feat(gatsby-core-utils): Add file download functions

packages/gatsby-core-utils/package.json

@@ -31,6 +31,7 @@
   "dependencies": {
     "ci-info": "2.0.0",
     "configstore": "^5.0.1",
+    "file-type": "^16.2.0",
     "fs-extra": "^8.1.0",
     "node-object-hash": "^2.0.0",
     "proper-lockfile": "^4.1.1",

packages/gatsby-core-utils/src/__tests__/create-remote-file-node-integration.js

@@ -0,0 +1,238 @@
+// @ts-check
+import path from "path"
+import zlib from "zlib"
+import os from "os"
+import { rest } from "msw"
+import { setupServer } from "msw/node"
+import { Writable } from "stream"
+import got from "got"
+import { fetchRemoteFile } from "../fetch-remote-file"
+
+const fs = jest.requireActual(`fs-extra`)
+
+const gotStream = jest.spyOn(got, `stream`)
+const urlCount = new Map()
+
+async function getFileSize(file) {
+  const stat = await fs.stat(file)
+
+  return stat.size
+}
+
+/**
+ * A utility to help create file responses
+ * - Url with attempts will use maxBytes for x amount of time until it delivers the full response
+ * - MaxBytes indicates how much bytes we'll be sending
+ *
+ * @param {string} file File path on disk
+ * @param {Object} req Is the request object from msw
+ * @param {{ compress?: boolean}} options Options for the getFilecontent (use gzip or not)
+ */
+async function getFileContent(file, req, options = {}) {
+  const cacheKey = req.url.origin + req.url.pathname
+  const maxRetry = req.url.searchParams.get(`attempts`)
+  const maxBytes = req.url.searchParams.get(`maxBytes`)
+  const currentRetryCount = urlCount.get(cacheKey) || 0
+  urlCount.set(cacheKey, currentRetryCount + 1)
+
+  let fileContentBuffer = await fs.readFile(file)
+  if (options.compress) {
+    fileContentBuffer = zlib.deflateSync(fileContentBuffer)
+  }
+
+  const content = await new Promise(resolve => {
+    const fileStream = fs.createReadStream(file, {
+      end:
+        currentRetryCount < Number(maxRetry)
+          ? Number(maxBytes)
+          : Number.MAX_SAFE_INTEGER,
+    })
+
+    const writableStream = new Writable()
+    const result = []
+    writableStream._write = (chunk, encoding, next) => {
+      result.push(chunk)
+
+      next()
+    }
+
+    writableStream.on(`finish`, () => {
+      resolve(Buffer.concat(result))
+    })
+
+    // eslint-disable-next-line no-unused-vars
+    let stream = fileStream
+    if (options.compress) {
+      stream = stream.pipe(zlib.createDeflate())
+    }
+
+    stream.pipe(writableStream)
+  })
+
+  return {
+    content,
+    contentLength:
+      req.url.searchParams.get(`contentLength`) === `false`
+        ? undefined
+        : fileContentBuffer.length,
+  }
+}
+
+const server = setupServer(
+  rest.get(`http://external.com/logo.svg`, async (req, res, ctx) => {
+    const { content, contentLength } = await getFileContent(
+      path.join(__dirname, `./fixtures/gatsby-logo.svg`),
+      req
+    )
+
+    return res(
+      ctx.set(`Content-Type`, `image/svg+xml`),
+      ctx.set(`Content-Length`, contentLength),
+      ctx.status(200),
+      ctx.body(content)
+    )
+  }),
+  rest.get(`http://external.com/logo-gzip.svg`, async (req, res, ctx) => {
+    const { content, contentLength } = await getFileContent(
+      path.join(__dirname, `./fixtures/gatsby-logo.svg`),
+      req,
+      {
+        compress: true,
+      }
+    )
+
+    return res(
+      ctx.set(`Content-Type`, `image/svg+xml`),
+      ctx.set(`content-encoding`, `gzip`),
+      ctx.set(`Content-Length`, contentLength),
+      ctx.status(200),
+      ctx.body(content)
+    )
+  }),
+  rest.get(`http://external.com/dog.jpg`, async (req, res, ctx) => {
+    const { content, contentLength } = await getFileContent(
