Update headers (#47)

- Fix capitalization
- Add gax version
- Change to space-separated
- Add todo and issue

Author: michaelbausor

src/AgentHeaderDescriptor.php

@@ -40,6 +40,9 @@
 class AgentHeaderDescriptor
 {
     const AGENT_HEADER_KEY = 'x-goog-api-client';
+    // TODO(michaelbausor): include bumping this version in a streamlined
+    // release process. Issue: https://github.com/googleapis/gax-php/issues/48
+    const GAX_VERSION = '0.5.0-dev';
 
     private $clientName;
     private $clientVersion;
@@ -75,11 +78,19 @@ public function __construct($headerInfo)
      */
     public function getHeader()
     {
-        return [self::AGENT_HEADER_KEY => ["$this->clientName/$this->clientVersion;".
-            "$this->codeGenName/$this->codeGenVersion;gax/$this->gaxVersion;".
+        return [self::AGENT_HEADER_KEY => ["$this->clientName/$this->clientVersion ".
+            "$this->codeGenName/$this->codeGenVersion gax/$this->gaxVersion ".
             "php/$this->phpVersion"]];
     }
 
+    /**
+     * Returns the version string for GAX.
+     */
+    public static function getGaxVersion()
+    {
+        return self::GAX_VERSION;
+    }
+
     private static function validate($descriptor)
     {
         $requiredFields = ['clientName', 'clientVersion', 'codeGenName',

src/GrpcCredentialsHelper.php

@@ -100,7 +100,7 @@ public function createCallCredentialsCallback()
         $credentialsLoader = $this->credentialsLoader;
         $callback = function () use ($credentialsLoader) {
             $token = $credentialsLoader->fetchAuthToken();
-            return ['Authorization' => array('Bearer ' . $token['access_token'])];
+            return ['authorization' => array('Bearer ' . $token['access_token'])];
         };
         return $callback;
     }

tests/ApiCallableTest.php

@@ -426,7 +426,7 @@ public function testCustomHeader()
         $actualCalls = $stub->actualCalls;
         $this->assertEquals(1, count($actualCalls));
         $expectedMetadata = [
-            'x-goog-api-client' => ['testClient/0.0.0;testCodeGen/0.9.0;gax/1.0.0;php/5.5.0']
+            'x-goog-api-client' => ['testClient/0.0.0 testCodeGen/0.9.0 gax/1.0.0 php/5.5.0']
         ];
         $this->assertEquals($expectedMetadata, $actualCalls[0]['metadata']);
     }

tests/GrpcCredentialsHelperTest.php

@@ -52,7 +52,7 @@ public function testCreateCallCredentialsCallbackDefault()
         $grpcCredentialsHelper = new GrpcCredentialsHelperForTesting($this->defaultScope);
         $callback = $grpcCredentialsHelper->createCallCredentialsCallback();
         $callbackResult = $callback();
-        $this->assertEquals(['Bearer adcAccessToken'], $callbackResult['Authorization']);
+        $this->assertEquals(['Bearer adcAccessToken'], $callbackResult['authorization']);
     }
 
     public function testCreateCallCredentialsCallbackCustomCredsLoader()
@@ -62,7 +62,7 @@ public function testCreateCallCredentialsCallbackCustomCredsLoader()
                 $this->defaultScope, $this->defaultTokens)]);
         $callback = $grpcCredentialsHelper->createCallCredentialsCallback();
         $callbackResult = $callback();
-        $this->assertEquals(['Bearer accessToken'], $callbackResult['Authorization']);
+        $this->assertEquals(['Bearer accessToken'], $callbackResult['authorization']);
     }
 
     public function testCreateCallCredentialsCallbackDisableCaching()
@@ -73,10 +73,10 @@ public function testCreateCallCredentialsCallbackDisableCaching()
             'enableCaching' => false]);
         $callback = $grpcCredentialsHelper->createCallCredentialsCallback();
         $callbackResult = $callback();
-        $this->assertEquals(['Bearer accessToken'], $callbackResult['Authorization']);
+        $this->assertEquals(['Bearer accessToken'], $callbackResult['authorization']);
         $callback = $grpcCredentialsHelper->createCallCredentialsCallback();
         $callbackResult = $callback();
-        $this->assertEquals(['Bearer accessToken2'], $callbackResult['Authorization']);
+        $this->assertEquals(['Bearer accessToken2'], $callbackResult['authorization']);
     }
 
     public function testCreateCallCredentialsCallbackCaching()
@@ -86,10 +86,10 @@ public function testCreateCallCredentialsCallbackCaching()
                 $this->defaultScope, $this->defaultTokens)]);
         $callback = $grpcCredentialsHelper->createCallCredentialsCallback();
         $callbackResult = $callback();
-        $this->assertEquals(['Bearer accessToken'], $callbackResult['Authorization']);
+        $this->assertEquals(['Bearer accessToken'], $callbackResult['authorization']);
         $callback = $grpcCredentialsHelper->createCallCredentialsCallback();
         $callbackResult = $callback();
-        $this->assertEquals(['Bearer accessToken'], $callbackResult['Authorization']);
+        $this->assertEquals(['Bearer accessToken'], $callbackResult['authorization']);
     }
 
     public function testCreateStubWithDefaultSslCreds()