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Server-side Setup

This guide will walk you through a server side upload flow in SvelteKit

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Start up SvelteKit Project

The easiest way to start building a SvelteKit app is to run npm create

npm create svelte@latest pinata-app
- Which Svelte app template? Skeleton project
- Add type checking with TypeScript? Yes, using TypeScript syntax
- Select additional options (use arrow keys/space bar) <- These are optional

After the project is created cd into the repo and install pinata-web3

npm i pinata-web3

In this demo we will be using tailwindcss with typography plugin. Follow other CSS Framework guides respectively.

npx svelte-add@latest tailwindcss

After making the project, create a .env.local file in the root of the project and put in the following variables:

PINATA_JWT=
PUBLIC_GATEWAY_URL=

Use the JWT from the API key creation in the previous step as well as the Gateway Domain. The format of the Gateway domain should be mydomain.mypinata.cloud.

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Setup Pinata

Create a directory called server in the src/lib folder of the project and then make a file called pinata.ts inside of it. In that file we’ll export an instance of the IPFS SDK that we can use throughout the rest of the app.

The use of the server directory prevents it being used client side.

src/lib/server/pinata.ts
import { PinataSDK } from "pinata-web3"
import { PINATA_JWT } from "$env/static/private";
import { PUBLIC_GATEWAY_URL } from "$env/static/public";

export const pinata = new PinataSDK({
  pinataJwt: `${PINATA_JWT}`,
  pinataGateway: `${PUBLIC_GATEWAY_URL}`
})

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Create Client Side Form

Next we’ll want to add a form on our home page that will allow someone to select a file and upload it. In the src/routes/+page.svelte file take out the boiler plate code and use the following. Lets also restrict the allowed extensions for the file. (e.g. jpg, jpeg, png, webp).

src/routes/+page.svelte
<script lang="ts">
  import { enhance } from '$app/forms';

  let uploading = false;

  function handleUpload() {
    uploading = true;
      return async ({ update }) => {
        await update();
        uploading = false;
      };
  }
</script>

<main class="w-full min-h-screen m-auto flex flex-col justify-center items-center">
  <form method="POST" enctype="multipart/form-data" use:enhance={handleUpload}>
    <input type="file" id="file" name="fileToUpload" accept=".jpg, .jpeg, .png, .webp" />
    <button disabled={uploading} type="submit">
      {uploading ? 'Uploading...' : 'Upload'}
    </button>
  </form>
</main>

This will take a file from the client side and upload it through a form Action we are going to make next.

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Create Server Action

Create a server file, src/routes/+page.server.ts, so that we can add a form action to use. Since this demo and page only has 1 form, we will keep the default action.

src/routes/+page.server.ts
import { fail, json, type Actions } from "@sveltejs/kit";
import { pinata } from "$lib/server/pinata";

export const actions: Actions = {
  default: async ({ request }) => {
    try {
      const formData = await request.formData();
      const uploadedFile = (formData?.get('fileToUpload') as File);

      if (!uploadedFile.name || uploadedFile.size === 0) {
        return fail(400, {
          error: true,
          message: "You must provide a file to upload"
        })
      }

      const upload = await pinata.upload.file(uploadedFile);
      const url = await pinata.gateways.convert(upload.IpfsHash);
      return { url, filename: uploadedFile.name, status: 200 };
    } catch (error) {
      console.log(error);
      return json(
        { error: "Internal Server Error" },
        { status: 500 }
      );
    }
  }
}

The form action will send an API request to Pinata with the upload, then make one more request to get a signed URL we can use to see the content. Once complete, we can define the return data sent to the client.

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Access the Returned value of the Form Action

We can access the returned data by exporting the form prop on our +page.svelte. Now, after submitting the form, the form prop will be updated and we can conditionally render the image we just uploaded.

src/routes/+page.svelte
<script lang="ts">
  import { enhance } from '$app/forms';
  import type { ActionData } from './$types';

  export let form: ActionData;
  let uploading = false;

  function handleUpload() {
    uploading = true;
      return async ({ update }) => {
        await update();
        uploading = false;
      };
  }
</script>

<main class="w-full min-h-screen m-auto flex flex-col justify-center items-center">
  <form method="POST" enctype="multipart/form-data" use:enhance={handleUpload}>
    <input type="file" id="file" name="fileToUpload" accept=".jpg, .jpeg, .png, .webp" />
    <button disabled={uploading} type="submit">
      {uploading ? 'Uploading...' : 'Upload'}
    </button>
  </form>
  {#if form && form.status === 200}
    <img src={form.url} alt={form.filename} />
  {/if}
</main>

And just like that we have uploaded an image to Pinata and recieved a usable URL in return! Remember that the url for the image is ephemeral, once you refresh the page the url and image will be gone.