Hono•3w ago

How to Connect to Services using context

I'm getting frustrated with the repetitive getDb(), getStorage(), and similar function calls in my Hono backend. In other backends I've worked with, I didn’t have to do this as often, which makes me feel like there might be a better way to handle it in Hono. Ideally, I want my services (like database and storage) to be injected into each request automatically, so I can write functions like:

function xyz(db, storage) {
  // Use db and storage without having to initialize them inside
}

function xyz(db, storage) {
  // Use db and storage without having to initialize them inside
}

function xyz(ctx) {
  ctx.db; // Already available
  ctx.storage; // Already available
}

function xyz(ctx) {
  ctx.db; // Already available
  ctx.storage; // Already available
}

without needing to await anything inside these functions because the necessary setup should have already been handled earlier. Additionally, I'm using Hono embedded inside a SvelteKit app. If possible, I'd like to leverage SvelteKit's locals to pass the already established database connection to Hono, so I don't have to create a new connection each time. Is there a way to achieve this in Hono while keeping things clean and efficient?

11 Replies

atoko•3w ago

You want the Context Api, specifically .set/.get https://hono.dev/docs/api/context note that the middleware runs per request, so you need to have the getDb awaited outside of the body of the middleware.

Context - Hono

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JustKiraOP•3w ago

so in a nutshell im doing same getDb flow but without needing to type getDb every single time

Arjix•3w ago

https://github.com/exuanbo/di-wise/issues/19

GitHub

showcase: di-wise hono middleware · Issue #19 · exuanbo/di-wise

I wrote a simple hono.js middleware to integrate di-wise into your routing! import { createMiddleware } from 'hono/factory'; import { Token } from 'di-wise'; // your custom global c...

Arjix•3w ago

That's what I do, really handy I highly recommend di-wise but you can probably adapt the middleware to other service providers

ambergristle•3w ago

not necessarily. it really depends on your setup. i assume you're running serverless though, so you've got two options: - init the db connection in the global scope + pass it around - init the db connection once per request, and expose it through Context as @atoko suggested

JustKiraOP•3w ago

well can't i init db connection and call getDb inside middelware to get global instance?

ambergristle•3w ago

idk what your getDb function does, if it's not creating the connection but yeah

const dbMiddleware = () => {
  return createMiddleware(async (c, next) => {
    const db = await getDb()
    c.set('db', db)
  })
}

const dbMiddleware = () => {
  return createMiddleware(async (c, next) => {
    const db = await getDb()
    c.set('db', db)
  })
}

this would work regardless and then you could use c.var.db or w/e to access that in downstream middleware or the handler

JustKiraOP•3w ago

well getDb() check if there is active client with connection if so it return it if not it create new cliecnt with connection and return it does types work?

ambergristle•3w ago

https://hono.dev/docs/api/context#set-get

JustKiraOP•3w ago

ouu intresting

ambergristle•3w ago

but automatic inference only works for handlers so if you wanted to access from a downstream middleware, you'd need to add the variable type to that one too

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How to Connect to Services using context

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