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Introduzione a Crow a "A Fast and Easy to use microframework for the web."

Autore: Fabio Di Matteo
Ultima revisione: 21/01/2024 - 22:03

Il seguente codice c++ imposta delle rotte che mostrano alcune caratteristiche del framework.

#include "crow.h"
#include "crow/middlewares/cookie_parser.h"
//#include "crow_all.h"
int main()
     //crow::SimpleApp app;
     crow::App<crow::CookieParser> app;
    //define your endpoint at the root directory
    CROW_ROUTE(app, "/")([](){
        auto page = crow::mustache::load_text("index.html");
        return page;
    CROW_ROUTE(app, "/ciao")([](){
        auto t = crow::mustache::load_text("ciao.html");
		const char* myname="Fabio Di Matteo";
		auto page = crow::mustache::compile(t);
		crow::mustache::context ctx;
		ctx["name"] = myname;
		return page.render(ctx);
    // localhost:8080/req?p=<my value>
    CROW_ROUTE(app, "/req")([](const crow::request& req){
        const char *page=req.url_params.get("p");
        return page;
    CROW_ROUTE(app, "/cookies")([&app](const crow::request& req)
        auto& ctx = app.get_context<crow::CookieParser>(req);
		std::string value = ctx.get_cookie("biscotto");
		std::string page;
		if (value.empty())
			ctx.set_cookie("biscotto", "cioccolato");
			page="Nessun cookie impostato.";
			page="Biscotto al gusto di : "+value;
        return page;
    // download file (esempio: /download?f=my file.png)
    CROW_ROUTE(app, "/download")([](const crow::request& req,crow::response& res){
		 const char *f=req.url_params.get("f");
    //set the port, set the app to run on multiple threads, and run the app


	g++ -o server

Upload di un file

Salvataggio di un file inviato attraverso un form multipart.

CROW_ROUTE(app, "/save").methods(crow::HTTPMethod::POST)([=](const crow::request& req ){
		std::string root_folder="/home/fabio/progetto"; 
		crow::multipart::message msg(req);
        crow::multipart::header myheader =[0].get_header_object("Content-Disposition");
        //std::string myheader_value=myheader.value;
		std::string  outfile_name=myheader.params["filename"];
		CROW_LOG_ERROR << "File Name ->"+outfile_name;
        std::ofstream out_file(root_folder+"/"+outfile_name);
         if (!out_file)
			  CROW_LOG_ERROR << " Write to file failed\n";
			  return "Write to file failed!";
                  out_file <<[0].body;
        return "ok";
<!DOCTYPE html><html><head>\
<title>Piso - Upload files</title>\
<meta name=\"viewport\" content=\"width=1280, initial-scale=1\">\
<h2>Upload a file</h2><hr/>\
<form action=\"{{{action}}}\" method=\"post\" enctype=\"multipart/form-data\">\
<input type=\"file\" id=\"myfile\" name=\"myfile\">\
<button type=\"submit\">Upload this file</button></hr>\

programmazione/crow/hello_world.txt · Ultima modifica: 27/01/2024 - 15:18 da Fabio Di Matteo