Add rule to check if the web app manifest content is valid

.sonarrc

@@ -10,6 +10,7 @@
         "lang-attribute": "warning",
         "manifest-exists": "warning",
         "manifest-file-extension": "warning",
+        "manifest-is-valid": "warning",
         "no-double-slash": "warning"
     }
 }

src/lib/rules/manifest-is-valid/manifest-is-valid.md

@@ -0,0 +1,9 @@
+# Disallow web app manifest file with invalid content (manifest-is-valid)
+
+## Rule Details
+
+TODO
+
+## Resources
+
+* [Web App Manifest Specification](https://www.w3.org/TR/appmanifest)

src/lib/rules/manifest-is-valid/manifest-is-valid.ts

@@ -0,0 +1,85 @@
+/**
+ * @fileoverview Check if the content of the web app manifest file is valid.
+ */
+
+// ------------------------------------------------------------------------------
+// Requirements
+// ------------------------------------------------------------------------------
+
+import * as url from 'url';
+
+import { Rule, RuleBuilder, ElementFoundEvent } from '../../types'; // eslint-disable-line no-unused-vars
+import { RuleContext } from '../../rule-context'; // eslint-disable-line no-unused-vars
+
+const debug = require('debug')('sonar:rules:manifest-is-valid');
+
+// ------------------------------------------------------------------------------
+// Public
+// ------------------------------------------------------------------------------
+
+const rule: RuleBuilder = {
+    create(context: RuleContext): Rule {
+
+        const manifestIsValid = async (data: ElementFoundEvent) => {
+            const { element, resource } = data;
+
+            if (element.getAttribute('rel') === 'manifest') {
+
+                const manifestHref = element.getAttribute('href');
+
+                if (!manifestHref) {
+                    debug(`Web app manifest specified with invalid 'href'`);
+
+                    return;
+                }
+
+                let manifestURL = '';
+
+                // Try to figure out the URL of the web app manifest file.
+
+                if (url.parse(manifestHref).protocol) {
+                    manifestURL = manifestHref;
+                } else {
+                    manifestURL = url.resolve(resource, manifestHref);
+                }
+
+                // Try to get the content of the web app manifest file.
+
+                try {
+                    const { response: { body, statusCode } } = await context.fetchContent(manifestURL);
+
+                    if (statusCode && statusCode !== 200) {
+                        debug(`Web app manifest file could not be fetched (status code: ${statusCode})`);
+                    }
+
+                    // Validate the content of the web app manifest file.
+
+                    try {
+                        JSON.parse(body);
+                        // TODO: Add more complex web app manifest file validation.
+                    } catch (e) {
+                        debug('Failed to parse the web app manifest file');
+                        context.report(resource, element, `Web app manifest file doesn't contain valid JSON`);
+                    }
+
+                } catch (e) {
+                    debug('Failed to fetch the web app manifest file');
+                }
+
+            }
+        };
+
+        return { 'element::link': manifestIsValid };
+    },
+    meta: {
+        docs: {
+            category: 'PWA',
+            description: 'Check if the content of the web app manifest is valid',
+            recommended: true
+        },
+        fixable: 'code',
+        schema: []
+    }
+};
+
+module.exports = rule;

src/tests/lib/rules/manifest-exists/tests.ts

@@ -12,10 +12,10 @@ const tests: Array<RuleTest> = [
         name: `Web app manifest is not specified`,
         events: [{
             name: 'element::link',
-            fixture: path.resolve(__dirname, './fixtures/no-manifest.html')
+            fixture: path.resolve(__dirname, './fixtures/manifest-not-specified.html')
         }, {
             name: 'traverse::end',
-            fixture: path.resolve(__dirname, './fixtures/no-manifest.html')
+            fixture: path.resolve(__dirname, './fixtures/manifest-not-specified.html')
         }],
         report: { message: 'Web app manifest not specified' }
     },

src/tests/lib/rules/manifest-is-valid/fixtures/manifest-not-specified.html

@@ -0,0 +1,10 @@
+<!doctype html>
+<html lang="en">
+    <head>
+        <title>test</title>
+        <link rel="stylesheet" href="style.css">
+    </head>
+    <body>
+
+    </body>
+</html>

src/tests/lib/rules/manifest-is-valid/fixtures/manifest-specified-as-full-url.html

