feat: add .path and .path.silent functions to detect binary (#40)

After installation if you wish to specify a path to the installed
binary, it's useful for this module to be able to tell the world
where it put the binary, so this PR adds `.path` and `.path.silent()`
functions to do that.

This way we can use the installed module without having to rely on
any external context or platform.

fixes #25

README.md

@@ -23,6 +23,22 @@ This module downloads `go-ipfs` binaries from https://dist.ipfs.io into your pro
 
 By default it will download the go-ipfs version that matches the npm version of this module. So depending on `go-ipfs-dep@0.4.19` will install `go-ipfs v0.4.19` for your current system architecture, in to your project at `node_modules/go-ipfs-dep/go-ipfs/ipfs`.
 
+After downloading you can find out the path of the installed binary by calling the `path` function exported by this module:
+
+```javascript
+const { path } = require('go-ipfs-dep')
+
+console.info('go-ipfs is installed at', path())
+```
+
+An error will be thrown if the path to the binary cannot be resolved - if you do not wish this to happen, call `path.silent()`:
+
+```javascript
+const { path: silent } = require('go-ipfs-dep')
+
+console.info('go-ipfs may installed at', silent())
+```
+
 ### Overriding the go-ipfs version
 
 You can override the version of go-ipfs that gets downloaded by adding by adding a `go-ipfs.version` field to your `package.json`

src/bin.js

@@ -16,6 +16,14 @@ const success = (output) => {
   process.exit(0)
 }
 
+const existingPath = download.path.silent()
+
+if (existingPath) {
+  process.stdout.write(`Detected existing binary at ${existingPath}\n`)
+  process.stdout.write(`Skipping download\n`)
+  process.exit(0)
+}
+
 // First param is the target version
 // Second param is the target platform
 // Third param is the target architecture

src/index.js

@@ -27,6 +27,7 @@ const unzip = require('unzip-stream')
 const fetch = require('node-fetch')
 const pkgConf = require('pkg-conf')
 const pkg = require('./../package.json')
+const fs = require('fs')
 
 function unpack ({ url, installPath, stream }) {
   return new Promise((resolve, reject) => {
@@ -115,3 +116,26 @@ module.exports = async function () {
     installPath: path.join(args.installPath, 'go-ipfs') + path.sep
   }
 }
+
+module.exports.path = function () {
+  const paths = [
+    path.resolve(path.join(__dirname, '..', 'go-ipfs', 'ipfs')),
+    path.resolve(path.join(__dirname, '..', 'go-ipfs', 'ipfs.exe'))
+  ]
+
+  for (const bin of paths) {
+    if (fs.existsSync(bin)) {
+      return bin
+    }
+  }
+
+  throw new Error('go-ipfs binary not found, it may not be installed or an error may have occured during installation')
+}
+
+module.exports.path.silent = function () {
+  try {
+    return module.exports.path()
+  } catch (err) {
+    // ignore
+  }
+}

test/index.js

@@ -39,7 +39,7 @@ function download (version, platform, arch, callback) {
 }
 
 test('Ensure ipfs gets downloaded (current version and platform)', (t) => {
-  t.plan(5)
+  t.plan(7)
   const dir = path.resolve(__dirname, '../go-ipfs')
   rimraf.sync(dir)
 
@@ -52,12 +52,17 @@ test('Ensure ipfs gets downloaded (current version and platform)', (t) => {
     fs.stat(dir, (err, stats) => {
       t.error(err, 'go-ipfs should stat without error')
       t.ok(stats, 'go-ipfs was downloaded')
+      // Check detected path
+      fs.stat(Download.path(), (err3, stats3) => {
+        t.error(err3, 'detected binary path should stat without error')
+        t.ok(stats3.mode, 'downloaded binary was detected')
+      })
     })
   })
 })
 
