Refactor internalApiRequest() and getEventFeedAction() for streaming via CLI

Fetching the event feed from the API via `internalApiRequest` wasn't
working since it returns a StreamedResponse. Fix this by only using
an output buffer in `internalApiRequest` and only calling `ob_flush`
from `getEventFeedAction` if the top-level output buffer allows it.

Also return contents from `internalApiRequest` without JSON decoding
it, since the event feed endpoint is NDJSON, *not* JSON. Explicitly
decode the JSON at the other places calling internalApiRequest`.

Author: eldering

webapp/src/Command/CallApiActionCommand.php

@@ -144,7 +144,7 @@ protected function execute(InputInterface $input, OutputInterface $output): int
         }
 
         try {
-            $response = null;
+            $response = '';
             $this->dj->withAllRoles(function () use ($input, $data, $files, &$response) {
                 $response = $this->dj->internalApiRequest('/' . $input->getArgument('endpoint'), $input->getOption('method'), $data, $files, true);
             }, $user);
@@ -154,7 +154,7 @@ protected function execute(InputInterface $input, OutputInterface $output): int
             return Command::FAILURE;
         }
 
-        $output->writeln(json_encode($response, JSON_PRESERVE_ZERO_FRACTION | JSON_UNESCAPED_SLASHES | JSON_THROW_ON_ERROR | JSON_PRETTY_PRINT));
+        $output->writeln($response);
         return Command::SUCCESS;
     }
 }

webapp/src/Controller/API/ContestController.php

@@ -871,7 +871,7 @@ public function getEventFeedAction(
                     }
 
                     echo Utils::jsonEncode($result) . "\n";
-                    ob_flush();
+                    Utils::ob_flush_if_possible();
                     flush();
                     $lastUpdate = Utils::now();
                     $lastIdSent = $event->getEventid();
@@ -896,7 +896,7 @@ public function getEventFeedAction(
                         # Send keep alive every 10s. Guarantee according to spec is 120s.
                         # However, nginx drops the connection if we don't update for 60s.
                         echo "\n";
-                        ob_flush();
+                        Utils::ob_flush_if_possible();
                         flush();
                         $lastUpdate = $now;
                     }

webapp/src/Service/DOMJudgeService.php

@@ -652,13 +652,15 @@ public function internalApiRequest(string $url, string $method = Request::METHOD
             return null;
         }
 
-        $content = $response->getContent();
-
-        if ($content === '') {
-            return null;
+        if ($response instanceof StreamedResponse) {
+            ob_start(flags: PHP_OUTPUT_HANDLER_REMOVABLE);
+            $response->sendContent();
+            $content = ob_get_clean();
+        } else {
+            $content = $response->getContent();
         }
 
-        return Utils::jsonDecode($content);
+        return $content;
     }
 
     public function getDomjudgeEtcDir(): string

webapp/src/Service/EventLogService.php

@@ -316,19 +316,22 @@ public function log(
             }
 
             $this->dj->withAllRoles(function () use ($query, $url, &$json) {
-                $json = $this->dj->internalApiRequest($url, Request::METHOD_GET, $query);
+                $response = $this->dj->internalApiRequest($url, Request::METHOD_GET, $query);
             });
 
-            if ($json === null) {
+            if ($response === '') {
                 $this->logger->warning(
-                    "EventLogService::log got no JSON data from '%s'", [ $url ]
+                    "EventLogService::log got no data from '%s'", [ $url ]
                 );
                 // If we didn't get data from the API, then that is probably
                 // because this particular data is not visible, for example
                 // because it belongs to an invisible jury team. If we don't
                 // have data, there's also no point in trying to insert
                 // anything in the eventlog table.
                 return;
+                $json = null;
+            } else {
+                $json = Utils::jsonDecode($response);
             }
         }
 
@@ -484,7 +487,8 @@ public function addMissingStateEvents(Contest $contest): void
                 $url = sprintf('/contests/%s/awards', $contest->getExternalid());
                 $awards = [];
                 $this->dj->withAllRoles(function () use ($url, &$awards) {
-                    $awards = $this->dj->internalApiRequest($url);
+                    $response = $this->dj->internalApiRequest($url);
+                    if ( !empty($response) ) $awards = Utils::jsonDecode($response);
                 });
                 foreach ($awards as $award) {
                     $this->insertEvent($contest, 'awards', $award['id'], $award);
@@ -625,7 +629,8 @@ public function initStaticEvents(Contest $contest): void
                 $urlPart = $endpoint === 'contests' ? '' : ('/' . $endpoint);
                 $url = sprintf('/contests/%s%s', $contestId, $urlPart);
                 $this->dj->withAllRoles(function () use ($url, &$data) {
-                    $data = $this->dj->internalApiRequest($url);
+                    $response = $this->dj->internalApiRequest($url);
+                    $data = (empty($response) ? null : Utils::jsonDecode($response));
                 });
 
                 // Get a partial reference to the contest,

webapp/src/Utils/Utils.php

@@ -1023,4 +1023,16 @@ public static function extendMaxExecutionTime(int $minimumMaxExecutionTime): voi
             ini_set('max_execution_time', $minimumMaxExecutionTime);
         }
     }
+
+    /**
+     * Call ob_flush() unless the top-level output buffer does not allow it.
+     */
+    public static function ob_flush_if_possible(): bool
+    {
+        $status = ob_get_status();
+        if ( empty($status) || ($status['flags'] & PHP_OUTPUT_HANDLER_CLEANABLE) ) {
+            return ob_flush();
+        }
+        return false;
+    }
 }