feat: added support for filters in WebServer library (#9842)

* feat: added support for filters in webserver

* feat: add setFilter function in StaticRequestHandler

* fix: ON_STA_FILTER & ON_AP_FILTER

* fix: make request handlers backward compatible

* fix: ON_STA_FILTER & ON_AP_FILTER

* fix: more filters to their own example

* chore: grammar

* fix: remove filters from header file

* fix: use same root route for both interfaces

* ci(pre-commit): Apply automatic fixes

---------

Co-authored-by: pre-commit-ci-lite[bot] <117423508+pre-commit-ci-lite[bot]@users.noreply.github.com>

libraries/WebServer/examples/Filters/Filters.ino

@@ -0,0 +1,110 @@
+#include <WiFi.h>
+#include <NetworkClient.h>
+#include <WebServer.h>
+#include <ESPmDNS.h>
+
+// Your STA WiFi Credentials
+// ( This is the AP your ESP will connect to )
+const char *ssid = "........";
+const char *password = "........";
+
+// Your AP WiFi Credentials
+// ( This is the AP your ESP will broadcast )
+const char *ap_ssid = "ESP32_Demo";
+const char *ap_password = "";
+
+WebServer server(80);
+
+const int led = 13;
+
+// ON_STA_FILTER - Only accept requests coming from STA interface
+bool ON_STA_FILTER(WebServer &server) {
+  return WiFi.STA.hasIP() && WiFi.STA.localIP() == server.client().localIP();
+}
+
+// ON_AP_FILTER - Only accept requests coming from AP interface
+bool ON_AP_FILTER(WebServer &server) {
+  return WiFi.AP.hasIP() && WiFi.AP.localIP() == server.client().localIP();
+}
+
+void handleNotFound() {
+  digitalWrite(led, 1);
+  String message = "File Not Found\n\n";
+  message += "URI: ";
+  message += server.uri();
+  message += "\nMethod: ";
+  message += (server.method() == HTTP_GET) ? "GET" : "POST";
+  message += "\nArguments: ";
+  message += server.args();
+  message += "\n";
+  for (uint8_t i = 0; i < server.args(); i++) {
+    message += " " + server.argName(i) + ": " + server.arg(i) + "\n";
+  }
+  server.send(404, "text/plain", message);
+  digitalWrite(led, 0);
+}
+
+void setup(void) {
+  pinMode(led, OUTPUT);
+  digitalWrite(led, 0);
+  Serial.begin(115200);
+  WiFi.mode(WIFI_AP_STA);
+  // Connect to STA
+  WiFi.begin(ssid, password);
+  // Start AP
+  WiFi.softAP(ap_ssid, ap_password);
+  Serial.println("");
+
+  // Wait for connection
+  while (WiFi.status() != WL_CONNECTED) {
+    delay(500);
+    Serial.print(".");
+  }
+  Serial.println("");
+  Serial.print("Connected to ");
+  Serial.println(ssid);
+  Serial.print("IP address: ");
+  Serial.println(WiFi.localIP());
+
+  if (MDNS.begin("esp32")) {
+    Serial.println("MDNS responder started");
+  }
+
+  // This route will be accessible by STA clients only
+  server
+    .on(
+      "/",
+      [&]() {
+        digitalWrite(led, 1);
+        server.send(200, "text/plain", "Hi!, This route is accessible for STA clients only");
+        digitalWrite(led, 0);
+      }
+    )
+    .setFilter(ON_STA_FILTER);
+
+  // This route will be accessible by AP clients only
+  server
+    .on(
+      "/",
+      [&]() {
+        digitalWrite(led, 1);
+        server.send(200, "text/plain", "Hi!, This route is accessible for AP clients only");
+        digitalWrite(led, 0);
+      }
+    )
+    .setFilter(ON_AP_FILTER);
+
+  server.on("/inline", []() {
+    server.send(200, "text/plain", "this works as well");
+  });
+
+  server.onNotFound(handleNotFound);
+
+  server.begin();
+  Serial.println("HTTP server started");
+}
+
+void loop(void) {
+  server.handleClient();
+  delay(2);  //allow the cpu to switch to other tasks
+}

