koajs/koa

Expressive middleware for node.js using generators

David Ojimba

@davidkayce_gitlab

yes, please I do, still havent been able to find a way to resolve it

Samuel Grave

@itsmegrave

hey guys! Do anyone have a list of "must-have" packages for a koa api?

Saad Quadri

@saadq

Check out https://github.com/koajs/koa/wiki#middleware

It really depends on your needs for your api, but at a minimum I would recommend having koa-helmet

Mike Hamilton

@gorbypark

hey guys, noob question here, but can anyone tell me why the body is only [1,2] and not [1,2,3]? I thought middleware flows down, then back up, then the response is sent?

app.use(async (ctx, next) => {
  arr.push(1);
  await next();
  arr.push(3);
});

app.use(async (ctx, next) => {
  arr.push(2);
  await next();
});

app.use(async ctx => {
  ctx.body = JSON.stringify(arr);
});

Jame

@jamemackson

the body is set on the response before 3 is added to the array. everything after a next is happening on the way back up the middleware stack.

Mike Hamilton

@gorbypark

ah, so it goes down, does the response, then goes up

Casey Britt

@yourfavorite

Anyone able to help me better understand a Middleware pattern? I'm wondering if there is an article or tutorial out there about how to add Middlewares to your own code rather than writing Middlewares for existing packages. Or even just one that breaksdown how Middlewares work in something like Koa. Searching google just gets me info on how to write better middelwares for things like Koa/Express.

I'm particularly interested in the pattern Koa uses with context and would love an article that pulls the general flow out into some easier to comprehend code as jumping through the many koa packages is difficult for me to follow.

Jame

@jamemackson

@yourfavorite i would start with https://koajs.com where they give some simple example of middleware in koa

the docs there are pretty simple and that’s simply because koa is pretty simple in what it does.

the one thing to note is that koa calls middleware down and then back up when a await next(); is called. so anything after the next call is happening on the way back up.

Casey Britt

@yourfavorite

@jamemackson I don't quite follow the way down and way back up. Are you saying that Koa goes mw1 -> next() -> mw2 -> await next() -> mw3 -> next() -> mw2 -> ??

Jame

@jamemackson

yes. next passes control down the middleware stack until something sets a response and the flow goes back up executing any code that follows the next call. see the example above that mike posted a day or two ago.

Casey Britt

@yourfavorite

Oh I see

So basically

ctx.before = true;
await next();
// Go do other middlewares...
ctx.after = true;

Jame

@jamemackson

yup. that’s about it.

Casey Britt

@yourfavorite

What is a practical reason for wanting to do this?

Jame

@jamemackson

there are times you want to do something with a response going out. maybe time a response or validate some data

Jeff Hansen

@jeffijoe

@yourfavorite https://medium.com/netscape/mastering-koa-middleware-f0af6d327a69

Jackie Gleason

@jrgleason

Can someone help me with koa-jwt. I have it configured but for some reason it is still throwing a 401 even after I am signed in.

Ghost

@ghost~5ac084b8d73408ce4f93eee9

Anyone know how i can modify a specific visitor sessions outside the scope of koa (ctx) ? Getting certain info from Jayson TCP sockets that i want to apply to the correct users session.

Kirk Gordon

@krg7880

Does Koa support keep-alive by default? If not, how can one enable it?

Nicholas

@NicholasCao

Here is a new project. https://github.com/goa-go/goa just like koa for golang, I'm looking for someone to join us.

Eyal Perry

@EyalPerry

@NicholasCao I love the name :D and I do love koa. Unfortunately I do not know go at all

Nicholas

@NicholasCao

@EyalPerry
It doesn't matter, thank you for your start

Aaron

@4aron

Wow no chat since 1 month...

Can I add an extra arguments to session.save with koa-session?

I want to add some data to the stored session in the same insert

Vamsi Ampolu

@vamsiampolu

Hi guys, a question for you:

tl;dr: Trying to create a mock context like this:

const ctx = createContext({
      method,
      headers,
      body,
    });

throws TypeErrors

https://stackoverflow.com/questions/57864117/koa-create-context-cannot-set-headers-or-body

delphi

@johndeguerto

@vamsiampolu I think headers, methods don’t have setting when an hTTP method is get other than post. So context are executed once upon start of the server. perhaps the app.use( ) where you intialize context to run should be higher in the code chain prior to other middleware?

Vimal Mistry

@vimalmistry

Hello everyone. I want to use Koa for my next project. What is actual real world advantage of koa over express?. I want it for my api backend.

Vimal Mistry

@vimalmistry

Screenshot 2019-09-19 at 11.59.28 PM.png

AuthorizationMiddleware is still calling on first routes why?

delphi

@johndeguerto

@vimalmistry are you having an issue or are you asking why auth is being called in your load routes?

Vimal Mistry

@vimalmistry

@johndeguerto Thanks for reply. I have solved this issue by calling authRoute.use(myMiddleware) :)

Nemo

@gpugems

Hi, what is best npm for koa/health

Kevin

@kevinludwig

Hi, having a problem with setting ctx.body = a stream (sort of). Im using csv-stringify npm module's streams support, so my code is generally doing something like this: ctx.body = stream; await someCodeThatGeneratesCsvRows(stream); stream.end();

I should first say that the code works. The thing that's confusing me is that no rows come to the browser until all rows are generated (e.g. until stream.end() is called). I changed my stream writer to be something a bit more complex, like this, which vaguely what they say to do anyway in the Writable stream docs,

const writer = (stream) => (obj) => {
    return new Promise((resolve) => {
        if (!stream.write(obj)) {
            stream.once('drain', resolve);
        } else {
            process.nextTick(resolve);
        }
    });
};

and when I do that, stream.write does indeed return false at some point but the drain event never arrives, so my request just hangs.

my vague guess is that Im doing something wrong and Koa isn't reading from the stream until .end() but I could be mistaken on that

Kevin

@kevinludwig

ok well I figure out how to get it working...after reading some koa source code. I need to not await someCodeThatGeneratesCsvRows(stream) and instead do ctx.body = stream; someCodeThatReturnsAPromiseThatIWontAwait(stream).then(() => stream.end());

...because Koa doesn't attach the pipe to the stream until after my middleware returns. Is this the way I'm supposed to be doing this? I don't think there's any examples that make this particularly clear in the docs...

If its not clear why I might be doing this, Imagine I'm reading blocks of data from a db (or another api) to fetch parts of a dataset, and then tranforming that data into CSV, and writing the CSV rows to a stream. So the method that generates the dataset is async, but I want koa to stream the results (obviously) as they arrive. And so given that Koa is built on top of async await it seemed natural to me that I could assign the stream and then pump data into the stream via awaiting as necessary...

Jonas Amundsen

@badeball

if I append a middleware in the runtime of another middleware (IE. during a request), will it be considered and possibly invoked for said request?

Guy Korland

@gkorland

Is there a way to load part of a session or lazy load part of it? And is there a way to store only part of the session and the all big session when only a small part of it changed?

Rajiv Mothilal

@rmothilal

Hi everyone, I'm a newbie to the koa framework. I need some assistance with an issue. I need to access the incoming request headers before request authentication is done. I need to insert additional headers to be used in subsequent functions/processes. Any help would be greatly appreciated. Thanks Rajiv

仇彦龙

@qiuyanlong

hello

Shashank Agarwal

@shashank1010

Hi, a NodeJS noob here,

I intend to create an application and reuse some app logic by forwarding an API call from one route to another.

for example. A request is made for /subscribed-users and i want to add to this context and call the /users route internally.

How can i achieve this with KOA?
Any help would be welcome.

Thanks.

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