support env vars in http headers (#146)

index.js

@@ -7,6 +7,41 @@ const LinkCheckResult = require('link-check').LinkCheckResult;
 const markdownLinkExtractor = require('markdown-link-extractor');
 const ProgressBar = require('progress');
 
+const envVarPatternMatcher = /(?<pattern>{{env\.(?<name>[a-zA-Z0-9\-_]+)}})/;
+
+/*
+ * Performs some special replacements for the following patterns:
+ * - {{BASEURL}} - to be replaced with opts.projectBaseUrl
+ * - {{env.<env_var_name>}} - to be replaced with the environment variable specified with <env_var_name>
+ */
+function performSpecialReplacements(str, opts) {
+    // replace the `{{BASEURL}}` with the opts.projectBaseUrl. Helpful to build absolute urls "relative" to project roots
+    str = str.replace('{{BASEURL}}', opts.projectBaseUrl);
+
+    // replace {{env.<env_var_name>}} with the corresponding environment variable or an empty string if none is set.
+    var envVarMatch;
+    do {
+        envVarMatch = envVarPatternMatcher.exec(str);
+
+        if(!envVarMatch) {
+            break;
+        }
+
+        var envVarPattern = envVarMatch.groups.pattern;
+        var envVarName = envVarMatch.groups.name;
+
+        var envVarPatternReplacement = '';
+
+        if(envVarName in process.env) {
+            envVarPatternReplacement = process.env[envVarName];
+        }
+
+        str = str.replace(envVarPattern, envVarPatternReplacement);
+    } while (true);
+
+    return str;
+}
+
 module.exports = function markdownLinkCheck(markdown, opts, callback) {
     if (arguments.length === 2 && typeof opts === 'function') {
         // optional 'opts' not supplied.
@@ -51,9 +86,7 @@ module.exports = function markdownLinkCheck(markdown, opts, callback) {
         if (opts.replacementPatterns) {
             for (let replacementPattern of opts.replacementPatterns) {
                 let pattern = replacementPattern.pattern instanceof RegExp ? replacementPattern.pattern : new RegExp(replacementPattern.pattern);
-                // replace the `{{BASEURL}}` with the opts.projectBaseUrl. Helpful to build absolute urls "relative" to project roots
-                const replacement = replacementPattern.replacement.replace('{{BASEURL}}', opts.projectBaseUrl);
-                link = link.replace(pattern, replacement);
+                link = link.replace(pattern, performSpecialReplacements(replacementPattern.replacement, opts));
             }
         }
 
@@ -62,6 +95,12 @@ module.exports = function markdownLinkCheck(markdown, opts, callback) {
 
         if (opts.httpHeaders) {
             for (const httpHeader of opts.httpHeaders) {
+                if (httpHeader.headers) {
+                    for (const header of Object.keys(httpHeader.headers)) {
+                        httpHeader.headers[header] = performSpecialReplacements(httpHeader.headers[header], opts);
+                    }
+                }
+
                 for (const url of httpHeader.urls) {
                     if (link.startsWith(url)) {
                         Object.assign(opts.headers, httpHeader.headers);

