Getting started

Requirements

What	Version
CE C toolchain	v15.0 or newer
lwIP-CE	3.0, installed into CEdev
ce-libify	v1.1.2, only to build LWHTTP itself
Calculator	TI-84 Plus CE with a USB Ethernet adapter or the lwIP-CE Wi-Fi bridge

Install the library

Build LWHTTP and copy its stub and header into CEdev:

git clone https://github.com/alessiodam/lwhttp
cd lwhttp
make install

This produces bin/LWHTTP.8xv (the LibLoad library) and bin/LWHTTP.lib (the link stub), and installs LWHTTP.lib plus lwhttp.h into $CEDEV/lib/libload and $CEDEV/include.

Prebuilt files are attached to every release.

Set up a program

Programs link LWHTTP like any other LibLoad library. Like every lwIP-CE program, the makefile must keep the heap below lwIP-CE’s memory:

NAME = MYAPP
BSSHEAP_LOW = 0xD072C6

include $(shell cedev-config --makefile)

Then include both headers:

#include <lwip.h>
#include <lwhttp.h>

Your first request

#include <stdio.h>
#include <ti/getcsc.h>
#include <ti/screen.h>
#include <lwip.h>
#include <lwhttp.h>

int main(void)
{
  lwhttp_request_t request = {0};
  lwhttp_client_t *client;
  char line[27];

  os_ClrHome();
  if (!lwip_start() || !lwip_network_up()) return 1;

  client = lwhttp_client_create(NULL);
  request.url = "https://tls13.akamai.io/";
  if (lwhttp_client_request_sync(client, &request, NULL, NULL) == LWHTTP_OK) {
    sprintf(line, "HTTP %u", lwhttp_client_status(client));
    os_PutStrFull(line);
  }

  lwhttp_client_destroy(client);
  while (!os_GetCSC()) lwhttp_service_events();
  lwip_stop();
  return 0;
}

lwip_start() brings up lwIP-CE and lwip_network_up() starts the network interface. After that, every LWHTTP call is non-blocking except the explicit wrappers lwhttp_client_request_sync() and lwhttp_client_wait().

Send it to the calculator

File	Purpose
LWHTTP.8xv	LWHTTP
lwIP-CE files	the lwIP-CE stub (lwip.8xv), its app installer and the truststore lwIPCERT.8xv
CE libraries	clibs.8xg (graphx, fileioc, usbdrvce and friends)
your program	MYAPP.8xp

Run the lwIP-CE installer once, then your program. The examples/http_get program in the repository is a complete, buildable version of the code above with progress callbacks.

Next steps

Event loop and callbacks

How requests progress and what you may do inside callbacks.

Event loop and callbacks

Sending requests

Methods, headers, in-memory and streamed bodies.

Requests