require-in-the-middle - npm Package Compare versions

Comparing version 6.0.0 to 7.0.0

index.js

@@ -7,5 +7,10 @@ 'use strict'
 const debug = require('debug')('require-in-the-middle')
-const parse = require('module-details-from-path')
+const moduleDetailsFromPath = require('module-details-from-path')
+const assert = require('assert')
 
+// Using the default export is discouraged, but kept for backward compatibility.
+// Use this instead:
+//    const { Hook } = require('require-in-the-middle')
 module.exports = Hook
+module.exports.Hook = Hook
 
@@ -32,2 +37,44 @@ /**
 
+// Cache `onrequire`-patched exports for modules.
+//
+// Exports for built-in (a.k.a. "core") modules are stored in an internal Map.
+// Exports for non-core modules are stored on a private field on the `Module`
+// object in `require.cache`. This allows users to delete from `require.cache`
+// to trigger a re-load (and re-run of the hook's `onrequire`) of a module the
+// next time it is required.
+// https://nodejs.org/docs/latest/api/all.html#all_modules_requirecache
+class ExportsCache {
+  constructor () {
+    this._exportsFromBuiltinId = new Map()
+    this._kRitmExports = Symbol('RitmExports')
+  }
+
+  has (filename, isBuiltin) {
+    if (isBuiltin) {
+      return this._exportsFromBuiltinId.has(filename)
+    } else {
+      const mod = require.cache[filename]
+      return !!(mod && this._kRitmExports in mod)
+    }
+  }
+
+  get (filename, isBuiltin) {
+    if (isBuiltin) {
+      return this._exportsFromBuiltinId.get(filename)
+    } else {
+      const mod = require.cache[filename]
+      return (mod && mod[this._kRitmExports])
+    }
+  }
+
+  set (filename, exports, isBuiltin) {
+    if (isBuiltin) {
+      this._exportsFromBuiltinId.set(filename, exports)
+    } else {
+      assert(filename in require.cache, `unexpected that there is no Module entry for "${filename}" in require.cache`)
+      require.cache[filename][this._kRitmExports] = exports
+    }
+  }
+}
+
 function Hook (modules, options, onrequire) {
@@ -50,3 +97,4 @@ if ((this instanceof Hook) === false) return new Hook(modules, options, onrequire)
 
-  this.cache = new Map()
+  this._cache = new ExportsCache()
+
   this._unhooked = false
@@ -84,3 +132,16 @@ this._origRequire = Module.prototype.require
     } else {
-      filename = Module._resolveFilename(id, this)
+      try {
+        filename = Module._resolveFilename(id, this)
+      } catch (resolveErr) {
+        // If someone *else* monkey-patches before this monkey-patch, then that
+        // code might expect `require(someId)` to get through so it can be
+        // handled, even if `someId` cannot be resolved to a filename. In this
+        // case, instead of throwing we defer to the underlying `require`.
+        //
+        // For example the Azure Functions Node.js worker module does this,
+        // where `@azure/functions-core` resolves to an internal object.
+        // https://github.com/Azure/azure-functions-nodejs-worker/blob/v3.5.2/src/setupCoreModule.ts#L46-L54
+        debug('Module._resolveFilename("%s") threw %j, calling original Module.require', id, resolveErr.message)
+        return self._origRequire.apply(this, arguments)
+      }
     }
@@ -93,5 +154,5 @@
     // return known patched modules immediately
-    if (self.cache.has(filename) === true) {
+    if (self._cache.has(filename, core) === true) {
       debug('returning already patched cached module: %s', filename)
-      return self.cache.get(filename)
+      return self._cache.get(filename, core)
     }
@@ -130,3 +191,3 @@
     } else {
-      const stat = parse(filename)
+      const stat = moduleDetailsFromPath(filename)
       if (stat === undefined) {
@@ -175,13 +236,11 @@ debug('could not parse filename: %s', filename)
 
-    // only call onrequire the first time a module is loaded
-    if (self.cache.has(filename) === false) {
-      // ensure that the cache entry is assigned a value before calling
-      // onrequire, in case calling onrequire requires the same module.
-      self.cache.set(filename, exports)
-      debug('calling require hook: %s', moduleName)
-      self.cache.set(filename, onrequire(exports, moduleName, basedir))
-    }
+    // ensure that the cache entry is assigned a value before calling
+    // onrequire, in case calling onrequire requires the same module.
+    self._cache.set(filename, exports, core)
+    debug('calling require hook: %s', moduleName)
+    const patchedExports = onrequire(exports, moduleName, basedir)
+    self._cache.set(filename, patchedExports, core)
 
     debug('returning module: %s', moduleName)
-    return self.cache.get(filename)
+    return patchedExports
   }
@@ -188,0 +247,0 @@ }

package.json

 {
   "name": "require-in-the-middle",
-  "version": "6.0.0",
+  "version": "7.0.0",
   "description": "Module to hook into the Node.js require function",
@@ -5,0 +5,0 @@ "main": "index.js",

README.md

@@ -20,6 +20,6 @@ # require-in-the-middle
 const path = require('path')
-const Hook = require('require-in-the-middle')
+const { Hook } = require('require-in-the-middle')
 
 // Hook into the express and mongodb module
-Hook(['express', 'mongodb'], function (exports, name, basedir) {
+new Hook(['express', 'mongodb'], function (exports, name, basedir) {
   const version = require(path.join(basedir, 'package.json')).version
@@ -41,3 +41,3 @@
 
-### `hook = Hook([modules][, options], onrequire)`
+### `hook = new Hook([modules][, options], onrequire)`
 
@@ -44,0 +44,0 @@ When called a `hook` object is returned.

New alerts

License Policy Violation

License

This package is not allowed per your license policy. Review the package's license to ensure compliance.

Found 1 instance in 1 package

Fixed alerts

License Policy Violation

License

This package is not allowed per your license policy. Review the package's license to ensure compliance.

Found 1 instance in 1 package

Improved metrics

Total package byte prevSize

14577

increased by19.42%

Lines of code

222

increased by32.14%

No dependency changes