Add no-meta-redirect-with-time-limit rule (ember-template-lint#868)

docs/rule/no-meta-redirect-with-time-limit.md

@@ -0,0 +1,30 @@
+## (no-meta-redirect-with-time-limit)
+
+Sometimes a page automatically redirects to a different page. When this happens after a timed delay, it is an unexpected change of context that may interrupt the user. Redirects without timed delays are okay, but pleasae consider a server-side method for redirecting instead (method will vary based on your server type).
+
+This rule checks for the meta tag with a redirect; if it exists, it checks for a timed delay greater than 0.
+
+### Examples
+
+This rule **forbids** the following:
+
+```hbs
+<meta http-equiv="refresh" content="5; url=http://www.example.com" />
+```
+
+This rule **allows** the following:
+
+```hbs
+<meta http-equiv="refresh" content="0; url=http://www.example.com" />
+```
+
+### Migration
+
+* To fix, reduce the timed delay to zero, or use the appropriate server-side redirect method for your server type.
+
+### References
+
+* [F40: Failure due to using meta redirect with a time limit](https://www.w3.org/WAI/WCAG21/Techniques/failures/F40)
+* [Success Criterion 2.2.1: Timing Adjustable](https://www.w3.org/WAI/WCAG21/Understanding/timing-adjustable)
+* [Success Criterion 2.2.4: Interruptions](https://www.w3.org/WAI/WCAG21/Understanding/interruptions)
+* [Success Criterion 3.2.5: Change on Request](https://www.w3.org/WAI/WCAG21/Understanding/change-on-request)

docs/rules.md

@@ -26,6 +26,7 @@
 * [no-input-tagname](rule/no-input-tagname.md)
 * [no-invalid-interactive](rule/no-invalid-interactive.md)
 * [no-log](rule/no-log.md)
+* [no-meta-redirect-with-time-limit](rule/no-meta-redirect-with-time-limit.md)
 * [no-negated-condition](rule/no-negated-condition.md)
 * [no-nested-interactive](rule/no-nested-interactive.md)
 * [no-obsolete-elements](rule/no-obsolete-elements.md)

lib/rules/index.js

@@ -30,6 +30,7 @@ module.exports = {
   'no-input-tagname': require('./lint-no-input-tagname'),
   'no-invalid-interactive': require('./lint-no-invalid-interactive'),
   'no-log': require('./lint-no-log'),
+  'no-meta-redirect-with-time-limit': require('./lint-no-meta-redirect-with-time-limit'),
   'no-negated-condition': require('./lint-no-negated-condition'),
   'no-nested-interactive': require('./lint-no-nested-interactive'),
   'no-obsolete-elements': require('./lint-no-obsolete-elements'),

lib/rules/lint-no-meta-redirect-with-time-limit.js

@@ -0,0 +1,39 @@
+'use strict';
+
+const AstNodeInfo = require('../helpers/ast-node-info');
+const Rule = require('./base');
+
+module.exports = class NoMetaRedirectWithTimeLimit extends Rule {
+  logNode({ node, message }) {
+    return this.log({
+      message,
+      line: node.loc && node.loc.start.line,
+      column: node.loc && node.loc.start.column,
+      source: this.sourceForNode(node),
+    });
+  }
+  visitor() {
+    return {
+      ElementNode(node) {
+        const isMeta = node.tag === 'meta';
+        const hasMetaRedirect = AstNodeInfo.hasAttribute(node, 'http-equiv');
+
+        if (isMeta && hasMetaRedirect) {
+          const contentAttr = AstNodeInfo.hasAttribute(node, 'content');
+          const contentAttrValue = AstNodeInfo.elementAttributeValue(node, 'content');
+          if (contentAttr) {
+            // since the content attribute will have both the delay (in seconds) and the new URL, we only need to check the first character in the value string.
+            if (contentAttrValue.charAt(0) !== '0') {
+              this.log({
+                message: 'a meta redirect should not have a delay value greater than zero',
+                line: node.loc && node.loc.start.line,
+                column: node.loc && node.loc.start.column,
+                source: this.sourceForNode(node),
+              });
+            }
+          }
+        }
+      },
+    };
+  }
+};

test/unit/rules/lint-no-meta-redirect-with-time-limit-test.js

@@ -0,0 +1,25 @@
+'use strict';
+
+const generateRuleTests = require('../../helpers/rule-test-harness');
+
+generateRuleTests({
+  name: 'no-meta-redirect-with-time-limit',
+
+  config: true,
+
+  good: ['<meta http-equiv="refresh" content="0; url=http://www.example.com">'],
+
+  bad: [
+    {
+      template: '<meta http-equiv="refresh" content="1; url=http://www.example.com">',
+
+      result: {
+        moduleId: 'layout.hbs',
+        message: 'a meta redirect should not have a delay value greater than zero',
+        line: 1,
+        column: 0,
+        source: '<meta http-equiv="refresh" content="1; url=http://www.example.com">',
+      },
+    },
+  ],
+});