test/markdown-link-check.test.js

@@ -249,4 +249,94 @@ describe('markdown-link-check', function () {
             done();
         });
     });
+
+    it('should enrich http headers with environment variables', function (done) {
+        process.env.BASIC_AUTH_TOKEN = 'Zm9vOmJhcg==';
+        markdownLinkCheck(
+            fs.readFileSync(path.join(__dirname, 'sample.md')).toString().replace(/%%BASE_URL%%/g, baseUrl),
+            {
+                baseUrl: baseUrl,
+                httpHeaders: [
+                    {
+                        urls: [baseUrl + '/basic-auth'],
+                        headers: { 'Authorization': 'Basic {{env.BASIC_AUTH_TOKEN}}', 'Foo': 'Bar' }
+                    }
+                ],
+                "aliveStatusCodes":[200, 206],
+                "retryOn429":true,
+                "retryCount": MAX_RETRY_COUNT,
+                "fallbackRetryDelay": "500ms"
+            }, function (err, results) {
+            expect(err).to.be(null);
+            done();
+        });
+    });
+
+    it('should enrich pattern replacement strings with environment variables', function (done) {
+        process.env.WORKSPACE = 'file://' + __dirname + '/..';
+        markdownLinkCheck(fs.readFileSync(path.join(__dirname, 'local-file.md')).toString().replace(/%%BASE_URL%%/g, 'file://' + __dirname), {baseUrl: 'file://' + __dirname, projectBaseUrl: 'file://' + __dirname + "/..",replacementPatterns: [{ pattern: '^/', replacement: "{{env.WORKSPACE}}/"}]}, function (err, results) {
+            expect(err).to.be(null);
+            expect(results).to.be.an('array');
+
+            const expected = [
+                { statusCode: 200, status: 'alive' },
+                { statusCode: 200, status: 'alive' },
+                { statusCode: 200, status: 'alive' },
+                { statusCode: 200, status: 'alive' },
+                { statusCode: 400, status:  'dead' },
+                { statusCode: 400, status:  'dead' },
+            ];
+
+            expect(results.length).to.be(expected.length);
+
+            for (let i = 0; i < results.length; i++) {
+                expect(results[i].statusCode).to.be(expected[i].statusCode);
+                expect(results[i].status).to.be(expected[i].status);
+            }
+
+            done();
+        });
+    });
+
+
+    it('should correctly resolve special replacement patterns', function (done) {
+        process.env.MixedCase = 'hello.jpg';
+        process.env.UPPERCASE = 'hello.jpg';
+        process.env.lowercase = 'hello.jpg';
+        process.env['WITH-Special_Characters-123'] = 'hello.jpg';
+
+        markdownLinkCheck(fs.readFileSync(path.join(__dirname, 'special-replacements.md')).toString().replace(/%%BASE_URL%%/g, 'file://' + __dirname), {baseUrl: 'file://' + __dirname, projectBaseUrl: 'file://' + __dirname + "/..",replacementPatterns: [
+            {pattern: '^/', replacement: "{{BASEURL}}/"},
+            {pattern: '%%ENVVAR_MIXEDCASE_TEST%%', replacement: "{{env.MixedCase}}"},
+            {pattern: '%%ENVVAR_UPPERCASE_TEST%%', replacement: "{{env.UPPERCASE}}"},
+            {pattern: '%%ENVVAR_LOWERCASE_TEST%%', replacement: "{{env.lowercase}}"},
+            {pattern: '%%ENVVAR_WITHSPECIALCHARACTERS_TEST%%', replacement: "{{env.WITH-Special_Characters-123}}"},
+            {pattern: '%%ENVVAR_NONEXISTENT_TEST%%', replacement: "{{env.ThisIsSomethingThatHopefullyDoesntExist}}"}
+        ]}, function (err, results) {
+            expect(err).to.be(null);
+            expect(results).to.be.an('array');
+
+            const expected = [
+                { statusCode: 200, status: 'alive' },
+                { statusCode: 200, status: 'alive' },
+                { statusCode: 200, status: 'alive' },
+                { statusCode: 200, status: 'alive' },
+                { statusCode: 200, status: 'alive' },
+                { statusCode: 200, status: 'alive' },
+                { statusCode: 200, status: 'alive' },
+                { statusCode: 200, status: 'alive' },
+                { statusCode: 200, status: 'alive' },
+                { statusCode: 200, status: 'alive' }
+            ];
+
+            expect(results.length).to.be(expected.length);
+
+            for (let i = 0; i < results.length; i++) {
+                expect(results[i].statusCode).to.be(expected[i].statusCode);
+                expect(results[i].status).to.be(expected[i].status);
+            }
+
+            done();
+        });
+    });
 });

test/special-replacements.md

@@ -0,0 +1,18 @@
+# Sample
+
+This is a test file leveraging special replacement patterns:
+
+![img](/test/%%ENVVAR_MIXEDCASE_TEST%%) (alive)
+![img](%%ENVVAR_MIXEDCASE_TEST%%) (alive)
+
+![img](/test/%%ENVVAR_UPPERCASE_TEST%%) (alive)
+![img](%%ENVVAR_UPPERCASE_TEST%%) (alive)
+
+![img](/test/%%ENVVAR_LOWERCASE_TEST%%) (alive)
+![img](%%ENVVAR_LOWERCASE_TEST%%) (alive)
+
+![img](/test/%%ENVVAR_WITHSPECIALCHARACTERS_TEST%%) (alive)
+![img](%%ENVVAR_WITHSPECIALCHARACTERS_TEST%%) (alive)
+
+![img](/test/%%ENVVAR_NONEXISTENT_TEST%%hello.jpg) (alive)
+![img](%%ENVVAR_NONEXISTENT_TEST%%hello.jpg) (alive)