HttpServer Firmware Upload

This example combines the libraries Multipart Parser for file uploads and Over-the-Air Firmware Upgrade, to create a browser based firmware upgrade solution akin to what’s found in many consumer devices. The example is kept as minimal as possible to serve as a starting point for your own applications.

About HTTP server file upload

The HTTP server coming with Sming is quite powerful but it is limited by the available resources of the underlining hardware (your favorite ESP8266 microcontroller).

This sample demonstrates how to use the Multipart Parser library to enable file upload of the HTTP server. On a normal computer the file uploads are usually using temporary space on the hard disk or in memory to store the incoming data.

On an embedded device that is a luxury that we can hardly afford. In this sample we demonstrate how to define which file upload fields should be recognized and what (file) streams are responsible for processing and storing the data. If a field is not specified then its content will be discarded.

About OtaUpgrade

The OtaUpgrade component provides the OtaUpgradeStream class which is hooked up to the web server to process a firmware upgrade file uploaded to the device. The component is also responsible for creating the upgrade files during the build process. A single upgrade file conveniently encapsulates all ROM images, thereby relieving the user from having to know the slot that is updated and manually selecting the corresponding ROM image in a Two-ROM configuration. The file format also supports state-of-the-art security features like a digital signature, encryption and downgrade protection. You are invited to play with them and observe their impact on code size. See also the Over-the-Air Firmware Upgrade documentation for further advice on how to use the security features properly.

Usage instructions

  1. Configure your flash memory layout. See Hardware configuration.

  2. Build the example by running:

  3. Connect your device via USB/Serial cable and run:

    make flashconfig

    to clear any remains of the previous flash layout configuration, followed by:

    make flash

    to install the example firmware. You need to do this only once. Subsequent updates can be performed wirelessly using the web interface.

  4. Point the browser to your ESP’s IP address to open the firmware upgrade page.

  5. Select the upgrade file, which has been automatically created alongside step 2 from out/Esp8266/<build-type>/firmware/firmware.ota and hit the “Update” button.

    After a few seconds, you should see a confirmation the the upgrade was successful. The device now reboots into the upgraded firmware.

    If the upgrade is not successful, rebuild with debug output enabled and check the serial console for error messages.


SoC support

  • esp32

  • esp32c2

  • esp32c3

  • esp32s2

  • esp32s3

  • esp8266

  • host

  • rp2040