Move HTTP_REDIRECTED_URL header handling to StackdriverExporter (#113)

Author: chingor13

src/Trace/Exporter/StackdriverExporter.php

@@ -259,6 +259,16 @@ private function addCommonAttributes(&$tracer, $headers = null)
                 $tracer->addAttribute($attributeKey, $val, ['span' => $rootSpan]);
             }
         }
+
+        $responseCode = http_response_code();
+        if ($responseCode == 301 || $responseCode == 302) {
+            foreach (headers_list() as $header) {
+                if (substr($header, 0, 9) == 'Location:') {
+                    $this->rootSpan->addAttribute(self::HTTP_REDIRECTED_URL, substr($header, 10));
+                    break;
+                }
+            }
+        }
         $tracer->addAttribute(self::PID, '' . getmypid(), ['span' => $rootSpan]);
         $tracer->addAttribute(self::AGENT, 'opencensus-php [' . self::VERSION . ']', ['span' => $rootSpan]);
     }

src/Trace/RequestHandler.php

@@ -121,14 +121,6 @@ public function __construct(
     public function onExit()
     {
         $responseCode = http_response_code();
-        if ($responseCode == 301 || $responseCode == 302) {
-            foreach (headers_list() as $header) {
-                if (substr($header, 0, 9) == 'Location:') {
-                    $this->rootSpan->addAttribute(self::HTTP_REDIRECTED_URL, substr($header, 10));
-                    break;
-                }
-            }
-        }
         $this->rootSpan->setStatus($responseCode, "HTTP status code: $responseCode");
 
         $this->scope->close();