Page Hotreloading

.gitmodules

@@ -7,3 +7,12 @@
 [submodule "incbin"]
 	path = incbin
 	url = https://github.com/graphitemaster/incbin.git
+[submodule "build-id"]
+	path = build-id
+	url = https://github.com/mattst88/build-id.git
+[submodule "cJSON"]
+	path = cJSON
+	url = https://github.com/DaveGamble/cJSON.git
+[submodule "md5-c"]
+	path = md5-c
+	url = https://github.com/Zunawe/md5-c.git

baked.c

@@ -13,6 +13,7 @@ INCBIN(page_missing_t, "./tmpls/page-missing.t");
 
 INCBIN(simple_min_css, "./etc/simple.min.css");
 INCBIN(favicon_ico, "./etc/favicon.ico");
+INCBIN(hotreload_js, "./etc/hotreload.js");
 
 Baked_Resource *baked_resources = NULL;
 
@@ -34,6 +35,7 @@ void init_baked_resources(void)
     add_baked_resource("gpp1", gpp1_data, gpp1_size);
     add_baked_resource("simple.min.css", simple_min_css_data, simple_min_css_size);
     add_baked_resource("favicon.ico", favicon_ico_data, favicon_ico_size);
+    add_baked_resource("hotreload.js", hotreload_js_data, hotreload_js_size);
 }
 
 void free_baked_resources(void)

baked.h

@@ -10,6 +10,7 @@ INCBIN_EXTERN(page_missing_t);
 
 INCBIN_EXTERN(simple_min_css);
 INCBIN_EXTERN(favicon_ico);
+INCBIN_EXTERN(hotreload_js);
 
 typedef struct {
     char *key;  // path

build.c

@@ -20,7 +20,8 @@ int main(int argc, char ** argv)
                 "./mongoose.o",
                 "./gpp1",
                 "./tmpls/home.t",
-                "./tmpls/page-missing.t"
+                "./tmpls/page-missing.t",
+                "./etc/hotreload.js"
         ) {
 
             RULE("./mongoose.o", "./mongoose/mongoose.c") {
@@ -36,13 +37,15 @@ int main(int argc, char ** argv)
             }
 
             #if DEBUG
-                CMD("cc", "-fPIC", "-ggdb", "-I.", "-D_GNU_SOURCE", "-DGEBS_NO_PREFIX",
+                CMD("cc", "-fPIC", "-ggdb", "-I.", "-DDEBUG=1", "-D_GNU_SOURCE", "-DGEBS_NO_PREFIX",
                     "-DINCBIN_PREFIX=", "-DINCBIN_STYLE=INCBIN_STYLE_SNAKE", "-o", "./aboba",
-                    "./main.c", "./routes.c", "./baked.c", "./mongoose.o");
+                    "./main.c", "./routes.c", "./baked.c", "./mongoose.o", "./cJSON/cJSON.c",
+                    "./md5-c/md5.c");
             #else
                 CMD("cc", "-fPIC", "-I.", "-D_GNU_SOURCE", "-DGEBS_NO_PREFIX",
                     "-DINCBIN_PREFIX=", "-DINCBIN_STYLE=INCBIN_STYLE_SNAKE", "-o", "./aboba",
-                    "./main.c", "./routes.c", "./baked.c", "./mongoose.o");
+                    "./main.c", "./routes.c", "./baked.c", "./mongoose.o", "./cJSON/cJSON.c",
+                    "./md5-c/md5.c");
             #endif
         }
     } else if (strcmp(cmd, "clean") == 0) {

etc/hotreload.js

@@ -0,0 +1,47 @@
+let build_id = "";
+
+async function fetch_build_id()
+{
+    const response = await fetch("/build-id");
+    const json = await response.json();
+    return json.build_id;
+}
+
+(async function() {
+    build_id = await fetch_build_id();
+})();
+
+
+const asyncIntervals = [];
+
+const runAsyncInterval = async (cb, interval, intervalIndex) => {
+  await cb();
+  if (asyncIntervals[intervalIndex]) {
+    setTimeout(() => runAsyncInterval(cb, interval, intervalIndex), interval);
+  }
+};
+
+const setAsyncInterval = (cb, interval) => {
+  if (cb && typeof cb === "function") {
+    const intervalIndex = asyncIntervals.length;
+    asyncIntervals.push(true);
+    runAsyncInterval(cb, interval, intervalIndex);
+    return intervalIndex;
+  } else {
+    throw new Error('Callback must be a function');
+  }
+};
+
+const clearAsyncInterval = (intervalIndex) => {
+  if (asyncIntervals[intervalIndex]) {
+    asyncIntervals[intervalIndex] = false;
+  }
+};
+
+setAsyncInterval(async function () {
+    let new_build_id = await fetch_build_id();
+    if (build_id !== new_build_id) {
+        location.reload(true);
+    }
+}, 1000);
+

main.c

@@ -2,9 +2,7 @@
 
 #define GEBS_IMPLEMENTATION
 #include "gebs/gebs.h"
-
 #include "mongoose/mongoose.h"
-
 #define STB_DS_IMPLEMENTATION
 #include "stb/stb_ds.h"
 
@@ -32,13 +30,15 @@ void event_handler(struct mg_connection *conn, int ev, void *ev_data)
     }
 }
 
