feat: reuse local du.zip

.eslintrc

@@ -3,5 +3,8 @@
   "env": {
     "node": true,
     "es6": true
+  },
+  "rules": {
+    "prefer-const": "error"
   }
 }

.gitignore

@@ -1,3 +1,4 @@
+.idea/
 node_modules/
 bin/
 .nyc_output/

README.md

@@ -8,7 +8,8 @@ Node CLI or module to calculate folder size.
 
 It uses:
 
-- [Sysinternals DU](https://docs.microsoft.com/en-us/sysinternals/downloads/du) on Windows, automatically downloaded at installation time because the license does not allow redistribution. See below about specifying the download location.
+- [Sysinternals DU](https://docs.microsoft.com/en-us/sysinternals/downloads/du) on Windows, automatically downloaded at
+  installation time because the license does not allow redistribution. See below about specifying the download location.
 - native `du` on other platforms
 
 ## Installation
@@ -57,9 +58,17 @@ fast-folder-size .
 
 By default the Sysinternals DU.zip is downloaded from https://download.sysinternals.com/files/DU.zip.
 
-If you need to change this, e.g. to download from an internal package repository, 
-set the **FAST_FOLDER_SIZE_DU_ZIP_LOCATION** environment variable. For example:
+If you need to change this, e.g. to download from an internal package repository
+or re-use an existing du.zip, you can set the **FAST_FOLDER_SIZE_DU_ZIP_LOCATION** environment variable.
+
+For example:
+
+```shell
+export FAST_FOLDER_SIZE_DU_ZIP_LOCATION="https://your.internal.repository/DU.zip"
+```
+
+or
 
 ```shell
-export FAST_FOLDER_SIZE_DU_ZIP_LOCATION=https://your.internal.repository/DU.zip
+export FAST_FOLDER_SIZE_DU_ZIP_LOCATION="D://download/du.zip"
 ```

get-sysinternals-du.js

@@ -5,45 +5,83 @@ const path = require('path')
 const decompress = require('decompress')
 const { HttpsProxyAgent } = require('https-proxy-agent')
 
-// Only run for Windows
-if (process.platform !== 'win32') {
-  process.exit(0)
+exports.onDuZipDownloaded = function (tempFilePath, workspace) {
+  decompress(tempFilePath, path.join(workspace, 'bin'))
 }
 
-// check if du is already installed
-if (
-  fs.existsSync(
-    path.join(__dirname, 'bin', `du${process.arch === 'x64' ? '64' : ''}.exe`)
-  )
-) {
-  process.exit(0)
-}
+exports.downloadDuZip = function (mirror, workspace) {
+  const duZipLocation =
+    mirror || 'https://download.sysinternals.com/files/DU.zip'
+
+  // checks for proxy variables in user environment
+  const proxyAddress =
+    process.env.HTTPS_PROXY ||
+    process.env.https_proxy ||
+    process.env.HTTP_PROXY ||
+    process.env.http_proxy
+
+  if (proxyAddress) {
+    https.globalAgent = new HttpsProxyAgent(proxyAddress)
+  }
 
-const duZipLocation =
-  process.env.FAST_FOLDER_SIZE_DU_ZIP_LOCATION ||
-  'https://download.sysinternals.com/files/DU.zip'
+  console.log(`downloading du.zip from ${duZipLocation}`)
+  if (!mirror) {
+    console.log(
+      `if you have trouble while downloading, try set process.env.FAST_FOLDER_SIZE_DU_ZIP_LOCATION to a proper mirror or local file path`
+    )
+  }
 
-// checks for proxy variables in user environment
-const proxyAddress =
-  process.env.HTTPS_PROXY ||
-  process.env.https_proxy ||
-  process.env.HTTP_PROXY ||
-  process.env.http_proxy
+  https.get(duZipLocation, function (res) {
+    const tempFilePath = path.join(os.tmpdir(), 'du.zip')
 
-if (proxyAddress) {
-  const agent = new HttpsProxyAgent(proxyAddress)
+    const fileStream = fs.createWriteStream(tempFilePath)
+    res.pipe(fileStream)
 
-  https.globalAgent = agent
+    fileStream.on('finish', function () {
+      fileStream.close()
+      exports.onDuZipDownloaded(tempFilePath, workspace)
+    })
+  })
 }
 
-https.get(duZipLocation, function (res) {
-  const tempFilePath = path.join(os.tmpdir(), 'du.zip')
+exports.default = function (workspace) {
+  // Only run for Windows
+  if (process.platform !== 'win32') {
+    return
+  }
 
-  const fileStream = fs.createWriteStream(tempFilePath)
-  res.pipe(fileStream)
+  // check if du is already installed
+  const duBinFilename = `du${process.arch === 'x64' ? '64' : ''}.exe`
+  const defaultDuBinPath = path.join(workspace, 'bin', duBinFilename)
 
