Api for saving heap when Client class is used by a Server (WiFiServer class): Client = Server.available().
Suppose the local end is the server and the remote end is the client, we will deal with heap memory at the local end.
When the local application (server) decides to close an active connection with a remote end it issues an Client.stop.
The stop() function calls the close() function of ClientContext class which in turn calls tcp_close.
The connexion is closed by tcp_close and the protocol control block (pcb) can be put in the following states depending on the requests sent by the remote: CLOSING, FIN_WAIT_1 and FIN_WAIT_2. In theses states pcbs are not freed, then consume some memory heap.
If an acknowledgment from the remote end is received, the pcb enter in TIME_WAIT state for some minutes but pcbs in TIME_WAIT state are not freed. Then consume some heap memory.
TIME_WAIT pcbs are automatically freed after some minutes or can be freed for instance issuing an tcp_kill_timewait()
in the local application which will free the oldest pcb in TIME_WAIT state.
If the connection is first closed from the remote end (the client), the local end (server) receive a connection termination request. It then acknowledge it and enter in CLOSE_WAIT state waiting for a connection termination request from the local application.
It then send a termination request and enter in LAST_ACK state until it receive an acknowledgment from the remote end.
After receiving the acknowledgment it enter in ClOSED state and the local pcb is freed leaving some room in the heap memory.
To summarize, when a connexion termination request is send by one end (remote or local), the local pcb is not freed immediatly.
This pcb can be in the following states: FIN_WAIT_1, FIN_WAIT_2, CLOSING, TIME_WAIT, CLOSE_WAIT, LAST_ACK.
As a consequence, some old pcbs from old closed connections are still consuming heap memory.
The local application can call tcp_kill_timewait hoping it will free some TIME_WAIT state pcbs. But if the server receive frequent connections requests and close them after sending whatever it has to send, there may be zero pcbs in TIME_WAIT state among all previously closed connections.
In case of insufficient memory to accept a new connection, lwip has developped a strategy: it successively tries to kill the oldest pcb in TIME_WAIT state, or in LAST_ACK state or in CLOSING state or the oldest active connection with lower priority than the new one.
As a matter of fact this "urgent" strategy is deployed only when very few heap memory remain available (less than some kb). In case of success, Client.available returns a valid Client but the local application will crash when sending or receiving data from the client (Client.read ou readuntil or available) because this need more heap memory and just some kb were freed in lwip to allocate the new pcb structure ans start the new connection.
The propose API is intended to avoid this drawback by calling the abort function of ClientContext which in turn calls tcp_abort which calls tcp_abandon. The connection is aborted and notified to the client with a RESET and the pcb and ressources associated are immediately released increasing the available heap memory.
- =default for default ctor, destructor, move ctor and the assignment move
- use `std::unique_ptr<WiFiClient>` instead of raw pointer to the client
- implement `virtual std::unique_ptr<WiFiClient> WiFiClient::clone()` to safely copy the WiFiClientSecure instance, without accidentally slicing it (i.e. using the pointer with incorrect type, calling base WiFiClient virtual methods)
- replace headers pointer array with `std::unique_ptr<T[]>` to simplify the move operations
- substitute userAgent with the default one when it is empty
(may be a subject to change though, b/c now there is a global static `String`)
Allow HTTPClient to be placed inside of movable classes (e.g. std::optional, requested in the linked issue) or to be returned from functions. Class logic stays as-is, only the underlying member types are changed.
Notice that WiFiClient connection object is now copied, and the internal ClientContext will be preserved even after the original WiFiClient object was destroyed.
replaces #8236resolves#8231
and, possibly #5734
Fixes#8079
Because WiFiClientSecure inherits WiFiClient, and WiFiClientSecureCtx also
inherits WiFiClient, they both end up in the list of TCP connections that
are used for WiFiClient::stopAllExcept(). This would cause the underlying
SSL connection to be closed whenever you attempted to
stopAllExcept(WiFiClientSecure)
Fix by adding a "_owned"(by) pointer in the WiFiClient object which points to
nullptr (default case) or to the associated lower-layer connection.
