`fetch` in endpoints

[furudean]

Is your feature request related to a problem? Please describe.

I'm hosting a blog post on /blog/[slug].svelte. This blog post is powered by /blog/[slug].json, generated by an endpoint. In the endpoint we want to include some html which serves as the body of the blog post. This html is composed by markdown, and its location is defined by an articleUrl parameter.

The final output for /blog/[slug].json might look something like this:

{
  "slug": "my-article",
  "articleUrl": "/articles/my-article.md",
  "articleHtml": "<h1>My article</h1>\n<p>This is my article</p>"
}

Making relative requests to fetch additional content, let's say /articles/my-article.md, is awkward if you use something like node-fetch. You have to make assumptions about the hosted environment, ergo:

import fetch from "node-fetch";

export async function get(request) {

  (...)

  const url = new URL(project.articleUrl, "http://localhost:3000");
  const res = await fetch(url);
  const markdown = await res.text();

  project.articleHtml = renderMarkdown(markdown);

  return {
    headers: {
      'Content-Type': 'application/json'
    },
    body: project
  }
}

Describe the solution you'd like

If fetch was available in endpoints, similar to how they are implemented in load() for pages, this could easily be solved like:

export async function get(request, fetch) {

  (...)

  const res = await fetch(project.articleUrl);
  const markdown = await res.text();

  project.articleHtml = renderMarkdown(markdown);

  return {
    headers: {
      'Content-Type': 'application/json'
    },
    body: project
  }
}

Describe alternatives you've considered
node-fetch would normally be an option, but since we are dealing a relative path to a locally hosted file there are the shortcomings elaborated on above.

How important is this feature to you?
It's not really obvious how to solve this particular issue without this feature, so it could help prevent some headaches in the future if there was parity with load().

[PatrickG]

Why are you fetching the content of a local file via fetch?
You could simply read the content of the file with nodes fs module.

[babichjacob]

Why are you fetching the content of a local file via fetch?
You could simply read the content of the file with nodes fs module.

That would only work during dev, since those files won't be available on e.x. a serverless platform.

[alteredorange]

All api endpoints would always run on the server, so if you were fetching something server side, then yes you'd have to use something like node-fetch.

But what you're describing could just be done in the load function, and that way you don't have to call your own api endpoint, which then calls the actual endpoint where the data is stored. Just call the data endpoint directly from the loading function.

[furudean]

All api endpoints would always run on the server, so if you were fetching something server side, then yes you'd have to use something like node-fetch.

But what you're describing could just be done in the load function, and that way you don't have to call your own api endpoint, which then calls the actual endpoint where the data is stored. Just call the data endpoint directly from the loading function.

I'm aware this particular case can be solved by using load(), but this is not what I'm asking for. I want to be able to do a relative fetch inside of endpoints.

[antony]

Yeah - I think the overarching thing here is that we provide fetch in load but we don't provide it in endpoints, which is somewhat odd. I felt the same when using server routes in Sapper.

I sort-of know the reasons, but my gut feel is that although it would be convenient, it also seems odd to just pass one thing into the endpoints. What if you were using graphql? Or a database of some sort? Why would we bless fetch in this way where it isn't strictly required (it's a special case in load)

[benmccann]

fetch seems a bit different to me than the other use cases you mentioned because we already provide a fetch implementation. If we don't make fetch available then users need to know the implementation detail that we use node-fetch or they might end up with two fetching implementations.

Also if you want to share code between a page and endpoint you'd hope the fetching works the same in both places. Right now we have to do some kind of ugly stuff like:

kit/examples/realworld.svelte.dev/src/lib/api.js

Line 15 in 5554acc

const fetch = typeof window !== 'undefined'

[antony]

Agreed, and this is why I felt it odd in Sapper. I'm definitely ok with adding it to handlers.

[benmccann]

Hmm. Counterpoint to this is that someone just asked about using fetch in hooks. I'm not sure we'd want to provide fetch to every hook. Maybe it's better to just document that you should use node-fetch in that case

[furudean]

I'm not sure we'd want to provide fetch to every hook.

Why is that a bad idea? I'm not super familiar with the context of hooks.