This fix prevents HTTP server from accepting new connections when the total count of connected
sockets has reached the max_open_sockets limit set during configuration. The pending connections
are kept in backlog until atleast one of the connected sockets is closed. The maximum number of
connection requests that can kept in backlog is specified as backlog_conn configuration option.
Note that this modification has no effect when LRU purge is enabled.
Also added sanity check on setting for max_open_sockets during configuration.
Solution suggested by jimparis https://github.com/espressif/esp-idf/issues/3183#issue-421234265
Closes https://github.com/espressif/esp-idf/issues/3183
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.
* 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