When stopping all connections except one, only look at the lowermost
connections.
fixes for WiFiClient::write(Stream) and Stream transfers
- remove deprecated WiFiClient::write(Stream,size)
- fix and deprecate WiFiClient::write(Stream) to use Stream::sendAll instead of ::sendAvailable
- update ESP8266WebServer::streamFile to use file.sendAll(client) instead of client.write(file)
- remove stream dependence in ClientContext
- Stream::send(): honor timeout in all case, avoid short transfer when output is temporarily full
- example WiFiEcho: show sendAll and sendAvailable
* move WiFiClientSecure to WiFiClientSecureCtx and add WiFiClientSecure wrapper to handle the context
* explicitely disable context copy constructor (similar to operator=)
* move (static) probeMaxFragmentLength back from ctx to WiFiClientSecure
* route sslclient::status() to context's ::status()
* Add Print::availableForWrite method
Adds an availableForWrite() method to the Print class, matching current
ArduinoCore-API commit 398e70f188e2b861c10d9ffe5e2bfcb6a4a4f489 .
Hook availableForWrite into the SDFS filesystem (other FSes don't have
this capability built-in).
Fixes#7650
* WiFiClient::availableForWrite proto matching Print
* Fix Netdump signedness warning
* Clean up Serial availableForWrite
This is evidently a breaking change due to the type difference.
Arduino's `availableForWrite` returns an `int`, while the
(multiply-implemented, non-virtual) core `availableForWrite` returned
`size_t`.
Adds SSL server mode for WiFiServerSecure, for plain SSL connections,
ESP8266WebServerSecure, for HTTPS web serving, and SecureHTTPSUpdater for
encrypted OTA updates.
Example code is provided for all new options, as well as a BASH script for
generating their own, self-signed certificates.
Both ESP8266WebServerSecure and SecureHTTPSUpdater are important for secure
password-based authentication. HTTP Basic Authentication, the only supported
model presently, sends the username and password in *cleartext* and therefore
should *never* be used in any un-SSL encrypted channel unless you don't mind
sharing your login and password with anyone else on the internet. Even if the
ESP8266 is not safety critical, this cleartext broadcast could expose you should
you reuse this password elsewhere on your network or the internet.
* minimum changes for libraries to compile with lwip2
* add WiFiClient::availableForWrite() (similar to Serial::) which indicates how much data can be sent without buffering
* WiFiClient: use DataSource for writes
* ESP8266WebServer: delegate writing to WiFiClient
* ESP8266WebServer: set write timeout before sending content
Arduino.h defines min/max which are then redefined with templates in stl_algobase.h imported from memory.h. This is the least impactful way I can find to get past this for now and unblock use of wificlient in more scenarios.
- use new AutoInterruptLock
- add delay to give the RTOS some time to handle TCP
WiFiClient.cpp
- add stopAllexcepted to cancel all TCP excepted one
ClientContext.h
- add getLocalPort()
ESP8266HTTPUpdate.cpp
- close all not needed TCP and UDP
osapi.h
- missing commit from SDK
When network interface is down, some nasty things happen, for instance tcp_connect returns without ever calling error callback.
This change adds some workarounds for that: before doing a tcp connect and DNS resolve we check if there is a route available.
Also added a listener for wifi events which stops (aborts) all the WiFiClients and WiFiUDPs when wifi is disconnected. This should
help libraries detect disconnect properly.
* ficeto-esp8266:
add template methods for stream to stream writes to SD and FS
alignment not needed. we use fixed addresses
Rework SPIFFS API to be more Arduino like
fix missed edits
disable automount
fix SPIFFS to work
pull get/set NoDelay for WiFiClient
Add SPIFFS Support
export sketch data folder to the build config
Revert "Revert "Edit SD Server example to use the new Write(Stream) method""
add template client write
Revert "Add WiFiClient.write for Stream"
Revert "Edit SD Server example to use the new Write(Stream) method"
Edit SD Server example to use the new Write(Stream) method
Add WiFiClient.write for Stream
make upload callback packets aligned to defined size
Conflicts:
hardware/esp8266com/esp8266/libraries/ESP8266WebServer/examples/SDWebServer/SDWebServer.ino
hardware/esp8266com/esp8266/libraries/ESP8266WebServer/src/ESP8266WebServer.cpp
hardware/esp8266com/esp8266/libraries/ESP8266WebServer/src/ESP8266WebServer.h