-static void init_route_hashtable(void)
+void init_route_hashtable(void)
 {
     shdefault(route_hashtable, &route_page_not_found);
     shput(route_hashtable,      "/page-missing",        &route_page_not_found);
     shput(route_hashtable,      "/simple.min.css",      &route_simple_css);
     shput(route_hashtable,      "/favicon.ico",         &route_favicon);
+    shput(route_hashtable,      "/hotreload.js",        &route_hotreload_js);
     shput(route_hashtable,      "/",                    &route_home);
+    shput(route_hashtable,      "/build-id",            &route_build_id);
 }
 
 int main(int argc, char ** argv)

routes.c

@@ -1,5 +1,7 @@
 #include "gebs/gebs.h"
 #include "mongoose/mongoose.h"
+#include "cJSON/cJSON.h"
+#include "md5-c/md5.h"
 
 #include "routes.h"
 #include "baked.h"
@@ -29,6 +31,31 @@ bool gpp_run(char *path, NString_List *env, String_Builder *out)
     return cmd_run_collect(&cmd, out) == 0;
 }
 
+void route_build_id(struct mg_connection *conn, struct mg_http_message *msg)
+{
+    cJSON *root = cJSON_CreateObject();
+    defer { cJSON_Delete(root); }
+
+    char *time = __TIME__;
+    uchar md5_buf[16];
+    md5String(time, md5_buf);
+    String_Builder sb = {0};
+    defer { sb_free(&sb); }
+    for (size_t i = 0; i < 16; i++) {
+        char tmp[3];
+        snprintf(tmp, sizeof(tmp), "%02x", md5_buf[i]);
+        sb_append_nstr(&sb, tmp);
+    }
+    sb_finish(&sb);
+
+    cJSON_AddItemToObject(root, "build_id", cJSON_CreateString(sb.items));
+
+    char *root_text = cJSON_PrintUnformatted(root);
+    defer { free(root_text); }
+
+    mg_http_reply(conn, 200, "Content-Type: application/json\r\n", root_text);
+}
+
 void route_page_not_found(struct mg_connection *conn, struct mg_http_message *msg)
 {
     NString_List env = {0};
@@ -45,6 +72,12 @@ void route_page_not_found(struct mg_connection *conn, struct mg_http_message *ms
         return;
     }
     
+    #if DEBUG
+        list_append(&env, "-DHOTRELOAD=1");
+    #else
+        list_append(&env, "-DHOTRELOAD=0");
+    #endif
+
     bool ok = gpp_run(path, &env, &out);
     sb_finish(&out);
 
@@ -93,6 +126,25 @@ void route_favicon(struct mg_connection *conn, struct mg_http_message *msg)
     mg_http_reply(conn, 200, "Content-Type: image/x-icon\r\n", "%s", sb.items);
 }
 
+void route_hotreload_js(struct mg_connection *conn, struct mg_http_message *msg)
+{
+    char path[PATH_MAX] = {0};
+    if (!get_baked_resource_path("hotreload.js", path, sizeof(path))) {
+        mg_http_reply(conn, 500, "Content-Type: text/plain\r\n", INTERNAL_SERVER_ERROR_MSG);
+        return;
+    }
+
+    String_Builder sb = {0};
+    defer { sb_free(&sb); }
+    if (!sb_read_file(&sb, path)) {
+        mg_http_reply(conn, 500, "Content-Type: text/plain\r\n", INTERNAL_SERVER_ERROR_MSG);
+        return;
+    }
+    sb_finish(&sb);
+
+    mg_http_reply(conn, 200, "Content-Type: text/javascript\r\n", "%s", sb.items);
+}
+
 void route_home(struct mg_connection *conn, struct mg_http_message *msg)
 {
     NString_List env = {0};
@@ -107,6 +159,12 @@ void route_home(struct mg_connection *conn, struct mg_http_message *msg)
         return;
     }
 
+    #if DEBUG
+        list_append(&env, "-DHOTRELOAD=1");
+    #else
+        list_append(&env, "-DHOTRELOAD=0");
+    #endif
+
     bool ok = gpp_run(path, &env, &out);
     sb_finish(&out);
 

routes.h

@@ -6,6 +6,8 @@
 void route_page_not_found(struct mg_connection *conn, struct mg_http_message *msg);
 void route_simple_css(struct mg_connection *conn, struct mg_http_message *msg);
 void route_favicon(struct mg_connection *conn, struct mg_http_message *msg);
+void route_hotreload_js(struct mg_connection *conn, struct mg_http_message *msg);
 void route_home(struct mg_connection *conn, struct mg_http_message *msg);
+void route_build_id(struct mg_connection *conn, struct mg_http_message *msg);
 
 #endif // ROUTES_H_

tmpls/home.t

@@ -41,5 +41,9 @@
         <footer>
             <a href="/">HOME</a>
         </footer>
+
+        <#if HOTRELOAD>
+            <script src="/hotreload.js"></script>
+        <#endif>
     </body>
 </html>

tmpls/page-missing.t

@@ -12,5 +12,9 @@
         <footer>
             <a href="/">HOME</a>
         </footer>
+        
+        <#if HOTRELOAD>
+            <script src="/hotreload.js"></script>
+        <#endif>
     </body>
 </html>