-  fileStream.on('finish', function () {
-    fileStream.close()
-    decompress(tempFilePath, path.join(__dirname, 'bin'))
-  })
-})
+  if (fs.existsSync(defaultDuBinPath)) {
+    console.log(`${duBinFilename} found at ${defaultDuBinPath}`)
+    return
+  }
+  console.log(`${duBinFilename} not found at ${defaultDuBinPath}`)
+
+  const mirrorOrCache = process.env.FAST_FOLDER_SIZE_DU_ZIP_LOCATION
+
+  if (
+    !mirrorOrCache ||
+    mirrorOrCache.startsWith('http://') ||
+    mirrorOrCache.startsWith('https://')
+  ) {
+    exports.downloadDuZip(mirrorOrCache, workspace)
+    return
+  }
+
+  if (fs.existsSync(mirrorOrCache)) {
+    exports.onDuZipDownloaded(mirrorOrCache, workspace)
+    return
+  }
+
+  const message = `du.zip not found at ${mirrorOrCache}`
+  // this will result the process to exit with code 1
+  throw Error(message)
+}
+
+// only auto execute default() function when its invoked directly
+if (require.main === module) {
+  exports.default(__dirname)
+}

get-sysinternals-du.test.js

@@ -0,0 +1,88 @@
+if (process.platform !== 'win32') {
+  // these test cases are only for win32
+  return
+}
+
+const { test, beforeEach } = require('tap')
+const path = require('path')
+const os = require('os')
+const fs = require('fs')
+const subject = require('./get-sysinternals-du.js')
+
+const workspace = path.join(os.tmpdir(), 'fast-folder-size-playground')
+beforeEach(() => {
+  if (fs.existsSync(workspace)) fs.rmSync(workspace, { recursive: true })
+  fs.mkdirSync(workspace)
+})
+
+test('it can use local file path as process.env.FAST_FOLDER_SIZE_DU_ZIP_LOCATION', t => {
+  t.test('C:\\**\\du.zip', t => {
+    const dummyDuZipPath = path.join(workspace, 'dummy-du.zip')
+    fs.writeFileSync(dummyDuZipPath, '')
+    process.env.FAST_FOLDER_SIZE_DU_ZIP_LOCATION = dummyDuZipPath
+
+    subject.onDuZipDownloaded = function (tempFilePath) {
+      t.equal(tempFilePath, dummyDuZipPath)
+      t.end()
+    }
+
+    subject.default(workspace)
+  })
+
+  t.test('C://**/du.zip', t => {
+    const dummyDuZipPath = path
+      .join(workspace, 'dummy-du.zip')
+      .replaceAll('\\', '/')
+      .replace(':/', '://')
+    fs.writeFileSync(dummyDuZipPath, '')
+    process.env.FAST_FOLDER_SIZE_DU_ZIP_LOCATION = dummyDuZipPath
+
+    subject.onDuZipDownloaded = function (tempFilePath) {
+      t.equal(tempFilePath, dummyDuZipPath)
+      t.end()
+    }
+
+    subject.default(workspace)
+  })
+
+  t.end()
+})
+
+test('it cannot use non-exists local file path as process.env.FAST_FOLDER_SIZE_DU_ZIP_LOCATION', t => {
+  process.env.FAST_FOLDER_SIZE_DU_ZIP_LOCATION = path.join(
+    workspace,
+    'non-exists-dummy-du.zip'
+  )
+
+  t.throws(
+    () => subject.default(workspace),
+    error => {
+      return error.message.startsWith('du.zip not found at')
+    }
+  )
+
+  t.end()
+})
+
+test('it can use http(s) url as process.env.FAST_FOLDER_SIZE_DU_ZIP_LOCATION', t => {
+  const dummyUrl = 'https://non-exists.localhost/du.zip'
+  process.env.FAST_FOLDER_SIZE_DU_ZIP_LOCATION = dummyUrl
+
+  subject.downloadDuZip = function (mirror) {
+    t.equal(mirror, dummyUrl)
+    t.end()
+  }
+
+  subject.default(workspace)
+})
+
+test('when process.env.FAST_FOLDER_SIZE_DU_ZIP_LOCATION not found, then download it directly', t => {
+  delete process.env.FAST_FOLDER_SIZE_DU_ZIP_LOCATION
+
+  subject.downloadDuZip = function (mirror) {
+    t.equal(mirror, undefined)
+    t.end()
+  }
+
+  subject.default(workspace)
+})

package.json

@@ -28,6 +28,7 @@
   },
   "devDependencies": {
     "@types/node": "^20.2.5",
+    "@types/tap": "^15.0.8",
     "eslint": "^8.41.0",
     "eslint-config-prettier": "^8.8.0",
     "eslint-plugin-prettier": "^4.2.1",