Issue : Restarting the server without 30sec delay between httpd_stop() and httpd_start() causes EADDRINUSE error
Resolution : Use setsockopt() to enable SO_REUSEADDR on listener socket
Closes https://github.com/espressif/esp-idf/issues/3381
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
The task that runs the HTTP server can now be pinned to a particular core by setting `core_id`
in the HTTP server configuration. By default, the core is set to `tskNO_AFFINITY`, meaning
it can run on any core.
Merges https://github.com/espressif/esp-idf/pull/3190
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
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
