Use value syntax for @header, and add explode option

[chrisradek]

Fixes #4114

One question is whether to add a new http-specs test for the explode scenarios as part of this PR. Currently there aren't any specs for headers defined as objects - I presume since swagger doesn't allow it.

Related typespec-azure PR: Azure/typespec-azure#2257

[azure-sdk]

All changed packages have been documented.

• ✅ @typespec/http-specs
• ✅ @typespec/http
• ✅ @typespec/openapi3

Show changes

@typespec/http - feature ✏️

Updates @header decorator to accept values and adds the explode option.,> Note that using the model expression syntax to pass in arguments, or using the,> format field, are now deprecated.,> ,> diff lang="tsp",> op example1(,> - @header({ name: "ETag" }) etag: string,> + @header(#{ name: "ETag" }) etag: string ,> ): void;,> ,> op example2(,> - @header({ format: "csv" }) list: string[],> + @header list: string[],> ): void;,>

@typespec/http-specs - internal ✏️

Updates http @header usage to value syntax

@typespec/openapi3 - feature ✏️

updates openapi3 to respect @headers explode option and use value syntax

[azure-sdk]

You can try these changes here

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[MaryGao]

@timotheeguerin @chrisradek hello I'd like to comfirm two questions here:

• would this deprecation happen in our March GA scope, I mean any format usage in typespec or compiler interface would be removed and not supported?
• for header parameter except explode option do we allow to customize allowReserved option for header value also?

/cc @qiaozha

[timotheeguerin]

Yes it is being removed. And no what does it mean for header param allow reserve tells uri template you can include / and other uri reserved char this makes not sense for header

[timotheeguerin]

The format option wasn't used a single time before in the spec repos, so you have some problem with a spec?