CLI argument to set http headers for the dev server

[bgirschig]

I'm facing an issue with my current project because I need to use a sharedArrayBuffer, which requires some specific CORS headers.
Parcel's dev server does not add these headers by default and It doesn't look like there is an option to add them manually.

I can solve this in two ways:

1. Hard-coding the headers in the setHeaders method (Easiest, but likely to cause side effects)
2. Adding a command-line argument: --header. For example in my case, I could start my dev server with

parcel index.html \
   --header "Cross-Origin-Opener-Policy: same-origin" \
   --header "Cross-Origin-Opener-Policy: same-origin"

So my questions are:

• If I make a CL with either of these, is it likely to be accepted ?
• Does the --header parameter name make sense ? Should it be --headers (to match webpack), or something else ?
• Reading contributing.md, it looks like anyone can release a new version. Is that really the case (More broadly, how does the release process work) ?

[mischnic]

Does this work for you? #6976 (comment) (still isn't described in the docs unfortunately: parcel-bundler/website#884)

We really want to avoid adding more and more CLI arguments...

[bgirschig]

I'll give it a try, thanks for the suggestion.

I understand not wanting to add arguments to the CLI.
Would the .parcelrc be a better place for this ? (I don't think there are any dev-server settings there, so I guess not...)

[mischnic]

No, compared to that CLI would be better, also because the CLI arguments correspond to this list of settings which already contains stuff like dev server port/host/https/...

parcel/packages/core/types/index.js

Lines 285 to 330 in c3bbe0a

	export type InitialParcelOptions = {|
	+entries?: FilePath | Array<FilePath>,
	+config?: DependencySpecifier,
	+defaultConfig?: DependencySpecifier,
	+env?: EnvMap,
	+targets?: ?(Array<string> | {+[string]: TargetDescriptor, ...}),
	+shouldDisableCache?: boolean,
	+cacheDir?: FilePath,
	+mode?: BuildMode,
	+hmrOptions?: ?HMROptions,
	+shouldContentHash?: boolean,
	+serveOptions?: InitialServerOptions | false,
	+shouldAutoInstall?: boolean,
	+logLevel?: LogLevel,
	+shouldProfile?: boolean,
	+shouldPatchConsole?: boolean,
	+shouldBuildLazily?: boolean,
	+shouldBundleIncrementally?: boolean,
	+inputFS?: FileSystem,
	+outputFS?: FileSystem,
	+cache?: Cache,
	+workerFarm?: WorkerFarm,
	+packageManager?: PackageManager,
	+detailedReport?: ?DetailedReportOptions,
	+defaultTargetOptions?: {|
	+shouldOptimize?: boolean,
	+shouldScopeHoist?: boolean,
	+sourceMaps?: boolean,
	+publicUrl?: string,
	+distDir?: FilePath,
	+engines?: Engines,
	+outputFormat?: OutputFormat,
	+isLibrary?: boolean,
	|},
	+additionalReporters?: Array<{|
	packageName: DependencySpecifier,
	resolveFrom: FilePath,
	|}>,
	// throwErrors
	// global?
	|};