[kotlin-spring] use spring resource for file handling

[sylvainmoindron]

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Description of the PR

Using spring ResponseEntity<Resource> for handling file when generating an API who return a file with

schema:  
  type: string
  format: binary

before it was ResponseEntity<File> which only responded filename

@jimschubert @dr4ke616

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[jimschubert]

I haven't used spring resource in this way. What's in the PR looks good side from the import of that full type.

Let me know if you need a hand looking into fixing it.

[sylvainmoindron]

with the correct sample the CI check are OK

[wing328]

Looks like the default should be null (without double quotes) or should be omitted.

I don't think it's related to this change so we will need to fix it later.

[sylvainmoindron]

I saw lot of change in the gérérated code (last time it was générated was 3.3.9 on Sep 2018).
i alsa saw a change in the body parameter name
(@Valid @RequestBody pet: Pet
changed to
@Valid @RequestBody body: Pet

[jimschubert]

@wing328 This looks like it's probably an issue with the spec document? An id path parameter, by definition, can't be null otherwise the request won't match the path definition.

[sylvainmoindron]

there is another PR for this problem i think
#2487

[sylvainmoindron]

there is a problem at the moment for a binary body, the API use Resource, the interface ApiService use multipart. i'm looking for the problem

[sylvainmoindron]

i fixed the multipart problem

[jimschubert]

This looks unrelated to this PR, but I don't think passing a null from Spring's internals to a Kotlin String will work. We may be missing nullable type work on the input parameter.

[jimschubert]

@wing328 This looks like it's probably an issue with the spec document? An id path parameter, by definition, can't be null otherwise the request won't match the path definition.

[jimschubert]

I think this needs to change org.springframework.web.multipart.MultipartFile to {{{dataType}}} to use Resource as well, otherwise it's hard-coded and the file type mapping will only work for models. I could be wrong as I've not used Resource, and jcenter is giving me 502 bad gateways so I can't download plugins required to build a sample.

Same issue in service.mustache and formParams.mustache.

[sylvainmoindron]

At first I wanted to treat all file as Resource, but after watching other générator I thought that keeping Multipart for form was a better idea (i was inspired by the spring-java générator).
Maybe i'm wrong ,it's my first job on openapi-genrator.

[sylvainmoindron]

i'm doing a POC where I remove all instance of MultipartFile; if i'm confident i break nothing, i will commit it.

[sylvainmoindron]

I followed your recommendations and did a push

[jimschubert]

I tested this against the petstore simple yaml and looks like Resource is working as expected for file input.

I restarted Shippable (failed on Elm client tests), but I think this is good to go once checks have completed.

[wing328]

Resolved the merge conflicts via 4f8a555

I'll update the Kotlin server samples later after merging the PR into master.

[wing328]

Samples updated via 1313cff