gridsome - download remote files

content-example.js

// /content/entries/entry1.md

---
title: First Post
excerpt: First Post
date: 2020-01-14T21:53:14.578Z
localImage: ./sumit-saharkar-d3_ssraccV8-unsplash.jpg
remoteImage: https://images.unsplash.com/photo-1580451998921-c1e6e1ababe0?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=2850&q=80
---

Image Credits: https://unsplash.com/@sumit_saharkar

gridsome.config.js

// /gridsome.config.js

module.exports = {
  siteName: 'Gridsome',
  plugins: [
    {
      use: '@gridsome/source-filesystem',
      options: {
        path: 'content/entries/*.md',
        typeName: 'Entry',
        remark: {
          // remark options
        }
      }
    },
    {
      use: '~/plugins/gridsome-plugin-image-download',
      options: {
        'typeName' : 'Entry',
        'sourceField': 'remoteImage',
        'targetField': 'imageDownloaded',
        'targetPath': 'static'
      }
    }
  ],
}

plugin-gridsome.server.js

// plugins/gridsome-plugin-image-download/gridsome.server.js

const got = require('got')
const crypto = require('crypto')
const hash = crypto.createHash('sha256')
const path = require('path')
const fs = require('fs')
const FileType = require('file-type')

module.exports = function (api, options) {

    api.loadSource(({addSchemaTypes}) => {
        console.log("##### ADD SCHEMA TYPE #####");
        addSchemaTypes(`
            type ${options.typeName} implements Node @infer {
                ${options.targetField}: Image
            }
        `)
    })

    api.loadSource(async actions => {

        console.log("##### DOWNLOAD IMAGES #####");
        var nodes = actions.getCollection(options.typeName);
                
        nodes.data().forEach(async function(node) {
            
            if(node[options.sourceField]) {
                                
                hash.update(node[options.sourceField]);
                var newFileName = hash.digest('hex');
                
                var localPath = await getRemoteImage(node[options.sourceField], options.targetPath, newFileName);

                node[options.targetField] = localPath;
                
                const newNode = nodes.updateNode(node);                
            }
        })
    })
}

async function getRemoteImage(sourceUrl, targetPath, targetFileName) {

    const stream = got.stream.get(sourceUrl);

    const fileType = await FileType.fromStream(stream);
    const filePath = path.resolve('./', targetPath, `${targetFileName}.${fileType.ext}`)

    stream
        .on('response', function (res) {
            res.pipe(fs.createWriteStream(filePath))
        }).resume()

    return filePath;
}

plugin-package.json

// plugins/gridsome-plugin-image-download/package.json

{
  "name": "gridsome-plugin-image-download",
  "version": "1.0.0",
  "description": "",
  "main": "gridsome.server.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "MIT",
  "dependencies": {
    "got": "^10.5.5",
    "file-type": "^14.1.1"
  }
}