HTTP Codes and Caching The http response code of a transfered object is the most important criteria on how to store/cache this object. The following table shows HTTP response codes and how the are handled by Squid.
Caching | Code | Explaination | HTTP |
---|---|---|---|
1xx | INFORMATIONAL | ||
100 | Continue | >=1.1 | |
101 | Switching Protocols | >=1.1 | |
102 | Extended | >=1.1 | |
2xx | SUCCESSFUL | ||
c | 200 | OK | >=1.0 |
201 | Created | >=1.0 | |
202 | Accepted | >=1.0 | |
c | 203 | Non-Authoriative Information | >=1.1 |
N | 204 | No Content | >=1.0 |
205 | Reset Content | >=1.1 | |
206 | Partial Content | >=1.1 | |
220 | Uses Protocol Extensions | >=1.2 | |
3xx | REDIRECTION | ||
C | 300 | Multiple Choices | >=1.1 |
C | 301 | Moved Permanently | >=1.0 |
E | 302 | Moved Temporarily | 1.0 |
E | 302 | Found | >=1.1 |
- | 303 | See Other | >=1.1 |
- | 304 | Not Modified | >=1.0 |
N | 305 | Use Proxy (proxy redirect) | >=1.1 |
307 | Temporary Redirect | >=1.1 | |
4xx | CLIENT ERROR | ||
N | 400 | Bad Request | >=1.0 |
- | 401 | Unauthorized | >=1.0 |
402 | Payment Required | >=1.1 | |
N | 403 | Forbidden | >=1.0 |
N | 404 | Not Found | >=1.0 |
N | 405 | Method Not Allowed | >=1.1 |
406 | Not Acceptable | >=1.1 | |
- | 407 | Proxy Authentication Required | >=1.1 |
408 | Request Timeout | >=1.1 | |
409 | Conflict | >=1.1 | |
C | 410 | Gone | >=1.1 |
411 | Length Required | >=1.1 | |
412 | Precondition Failed | >=1.1 | |
413 | Request Entity To Large | >=1.1 | |
N | 414 | Request-URI Too Long | >=1.1 |
415 | Unsupported Media Type | >=1.0 | |
416 | Requested range not satisfiable | >=1.1 | |
417 | Expectation Failed | >=1.1 | |
420 | Bad Protocol Extension Request | >=1.2 | |
421 | Protocol Extension Unknown | >=1.2 | |
422 | Protocol Extension Refused | >=1.2 | |
423 | Bad Protocol Extension Parameters | >=1.2 | |
5xx | SERVER ERROR | ||
N | 500 | Internal Server Error | >=1.0 |
N | 501 | Not Implemented | >=1.0 |
N | 502 | Bad Gateway | >=1.0 |
N | 503 | Service Unavailable | >=1.0 |
N | 504 | Gateway Timeout | >=1.1 |
505 | HTTP Version Not Supported | >=1.1 | |
510 | Not Extended | >=1.1 | |
520 | Protocol Extension Error | >=1.2 | |
521 | Protocol Extension Not Implemented | >=1.2 | |
522 | Protocol Extension Parameters Not Acceptable | >=1.2 | |
6xx | SQUID ERROR | ||
- | 600 | Squid header parsing error | Squid only |
C | ... | Cached |
c | ... | Cached unless a query response without expiry information (i.e. without `Last modified' and `Date' and `Expires' header line) |
E | ... | Cached only if expiry information |
N | ... | Negatively cached if no expiry headers. |
- | ... | Not cached |
... | Unless other said, the response code is not cached |