Add setting to yield next on OPTION request

[bearline]

In most cases it makes sense to just return a 204 on an OPTIONS request, but the specification says that a body can be included with the response. Could we have some sort of setting that makes the module not capture the OPTIONS request?

To clarify, I need a setting that does something like below:

if (options.captureOptions === true && this.method === 'OPTIONS') {
    this.status = 204;
} else {
    yield next;
}

[andrenarchy]

+1

This also makes sense if koa-router is used with allowedMethods. This middleware sets the Allow: headers in response to an OPTIONS request. If koa-cors runs first, the Allow: headers from koa-router are missing in the response.

[fritx]

+1 Related:

• "koa-router doesn't support Cross Domain request?" koa-router doesn't support Cross Domain request? ZijianHe/koa-router#171
• "cannot get cross-site POST to work" cannot get cross-site POST to work axios/axios#191

I was having a problem with OPTIONS in koa-router, if a xhr library sends an OPTIONS request, the koa-cors wouldn't work.

I solved it by using the following code:

// drop koa-cors

// api cors
apiRouter.use(async (ctx, next) => {
  ctx.set('Access-Control-Allow-Credentials', 'true')
  ctx.set('Access-Control-Allow-Origin', '*')
  await next()
})

// api options method
apiRouter.options('*', async (ctx, next) => {
  ctx.set('Access-Control-Allow-Methods', 'GET, POST, OPTIONS')
  ctx.set('Access-Control-Allow-Origin', '*')
  ctx.status = 204
  await next()
})

[superman66]

I had met this problem. And I solved it by setting options foo koa-cors, add PATCH in methods:

const options = {
  origin: true,
  methods: 'GET,HEAD,PUT,PATCH,POST,DELETE',
};
app.use(cors(options))

[niftylettuce]

@fritx you are missing this from your example above:

  ctx.set(
    'Access-Control-Allow-Headers',
    ctx.get('Access-Control-Request-Headers')
  );

working code:

// Instead of using `@koa/cors` which conflicts with `koa-router`:
// https://github.com/evert0n/koa-cors/issues/30#issuecomment-301310688
routes.use(async (ctx, next) => {
  ctx.set('Access-Control-Allow-Credentials', 'true');
  ctx.set('Access-Control-Allow-Origin', '*');
  await next();
});
routes.options('*', async (ctx, next) => {
  ctx.set('Access-Control-Allow-Methods', 'GET, POST, OPTIONS');
  ctx.set('Access-Control-Allow-Origin', '*');
  ctx.set(
    'Access-Control-Allow-Headers',
    ctx.get('Access-Control-Request-Headers')
  );
  ctx.status = 204;
  await next();
});