Problem with http server on Esp8266 with response of about 25kByte

[Rolf]

Hi all,

AS a http Server, I like to send a (quite long) response back to a http Client by reading it from a file in the spiffs block by block (blocksize is 2048) and sending it towards the client (using ‘mg_send’)
Sometimes it works fine and sometimes is seems to lose some data.
Checking the resulting html-Page in the Browser, I can see missing Code at the end or in the middle.
Is it possible to be too fast sending the blocks, so that data is lost?
If so, is there a possibility to wait for the sender to finish?

Thanks a Lot!
Rolf

[scaprile]

I seem to remember some post somewhere from one of the developers… did you try using the RPC interface instead ?
Anyway, searching for ‘mg_send’ in this forum returns interesting results (and it’s free!):

Sending HTTP response in pieces

Yes, check the send_iobuf length before mg_send_, and if it is larger than some reasonable threshold, do not send but rather wait for another poll cycle. This is what default file handler does. See https://github.com/cesanta/mongoose/blob/master/src/mg_http.c Function mg_http_transfer_file_data()

Need a way to flush tcp send buffer

Also, https://github.com/mongoose-os-apps/http-fetch If you’re not using Mongoose OS but plain Mongoose Library, you can process the MG_EV_HTTP_CHUNK message which is fired for every chunk in the upload. Alternatively, for a non-chunked upload, use MS_EV_RECV. Using Mongoose OS is preferrable however, because there is already a FS.* set of functions for managing files, and you can upload large files to ESP8266 with no issues.

[Rolf]

Thanks a lot for your input, Scaprile.

If I do not close the connection after sending a block of data, I would expect to get a MG_EV_SEND.
But there is none! Do I have to register MG_EV_SEND separately?
I register using ‘mgos_register_http_endpoint’ only. Does this not register the MG_EV_SEND, too?

Rolf