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class="picker-header"> 117 <a href="#"> 118 <span class="collapsed-arrow">►</span><span class="expanded-arrow">▼</span> 119 Table of contents 120 </a> 121 122 <div class="picker"><div class="toc"><ul> 123<li><a href="#permissions">Permissions</a> 124<ul> 125<li><a href="#module-based-permissions">Module-based permissions</a> 126<ul> 127<li><span class="stability_1"><a href="#policies">Policies</a></span> 128<ul> 129<li><a href="#enabling">Enabling</a></li> 130<li><a href="#features">Features</a> 131<ul> 132<li><a href="#error-behavior">Error behavior</a></li> 133<li><a href="#integrity-checks">Integrity checks</a></li> 134<li><a href="#dependency-redirection">Dependency redirection</a></li> 135<li><a href="#example-patched-dependency">Example: Patched dependency</a></li> 136</ul> 137</li> 138<li><a href="#scopes">Scopes</a> 139<ul> 140<li><a href="#example">Example</a></li> 141<li><a href="#integrity-using-scopes">Integrity using scopes</a></li> 142<li><a href="#dependency-redirection-using-scopes">Dependency redirection using scopes</a></li> 143<li><a href="#example-import-maps-emulation">Example: import maps emulation</a></li> 144</ul> 145</li> 146</ul> 147</li> 148</ul> 149</li> 150</ul> 151</li> 152</ul></div></div> 153 </li> 154 155 156 <li class="picker-header"> 157 <a href="#"> 158 <span class="collapsed-arrow">►</span><span class="expanded-arrow">▼</span> 159 Index 160 </a> 161 162 <div class="picker"><ul> 163<li><a href="documentation.html" class="nav-documentation">About this documentation</a></li> 164<li><a href="synopsis.html" class="nav-synopsis">Usage and example</a></li> 165 166 <li> 167 <a href="index.html">Index</a> 168 </li> 169 </ul> 170 171<hr class="line"> 172<ul> 173<li><a href="assert.html" class="nav-assert">Assertion testing</a></li> 174<li><a href="async_context.html" class="nav-async_context">Asynchronous context tracking</a></li> 175<li><a href="async_hooks.html" class="nav-async_hooks">Async hooks</a></li> 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252<li><a href="https://nodejs.org/docs/latest-v14.x/api/permissions.html">14.x</a></li> 253<li><a href="https://nodejs.org/docs/latest-v13.x/api/permissions.html">13.x</a></li> 254<li><a href="https://nodejs.org/docs/latest-v12.x/api/permissions.html">12.x</a></li> 255<li><a href="https://nodejs.org/docs/latest-v11.x/api/permissions.html">11.x</a></li></ol></div> 256 </li> 257 258 <li class="picker-header"> 259 <a href="#"> 260 <span class="collapsed-arrow">►</span><span class="expanded-arrow">▼</span> 261 Options 262 </a> 263 264 <div class="picker"> 265 <ul> 266 <li> 267 <a href="all.html">View on single page</a> 268 </li> 269 <li> 270 <a href="permissions.json">View as JSON</a> 271 </li> 272 <li class="edit_on_github"><a href="https://github.com/nodejs/node/edit/main/doc/api/permissions.md">Edit on GitHub</a></li> 273 </ul> 274 </div> 275 </li> 276 </ul> 277 </div> 278 <hr> 279 </header> 280 281 <details id="toc" open><summary>Table of contents</summary><ul> 282<li><a href="#permissions">Permissions</a> 283<ul> 284<li><a href="#module-based-permissions">Module-based permissions</a> 285<ul> 286<li><span class="stability_1"><a href="#policies">Policies</a></span> 287<ul> 288<li><a href="#enabling">Enabling</a></li> 289<li><a href="#features">Features</a> 290<ul> 291<li><a href="#error-behavior">Error behavior</a></li> 292<li><a href="#integrity-checks">Integrity checks</a></li> 293<li><a href="#dependency-redirection">Dependency redirection</a></li> 294<li><a href="#example-patched-dependency">Example: Patched dependency</a></li> 295</ul> 296</li> 297<li><a href="#scopes">Scopes</a> 298<ul> 299<li><a href="#example">Example</a></li> 300<li><a href="#integrity-using-scopes">Integrity using scopes</a></li> 301<li><a href="#dependency-redirection-using-scopes">Dependency redirection using scopes</a></li> 302<li><a href="#example-import-maps-emulation">Example: import maps emulation</a></li> 303</ul> 304</li> 305</ul> 306</li> 307</ul> 308</li> 309</ul> 310</li> 311</ul></details> 312 313 <div id="apicontent"> 314 <h2>Permissions<span><a class="mark" href="#permissions" id="permissions">#</a></span><a aria-hidden="true" class="legacy" id="permissions_permissions"></a></h2> 315<p>Permissions can be used to control what system resources the 316Node.js process has access to or what actions the process can take 317with those resources. Permissions can also control what modules can 318be accessed by other modules.