+      path.join(__dirname, `./fixtures/dog-thumbnail.jpg`),
+      req
+    )
+
+    return res(
+      ctx.set(`Content-Type`, `image/svg+xml`),
+      ctx.set(`Content-Length`, contentLength),
+      ctx.status(200),
+      ctx.body(content)
+    )
+  })
+)
+
+function createMockCache() {
+  const tmpDir = fs.mkdtempSync(
+    path.join(os.tmpdir(), `gatsby-source-filesystem-`)
+  )
+
+  return {
+    get: jest.fn(),
+    set: jest.fn(),
+    directory: tmpDir,
+  }
+}
+
+describe(`create-remote-file-node`, () => {
+  let cache
+
+  beforeAll(() => {
+    cache = createMockCache()
+    // Establish requests interception layer before all tests.
+    server.listen()
+  })
+  afterAll(() => {
+    if (cache) {
+      fs.removeSync(cache.directory)
+    }
+
+    // Clean up after all tests are done, preventing this
+    // interception layer from affecting irrelevant tests.
+    server.close()
+  })
+
+  beforeEach(() => {
+    gotStream.mockClear()
+    urlCount.clear()
+  })
+
+  it(`downloads and create a file`, async () => {
+    const filePath = await fetchRemoteFile({
+      url: `http://external.com/logo.svg`,
+      cache,
+    })
+
+    expect(path.basename(filePath)).toBe(`logo.svg`)
+    expect(gotStream).toBeCalledTimes(1)
+  })
+
+  it(`downloads and create a gzip file`, async () => {
+    const filePath = await fetchRemoteFile({
+      url: `http://external.com/logo-gzip.svg`,
+      cache,
+    })
+
+    expect(path.basename(filePath)).toBe(`logo-gzip.svg`)
+    expect(getFileSize(filePath)).resolves.toBe(
+      await getFileSize(path.join(__dirname, `./fixtures/gatsby-logo.svg`))
+    )
+    expect(gotStream).toBeCalledTimes(1)
+  })
+
+  it(`downloads and create a file`, async () => {
+    const filePath = await fetchRemoteFile({
+      url: `http://external.com/dog.jpg`,
+      cache,
+    })
+
+    expect(path.basename(filePath)).toBe(`dog.jpg`)
+    expect(getFileSize(filePath)).resolves.toBe(
+      await getFileSize(path.join(__dirname, `./fixtures/dog-thumbnail.jpg`))
+    )
+    expect(gotStream).toBeCalledTimes(1)
+  })
+
+  it(`doesn't retry when no content-length is given`, async () => {
+    const filePath = await fetchRemoteFile({
+      url: `http://external.com/logo-gzip.svg?attempts=1&maxBytes=300&contentLength=false`,
+      cache,
+    })
+
+    expect(path.basename(filePath)).toBe(`logo-gzip.svg`)
+    expect(getFileSize(filePath)).resolves.not.toBe(
+      await getFileSize(path.join(__dirname, `./fixtures/gatsby-logo.svg`))
+    )
+    expect(gotStream).toBeCalledTimes(1)
+  })
+
+  describe(`retries the download`, () => {
+    it(`Retries when gzip compression file is incomplete`, async () => {
+      const filePath = await fetchRemoteFile({
+        url: `http://external.com/logo-gzip.svg?attempts=1&maxBytes=300`,
+        cache,
+      })
+
+      expect(path.basename(filePath)).toBe(`logo-gzip.svg`)
+      expect(getFileSize(filePath)).resolves.toBe(
+        await getFileSize(path.join(__dirname, `./fixtures/gatsby-logo.svg`))
+      )
+      expect(gotStream).toBeCalledTimes(2)
+    })
+
+    it(`Retries when binary file is incomplete`, async () => {
+      const filePath = await fetchRemoteFile({
+        url: `http://external.com/dog.jpg?attempts=1&maxBytes=300`,
+        cache,
+      })
+
+      expect(path.basename(filePath)).toBe(`dog.jpg`)
+      expect(getFileSize(filePath)).resolves.toBe(
+        await getFileSize(path.join(__dirname, `./fixtures/dog-thumbnail.jpg`))
+      )
+      expect(gotStream).toBeCalledTimes(2)
+    })
+  })
+})

packages/gatsby-core-utils/src/__tests__/fixtures/file.json

@@ -0,0 +1 @@
+{"yo": "dog"}