urllib.error — Exception classes raised by urllib.request

Source code: Lib/urllib/error.py

The urllib.error module defines the exception classes for exceptions raised by urllib.request. The base exception class is URLError.

The following exceptions are raised by urllib.error as appropriate:

exception urllib.error.URLError

The handlers raise this exception (or derived exceptions) when they run into a problem. It is a subclass of OSError.

reason

The reason for this error. It can be a message string or another exception instance.

Changed in version 3.3: URLError used to be a subtype of IOError, which is now an alias of OSError.

exception urllib.error.HTTPError(url, code, msg, hdrs, fp)

Though being an exception (a subclass of URLError), an HTTPError can also function as a non-exceptional file-like return value (the same thing that urlopen() returns). This is useful when handling exotic HTTP errors, such as requests for authentication.

url

Contains the request URL. An alias for filename attribute.

code

An HTTP status code as defined in RFC 2616. This numeric value corresponds to a value found in the dictionary of codes as found in http.server.BaseHTTPRequestHandler.responses.

reason

This is usually a string explaining the reason for this error. An alias for msg attribute.

headers

The HTTP response headers for the HTTP request that caused the HTTPError. An alias for hdrs attribute.

New in version 3.4.

fp

A file-like object where the HTTP error body can be read from.

exception urllib.error.ContentTooShortError(msg, content)

This exception is raised when the urlretrieve() function detects that the amount of the downloaded data is less than the expected amount (given by the Content-Length header).

content

The downloaded (and supposedly truncated) data.