├── README.md
└── WebOTA.ino


/README.md:
--------------------------------------------------------------------------------
1 | # webota-esp32
2 | 
3 | Full tutorial: https://www.teachmemicro.com/update-esp32-firmware-external-web-server/
4 | 
5 | 
6 | Notes:
7 |   - doesn't support https remote location for firmware file (for now)
8 | 


--------------------------------------------------------------------------------
/WebOTA.ino:
--------------------------------------------------------------------------------
 1 | /* WebOTA.ino
 2 |  *  
 3 |  * by Roland Pelayo 
 4 |  * 
 5 |  * Update ESP32 firmware via external web server
 6 |  */
 7 |  
 8 | #include <WiFi.h>
 9 | #include <HTTPClient.h>
10 | #include <Update.h>
11 | 
12 | // location of firmware file on external web server
13 | // change to your actual .bin location
14 | #define HOST "http://server.com/esp32fw.bin"
15 | 
16 | HTTPClient client;
17 | // Your WiFi credentials
18 | const char* ssid = "Your WiFi SSID";
19 | const char* password = "Your WiFi Password";
20 | // Global variables
21 | int totalLength;       //total size of firmware
22 | int currentLength = 0; //current size of written firmware
23 | 
24 | void setup() {
25 |   Serial.begin(9600);
26 |   // Start WiFi connection
27 |   WiFi.mode(WIFI_MODE_STA);        
28 |   WiFi.begin(ssid, password);
29 |   while (WiFi.status() != WL_CONNECTED) {
30 |       delay(500);
31 |       Serial.print(".");
32 |   }
33 | 
34 |   Serial.println("");
35 |   Serial.println("WiFi connected");
36 |   Serial.println("IP address: ");
37 |   Serial.println(WiFi.localIP());
38 |   // Connect to external web server
39 |   client.begin(HOST);
40 |   // Get file, just to check if each reachable
41 |   int resp = client.GET();
42 |   Serial.print("Response: ");
43 |   Serial.println(resp);
44 |   // If file is reachable, start downloading
45 |   if(resp == 200){
46 |       // get length of document (is -1 when Server sends no Content-Length header)
47 |       totalLength = client.getSize();
48 |       // transfer to local variable
49 |       int len = totalLength;
50 |       // this is required to start firmware update process
51 |       Update.begin(UPDATE_SIZE_UNKNOWN);
52 |       Serial.printf("FW Size: %u\n",totalLength);
53 |       // create buffer for read
54 |       uint8_t buff[128] = { 0 };
55 |       // get tcp stream
56 |       WiFiClient * stream = client.getStreamPtr();
57 |       // read all data from server
58 |       Serial.println("Updating firmware...");
59 |       while(client.connected() && (len > 0 || len == -1)) {
60 |            // get available data size
61 |            size_t size = stream->available();
62 |            if(size) {
63 |               // read up to 128 byte
64 |               int c = stream->readBytes(buff, ((size > sizeof(buff)) ? sizeof(buff) : size));
65 |               // pass to function
66 |               updateFirmware(buff, c);
67 |               if(len > 0) {
68 |                  len -= c;
69 |               }
70 |            }
71 |            delay(1);
72 |       }
73 |   }else{
74 |     Serial.println("Cannot download firmware file. Only HTTP response 200: OK is supported. Double check firmware location #defined in HOST.");
75 |   }
76 |   client.end();
77 |   
78 | }
79 | 
80 | void loop() {}
81 | 
82 | // Function to update firmware incrementally
83 | // Buffer is declared to be 128 so chunks of 128 bytes
84 | // from firmware is written to device until server closes
85 | void updateFirmware(uint8_t *data, size_t len){
86 |   Update.write(data, len);
87 |   currentLength += len;
88 |   // Print dots while waiting for update to finish
89 |   Serial.print('.');
90 |   // if current length of written firmware is not equal to total firmware size, repeat
91 |   if(currentLength != totalLength) return;
92 |   Update.end(true);
93 |   Serial.printf("\nUpdate Success, Total Size: %u\nRebooting...\n", currentLength);
94 |   // Restart ESP32 to see changes 
95 |   ESP.restart();
96 | }
97 | 


--------------------------------------------------------------------------------