Add back Azure Functions correlation context hook

[hectorhdzg]

No description provided.

[ejizba]

It's annoying, but there's actually three ways for users to set the response. Instead of just using ctx.res, here's a method I would use to get the response:

private _getResponse(postInvocationContext: PostInvocationContext, ctx: Context): HttpResponse {
    const httpOutputBinding = ctx.bindingDefinitions.find(b => b.direction === "out" && b.type.toLowerCase() === "http");
    if (httpOutputBinding.name === "$return") {
        return postInvocationContext.result;
    } else if (ctx.bindings[httpOutputBinding.name] !== undefined) {
        return ctx.bindings[httpOutputBinding.name];
    } else {
        return ctx.res;
    }
}

If you're curious, here is sample code for each way you can set the response. (Also documented here to some extent)

Option 1

index.ts:

context.res = {
    // status: 200, /* Defaults to 200 */
    body: 'Hello context.res',
    statusCode: 201,
};

function.json:

{
  "type": "http",
  "direction": "out",
  "name": "canBeAnything" // This is ignored if they use `context.res`
}

Option 2

index.ts:

context.bindings.res123 = {
    // status: 200, /* Defaults to 200 */
    body: 'Hello res123 binding',
    statusCode: 202,
};

function.json:

{
  "type": "http",
  "direction": "out",
  "name": "res123" // must match if they use `context.bindings`
}

Option 3

index.ts:

return {
    // status: 200, /* Defaults to 200 */
    body: 'Hello return',
    statusCode: 203,
};

function.json:

{
  "type": "http",
  "direction": "out",
  "name": "$return"
}

[ejizba]

🎉