libraries/WebServer/examples/Filters/ci.json

@@ -0,0 +1,5 @@
+{
+  "targets": {
+    "esp32h2": false
+  }
+}

libraries/WebServer/src/Parsing.cpp

@@ -124,7 +124,7 @@ bool WebServer::_parseRequest(NetworkClient &client) {
   //attach handler
   RequestHandler *handler;
   for (handler = _firstHandler; handler; handler = handler->next()) {
-    if (handler->canHandle(_currentMethod, _currentUri)) {
+    if (handler->canHandle(*this, _currentMethod, _currentUri)) {
       break;
     }
   }
@@ -176,7 +176,7 @@ bool WebServer::_parseRequest(NetworkClient &client) {
       }
     }
 
-    if (!isForm && _currentHandler && _currentHandler->canRaw(_currentUri)) {
+    if (!isForm && _currentHandler && _currentHandler->canRaw(*this, _currentUri)) {
       log_v("Parse raw");
       _currentRaw.reset(new HTTPRaw());
       _currentRaw->status = RAW_START;
@@ -334,7 +334,7 @@ void WebServer::_parseArguments(String data) {
 
 void WebServer::_uploadWriteByte(uint8_t b) {
   if (_currentUpload->currentSize == HTTP_UPLOAD_BUFLEN) {
-    if (_currentHandler && _currentHandler->canUpload(_currentUri)) {
+    if (_currentHandler && _currentHandler->canUpload(*this, _currentUri)) {
       _currentHandler->upload(*this, _currentUri, *_currentUpload);
     }
     _currentUpload->totalSize += _currentUpload->currentSize;
@@ -449,7 +449,7 @@ bool WebServer::_parseForm(NetworkClient &client, String boundary, uint32_t len)
             _currentUpload->totalSize = 0;
             _currentUpload->currentSize = 0;
             log_v("Start File: %s Type: %s", _currentUpload->filename.c_str(), _currentUpload->type.c_str());
-            if (_currentHandler && _currentHandler->canUpload(_currentUri)) {
+            if (_currentHandler && _currentHandler->canUpload(*this, _currentUri)) {
               _currentHandler->upload(*this, _currentUri, *_currentUpload);
             }
             _currentUpload->status = UPLOAD_FILE_WRITE;
@@ -488,12 +488,12 @@ bool WebServer::_parseForm(NetworkClient &client, String boundary, uint32_t len)
               }
             }
             // Found the boundary string, finish processing this file upload
-            if (_currentHandler && _currentHandler->canUpload(_currentUri)) {
+            if (_currentHandler && _currentHandler->canUpload(*this, _currentUri)) {
               _currentHandler->upload(*this, _currentUri, *_currentUpload);
             }
             _currentUpload->totalSize += _currentUpload->currentSize;
             _currentUpload->status = UPLOAD_FILE_END;
-            if (_currentHandler && _currentHandler->canUpload(_currentUri)) {
+            if (_currentHandler && _currentHandler->canUpload(*this, _currentUri)) {
               _currentHandler->upload(*this, _currentUri, *_currentUpload);
             }
             log_v("End File: %s Type: %s Size: %d", _currentUpload->filename.c_str(), _currentUpload->type.c_str(), (int)_currentUpload->totalSize);
@@ -567,7 +567,7 @@ String WebServer::urlDecode(const String &text) {
 
 bool WebServer::_parseFormUploadAborted() {
   _currentUpload->status = UPLOAD_FILE_ABORTED;
-  if (_currentHandler && _currentHandler->canUpload(_currentUri)) {
+  if (_currentHandler && _currentHandler->canUpload(*this, _currentUri)) {
     _currentHandler->upload(*this, _currentUri, *_currentUpload);
   }
   return false;

libraries/WebServer/src/WebServer.cpp

@@ -306,16 +306,18 @@ void WebServer::requestAuthentication(HTTPAuthMethod mode, const char *realm, co
   send(401, String(FPSTR(mimeTable[html].mimeType)), authFailMsg);
 }
 