</p> 319<ul> 320<li><a href="#module-based-permissions">Module-based permissions</a> control which files 321or URLs are available to other modules during application execution. 322This can be used to control what modules can be accessed by third-party 323dependencies, for example.</li> 324</ul> 325<p>If you find a potential security vulnerability, please refer to our 326<a href="https://github.com/nodejs/node/blob/main/SECURITY.md">Security Policy</a>.</p> 327<section><h3>Module-based permissions<span><a class="mark" href="#module-based-permissions" id="module-based-permissions">#</a></span><a aria-hidden="true" class="legacy" id="permissions_module_based_permissions"></a></h3> 328<h4>Policies<span><a class="mark" href="#policies" id="policies">#</a></span><a aria-hidden="true" class="legacy" id="permissions_policies"></a></h4> 329 330 331<p></p><div class="api_stability api_stability_1"><a href="documentation.html#stability-index">Stability: 1</a> - Experimental</div><p></p> 332 333<p>Node.js contains experimental support for creating policies on loading code.</p> 334<p>Policies are a security feature intended to allow guarantees 335about what code Node.js is able to load. The use of policies assumes 336safe practices for the policy files such as ensuring that policy 337files cannot be overwritten by the Node.js application by using 338file permissions.</p> 339<p>A best practice would be to ensure that the policy manifest is read-only for 340the running Node.js application and that the file cannot be changed 341by the running Node.js application in any way. A typical setup would be to 342create the policy file as a different user id than the one running Node.js 343and granting read permissions to the user id running Node.js.</p> 344<h5>Enabling<span><a class="mark" href="#enabling" id="enabling">#</a></span><a aria-hidden="true" class="legacy" id="permissions_enabling"></a></h5> 345 346<p>The <code>--experimental-policy</code> flag can be used to enable features for policies 347when loading modules.</p> 348<p>Once this has been set, all modules must conform to a policy manifest file 349passed to the flag:</p> 350<pre><code class="language-bash">node --experimental-policy=policy.json app.js</code> <button class="copy-button">copy</button></pre> 351<p>The policy manifest will be used to enforce constraints on code loaded by 352Node.js.</p> 353<p>To mitigate tampering with policy files on disk, an integrity for 354the policy file itself may be provided via <code>--policy-integrity</code>. 355This allows running <code>node</code> and asserting the policy file contents 356even if the file is changed on disk.</p> 357<pre><code class="language-bash">node --experimental-policy=policy.json --policy-integrity=<span class="hljs-string">"sha384-SggXRQHwCG8g+DktYYzxkXRIkTiEYWBHqev0xnpCxYlqMBufKZHAHQM3/boDaI/0"</span> app.js</code> <button class="copy-button">copy</button></pre> 358<h5>Features<span><a class="mark" href="#features" id="features">#</a></span><a aria-hidden="true" class="legacy" id="permissions_features"></a></h5> 359<h6>Error behavior<span><a class="mark" href="#error-behavior" id="error-behavior">#</a></span><a aria-hidden="true" class="legacy" id="permissions_error_behavior"></a></h6> 360<p>When a policy check fails, Node.js by default will throw an error. 361It is possible to change the error behavior to one of a few possibilities 362by defining an "onerror" field in a policy manifest. The following values are 363available to change the behavior:</p> 364<ul> 365<li><code>"exit"</code>: will exit the process immediately. 366No cleanup code will be allowed to run.</li> 367<li><code>"log"</code>: will log the error at the site of the failure.</li> 368<li><code>"throw"</code>: will throw a JS error at the site of the failure. This is the 369default.