Use gzip fallback for WebConfig clients

scripts/generate_webconfig_html.py

@@ -1,8 +1,8 @@
 #!/usr/bin/env python
 #
-# Pre-build script: Brotli-compress webui/index.html into a PROGMEM C header so the
+# Pre-build script: compress webui/index.html into a PROGMEM C header so the
 # webconfig portal can serve the page straight from flash with
-# Content-Encoding: br. The generated header is tracked so ESP32 targets
+# Content-Encoding: br or gzip. The generated header is tracked so ESP32 targets
 # that replace extra_scripts still compile from a clean checkout; this script
 # rewrites it only when the emitted firmware bytes actually change.
 #
@@ -12,8 +12,8 @@
 #
 # Output: src/helpers/esp32/WebConfigHtml.h
 #   WEBCONFIG_HTML_LOADER[] - small bootstrap page (PROGMEM)
-#   WEBCONFIG_HTML_RAW[]    - complete stripped page (PROGMEM)
 #   WEBCONFIG_HTML_BR[]     - complete Brotli-compressed page (PROGMEM)
+#   WEBCONFIG_HTML_GZ[]     - complete gzip-compressed page (PROGMEM)
 #   WEBCONFIG_HTML_ETAG     - quoted strong ETag for the loader page
 #
 # Runnable outside SCons to inspect exactly what gets shipped:
@@ -21,6 +21,7 @@
 # or served directly by the mock backend with its --minify flag.
 
 import hashlib
+import gzip
 import os
 import sys
 
@@ -92,6 +93,7 @@ def main():
     src_hash = content_hash(raw)
 
     br = compress_html(raw)
+    gz = gzip.compress(raw, compresslevel=9, mtime=0)
     version = hashlib.sha256(br).hexdigest()[:16]
     loader = ("<!doctype html><meta charset=utf-8><meta name=viewport "
               "content=\"width=device-width,initial-scale=1\"><title>MeshCore "
@@ -112,24 +114,24 @@ def main():
     lines = []
     lines.append("// Auto-generated by scripts/generate_webconfig_html.py from %s" % SOURCE.replace(os.sep, "/"))
     lines.append("// DO NOT EDIT - edit webui/index.html instead.")
-    lines.append("// Compressed with Google Brotli %s (quality %d, lgwin %d)." %
+    lines.append("// Compressed with Google Brotli %s (quality %d, lgwin %d) and gzip." %
                  (BROTLI_VERSION, QUALITY, LGWIN))
     lines.append("%s%s" % (HASH_MARKER, src_hash))
     lines.append("#pragma once")
     lines.append("#include <stdint.h>")
     lines.append("#include <pgmspace.h>")
     lines.append("")
-    lines.append("const uint32_t WEBCONFIG_HTML_RAW_LEN = %d;" % len(raw))
     lines.append("const uint32_t WEBCONFIG_HTML_BR_LEN = %d;" % len(br))
+    lines.append("const uint32_t WEBCONFIG_HTML_GZ_LEN = %d;" % len(gz))
     lines.append('const char WEBCONFIG_HTML_ETAG[] = "\\"%s\\"";' % etag)
     lines.append('const char WEBCONFIG_HTML_VERSION[] = "%s";' % version)
     lines.append("const uint16_t WEBCONFIG_HTML_LOADER_LEN = %d;" % len(loader_bytes))
     append_byte_array(lines, "WEBCONFIG_HTML_LOADER", loader_bytes)
     lines.append("")
-    append_byte_array(lines, "WEBCONFIG_HTML_RAW", raw)
-    lines.append("")
     append_byte_array(lines, "WEBCONFIG_HTML_BR", br)
     lines.append("")
+    append_byte_array(lines, "WEBCONFIG_HTML_GZ", gz)
+    lines.append("")
 
     rendered = "\n".join(lines)
     try:
@@ -143,8 +145,8 @@ def main():
     with open(OUTPUT, "w", encoding="utf-8", newline="") as f:
         f.write(rendered)
 
-    status("%s -> %s (%d bytes source, %d stripped, %d Brotli)"
-           % (SOURCE, OUTPUT, len(src.encode("utf-8")), len(raw), len(br)))
+    status("%s -> %s (%d bytes source, %d stripped, %d Brotli, %d gzip)"
+           % (SOURCE, OUTPUT, len(src.encode("utf-8")), len(raw), len(br), len(gz)))
 
 
 # This script is attached only to esp32_base. Generate unconditionally here:

src/helpers/esp32/WebConfigServer.cpp

@@ -1647,7 +1647,8 @@ void WebConfigServer::handleRoot(AsyncWebServerRequest* req) {
   req->send(res);
 }
 
-static bool webConfigClientAcceptsBrotli(AsyncWebServerRequest* req) {
+static bool webConfigClientAcceptsEncoding(AsyncWebServerRequest* req,
+                                           const char* wanted) {
   if (!req || !req->hasHeader("Accept-Encoding")) return false;
   String encodings = req->getHeader("Accept-Encoding")->value();
   encodings.toLowerCase();
@@ -1660,7 +1661,7 @@ static bool webConfigClientAcceptsBrotli(AsyncWebServerRequest* req) {
     int semi = item.indexOf(';');
     String coding = semi < 0 ? item : item.substring(0, semi);
     coding.trim();
-    if (coding == "br") {
+    if (coding == wanted || coding == "*") {
       if (semi < 0) return true;
       String params = item.substring(semi + 1);
       params.trim();
@@ -1686,7 +1687,7 @@ void WebConfigServer::handleUi(AsyncWebServerRequest* req) {
     return;
   }
   AsyncWebServerResponse* res = nullptr;
-  if (webConfigClientAcceptsBrotli(req)) {
+  if (webConfigClientAcceptsEncoding(req, "br")) {
     res = new WebConfigPacedProgmemResponse("text/html; charset=utf-8",
                                              WEBCONFIG_HTML_BR,
                                              WEBCONFIG_HTML_BR_LEN);
@@ -1694,12 +1695,16 @@ void WebConfigServer::handleUi(AsyncWebServerRequest* req) {
     // precompressed bytes.
     res->addHeader("Content-Encoding", "br");
     res->addHeader("Cache-Control", "public, max-age=31536000, immutable");
-  } else {
-    // Never send Brotli to clients that did not advertise support for it.
+  } else if (webConfigClientAcceptsEncoding(req, "gzip")) {
     res = new WebConfigPacedProgmemResponse("text/html; charset=utf-8",
-                                             WEBCONFIG_HTML_RAW,
-                                             WEBCONFIG_HTML_RAW_LEN);
+                                             WEBCONFIG_HTML_GZ,
+                                             WEBCONFIG_HTML_GZ_LEN);
+    res->addHeader("Content-Encoding", "gzip");
     res->addHeader("Cache-Control", "no-cache");
+  } else {
+    req->send(406, "text/plain",
+              "WebConfig requires Brotli or gzip support");
+    return;
   }
   req->send(res);
 }