 test('Ensure Windows version gets downloaded', (t) => {
-  t.plan(7)
+  t.plan(9)
   const dir = path.resolve(__dirname, '../go-ipfs')
   rimraf.sync(dir)
   download(version, 'windows', (err, res) => {
@@ -72,13 +77,18 @@ test('Ensure Windows version gets downloaded', (t) => {
       fs.stat(path.join(dir, 'ipfs.exe'), (err2, stats2) => {
         t.error(err2, 'windows bin should stat without error')
         t.ok(stats2, 'windows bin was downloaded')
+        // Check detected path
+        fs.stat(Download.path(), (err3, stats3) => {
+          t.error(err3, 'detected binary path should stat without error')
+          t.ok(stats3.mode, 'downloaded binary was detected')
+        })
       })
     })
   })
 })
 
 test('Ensure Linux version gets downloaded', (t) => {
-  t.plan(7)
+  t.plan(9)
   const dir = path.resolve(__dirname, '../go-ipfs')
   rimraf.sync(dir)
   download(version, 'linux', (err, res) => {
@@ -93,13 +103,18 @@ test('Ensure Linux version gets downloaded', (t) => {
       fs.stat(path.join(dir, 'ipfs'), (err2, stats2) => {
         t.error(err2, 'linux bin should stat without error')
         t.ok(stats2, 'linux bin was downloaded')
+        // Check detected path
+        fs.stat(Download.path(), (err3, stats3) => {
+          t.error(err3, 'detected binary path should stat without error')
+          t.ok(stats3.mode, 'downloaded binary was detected')
+        })
       })
     })
   })
 })
 
 test('Ensure OSX version gets downloaded', (t) => {
-  t.plan(7)
+  t.plan(9)
   const dir = path.resolve(__dirname, '../go-ipfs')
   rimraf.sync(dir)
   download(version, 'darwin', (err, res) => {
@@ -114,13 +129,18 @@ test('Ensure OSX version gets downloaded', (t) => {
       fs.stat(path.join(dir, 'ipfs'), (err2, stats2) => {
         t.error(err2, 'OSX bin should stat without error')
         t.ok(stats2, 'OSX bin was downloaded')
+        // Check detected path
+        fs.stat(Download.path(), (err3, stats3) => {
+          t.error(err3, 'detected binary path should stat without error')
+          t.ok(stats3.mode, 'downloaded binary was detected')
+        })
       })
     })
   })
 })
 
 test('Ensure TARGET_OS, TARGET_VERSION and TARGET_ARCH version gets downloaded', (t) => {
-  t.plan(7)
+  t.plan(9)
   const dir = path.resolve(__dirname, '../go-ipfs')
   rimraf.sync(dir)
   process.env.TARGET_OS = 'windows'
@@ -142,9 +162,14 @@ test('Ensure TARGET_OS, TARGET_VERSION and TARGET_ARCH version gets downloaded',
       fs.stat(path.join(dir, 'ipfs.exe'), (err2, stats2) => {
         t.error(err2, 'windows bin should stat without error')
         t.ok(stats2, 'windows bin was downloaded')
-        delete process.env.TARGET_OS
-        delete process.env.TARGET_VERSION
-        delete process.env.TARGET_ARCH
+        // Check detected path
+        fs.stat(Download.path(), (err3, stats3) => {
+          t.error(err3, 'detected binary path should stat without error')
+          t.ok(stats3.mode, 'downloaded binary was detected')
+          delete process.env.TARGET_OS
+          delete process.env.TARGET_VERSION
+          delete process.env.TARGET_ARCH
+        })
       })
     })
   })
@@ -171,3 +196,18 @@ test('Returns an error when dist url is 404', (t) => {
     delete process.env.GO_IPFS_DIST_URL
   })
 })
+
+test('Path returns undefined when no binary has been downloaded', (t) => {
+  t.plan(1)
+  const dir = path.resolve(__dirname, '../go-ipfs')
+  rimraf.sync(dir)
+  t.ok(Download.path.silent() === undefined, 'Path is undefined before installation')
+})
+
+test('Path returns undefined when no binary has been downloaded', (t) => {
+  t.plan(1)
+  const dir = path.resolve(__dirname, '../go-ipfs')
+  rimraf.sync(dir)
+
+  t.throws(Download.path, /not found/, 'Path throws if binary is not installed')
+})