* WiFiClient: use DataSource for writes
* ESP8266WebServer: delegate writing to WiFiClient
* ESP8266WebServer: set write timeout before sending content
Fix handling of case when Content-Length is 0.
Change do {} while() loop into while(){} so that we don't wait 1000ms for data in case Content-Length is 0.
Also fix handling of cases when malloc or realloc return null.
If there is a delay before data becomes available on a new connection
then the handler function blocks for up to 1 second, and there's another
wait on connection close for up to 2 seconds.
This doesn't make the whole server process asynchronous (there is another
delay between headers/data) but it helps when there are other events
that need attention while handling web requests.
This is needed since when the content-length header is not sent the clients will
wait for data anyways. Sending a content length of zero will tell the client not
to expect any content and it will close the connection immediately.
If RequestHandler::canHandle returns true, but subsequent RequestHandler::handle returns false, we should return some HTTP response instead of an empty one.
In addition to the existing constructors (WiFiServer::WiFiServer(port) and WiFiWebServer::WiFiWebServer(port)), new constructors are added:
WiFiServer::WiFiServer(IPAddress, port) and WiFiWebServer::WiFiWebServer(IPAddress, port).
The terminator should not be sent by sendContent_P. For example, if you
have a null-terminated string, the null itself should not be sent to the
client. This change decrements the number of bytes to send so it does
not include the termination character.
If the client connection gets closed during a form upload,
the fileUploadHandler is notified with the new
UPLOAD_FILE_ABORTED status, and the loop is ended
gracefully.