</li> 370</ul> 371<pre><code class="language-json"><span class="hljs-punctuation">{</span> 372 <span class="hljs-attr">"onerror"</span><span class="hljs-punctuation">:</span> <span class="hljs-string">"log"</span><span class="hljs-punctuation">,</span> 373 <span class="hljs-attr">"resources"</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span> 374 <span class="hljs-attr">"./app/checked.js"</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span> 375 <span class="hljs-attr">"integrity"</span><span class="hljs-punctuation">:</span> <span class="hljs-string">"sha384-SggXRQHwCG8g+DktYYzxkXRIkTiEYWBHqev0xnpCxYlqMBufKZHAHQM3/boDaI/0"</span> 376 <span class="hljs-punctuation">}</span> 377 <span class="hljs-punctuation">}</span> 378<span class="hljs-punctuation">}</span></code> <button class="copy-button">copy</button></pre> 379<h6>Integrity checks<span><a class="mark" href="#integrity-checks" id="integrity-checks">#</a></span><a aria-hidden="true" class="legacy" id="permissions_integrity_checks"></a></h6> 380<p>Policy files must use integrity checks with Subresource Integrity strings 381compatible with the browser 382<a href="https://www.w3.org/TR/SRI/#the-integrity-attribute">integrity attribute</a> 383associated with absolute URLs.</p> 384<p>When using <code>require()</code> or <code>import</code> all resources involved in loading are checked 385for integrity if a policy manifest has been specified. If a resource does not 386match the integrity listed in the manifest, an error will be thrown.</p> 387<p>An example policy file that would allow loading a file <code>checked.js</code>:</p> 388<pre><code class="language-json"><span class="hljs-punctuation">{</span> 389 <span class="hljs-attr">"resources"</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span> 390 <span class="hljs-attr">"./app/checked.js"</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span> 391 <span class="hljs-attr">"integrity"</span><span class="hljs-punctuation">:</span> <span class="hljs-string">"sha384-SggXRQHwCG8g+DktYYzxkXRIkTiEYWBHqev0xnpCxYlqMBufKZHAHQM3/boDaI/0"</span> 392 <span class="hljs-punctuation">}</span> 393 <span class="hljs-punctuation">}</span> 394<span class="hljs-punctuation">}</span></code> <button class="copy-button">copy</button></pre> 395<p>Each resource listed in the policy manifest can be of one the following 396formats to determine its location:</p> 397<ol> 398<li>A <a href="https://url.spec.whatwg.org/#relative-url-with-fragment-string">relative-URL string</a> to a resource from the manifest such as <code>./resource.js</code>, <code>../resource.js</code>, or <code>/resource.js</code>.</li> 399<li>A complete URL string to a resource such as <code>file:///resource.js</code>.</li> 400</ol> 401<p>When loading resources the entire URL must match including search parameters 402and hash fragment. <code>./a.js?b</code> will not be used when attempting to load 403<code>./a.js</code> and vice versa.</p> 404<p>To generate integrity strings, a script such as 405<code>node -e 'process.stdout.write("sha256-");process.stdin.pipe(crypto.createHash("sha256").setEncoding("base64")).pipe(process.stdout)' < FILE</code> 406can be used.</p> 407<p>Integrity can be specified as the boolean value <code>true</code> to accept any 408body for the resource which can be useful for local development. It is not 409recommended in production since it would allow unexpected alteration of 410resources to be considered valid.</p> 411<h6>Dependency redirection<span><a class="mark" href="#dependency-redirection" id="dependency-redirection">#</a></span><a aria-hidden="true" class="legacy" id="permissions_dependency_redirection"></a></h6> 412<p>An application may need to ship patched versions of modules or to prevent 413modules from allowing all modules access to all other modules. Redirection 414can be used by intercepting attempts to load the modules wishing to be 415replaced.