open_fn() was introduced in the context of HTTPS server, as a configurable callback function that is called by the HTTP server, on every newly created socket. It is responsible of allocating resources for per session transport security.
Earlier, if open_fn were to fail, the newly created socket would be closed by the server but the corresponding entry, for the now invalid socket, will remain in the internal socket database until that invalid socket is detected due to error when calling select(). Because of this delayed closing of sockets, the HTTPS server would quickly face shortage of available sessions when a lot of SSL handshake errors are happening (this typically occurs when a browser finds that the server certificate is self signed). This changes in this MR fix this issue by clearing up the socket from internal database, right after open_fn fails.
Closes https://github.com/espressif/esp-idf/issues/3479
By default, if a URI handler changes the http session context,
the webserver internally clears the older context after the handler
returns. However, if applications want to change this behavior and
manage the allocation/de-allocation/freeing themselves and let the
server handle only the "socket close" case, this commit provides such
an option.
Added APIs :
* httpd_resp_send_err() : for sending HTTP error responses for error codes given by httpd_err_code_t. It uses TCP_NODELAY option to ensure that HTTP error responses reach the client before socket is closed.
* httpd_register_err_handler() : for registering HTTP error handler functions of type httpd_err_handler_func_t.
The default behavior, on encountering errors during processing of HTTP requests, is now to send HTTP error response (if possible) and close the underlying socket. User configurable handlers can be used to override this behavior for each error individually (except for 500 Internal Server Error).
Also fixed some typos.
Closes https://github.com/espressif/esp-idf/issues/3005
Note : In future consider deprecating usage of -1 for setting
buffer length equal to string length in APIs httpd_resp_send()
and httpd_resp_send_chunk()
* http_sess_set_*_override APIs are now the only ones available to set custom recv/send/pending functions
* Fixed side effects to using http_sess_set/get_context inside URI handlers
Changes:
- renamed `httpd_free_sess_ctx_fn_t` to `httpd_free_ctx_fn_t`
- added a `httpd_handle_t` argument to `httpd_send_func_t` and `httpd_recv_func_t`
- internal function `httpd_sess_get()` is no longer static, as it's used in other
files besides httpd_sess.c
Bug fixes:
- removed a trailing semicolon from `HTTPD_DEFAULT_CONFIG()`
- fixed issue with failed `select()`, now it automatically closes invalid sockets
instead of shutting down the entire server
New features:
- `httpd_resp_send()` and `httpd_resp_send_chunk()` now accept -1 as length to use
`strlen()` internally
- added `httpd_sess_set_ctx()` to accompany `httpd_sess_get_ctx()`
- added a "transport context" to the session structure (next to user context)
- added `httpd_sess_{get,set}_transport_ctx()` to work with this transport context
- added "global user context" and "global transport context" stored in the server
config (and then the handle); supports a user-provided free_fn
- added a "pending func" to e.g. check for data in the transport layer receive
buffer
- added functions `httpd_set_sess_{send,recv,pending}_override()` that target
a session by ID (i.e. not using a request object)
- added `httpd_set_pending_override()`
- added a "open_fn" and "close_fn" - functions called when creating and closing
a session. These may be used to set up transport layer encryption or some other
session-wide feature