-void WebServer::on(const Uri &uri, WebServer::THandlerFunction handler) {
-  on(uri, HTTP_ANY, handler);
+RequestHandler &WebServer::on(const Uri &uri, WebServer::THandlerFunction handler) {
+  return on(uri, HTTP_ANY, handler);
 }
 
-void WebServer::on(const Uri &uri, HTTPMethod method, WebServer::THandlerFunction fn) {
-  on(uri, method, fn, _fileUploadHandler);
+RequestHandler &WebServer::on(const Uri &uri, HTTPMethod method, WebServer::THandlerFunction fn) {
+  return on(uri, method, fn, _fileUploadHandler);
 }
 
-void WebServer::on(const Uri &uri, HTTPMethod method, WebServer::THandlerFunction fn, WebServer::THandlerFunction ufn) {
-  _addRequestHandler(new FunctionRequestHandler(fn, ufn, uri, method));
+RequestHandler &WebServer::on(const Uri &uri, HTTPMethod method, WebServer::THandlerFunction fn, WebServer::THandlerFunction ufn) {
+  FunctionRequestHandler *handler = new FunctionRequestHandler(fn, ufn, uri, method);
+  _addRequestHandler(handler);
+  return *handler;
 }
 
 bool WebServer::removeRoute(const char *uri) {

libraries/WebServer/src/WebServer.h

@@ -144,9 +144,10 @@ public:
   void requestAuthentication(HTTPAuthMethod mode = BASIC_AUTH, const char *realm = NULL, const String &authFailMsg = String(""));
 
   typedef std::function<void(void)> THandlerFunction;
-  void on(const Uri &uri, THandlerFunction fn);
-  void on(const Uri &uri, HTTPMethod method, THandlerFunction fn);
-  void on(const Uri &uri, HTTPMethod method, THandlerFunction fn, THandlerFunction ufn);  //ufn handles file uploads
+  typedef std::function<bool(WebServer &server)> FilterFunction;
+  RequestHandler &on(const Uri &uri, THandlerFunction fn);
+  RequestHandler &on(const Uri &uri, HTTPMethod method, THandlerFunction fn);
+  RequestHandler &on(const Uri &uri, HTTPMethod method, THandlerFunction fn, THandlerFunction ufn);  //ufn handles file uploads
   bool removeRoute(const char *uri);
   bool removeRoute(const char *uri, HTTPMethod method);
   bool removeRoute(const String &uri);

libraries/WebServer/src/detail/RequestHandler.h

@@ -7,6 +7,11 @@
 class RequestHandler {
 public:
   virtual ~RequestHandler() {}
+
+  /*
+    note: old handler API for backward compatibility
+  */
+
   virtual bool canHandle(HTTPMethod method, String uri) {
     (void)method;
     (void)uri;
@@ -20,6 +25,27 @@ public:
     (void)uri;
     return false;
   }
+
+  /*
+    note: new handler API with support for filters etc.
+  */
+
+  virtual bool canHandle(WebServer &server, HTTPMethod method, String uri) {
+    (void)server;
+    (void)method;
+    (void)uri;
+    return false;
+  }
+  virtual bool canUpload(WebServer &server, String uri) {
+    (void)server;
+    (void)uri;
+    return false;
+  }
+  virtual bool canRaw(WebServer &server, String uri) {
+    (void)server;
+    (void)uri;
+    return false;
+  }
   virtual bool handle(WebServer &server, HTTPMethod requestMethod, String requestUri) {
     (void)server;
     (void)requestMethod;
@@ -37,6 +63,11 @@ public:
     (void)raw;
   }
 