</p> 416<pre><code class="language-json"><span class="hljs-punctuation">{</span> 417 <span class="hljs-attr">"resources"</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span> 418 <span class="hljs-attr">"./app/checked.js"</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span> 419 <span class="hljs-attr">"dependencies"</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span> 420 <span class="hljs-attr">"fs"</span><span class="hljs-punctuation">:</span> <span class="hljs-literal"><span class="hljs-keyword">true</span></span><span class="hljs-punctuation">,</span> 421 <span class="hljs-attr">"os"</span><span class="hljs-punctuation">:</span> <span class="hljs-string">"./app/node_modules/alt-os"</span><span class="hljs-punctuation">,</span> 422 <span class="hljs-attr">"http"</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span> <span class="hljs-attr">"import"</span><span class="hljs-punctuation">:</span> <span class="hljs-literal"><span class="hljs-keyword">true</span></span> <span class="hljs-punctuation">}</span> 423 <span class="hljs-punctuation">}</span> 424 <span class="hljs-punctuation">}</span> 425 <span class="hljs-punctuation">}</span> 426<span class="hljs-punctuation">}</span></code> <button class="copy-button">copy</button></pre> 427<p>The dependencies are keyed by the requested specifier string and have values 428of either <code>true</code>, <code>null</code>, a string pointing to a module to be resolved, 429or a conditions object.</p> 430<p>The specifier string does not perform any searching and must match exactly what 431is provided to the <code>require()</code> or <code>import</code> except for a canonicalization step. 432Therefore, multiple specifiers may be needed in the policy if it uses multiple 433different strings to point to the same module (such as excluding the extension).</p> 434<p>Specifier strings are canonicalized but not resolved prior to be used for 435matching in order to have some compatibility with import maps, for example if a 436resource <code>file:///C:/app/server.js</code> was given the following redirection from a 437policy located at <code>file:///C:/app/policy.json</code>:</p> 438<pre><code class="language-json"><span class="hljs-punctuation">{</span> 439 <span class="hljs-attr">"resources"</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span> 440 <span class="hljs-attr">"file:///C:/app/utils.js"</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span> 441 <span class="hljs-attr">"dependencies"</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span> 442 <span class="hljs-attr">"./utils.js"</span><span class="hljs-punctuation">:</span> <span class="hljs-string">"./utils-v2.js"</span> 443 <span class="hljs-punctuation">}</span> 444 <span class="hljs-punctuation">}</span> 445 <span class="hljs-punctuation">}</span> 446<span class="hljs-punctuation">}</span></code> <button class="copy-button">copy</button></pre> 447<p>Any specifier used to load <code>file:///C:/app/utils.js</code> would then be intercepted 448and redirected to <code>file:///C:/app/utils-v2.js</code> instead regardless of using an 449absolute or relative specifier. However, if a specifier that is not an absolute 450or relative URL string is used, it would not be intercepted. So, if an import 451such as <code>import('#utils')</code> was used, it would not be intercepted.</p> 452<p>If the value of the redirection is <code>true</code>, a "dependencies" field at the top of 453the policy file will be used. If that field at the top of the policy file is 454<code>true</code> the default node searching algorithms are used to find the module.</p> 455<p>If the value of the redirection is a string, it is resolved relative to 456the manifest and then immediately used without searching.</p> 457<p>Any specifier string for which resolution is attempted and that is not listed in 458the dependencies results in an error according to the policy.</p> 459<p>Redirection does not prevent access to APIs through means such as direct access 460to <code>require.cache</code> or through <code>module.constructor</code> which allow access to 461loading modules. Policy redirection only affects specifiers to <code>require()</code> and 462<code>import</code>. Other means, such as to prevent undesired access to APIs through 463variables, are necessary to lock down that path of loading modules.</p> 464<p>A boolean value of <code>true</code> for the dependencies map can be specified to allow a 465module to load any specifier without redirection. This can be useful for local 466development and may have some valid usage in production, but should be used 467only with care after auditing a module to ensure its behavior is valid.