[enh] record details exception per engine

add an new API /stats/errors

searx/exceptions.py

@@ -34,8 +34,45 @@ class SearxParameterException(SearxException):
 
 
 class SearxSettingsException(SearxException):
+    """Error while loading the settings"""
 
     def __init__(self, message, filename):
         super().__init__(message)
         self.message = message
         self.filename = filename
+
+
+class SearxEngineException(SearxException):
+    """Error inside an engine"""
+
+
+class SearxXPathSyntaxException(SearxEngineException):
+    """Syntax error in a XPATH"""
+
+    def __init__(self, xpath_spec, message):
+        super().__init__(str(xpath_spec) + " " + message)
+        self.message = message
+        # str(xpath_spec) to deal with str and XPath instance
+        self.xpath_str = str(xpath_spec)
+
+
+class SearxEngineResponseException(SearxEngineException):
+    """Impossible to parse the result of an engine"""
+
+
+class SearxEngineAPIException(SearxEngineResponseException):
+    """The website has returned an application error"""
+
+
+class SearxEngineCaptchaException(SearxEngineResponseException):
+    """The website has returned a CAPTCHA"""
+
+
+class SearxEngineXPathException(SearxEngineResponseException):
+    """Error while getting the result of an XPath expression"""
+
+    def __init__(self, xpath_spec, message):
+        super().__init__(str(xpath_spec) + " " + message)
+        self.message = message
+        # str(xpath_spec) to deal with str and XPath instance
+        self.xpath_str = str(xpath_spec)