+  virtual RequestHandler &setFilter(std::function<bool(WebServer &)> filter) {
+    (void)filter;
+    return *this;
+  }
+
   RequestHandler *next() {
     return _next;
   }

libraries/WebServer/src/detail/RequestHandlersImpl.h

@@ -36,6 +36,7 @@ public:
 
     return true;
   }
+
   bool canRaw(String requestUri) override {
     if (!_ufn || _method == HTTP_GET) {
       return false;
@@ -44,9 +45,32 @@ public:
     return true;
   }
 
+  bool canHandle(WebServer &server, HTTPMethod requestMethod, String requestUri) override {
+    if (_method != HTTP_ANY && _method != requestMethod) {
+      return false;
+    }
+
+    return _uri->canHandle(requestUri, pathArgs) && (_filter != NULL ? _filter(server) : true);
+  }
+
+  bool canUpload(WebServer &server, String requestUri) override {
+    if (!_ufn || !canHandle(server, HTTP_POST, requestUri)) {
+      return false;
+    }
+
+    return true;
+  }
+
+  bool canRaw(WebServer &server, String requestUri) override {
+    if (!_ufn || _method == HTTP_GET || (_filter != NULL ? _filter(server) == false : false)) {
+      return false;
+    }
+
+    return true;
+  }
+
   bool handle(WebServer &server, HTTPMethod requestMethod, String requestUri) override {
-    (void)server;
-    if (!canHandle(requestMethod, requestUri)) {
+    if (!canHandle(server, requestMethod, requestUri)) {
       return false;
     }
 
@@ -55,24 +79,30 @@ public:
   }
 
   void upload(WebServer &server, String requestUri, HTTPUpload &upload) override {
-    (void)server;
     (void)upload;
-    if (canUpload(requestUri)) {
+    if (canUpload(server, requestUri)) {
       _ufn();
     }
   }
 
   void raw(WebServer &server, String requestUri, HTTPRaw &raw) override {
-    (void)server;
     (void)raw;
-    if (canRaw(requestUri)) {
+    if (canRaw(server, requestUri)) {
       _ufn();
     }
   }
 
+  FunctionRequestHandler &setFilter(WebServer::FilterFunction filter) {
+    _filter = filter;
+    return *this;
+  }
+
 protected:
   WebServer::THandlerFunction _fn;
   WebServer::THandlerFunction _ufn;
+  // _filter should return 'true' when the request should be handled
+  // and 'false' when the request should be ignored
+  WebServer::FilterFunction _filter;
   Uri *_uri;
   HTTPMethod _method;
 };
@@ -100,8 +130,24 @@ public:
     return true;
   }
 
+  bool canHandle(WebServer &server, HTTPMethod requestMethod, String requestUri) override {
+    if (requestMethod != HTTP_GET) {
+      return false;
+    }
+
+    if ((_isFile && requestUri != _uri) || !requestUri.startsWith(_uri)) {
+      return false;
+    }
+
+    if (_filter != NULL ? _filter(server) == false : false) {
+      return false;
+    }
+
+    return true;
+  }
+
   bool handle(WebServer &server, HTTPMethod requestMethod, String requestUri) override {
-    if (!canHandle(requestMethod, requestUri)) {
+    if (!canHandle(server, requestMethod, requestUri)) {
       return false;
     }
 
@@ -197,7 +243,15 @@ public:
     return (result);
   }  // calcETag
 
+  StaticRequestHandler &setFilter(WebServer::FilterFunction filter) {
+    _filter = filter;
+    return *this;
+  }
+
 protected:
+  // _filter should return 'true' when the request should be handled
+  // and 'false' when the request should be ignored
+  WebServer::FilterFunction _filter;
   FS _fs;
   String _uri;
   String _path;