</p> 468<p>Similar to <code>"exports"</code> in <code>package.json</code>, dependencies can also be specified to 469be objects containing conditions which branch how dependencies are loaded. In 470the preceding example, <code>"http"</code> is allowed when the <code>"import"</code> condition is 471part of loading it.</p> 472<p>A value of <code>null</code> for the resolved value causes the resolution to fail. This 473can be used to ensure some kinds of dynamic access are explicitly prevented.</p> 474<p>Unknown values for the resolved module location cause failures but are 475not guaranteed to be forward compatible.</p> 476<h6>Example: Patched dependency<span><a class="mark" href="#example-patched-dependency" id="example-patched-dependency">#</a></span><a aria-hidden="true" class="legacy" id="permissions_example_patched_dependency"></a></h6> 477<p>Redirected dependencies can provide attenuated or modified functionality as fits 478the application. For example, log data about timing of function durations by 479wrapping the original:</p> 480<pre><code class="language-js"><span class="hljs-keyword">const</span> original = <span class="hljs-built_in">require</span>(<span class="hljs-string">'fn'</span>); 481<span class="hljs-variable language_">module</span>.<span class="hljs-property">exports</span> = <span class="hljs-keyword">function</span> <span class="hljs-title function_">fn</span>(<span class="hljs-params">...args</span>) { 482 <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">time</span>(); 483 <span class="hljs-keyword">try</span> { 484 <span class="hljs-keyword">return</span> <span class="hljs-keyword">new</span>.<span class="hljs-property">target</span> ? 485 <span class="hljs-title class_">Reflect</span>.<span class="hljs-title function_">construct</span>(original, args) : 486 <span class="hljs-title class_">Reflect</span>.<span class="hljs-title function_">apply</span>(original, <span class="hljs-variable language_">this</span>, args); 487 } <span class="hljs-keyword">finally</span> { 488 <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">timeEnd</span>(); 489 } 490};</code> <button class="copy-button">copy</button></pre> 491<h5>Scopes<span><a class="mark" href="#scopes" id="scopes">#</a></span><a aria-hidden="true" class="legacy" id="permissions_scopes"></a></h5> 492<p>Use the <code>"scopes"</code> field of a manifest to set configuration for many resources 493at once. The <code>"scopes"</code> field works by matching resources by their segments. 494If a scope or resource includes <code>"cascade": true</code>, unknown specifiers will 495be searched for in their containing scope. The containing scope for cascading 496is found by recursively reducing the resource URL by removing segments for 497<a href="https://url.spec.whatwg.org/#special-scheme">special schemes</a>, keeping trailing <code>"/"</code> suffixes, and removing the query and 498hash fragment. This leads to the eventual reduction of the URL to its origin. 499If the URL is non-special the scope will be located by the URL's origin. If no 500scope is found for the origin or in the case of opaque origins, a protocol 501string can be used as a scope. If no scope is found for the URL's protocol, a 502final empty string <code>""</code> scope will be used.</p> 503<p>Note, <code>blob:</code> URLs adopt their origin from the path they contain, and so a scope 504of <code>"blob:https://nodejs.org"</code> will have no effect since no URL can have an 505origin of <code>blob:https://nodejs.org</code>; URLs starting with 506<code>blob:https://nodejs.org/</code> will use <code>https://nodejs.org</code> for its origin and 507thus <code>https:</code> for its protocol scope. For opaque origin <code>blob:</code> URLs they will 508have <code>blob:</code> for their protocol scope since they do not adopt origins.