Add http redirect example

tutorials/http/redirect-to-https/Makefile

@@ -0,0 +1,31 @@
+PROG ?= example                   # Program we are building
+DELETE = rm -rf                   # Command to remove files
+OUT ?= -o $(PROG)                 # Compiler argument for output file
+SOURCES = main.c mongoose.c       # Source code files
+CFLAGS = -W -Wall -Wextra -g -I.  # Build options
+#CFLAGS += -fsanitize=address,undefined,alignment
+
+# Mongoose build options. See https://mongoose.ws/documentation/#build-options
+CFLAGS_MONGOOSE += -DMG_HTTP_DIRLIST_TIME_FMT="%Y/%m/%d %H:%M:%S"
+CFLAGS_MONGOOSE += -DMG_ENABLE_LINES=1 -DMG_ENABLE_IPV6=1 -DMG_ENABLE_SSI=1
+CFLAGS_EXTRA ?= -DMG_TLS=MG_TLS_BUILTIN
+
+ifeq ($(OS),Windows_NT)   # Windows settings. Assume MinGW compiler. To use VC: make CC=cl CFLAGS=/MD OUT=/Feprog.exe
+  PROG ?= example.exe           # Use .exe suffix for the binary
+  CC = gcc                      # Use MinGW gcc compiler
+  CFLAGS += -lws2_32 -lbcrypt   # Link against Winsock library
+  DELETE = cmd /C del /Q /F /S  # Command prompt command to delete files
+  OUT ?= -o $(PROG)             # Build output
+endif
+
+all: $(PROG)              # Default target. Build and run program
+	$(RUN) ./$(PROG) $(ARGS)
+
+$(PROG): $(SOURCES)       # Build program from sources
+	$(CC) $(SOURCES) $(CFLAGS) $(CFLAGS_MONGOOSE) $(CFLAGS_EXTRA) $(OUT)
+
+vc98:
+	cl $(SOURCES) -DMG_ENABLE_SSI=1 -DMG_TLS=MG_TLS_BUILTIN
+
+clean:                    # Cleanup. Delete built program and all build artifacts
+	$(DELETE) $(PROG) *.o *.obj *.exe *.dSYM

tutorials/http/redirect-to-https/main.c

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+// Copyright (c) 2026 Cesanta Software Limited
+// All rights reserved
+
+#include "mongoose.h"
+
+static int s_debug_level = MG_LL_DEBUG;
+static const char *s_http_addr = "http://0.0.0.0:8000";
+static const char *s_https_addr = "https://0.0.0.0:8443";
+
+// Self signed certificates, see
+// https://github.com/cesanta/mongoose/blob/master/test/certs/generate.sh
+static const char *s_tls_cert =
+    "-----BEGIN CERTIFICATE-----\n"
+    "MIIBMTCB2aADAgECAgkAluqkgeuV/zUwCgYIKoZIzj0EAwIwEzERMA8GA1UEAwwI\n"
+    "TW9uZ29vc2UwHhcNMjQwNTA3MTQzNzM2WhcNMzQwNTA1MTQzNzM2WjARMQ8wDQYD\n"
+    "VQQDDAZzZXJ2ZXIwWTATBgcqhkjOPQIBBggqhkjOPQMBBwNCAASo3oEiG+BuTt5y\n"
+    "ZRyfwNr0C+SP+4M0RG2pYkb2v+ivbpfi72NHkmXiF/kbHXtgmSrn/PeTqiA8M+mg\n"
+    "BhYjDX+zoxgwFjAUBgNVHREEDTALgglsb2NhbGhvc3QwCgYIKoZIzj0EAwIDRwAw\n"
+    "RAIgTXW9MITQSwzqbNTxUUdt9DcB+8pPUTbWZpiXcA26GMYCIBiYw+DSFMLHmkHF\n"
+    "+5U3NXW3gVCLN9ntD5DAx8LTG8sB\n"
+    "-----END CERTIFICATE-----\n";
+
+static const char *s_tls_key =
+    "-----BEGIN EC PRIVATE KEY-----\n"
+    "MHcCAQEEIAVdo8UAScxG7jiuNY2UZESNX/KPH8qJ0u0gOMMsAzYWoAoGCCqGSM49\n"
+    "AwEHoUQDQgAEqN6BIhvgbk7ecmUcn8Da9Avkj/uDNERtqWJG9r/or26X4u9jR5Jl\n"
+    "4hf5Gx17YJkq5/z3k6ogPDPpoAYWIw1/sw==\n"
+    "-----END EC PRIVATE KEY-----\n";
+
+// HTTPS listener serves requests
+static void https_ev_handler(struct mg_connection *c, int ev, void *ev_data) {
+  if (ev == MG_EV_ACCEPT && c->is_tls) {
+    struct mg_tls_opts opts;
+    memset(&opts, 0, sizeof(opts));
+    opts.cert = mg_str(s_tls_cert);
+    opts.key = mg_str(s_tls_key);
+    mg_tls_init(c, &opts);
+  }
+
+  if (ev == MG_EV_HTTP_MSG) {
+    struct mg_http_message *hm = (struct mg_http_message *) ev_data;
+    if (mg_match(hm->uri, mg_str("/api/hello"), NULL)) {
+      mg_http_reply(c, 200, "", "{%m:%d}\n", MG_ESC("status"), 1);
+    } else {
+      mg_http_reply(c, 200, "", "Hi! Curent time is %llu", mg_now());
+    }
+  }
+}
+
+// HTTP listener sends redirects to HTTPS
+static void http_ev_handler(struct mg_connection *c, int ev, void *ev_data) {
+  if (ev == MG_EV_HTTP_MSG) {
+    struct mg_http_message *hm = (struct mg_http_message *) ev_data;
+    char buf[256];
+    mg_snprintf(buf, sizeof(buf), "Location: %s%.*s\r\n", s_https_addr,
+                hm->uri.len, hm->uri.buf);
+    mg_http_reply(c, 302, buf, "%s", buf);  // 302 redirect
+  }
+}
+
+int main(void) {
+  struct mg_mgr mgr;
+
+  mg_log_set(s_debug_level);
+  mg_mgr_init(&mgr);
+
+  if (mg_http_listen(&mgr, s_http_addr, http_ev_handler, NULL) == NULL) {
+    exit(EXIT_FAILURE);
+  }
+
+  if (mg_http_listen(&mgr, s_https_addr, https_ev_handler, NULL) == NULL) {
+    exit(EXIT_FAILURE);
+  }
+
+  MG_INFO(("Mongoose version : v%s", MG_VERSION));
+  MG_INFO(("HTTP listener    : %s", s_http_addr));
+  MG_INFO(("HTTPS listener   : %s", s_https_addr));
+  for (;;) {
+    mg_mgr_poll(&mgr, 1000);
+  }
+
+  mg_mgr_free(&mgr);
+  return 0;
+}

tutorials/http/redirect-to-https/mongoose.c

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+../../../mongoose.c

tutorials/http/redirect-to-https/mongoose.h

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+../../../mongoose.h