@@ -0,0 +1,10 @@
+<!doctype html>
+<html lang="en">
+    <head>
+        <title>test</title>
+        <link rel="manifest" href="https://example.com/site.webmanifest">
+    </head>
+    <body>
+
+    </body>
+</html>

src/tests/lib/rules/manifest-is-valid/fixtures/manifest-specified-with-empty-href.html

@@ -0,0 +1,10 @@
+<!doctype html>
+<html lang="en">
+    <head>
+        <title>test</title>
+        <link rel="manifest" href="">
+    </head>
+    <body>
+
+    </body>
+</html>

src/tests/lib/rules/manifest-is-valid/fixtures/manifest-specified-with-no-href.html

@@ -0,0 +1,10 @@
+<!doctype html>
+<html lang="en">
+    <head>
+        <title>test</title>
+        <link rel="manifest">
+    </head>
+    <body>
+
+    </body>
+</html>

src/tests/lib/rules/manifest-is-valid/fixtures/manifest-specified.html

@@ -0,0 +1,10 @@
+<!doctype html>
+<html lang="en">
+    <head>
+        <title>test</title>
+        <link rel="manifest" href="site.webmanifest">
+    </head>
+    <body>
+
+    </body>
+</html>

src/tests/lib/rules/manifest-is-valid/tests.ts

@@ -0,0 +1,102 @@
+/* eslint sort-keys: 0, no-undefined: 0 */
+import * as path from 'path';
+
+import { Rule } from '../../../../lib/types'; // eslint-disable-line no-unused-vars
+import { RuleTest } from '../../../helpers/rule-test-type'; // eslint-disable-line no-unused-vars
+
+import * as ruleRunner from '../../../helpers/rule-runner';
+import * as rule from '../../../../lib/rules/manifest-is-valid/manifest-is-valid';
+
+const tests: Array<RuleTest> = [
+    {
+        name: `Web app manifest is not specified`,
+        events: [{
+            name: 'element::link',
+            fixture: path.resolve(__dirname, './fixtures/manifest-not-specified.html')
+        }]
+    },
+    {
+        name: `Web app manifest is specified with no 'href'`,
+        events: [{
+            name: 'element::link',
+            fixture: path.resolve(__dirname, './fixtures/manifest-specified-with-no-href.html')
+        }]
+    },
+    {
+        name: `Web app manifest is specified with empty 'href'`,
+        events: [{
+            name: 'element::link',
+            fixture: path.resolve(__dirname, './fixtures/manifest-specified-with-empty-href.html')
+        }]
+    },
+    {
+        name: `Web app manifest is specified and its content is valid JSON`,
+        events: [{
+            name: 'element::link',
+            fixture: path.resolve(__dirname, './fixtures/manifest-specified.html'),
+            networkData: [{
+                request: { headers: null },
+                response: {
+                    body: '{}',
+                    headers: null,
+                    statusCode: 200
+                }
+            }]
+        }]
+    },
+    {
+        name: `Web app manifest is specified and its content is not valid JSON`,
+        events: [{
+            name: 'element::link',
+            fixture: path.resolve(__dirname, './fixtures/manifest-specified-as-full-url.html'),
+            networkData: [{
+                request: { headers: null },
+                response: {
+                    body: 'x',
+                    headers: null,
+                    statusCode: 200
+                }
+            }]
+        }],
+        report: { message: `Web app manifest file doesn't contain valid JSON` }
+    },
+    {
+        name: `Web app manifest is specified as a full URL and its content is valid JSON`,
+        events: [{
+            name: 'element::link',
+            fixture: path.resolve(__dirname, './fixtures/manifest-specified-as-full-url.html'),
+            networkData: [{
+                request: { headers: null },
+                response: {
+                    body: '{}',
+                    headers: null,
+                    statusCode: 200
+                }
+            }]
+        }]
+    },
+    {
+        name: `Web app manifest is specified and request for file fails`,
+        events: [{
+            name: 'element::link',
+            fixture: path.resolve(__dirname, './fixtures/manifest-specified.html')
+        }]
+    },
+    {
+        name: `Web app manifest is specified and request for file fails with status code`,
+        events: [{
+            name: 'element::link',
+            fixture: path.resolve(__dirname, './fixtures/manifest-specified.html'),
+            networkData: [{
+                request: { headers: null },
+                response: {
+                    body: null,
+                    headers: null,
+                    statusCode: 404
+                }
+            }]
+        }]
+    }
+];
+
+ruleRunner.testRule(<Rule>rule, tests);