Update app.py

app.py

@@ -796,6 +796,187 @@ language_codes = {
     "zulu": "zu",
 }
 
+class BaseError(Exception):
+    """
+    base error structure class
+    """
+
+    def __init__(self, val, message):
+        """
+        @param val: actual value
+        @param message: message shown to the user
+        """
+        self.val = val
+        self.message = message
+        super().__init__()
+
+    def __str__(self):
+        return "{} --> {}".format(self.val, self.message)
+
+
+class LanguageNotSupportedException(BaseError):
+    """
+    exception thrown if the user uses a language
+    that is not supported by the deep_translator
+    """
+
+    def __init__(
+        self, val, message="There is no support for the chosen language"
+    ):
+        super().__init__(val, message)
+
+
+class NotValidPayload(BaseError):
+    """
+    exception thrown if the user enters an invalid payload
+    """
+
+    def __init__(
+        self,
+        val,
+        message="text must be a valid text with maximum 5000 character,"
+        "otherwise it cannot be translated",
+    ):
+        super(NotValidPayload, self).__init__(val, message)
+
+
+class InvalidSourceOrTargetLanguage(BaseError):
+    """
+    exception thrown if the user enters an invalid payload
+    """
+
+    def __init__(self, val, message="Invalid source or target language!"):
+        super(InvalidSourceOrTargetLanguage, self).__init__(val, message)
+
+
+class TranslationNotFound(BaseError):
+    """
+    exception thrown if no translation was found for the text provided by the user
+    """
+
+    def __init__(
+        self,
+        val,
+        message="No translation was found using the current translator. Try another translator?",
+    ):
+        super(TranslationNotFound, self).__init__(val, message)
+
+
+class ElementNotFoundInGetRequest(BaseError):
+    """
+    exception thrown if the html element was not found in the body parsed by beautifulsoup
+    """
+
+    def __init__(
+        self, val, message="Required element was not found in the API response"
+    ):
+        super(ElementNotFoundInGetRequest, self).__init__(val, message)
+
+
+class NotValidLength(BaseError):
+    """
+    exception thrown if the provided text exceed the length limit of the translator
+    """
+
+    def __init__(self, val, min_chars, max_chars):
+        message = f"Text length need to be between {min_chars} and {max_chars} characters"
+        super(NotValidLength, self).__init__(val, message)
+
+
+class RequestError(Exception):
+    """
+    exception thrown if an error occurred during the request call, e.g a connection problem.
+    """
+
+    def __init__(
+        self,
+        message="Request exception can happen due to an api connection error. "
+        "Please check your connection and try again",
+    ):
+        self.message = message
+
+    def __str__(self):
+        return self.message
+
+
+
+class TooManyRequests(Exception):
+    """
+    exception thrown if an error occurred during the request call, e.g a connection problem.
+    """
+
+    def __init__(
+        self,
+        message="Server Error: You made too many requests to the server."
+        "According to google, you are allowed to make 5 requests per second"
+        "and up to 200k requests per day. You can wait and try again later or"
+        "you can try the translate_batch function",
+    ):
+        self.message = message
+
+    def __str__(self):
+        return self.message
+
+class ServerException(Exception):
+    """
+    Default YandexTranslate exception from the official website
+    """
+
+    errors = {
+        400: "ERR_BAD_REQUEST",
+        401: "ERR_KEY_INVALID",
+        402: "ERR_KEY_BLOCKED",
+        403: "ERR_DAILY_REQ_LIMIT_EXCEEDED",
+        404: "ERR_DAILY_CHAR_LIMIT_EXCEEDED",
+        413: "ERR_TEXT_TOO_LONG",
+        429: "ERR_TOO_MANY_REQUESTS",
+        422: "ERR_UNPROCESSABLE_TEXT",
+        500: "ERR_INTERNAL_SERVER_ERROR",
+        501: "ERR_LANG_NOT_SUPPORTED",
+        503: "ERR_SERVICE_NOT_AVAIBLE",
+    }
+
+    def __init__(self, status_code, *args):
+        message = self.errors.get(status_code, "API server error")
+        super(ServerException, self).__init__(message, *args)
+
+def is_empty(text: str) -> bool:
+    return text == ""
+
+
+def request_failed(status_code: int) -> bool:
+    """Check if a request has failed or not.
+    A request is considered successfull if the status code is in the 2** range.
+
+    Args:
+        status_code (int): status code of the request
+
+    Returns:
+        bool: indicates request failure
+    """
+    if status_code > 299 or status_code < 200:
+        return True
+    return False
+
+
+def is_input_valid(
+    text: str, min_chars: int = 0, max_chars: Optional[int] = None
+) -> bool:
+    """
+    validate the target text to translate
+    @param min_chars: min characters
+    @param max_chars: max characters
+    @param text: text to translate
+    @return: bool
+    """
+
+    if not isinstance(text, str):
+        raise NotValidPayload(text)
+    if max_chars and (not min_chars <= len(text) < max_chars):
+        raise NotValidLength(text, min_chars, max_chars)
+
+    return True
+
 class BaseTranslator(ABC):
     """
     Abstract class that serve as a base translator for other different translators