fix: functions slack sample (GoogleCloudPlatform#1345)

- fix timestamp - it was evaluating as empty because it was set to the string `'0'`
- Wrote a unit test for debugging and figured we might as well keep it
- misc test / function cleanup

Author: bshaffer

functions/slack_slash_command/index.php

@@ -38,8 +38,8 @@ function isValidSlackWebhook(ServerRequestInterface $request): bool
     }
 
     // Compute signature
-    $plaintext = 'v0:' . $timestamp . ':' . (string) $request->getBody();
-    $hash = 'v0=' . hash_hmac('sha256', $plaintext, $SLACK_SECRET);
+    $plaintext = sprintf('v0:%s:%s', $timestamp, $request->getBody());
+    $hash = sprintf('v0=%s', hash_hmac('sha256', $plaintext, $SLACK_SECRET));
 
     return $hash === $signature;
 }
@@ -83,7 +83,7 @@ function formatSlackMessage(Google_Service_Kgsearch_SearchResponse $kgResponse,
         ], $attachmentJson);
     }
 
-    if ($entity['image']) {
+    if (isset($entity['image'])) {
         $imageJson = $entity['image'];
         $attachmentJson['image_url'] = $imageJson['contentUrl'];
     }

functions/slack_slash_command/test/DeployTest.php

@@ -38,8 +38,6 @@ class DeployTest extends TestCase
     use CloudFunctionDeploymentTrait;
     use TestCasesTrait;
 
-    private static $entryPoint = 'receiveRequest';
-
     /**
      * @dataProvider cases
      */
@@ -76,8 +74,11 @@ public function testFunction(
     private static function doDeploy()
     {
         // Forward required env variables to Cloud Functions.
-        $envVars = 'SLACK_SECRET=' . self::requireEnv('SLACK_SECRET') . ',';
-        $envVars .= 'KG_API_KEY=' . self::requireEnv('KG_API_KEY');
+        $envVars = sprintf(
+            'SLACK_SECRET=%s,KG_API_KEY=%s',
+            self::$slackSecret,
+            self::$kgApiKey
+        );
 
         self::$fn->deploy(['--update-env-vars' => $envVars]);
     }

functions/slack_slash_command/test/IntegrationTest.php

@@ -32,8 +32,6 @@ class IntegrationTest extends TestCase
     use CloudFunctionLocalTestTrait;
     use TestCasesTrait;
 
-    private static $entryPoint = 'receiveRequest';
-
     /**
      * Run the PHP server locally for the defined function.
      *
@@ -42,8 +40,8 @@ class IntegrationTest extends TestCase
     private static function doRun()
     {
         self::$fn->run([
-            'SLACK_SECRET' => self::requireEnv('SLACK_SECRET'),
-            'KG_API_KEY' => self::requireEnv('KG_API_KEY'),
+            'SLACK_SECRET' => self::$slackSecret,
+            'KG_API_KEY' => self::$kgApiKey,
         ]);
     }
 

functions/slack_slash_command/test/TestCasesTrait.php

@@ -18,35 +18,34 @@
 
 namespace Google\Cloud\Samples\Functions\SlackSlashCommand\Test;
 
-function _valid_headers($body): array
-{
-    // Calculate test case signature
-    $key = getenv('SLACK_SECRET');
-    $plaintext = 'v0:0:' . $body;
-    //var_dump($plaintext);
-    $hash = 'v0=' . hash_hmac('sha256', $plaintext, $key);
-    //var_dump($hash);
-
-    // Return new test case
-    return [
-        'plaintext' => $plaintext,
-        'X-Slack-Request-Timestamp' => '0',
-        'X-Slack-Signature' => $hash,
-    ];
-}
+use Google\Cloud\TestUtils\TestTrait;
 