</p> 509<h6>Example<span><a class="mark" href="#example" id="example">#</a></span><a aria-hidden="true" class="legacy" id="permissions_example"></a></h6> 510<pre><code class="language-json"><span class="hljs-punctuation">{</span> 511 <span class="hljs-attr">"scopes"</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span> 512 <span class="hljs-attr">"file:///C:/app/"</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span><span class="hljs-punctuation">}</span><span class="hljs-punctuation">,</span> 513 <span class="hljs-attr">"file:"</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span><span class="hljs-punctuation">}</span><span class="hljs-punctuation">,</span> 514 <span class="hljs-attr">""</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span><span class="hljs-punctuation">}</span> 515 <span class="hljs-punctuation">}</span> 516<span class="hljs-punctuation">}</span></code> <button class="copy-button">copy</button></pre> 517<p>Given a file located at <code>file:///C:/app/bin/main.js</code>, the following scopes would 518be checked in order:</p> 519<ol> 520<li><code>"file:///C:/app/bin/"</code></li> 521</ol> 522<p>This determines the policy for all file based resources within 523<code>"file:///C:/app/bin/"</code>. This is not in the <code>"scopes"</code> field of the policy and 524would be skipped. Adding this scope to the policy would cause it to be used 525prior to the <code>"file:///C:/app/"</code> scope.</p> 526<ol start="2"> 527<li><code>"file:///C:/app/"</code></li> 528</ol> 529<p>This determines the policy for all file based resources within 530<code>"file:///C:/app/"</code>. This is in the <code>"scopes"</code> field of the policy and it would 531determine the policy for the resource at <code>file:///C:/app/bin/main.js</code>. If the 532scope has <code>"cascade": true</code>, any unsatisfied queries about the resource would 533delegate to the next relevant scope for <code>file:///C:/app/bin/main.js</code>, <code>"file:"</code>.</p> 534<ol start="3"> 535<li><code>"file:///C:/"</code></li> 536</ol> 537<p>This determines the policy for all file based resources within <code>"file:///C:/"</code>. 538This is not in the <code>"scopes"</code> field of the policy and would be skipped. It would 539not be used for <code>file:///C:/app/bin/main.js</code> unless <code>"file:///"</code> is set to 540cascade or is not in the <code>"scopes"</code> of the policy.</p> 541<ol start="4"> 542<li><code>"file:///"</code></li> 543</ol> 544<p>This determines the policy for all file based resources on the <code>localhost</code>. This 545is not in the <code>"scopes"</code> field of the policy and would be skipped. It would not 546be used for <code>file:///C:/app/bin/main.js</code> unless <code>"file:///"</code> is set to cascade 547or is not in the <code>"scopes"</code> of the policy.</p> 548<ol start="5"> 549<li><code>"file:"</code></li> 550</ol> 551<p>This determines the policy for all file based resources. It would not be used 552for <code>file:///C:/app/bin/main.js</code> unless <code>"file:///"</code> is set to cascade or is not 553in the <code>"scopes"</code> of the policy.</p> 554<ol start="6"> 555<li><code>""</code></li> 556</ol> 557<p>This determines the policy for all resources. It would not be used for 558<code>file:///C:/app/bin/main.js</code> unless <code>"file:"</code> is set to cascade.</p> 559<h6>Integrity using scopes<span><a class="mark" href="#integrity-using-scopes" id="integrity-using-scopes">#</a></span><a aria-hidden="true" class="legacy" id="permissions_integrity_using_scopes"></a></h6> 560<p>Setting an integrity to <code>true</code> on a scope will set the integrity for any 561resource not found in the manifest to <code>true</code>.</p> 562<p>Setting an integrity to <code>null</code> on a scope will set the integrity for any 563resource not found in the manifest to fail matching.</p> 564<p>Not including an integrity is the same as setting the integrity to <code>null</code>.</p> 565<p><code>"cascade"</code> for integrity checks will be ignored if <code>"integrity"</code> is explicitly 566set.