使用curl发生API错误时如何读取响应体?

How to read the response body when API error happen using curl?

我使用 Slim v3 开发了一个 API,当出现异常时,我有一个 ErrorHandler,其中 return 以下内容:

public function __invoke(Request $request, Response $response, \Exception $exception)
{
    $status = $exception->getCode() ? : 500;
    $error = [
        "status" => ERROR_MSG,
        "data" => [
            "stack_trace" => ($this->_container['settings']['displayErrorDetails']) ? $exception->getTraceAsString() : '',
        ],
        "message" => $exception->getMessage()
    ];

    $body = json_encode($error, JSON_UNESCAPED_SLASHES | JSON_PRETTY_PRINT);

    return $response
        ->withStatus($status)
        ->withHeader("Content-type", "application/json")
        ->write($body);
}

所以基本上当 API 中发生异常时,例如:

throw new Exception('Invalid user credentials');

API 将 return 此响应:

{
    "status": "error",
    "data": {
        "stack_trace": "some stack trace.."
    },
    "message": "Invalid user credentials"
}

现在的问题是,当我使用 curl 启动请求时,我只得到:

string(59) "The requested URL returned error: 500 Internal Server Error"

来自以下代码:

curl_error($this->session);

其中 $this->session 包含请求。

我还尝试使用以下方法调试请求:

$this->response = curl_exec($this->session);
$this->info = curl_getinfo($this->session);
$errno = curl_errno($this->session);
$error = curl_error($this->session);

我得到:

bool(false)
array(26) {
  ["url"]=>
  string(48) "http://localhost/ci3-api/v1/installation/install"
  ["content_type"]=>
  NULL
  ["http_code"]=>
  int(500)
  ["header_size"]=>
  int(0)
  ["request_size"]=>
  int(148)
  ["filetime"]=>
  int(-1)
  ["ssl_verify_result"]=>
  int(0)
  ["redirect_count"]=>
  int(0)
  ["total_time"]=>
  float(0.25)
  ["namelookup_time"]=>
  float(0.016)
  ["connect_time"]=>
  float(0.219)
  ["pretransfer_time"]=>
  float(0.219)
  ["size_upload"]=>
  float(0)
  ["size_download"]=>
  float(0)
  ["speed_download"]=>
  float(0)
  ["speed_upload"]=>
  float(0)
  ["download_content_length"]=>
  float(-1)
  ["upload_content_length"]=>
  float(0)
  ["starttransfer_time"]=>
  float(0.25)
  ["redirect_time"]=>
  float(0)
  ["redirect_url"]=>
  string(0) ""
  ["primary_ip"]=>
  string(9) "127.0.0.1"
  ["certinfo"]=>
  array(0) {
  }
  ["primary_port"]=>
  int(80)
  ["local_ip"]=>
  string(9) "127.0.0.1"
  ["local_port"]=>
  int(65036)
}
int(22)
string(59) "The requested URL returned error: 500 Internal Server Error"

如何阅读 API 响应消息? 当 API 引发错误 500 时,似乎不可能这样做。 我尝试使用其他错误代码,例如 400,我可以读取响应,但是对于错误代码 500,我总是得到响应 false.

这是我的设置;我认为对你来说重要的是 CURLOPT_RETURNTRANSFER 并且主要是 CURLOPT_FAILONERROR

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, 'your api url');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_FAILONERROR, false); // this is important for you I think

// other stuff you need to set

$output = curl_exec($ch);

$curlError = curl_error($ch);
$curlErrNo = curl_errno($ch);
$httpCode = (int)curl_getinfo($ch, CURLINFO_HTTP_CODE);

if($output === false) {
// if header CURLOPT_FAILONERROR is true, always throw here
throw new RuntimeException('curl fail');
}

curl_close($ch);
// here process your output

关键是将CURLOPT_FAILONERROR设置为false。当 third-party Web 服务的 http 响应代码 >= 400 时,我在获取响应正文时遇到了同样的问题,这解决了问题。

curl_setopt($ch, CURLOPT_FAILONERROR, false);