dox(examples): Added Upload example for text upload, binary upload and file upload

Author: mathieucarbou

examples/Upload/Upload.ino

@@ -0,0 +1,171 @@
+// SPDX-License-Identifier: LGPL-3.0-or-later
+// Copyright 2016-2025 Hristo Gochkov, Mathieu Carbou, Emil Muratov
+
+//
+// Demo text, binary and file upload
+//
+
+#include <Arduino.h>
+#ifdef ESP32
+#include <AsyncTCP.h>
+#include <WiFi.h>
+#elif defined(ESP8266)
+#include <ESP8266WiFi.h>
+#include <ESPAsyncTCP.h>
+#elif defined(TARGET_RP2040)
+#include <WebServer.h>
+#include <WiFi.h>
+#endif
+
+#include <ESPAsyncWebServer.h>
+#include <StreamString.h>
+#include <LittleFS.h>
+
+static AsyncWebServer server(80);
+
+void setup() {
+  Serial.begin(115200);
+
+  if (!LittleFS.begin()) {
+    LittleFS.format();
+    LittleFS.begin();
+  }
+
+#ifndef CONFIG_IDF_TARGET_ESP32H2
+  WiFi.mode(WIFI_AP);
+  WiFi.softAP("esp-captive");
+#endif
+
+  // 1. Generate a Lorem_ipsum.txt file of about 20KB of text
+  //
+  // 3. Run: curl -v -F "data=@Lorem_ipsum.txt" http://192.168.4.1/upload/text
+  //
+  server.on(
+    "/upload/text", HTTP_POST,
+    [](AsyncWebServerRequest *request) {
+      if (!request->_tempObject) {
+        return request->send(400, "text/plain", "Nothing uploaded");
+      }
+      StreamString *buffer = reinterpret_cast<StreamString *>(request->_tempObject);
+      Serial.printf("Text uploaded:\n%s\n", buffer->c_str());
+      delete buffer;
+      request->_tempObject = nullptr;
+      request->send(200, "text/plain", "OK");
+    },
+    [](AsyncWebServerRequest *request, String filename, size_t index, uint8_t *data, size_t len, bool final) {
+      Serial.printf("Upload[%s]: start=%u, len=%u, final=%d\n", filename.c_str(), index, len, final);
+
+      if (!index) {
+        // first pass
+        StreamString *buffer = new StreamString();
+        size_t size = std::max(4094l, request->header("Content-Length").toInt());
+        Serial.printf("Allocating string buffer of %u bytes\n", size);
+        if (!buffer->reserve(size)) {
+          delete buffer;
+          request->abort();
+        }
+        request->_tempObject = buffer;
+      }
+
+      if (len) {
+        reinterpret_cast<StreamString *>(request->_tempObject)->write(data, len);
+      }
+    }
+  );
+
+  // 1. Generate a Lorem_ipsum.txt file of about 20KB of text
+  //
+  // 3. Run: curl -v -F "data=@Lorem_ipsum.txt" http://192.168.4.1/upload/file
+  //
+  server.on(
+    "/upload/file", HTTP_POST,
+    [](AsyncWebServerRequest *request) {
+      if (request->getResponse()) {
+        // 400 File not available for writing
+        return;
+      }
+
+      if (!LittleFS.exists("/my_file.txt")) {
+        return request->send(400, "text/plain", "Nothing uploaded");
+      }
+
+      // sends back the uploaded file
+      request->send(LittleFS, "/my_file.txt", "text/plain");
+    },
+    [](AsyncWebServerRequest *request, String filename, size_t index, uint8_t *data, size_t len, bool final) {
+      Serial.printf("Upload[%s]: start=%u, len=%u, final=%d\n", filename.c_str(), index, len, final);
+
+      if (!index) {
+        request->_tempFile = LittleFS.open("/my_file.txt", "w");
+
+        if (!request->_tempFile) {
+          request->send(400, "text/plain", "File not available for writing");
+        }
+      }
+      if (len) {
+        request->_tempFile.write(data, len);
+      }
+      if (final) {
+        request->_tempFile.close();
+      }
+    }
+  );
+
+  //
+  // Upload a binary file: curl -v -F "[email protected]" http://192.168.4.1/upload/binary
+  //
+  server.on(
+    "/upload/binary", HTTP_POST,
+    [](AsyncWebServerRequest *request) {
+      // response already set ?
+      if (request->getResponse()) {
+        // 400 No Content-Length
+        return;
+      }
+
+      // nothing uploaded ?
+      if (!request->_tempObject) {
+        return request->send(400, "text/plain", "Nothing uploaded");
+      }
+
+      uint8_t *buffer = reinterpret_cast<uint8_t *>(request->_tempObject);
+      // process the buffer
+
+      delete buffer;
+      request->_tempObject = nullptr;
+
+      request->send(200, "text/plain", "OK");
+    },
+    [](AsyncWebServerRequest *request, String filename, size_t index, uint8_t *data, size_t len, bool final) {
+      Serial.printf("Upload[%s]: start=%u, len=%u, final=%d\n", filename.c_str(), index, len, final);
+
+      // first pass ?
+      if (!index) {
+        size_t size = request->header("Content-Length").toInt();
+        if (!size) {
+          request->send(400, "text/plain", "No Content-Length");
+        } else {
+          Serial.printf("Allocating buffer of %u bytes\n", size);
+          uint8_t *buffer = new (std::nothrow) uint8_t[size];
+          if (!buffer) {
+            // not enough memory
+            request->abort();
+          } else {
+            request->_tempObject = buffer;
+          }
+        }
+      }
+
+      if (len) {
+        memcpy(reinterpret_cast<uint8_t *>(request->_tempObject) + index, data, len);
+      }
+    }
+  );
+
+  server.begin();
+}
+
+// not needed
+void loop() {
+  delay(100);
+}

platformio.ini

@@ -28,6 +28,7 @@ src_dir = examples/PerfTests
 ; src_dir = examples/SlowChunkResponse
 ; src_dir = examples/StaticFile
 ; src_dir = examples/Templates
+; src_dir = examples/Upload
 ; src_dir = examples/WebSocket
 
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