oxomoxo / jsl-esp32-http

A lean C++ http server and app router. Handcrafted for esp32.

A lean C++ http server and app router. Handcrafted for esp32.

What is it

The http server is based on LWIP IP stack and has very small codebase (< 1K loc).

Yet it has a very nice app router that can gather arguments along the url according to possible regexes in the route definition.

Use

void static_target(const jsl_http_common::req_t& _req, jsl_http_common::res_t& _res)
{
	ESP_LOGI(LOGTAG, "static_target called.");
	std::ostringstream& out = _res;

	std::string fname = "/static";
	if(_req.path().size() > 1)
	{
		fname += "/res";
	}
	fname += "/" + _req.args().at("file");

	ESP_LOGI(LOGTAG, "Opening file : %s",fname.c_str());

	if(!load_file(fname.c_str(),out))
	{
		out << jsl_http_common::dump_path("Path",_req.path());
		out << jsl_http_common::dump_pmap("Args",_req.args());
		out << jsl_http_common::dump_pmap("Query",_req.query());
		_res.write_file("text/plain");
		return;
	}

	_res.write_file(jsl_http_common::mime.at(fname.substr(fname.find('.'))).c_str());
}

void app_main()
{
	jsl_http::addRoute("GET","/{file}",static_target);
	jsl_http::addRoute("GET","/res/{file}",static_target);
	jsl_http::addRoute("GET","/ok/this/is/a/long/{address:\\d+(?:\\.\\d*)?}/with/some/regexes/{along:\\d+}",test_target);

	jsl_http::start();
}

The above code snippet

• declares a callback for serving hypothetical static files
• declares two possible routes for static content
• declare a parametric route with regexes

How it works

The router works as follows:

• When a route is declared, the router splits the path segments and arranges a tree of routes branches according to plain or regex segments, and stores the callback as the leaf.
• When the server receives a request it splits the url segments, the query arguments and handles the data to the router.
• When the router processes the material form the server it walks the routes branches recursively matching from "most defined" to "least defined" (a matching plain segment is more defined than a matching regex, a longer match is more defined than a shorter match)
  • plain segments: if the incoming segment matches a child name search the branch for a matching leaf, if no leaf is returned test regexes
  • regex segments: if the incoming segment matches a regex search the branch for a matching leaf, if no leaf is returned possibly return the leaf (the actual callback)
  • branch leaf (if present)

The regexes (Ecmascript) have a simple integration syntax : {argname:regex} where the match from the regex will be stored in argname.

Install

git clone https://github.com/oxomoxo/jsl-esp32-http.git server

Or

git submodule add https://github.com/oxomoxo/jsl-esp32-http.git server

In component.mk add the folder to the COMPONENT_ADD_INCLUDEDIRS and COMPONENT_SRCDIRS

COMPONENT_ADD_INCLUDEDIRS := . \
	...
	server \

COMPONENT_SRCDIRS := . \
	...
	server \

Build :

make -j4 flash monitor

And, Voila !

Neat isn't it ?