fix(json-serializer): fixes serialization for strings including backslashes. (#189)

* fix(json-serializer): fixes serialization for strings including backslashes.

* chore(json-serializer): improves serialization.

* chore(lint): makes lint happy.

Author: jcchavezs

src/Zipkin/Reporters/JsonV2Serializer.php

@@ -33,7 +33,7 @@ public function serialize(array $spans): string
 
     private static function serializeEndpoint(Endpoint $endpoint): string
     {
-        $endpointStr =  '{"serviceName":"' . \strtolower($endpoint->getServiceName()) . '"';
+        $endpointStr =  '{"serviceName":"' . \strtolower(self::escapeString($endpoint->getServiceName())) . '"';
 
         if ($endpoint->getIpv4() !== null) {
             $endpointStr .= ',"ipv4":"' . $endpoint->getIpv4() . '"';
@@ -50,10 +50,10 @@ private static function serializeEndpoint(Endpoint $endpoint): string
         return $endpointStr . '}';
     }
 
-    private static function escapeQuotes(string $s): string
+    private static function escapeString(string $s): string
     {
-        $encodedString = json_encode($s);
-        return $encodedString ? trim($encodedString, '"') : $s;
+        $encodedString = \json_encode($s);
+        return $encodedString === false ? $s : \mb_substr($encodedString, 1, -1);
     }
 
     private function serializeSpan(ReadbackSpan $span): string
@@ -64,7 +64,7 @@ private function serializeSpan(ReadbackSpan $span): string
             . ',"timestamp":' . $span->getTimestamp();
 
         if ($span->getName() !== null) {
-            $spanStr .= ',"name":"' . \strtolower($span->getName()) . '"';
+            $spanStr .= ',"name":"' . \strtolower(self::escapeString($span->getName())) . '"';
         }
 
         if ($span->getDuration() !== null) {
@@ -104,7 +104,7 @@ private function serializeSpan(ReadbackSpan $span): string
                 } else {
                     $spanStr .= ',';
                 }
-                $spanStr .= '{"value":"' . self::escapeQuotes($annotation['value'])
+                $spanStr .= '{"value":"' . self::escapeString($annotation['value'])
                     . '","timestamp":' . $annotation['timestamp'] . '}';
             }
             $spanStr .= ']';
@@ -125,7 +125,7 @@ private function serializeSpan(ReadbackSpan $span): string
                 } else {
                     $spanStr .= ',';
                 }
-                $spanStr .= '"' . $key . '":"' . self::escapeQuotes($value) . '"';
+                $spanStr .= '"' . $key . '":"' . self::escapeString($value) . '"';
             }
             $spanStr .= '}';
         }

tests/Integration/Reporters/Http/CurlFactoryTest.php

@@ -41,7 +41,7 @@ function (RequestInterface $request, ResponseInterface &$response) use ($t) {
                 'endpoint_url' => $server->getUrl(),
             ]);
 
-            $curlClient(json_encode([]));
+            $curlClient(\json_encode([]));
             $this->assertTrue(true);
         } finally {
             $server->stop();
@@ -69,7 +69,7 @@ function (RequestInterface $request, ResponseInterface &$response) use ($t) {
                 'headers' => ['From' => 'user@example.com', 'Content-Type' => 'test'],
             ]);
 
-            $curlClient(json_encode([]));
+            $curlClient(\json_encode([]));
             $this->assertTrue(true);
         } finally {
             $server->stop();
@@ -137,7 +137,7 @@ function (RequestInterface $request, ResponseInterface &$response) use ($t) {
             ]);
 
             ob_start();
-            $curlClient(json_encode([]));
+            $curlClient(\json_encode([]));
         } finally {
             $server->stop();
             $output = ob_get_clean();

tests/Unit/Reporters/JsonV2SerializerTest.php

@@ -62,7 +62,7 @@ public function testErrorTagIsNotClobberedBySpanError()
         $this->assertEquals($expectedSerialization, $serializedSpans);
     }
 
-    public function testJSONTagsAreSerializedCorrectly()
+    public function testStringValuesAreEscapedAndSerializedCorrectly()
     {
         $jsonValue = '{"name":"Kurt"}';
         $mutilineValue = <<<EOD
@@ -75,16 +75,16 @@ public function testJSONTagsAreSerializedCorrectly()
         $span = Span::createFromContext($context, $localEndpoint);
         $startTime = 1594044779509687;
         $span->start($startTime);
-        $span->setName('Test');
+        $span->setName('My\Command');
         $span->tag('test_key_1', $jsonValue);
         $span->tag('test_key_2', $mutilineValue);
         $span->finish($startTime + 1000);
         $serializer = new JsonV2Serializer();
         $serializedSpans = $serializer->serialize([$span]);
 
         $expectedSerialization = '[{'
-            . '"id":"186f11b67460db4e","traceId":"186f11b67460db4e","timestamp":1594044779509687,"name":"test",'
-            . '"duration":1000,"localEndpoint":{"serviceName":"service1"},'
+            . '"id":"186f11b67460db4e","traceId":"186f11b67460db4e","timestamp":1594044779509687,'
+            . '"name":"my\\\\command","duration":1000,"localEndpoint":{"serviceName":"service1"},'
             . '"tags":{"test_key_1":"{\"name\":\"Kurt\"}","test_key_2":"foo\nbar"}'
             . '}]';