fix: observe validateApiSpec and avoid schema re-checks (performance)

[cdimascio]

related to @aaronluman's #543

fixes:

• validateApiSpec: false does not appear to be working #541
• avoid schema re-checks (perf improvement)

behavior:

• ensure validateApiSpec is observed. currently, setting it to false is ignored
• disables schema validation on subsequent validations since validation will have occurred on startup if validateApiSpec is true.
• if validateApiSpec is false schema validation is skipped entirely which was the initial intended behavior

[aaronluman]

What do you mean by "only needed on startup"?
With this set to false it blocks ajv validations from running regardless of the value of validateApiSpec. (the ajv check catches duplicate enum values, for example).

adding validateApiSpec to the const { ... } = this.options on line 48 and changing this line to validateSchema: validateApiSpec allows for full validation suppression when validateApiSpec is set to false but still allows for full schema validation otherwise

[cdimascio]

Good catch...

Schema validation occurs here on startup https://github.com/cdimascio/express-openapi-validator/blob/master/src/framework/openapi.schema.validator.ts#L10

that said, ajv isn’t set up the same way there as it is for request and response validation. Perhaps it should be. It may make sense for the startup code above to create an ajv instance by calling the code below (but setting validateSchema true and skipping the req/res specific logic) https://github.com/cdimascio/express-openapi-validator/blob/master/src/framework/ajv/index.ts#L21.
And, in addition, the startup ajv instance will still need the draft schema and open api schema, etc setup.

Doing something like this may make it possible to do a complete validate on startup, which should make it okay to set validateSchema to false in all other cases

[aaronluman]

interesting. running the tests this morning everything appears to be working as expected. The startup check is catching the schema errors when I set validateApiSpec: true.

[cdimascio]

fantastic! i'll work to get this merged in. thanks for your help

[cdimascio]

@all-contributors add @aaronluman for code and test

[allcontributors]

@cdimascio

I've put up a pull request to add @aaronluman! 🎉