "#/parameters/param14"
      - $ref: "#/parameters/param15"
      - $ref: "#/parameters/param16"
      - $ref: "#/parameters/param17"
    responses:
        200:
          description: OK

With the enhancement we could write it like this and manage the items of each group in one place:

/test/:
  get:
    tags:
      - TEST
    operationId: routes.test
    parameters:
      # In path parameter
      - $ref: "#/parameters/event_type"
      - $ref: "#/parameters/appearance_date"

      # Meta Data Properties
      - $ref: "#/parameters/MetaDataParamGroup"

      # Data Properties
      - $ref: "#/parameters/DataParamGroup"

      # Specific Properties
      - $ref: "#/parameters/SpecificParamGroup"
    responses:
        200:
          description: OK

[webron]

Okay, thank you for the clarification. The reason I asked is because we have a feature request for global parameters already.

People have asked for parameter groups in various places, but nobody opened a feature request, so thank you for taking the time to do so. The value of it is understandable. I'm not sure the syntax you shared works, but we can evaluate it further over time.

[mohsen1]

If $ref: "#/parameters/MetaDataParamGroup" resolves to a hash (as described above) parameters will have that hash in it which is not valid as Swagger 2.0. Unless we change the parameters array format to allow hashs (which I don't think it's a good idea) it will not work.

[cansik]

@mohsen1 Ok and what is the problem with hashes for parameters? Is there a discussion in another issue about this?

[mohsen1]

parameters is an array of parameter objects. I'm not sure if we want parameterName:parameterObject hashs in the spec also.

[dolmen]

@cansik, @mohsen1: /parameters is a hash of parameter objects but /paths/{path}/parameters and /paths/{path}/{operation}/parameters are arrays of parameters objects. There is no confusion.

[dolmen]

@cansik For your request, I suggest that you define your own vendor extension for parameter groups, and write a processing tool that would inline your group references into a pure Swagger 2.0 spec for external consumption.
This is how I work for my own API: I write my spec in YAML (that allows me to use comments) and will only publish the JSON version of it.

I already find that many tools do not fully support the current spec (for example I found issues with /parameters and /paths/{path}/parameters and I had to write a processor to inline them). We don't need now to complexify the spec if tools do not follow it.

[project0]

+1
Want to see this feature as well.

[0x62ash]

+1
we too have predefined query params to almost all api paths

[renanmt]

+1 this would save me a lot of time and lines in my doc spec

[Growiel]

+1 this too, everything that gets me to reuse code is a huge +1.

[mkostin]

+1
would love to see it

[rafael84]

+1