</p> 567<p>The following example allows loading any file:</p> 568<pre><code class="language-json"><span class="hljs-punctuation">{</span> 569 <span class="hljs-attr">"scopes"</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span> 570 <span class="hljs-attr">"file:"</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span> 571 <span class="hljs-attr">"integrity"</span><span class="hljs-punctuation">:</span> <span class="hljs-literal"><span class="hljs-keyword">true</span></span> 572 <span class="hljs-punctuation">}</span> 573 <span class="hljs-punctuation">}</span> 574<span class="hljs-punctuation">}</span></code> <button class="copy-button">copy</button></pre> 575<h6>Dependency redirection using scopes<span><a class="mark" href="#dependency-redirection-using-scopes" id="dependency-redirection-using-scopes">#</a></span><a aria-hidden="true" class="legacy" id="permissions_dependency_redirection_using_scopes"></a></h6> 576<p>The following example, would allow access to <code>fs</code> for all resources within 577<code>./app/</code>:</p> 578<pre><code class="language-json"><span class="hljs-punctuation">{</span> 579 <span class="hljs-attr">"resources"</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span> 580 <span class="hljs-attr">"./app/checked.js"</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span> 581 <span class="hljs-attr">"cascade"</span><span class="hljs-punctuation">:</span> <span class="hljs-literal"><span class="hljs-keyword">true</span></span><span class="hljs-punctuation">,</span> 582 <span class="hljs-attr">"integrity"</span><span class="hljs-punctuation">:</span> <span class="hljs-literal"><span class="hljs-keyword">true</span></span> 583 <span class="hljs-punctuation">}</span> 584 <span class="hljs-punctuation">}</span><span class="hljs-punctuation">,</span> 585 <span class="hljs-attr">"scopes"</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span> 586 <span class="hljs-attr">"./app/"</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span> 587 <span class="hljs-attr">"dependencies"</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span> 588 <span class="hljs-attr">"fs"</span><span class="hljs-punctuation">:</span> <span class="hljs-literal"><span class="hljs-keyword">true</span></span> 589 <span class="hljs-punctuation">}</span> 590 <span class="hljs-punctuation">}</span> 591 <span class="hljs-punctuation">}</span> 592<span class="hljs-punctuation">}</span></code> <button class="copy-button">copy</button></pre> 593<p>The following example, would allow access to <code>fs</code> for all <code>data:</code> resources:</p> 594<pre><code class="language-json"><span class="hljs-punctuation">{</span> 595 <span class="hljs-attr">"resources"</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span> 596 <span class="hljs-attr">"data:text/javascript,import('node:fs');"</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span> 597 <span class="hljs-attr">"cascade"</span><span class="hljs-punctuation">:</span> <span class="hljs-literal"><span class="hljs-keyword">true</span></span><span class="hljs-punctuation">,</span> 598 <span class="hljs-attr">"integrity"</span><span class="hljs-punctuation">:</span> <span class="hljs-literal"><span class="hljs-keyword">true</span></span> 599 <span class="hljs-punctuation">}</span> 600 <span class="hljs-punctuation">}</span><span class="hljs-punctuation">,</span> 601 <span class="hljs-attr">"scopes"</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span> 602 <span class="hljs-attr">"data:"</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span> 603 <span class="hljs-attr">"dependencies"</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span> 604 <span class="hljs-attr">"fs"</span><span class="hljs-punctuation">:</span> <span class="hljs-literal"><span class="hljs-keyword">true</span></span> 605 <span class="hljs-punctuation">}</span> 606 <span class="hljs-punctuation">}</span> 607 <span class="hljs-punctuation">}</span> 608<span class="hljs-punctuation">}</span></code> <button class="copy-button">copy</button></pre> 609<h6>Example: import maps emulation<span><a class="mark" href="#example-import-maps-emulation" id="example-import-maps-emulation">#</a></span><a aria-hidden="true" class="legacy" id="permissions_example_import_maps_emulation"></a></h6> 610<p>Given an import map:</p> 611<pre><code class="language-json"><span class="hljs-punctuation">{</span> 612 <span class="hljs-attr">"imports"</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span> 613 <span class="hljs-attr">"react"</span><span class="hljs-punctuation">:</span> <span