6.8 Protected Exports

► |  | The Racket Guide

1 | Welcome to Racket
2 | Racket Essentials
3 | Built-In Datatypes
4 | Expressions and Definitions
5 | Programmer-Defined Datatypes
6 | Modules
7 | Contracts
8 | Input and Output
9 | Regular Expressions
10 | Exceptions and Control
11 | Iterations and Comprehensions
12 | Pattern Matching
13 | Classes and Objects
14 | Units
15 | Reflection and Dynamic Evaluation
16 | Macros
17 | Creating Languages
18 | Concurrency and Synchronization
19 | Performance
20 | Parallelism
21 | Running and Creating Executables
22 | More Libraries
23 | Dialects of Racket and Scheme
24 | Command-Line Tools and Your Editor of Choice
| Bibliography
| Index

▼ | 6 | Modules

6.1 | Module Basics
6.2 | Module Syntax
6.3 | Module Paths
6.4 | Imports: require
6.5 | Exports: provide
6.6 | Assignment and Redefinition
6.7 | Modules and Macros
6.8 | Protected Exports

top contents ← prev up next →

#### 6.8`` Protected Exports🔗ℹ

Sometimes, a module needs to export bindings to other modules that are at the same trust level as the exporting module, while at the same time preventing access from untrusted modules. Such exports should use the protect-out form in provide. For example, ffi/unsafe exports all of its unsafe bindings as protected in this sense.

Levels of trust are implemented with code inspectors (see Code Inspectors for Trusted and Untrusted Code). Only modules loaded with an equally strong code inspector as an exporting module can use protected bindings from the exporting module. Operations like dynamic-require are granted access depending on the current code inspector as determined by current-code-inspector.

When a module re-exports a protected binding, it does not need to use protect-out again. Access is always determined by the code inspector of the module that originally defines a protected binding. When using a protected binding within a module, take care to either provide new bindings from the module with protect-out or ensure that no provided bindings expose functionality that was meant to be protected in the first place.

top contents ← prev up next →