bpo-40321: Support HTTP response status code 308 in urllib.request (pythonGH-19588)

* Support HTTP response status code 308 in urllib.

HTTP response status code 308 is defined in https://tools.ietf.org/html/rfc7538 to be the permanent redirect variant of 307 (temporary redirect).

* Update documentation to include http_error_308()

* Add blurb for bpo-40321 fix

Co-authored-by: Roland Crosby <[email protected]>
(cherry picked from commit c379bc5)

Co-authored-by: Jochem Schulenklopper <[email protected]>

Author: jschulenklopper

Doc/library/urllib.request.rst

@@ -874,6 +874,12 @@ HTTPRedirectHandler Objects
    response.
 
 
+.. method:: HTTPRedirectHandler.http_error_308(req, fp, code, msg, hdrs)
+
+   The same as :meth:`http_error_301`, but called for the 'permanent redirect'
+   response.
+
+
 .. _http-cookie-processor:
 
 HTTPCookieProcessor Objects

Lib/urllib/request.py

@@ -11,8 +11,8 @@
 Handlers needed to open the requested URL.  For example, the
 HTTPHandler performs HTTP GET and POST requests and deals with
 non-error returns.  The HTTPRedirectHandler automatically deals with
-HTTP 301, 302, 303 and 307 redirect errors, and the HTTPDigestAuthHandler
-deals with digest authentication.
+HTTP 301, 302, 303, 307 and 308 redirect errors, and the
+HTTPDigestAuthHandler deals with digest authentication.
 
 urlopen(url, data=None) -- Basic usage is the same as original
 urllib.  pass the url and optionally data to post to an HTTP URL, and
@@ -659,7 +659,7 @@ def redirect_request(self, req, fp, code, msg, headers, newurl):
         but another Handler might.
         """
         m = req.get_method()
-        if (not (code in (301, 302, 303, 307) and m in ("GET", "HEAD")
+        if (not (code in (301, 302, 303, 307, 308) and m in ("GET", "HEAD")
             or code in (301, 302, 303) and m == "POST")):
             raise HTTPError(req.full_url, code, msg, headers, fp)
 
@@ -746,7 +746,7 @@ def http_error_302(self, req, fp, code, msg, headers):
 
         return self.parent.open(new, timeout=req.timeout)
 
-    http_error_301 = http_error_303 = http_error_307 = http_error_302
+    http_error_301 = http_error_303 = http_error_307 = http_error_308 = http_error_302
 
     inf_msg = "The HTTP server returned a redirect error that would " \
               "lead to an infinite loop.\n" \
@@ -2209,6 +2209,13 @@ def http_error_307(self, url, fp, errcode, errmsg, headers, data=None):
         else:
             return self.http_error_default(url, fp, errcode, errmsg, headers)
 
+    def http_error_308(self, url, fp, errcode, errmsg, headers, data=None):
+        """Error 308 -- relocated, but turn POST into error."""
+        if data is None:
+            return self.http_error_301(url, fp, errcode, errmsg, headers, data)
+        else:
+            return self.http_error_default(url, fp, errcode, errmsg, headers)
+
     def http_error_401(self, url, fp, errcode, errmsg, headers, data=None,
             retry=False):
         """Error 401 -- authentication required.

Misc/NEWS.d/next/Library/2021-07-22-21-25-56.bpo-40321.gBlFmw.rst

@@ -0,0 +1,2 @@
+Adds support for HTTP 308 redirects to :mod:`urllib`. Patch by Jochem
+Schulenklopper.