class="hljs-string">"./app/node_modules/react/index.js"</span> 614 <span class="hljs-punctuation">}</span><span class="hljs-punctuation">,</span> 615 <span class="hljs-attr">"scopes"</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span> 616 <span class="hljs-attr">"./ssr/"</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span> 617 <span class="hljs-attr">"react"</span><span class="hljs-punctuation">:</span> <span class="hljs-string">"./app/node_modules/server-side-react/index.js"</span> 618 <span class="hljs-punctuation">}</span> 619 <span class="hljs-punctuation">}</span> 620<span class="hljs-punctuation">}</span></code> <button class="copy-button">copy</button></pre> 621<pre><code class="language-json"><span class="hljs-punctuation">{</span> 622 <span class="hljs-attr">"dependencies"</span><span class="hljs-punctuation">:</span> <span class="hljs-literal"><span class="hljs-keyword">true</span></span><span class="hljs-punctuation">,</span> 623 <span class="hljs-attr">"scopes"</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span> 624 <span class="hljs-attr">""</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span> 625 <span class="hljs-attr">"cascade"</span><span class="hljs-punctuation">:</span> <span class="hljs-literal"><span class="hljs-keyword">true</span></span><span class="hljs-punctuation">,</span> 626 <span class="hljs-attr">"dependencies"</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span> 627 <span class="hljs-attr">"react"</span><span class="hljs-punctuation">:</span> <span class="hljs-string">"./app/node_modules/react/index.js"</span> 628 <span class="hljs-punctuation">}</span> 629 <span class="hljs-punctuation">}</span><span class="hljs-punctuation">,</span> 630 <span class="hljs-attr">"./ssr/"</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span> 631 <span class="hljs-attr">"cascade"</span><span class="hljs-punctuation">:</span> <span class="hljs-literal"><span class="hljs-keyword">true</span></span><span class="hljs-punctuation">,</span> 632 <span class="hljs-attr">"dependencies"</span><span class="hljs-punctuation">:</span> <span class="hljs-punctuation">{</span> 633 <span class="hljs-attr">"react"</span><span class="hljs-punctuation">:</span> <span class="hljs-string">"./app/node_modules/server-side-react/index.js"</span> 634 <span class="hljs-punctuation">}</span> 635 <span class="hljs-punctuation">}</span> 636 <span class="hljs-punctuation">}</span> 637<span class="hljs-punctuation">}</span></code> <button class="copy-button">copy</button></pre> 638<p><a href="https://url.spec.whatwg.org/#relative-url-with-fragment-string">Import maps</a> assume you can get any resource by default. This means 639<code>"dependencies"</code> at the top level of the policy should be set to <code>true</code>. 640Policies require this to be opt-in since it enables all resources of the 641application cross linkage which doesn't make sense for many scenarios. They also 642assume any given scope has access to any scope above its allowed dependencies; 643all scopes emulating import maps must set <code>"cascade": true</code>.</p> 644<p>Import maps only have a single top level scope for their "imports". So for 645emulating <code>"imports"</code> use the <code>""</code> scope. For emulating <code>"scopes"</code> use the 646<code>"scopes"</code> in a similar manner to how <code>"scopes"</code> works in import maps.</p> 647<p>Caveats: Policies do not use string matching for various finding of scope. They 648do URL traversals. This means things like <code>blob:</code> and <code>data:</code> URLs might not be 649entirely interoperable between the two systems. For example import maps can 650partially match a <code>data:</code> or <code>blob:</code> URL by partitioning the URL on a <code>/</code> 651character, policies intentionally cannot. For <code>blob:</code> URLs import map scopes do 652not adopt the origin of the <code>blob:</code> URL.</p> 653<p>Additionally, import maps only work on <code>import</code> so it may be desirable to add a 654<code>"import"</code> condition to all dependency mappings.</p></section> 655 <!-- API END --> 656 </div> 657 </div> 658 </div> 659</body> 660</html> 661