/*
This file is part of libhttpserver
Copyright (C) 2011, 2012, 2013, 2014, 2015 Sebastiano Merlino
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
USA
*/
// This example demonstrates how to serve binary data (e.g., images) directly
// from an in-memory buffer using string_response. Despite its name,
// string_response works with arbitrary binary content because std::string can
// hold any bytes, including null characters.
//
// This is useful when you generate or receive binary data at runtime (e.g.,
// from a camera, an image library, or a database) and want to serve it over
// HTTP without writing it to disk first.
//
// To test:
// curl -o output.png http://localhost:8080/image
#include
#include
#include
#include
// Generate a minimal valid 1x1 red PNG image in memory.
// In a real application, this could come from a camera capture, image
// processing library, database blob, etc.
static std::string generate_png_data() {
// Minimal 1x1 red pixel PNG (68 bytes)
static const unsigned char png[] = {
0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a, // PNG signature
0x00, 0x00, 0x00, 0x0d, 0x49, 0x48, 0x44, 0x52, // IHDR chunk
0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x01, // 1x1
0x08, 0x02, 0x00, 0x00, 0x00, 0x90, 0x77, 0x53, // 8-bit RGB
0xde, 0x00, 0x00, 0x00, 0x0c, 0x49, 0x44, 0x41, // IDAT chunk
0x54, 0x08, 0xd7, 0x63, 0xf8, 0xcf, 0xc0, 0x00, // compressed data
0x00, 0x00, 0x03, 0x00, 0x01, 0x36, 0x28, 0x19,
0x00, 0x00, 0x00, 0x00, 0x00, 0x49, 0x45, 0x4e, // IEND chunk
0x44, 0xae, 0x42, 0x60, 0x82
};
return std::string(reinterpret_cast(png), sizeof(png));
}
class image_resource : public httpserver::http_resource {
public:
std::shared_ptr render_GET(const httpserver::http_request&) {
// Build binary content as a std::string. The string can contain any
// bytes — it is not limited to printable characters or null-terminated
// C strings. The size is tracked internally by std::string::size().
std::string image_data = generate_png_data();
// Use string_response with the appropriate content type. The response
// will send the exact bytes contained in the string.
return std::make_shared(
std::move(image_data), 200, "image/png");
}
};
int main() {
httpserver::webserver ws = httpserver::create_webserver(8080);
image_resource ir;
ws.register_resource("/image", &ir);
ws.start(true);
return 0;
}