 trait TestCasesTrait
 {
+    use TestTrait;
+
+    private static $entryPoint = 'receiveRequest';
+    private static $slackSecret;
+    private static $kgApiKey;
+
+    public static function getEnvVars()
+    {
+        self::$slackSecret = self::requireEnv('SLACK_SECRET');
+        self::$kgApiKey = self::requireEnv('KG_API_KEY');
+    }
+
     public static function cases(): array
     {
+        self::getEnvVars();
+
         return [
             [
                 'label' => 'Only allows POST',
                 'body' => '',
                 'method' => 'GET',
                 'expected' => null,
                 'statusCode' => '405',
-                'headers' => _valid_headers('')
+                'headers' => self::validHeaders('')
             ],
             [
                 'label' => 'Requires valid auth headers',
@@ -62,7 +61,7 @@ public static function cases(): array
                 'method' => 'POST',
                 'expected' => null,
                 'statusCode' => '400',
-                'headers' => _valid_headers(''),
+                'headers' => self::validHeaders(''),
             ],
             [
                 'label' => 'Prohibits invalid signature',
@@ -82,24 +81,40 @@ public static function cases(): array
                 'method' => 'POST',
                 'expected' => 'No results match your query',
                 'statusCode' => '200',
-                'headers' => _valid_headers('text=asdfjkl13579'),
+                'headers' => self::validHeaders('text=asdfjkl13579'),
             ],
             [
                 'label' => 'Handles query with results',
                 'body' => 'text=lion',
                 'method' => 'POST',
                 'expected' => 'https:\/\/en.wikipedia.org\/wiki\/Lion',
                 'statusCode' => '200',
-                'headers' => _valid_headers('text=lion'),
+                'headers' => self::validHeaders('text=lion'),
             ],
             [
                 'label' => 'Ignores extra URL parameters',
                 'body' => 'unused=foo&text=lion',
                 'method' => 'POST',
                 'expected' => 'https:\/\/en.wikipedia.org\/wiki\/Lion',
                 'statusCode' => '200',
-                'headers' => _valid_headers('unused=foo&text=lion'),
+                'headers' => self::validHeaders('unused=foo&text=lion'),
             ],
         ];
     }
+
+    private static function validHeaders($body): array
+    {
+        // Calculate test case signature
+        $timestamp = date('U');
+        $plaintext = sprintf('v0:%s:%s', $timestamp, $body);
+        $hash = hash_hmac('sha256', $plaintext, self::$slackSecret);
+        $signature = sprintf('v0=%s', $hash);
+
+        // Return new test case
+        return [
+            'plaintext' => $plaintext,
+            'X-Slack-Request-Timestamp' => $timestamp,
+            'X-Slack-Signature' => $signature,
+        ];
+    }
 }

functions/slack_slash_command/test/UnitTest.php

@@ -0,0 +1,68 @@
+
+/**
+ * Copyright 2021 Google LLC.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+declare(strict_types=1);
+
+namespace Google\Cloud\Samples\Functions\SlackSlashCommand\Test;
+
+use GuzzleHttp\Psr7\ServerRequest;
+use GuzzleHttp\Psr7\Response;
+use PHPUnit\Framework\TestCase;
+
+require_once __DIR__ . '/TestCasesTrait.php';
+
+/**
+ * Unit tests for the Cloud Function.
+ */
+class UnitTest extends TestCase
+{
+    use TestCasesTrait;
+
+    public static function setUpBeforeClass(): void
+    {
+        require_once __DIR__ . '/../index.php';
+    }
+
+    /**
+      * @dataProvider cases
+      */
+    public function testFunction(
+        $label,
+        $body,
+        $method,
+        $expected,
+        $statusCode,
+        $headers
+    ): void {
+        $request = new ServerRequest($method, '/', $headers, $body);
+        $response = $this->runFunction(self::$entryPoint, [$request]);
+        $this->assertEquals(
+            $statusCode,
+            $response->getStatusCode(),
+            $label . ": status code"
+        );
+
+        if ($expected !== null) {
+            $output = (string) $response->getBody();
+            $this->assertStringContainsString($expected, $output);
+        }
+    }
+
+    private static function runFunction($functionName, array $params = []): Response
+    {
+        return call_user_func_array($functionName, $params);
+    }
+}