Problem:
When using ESPAsyncWebserver with websockets, you see the following error messages while linking:
Linking .pio/build/esp32dev/firmware.elf /home/uli/.platformio/packages/[email protected]+2021r2-patch3/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld: .pio/build/esp32dev/lib67a/libESP Async WebServer.a(AsyncWebSocket.cpp.o):(.literal._ZN22AsyncWebSocketResponseC2ERK6StringP14AsyncWebSocket+0x10): undefined reference to `SHA1Init' /home/uli/.platformio/packages/[email protected]+2021r2-patch3/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld: .pio/build/esp32dev/lib67a/libESP Async WebServer.a(AsyncWebSocket.cpp.o):(.literal._ZN22AsyncWebSocketResponseC2ERK6StringP14AsyncWebSocket+0x18): undefined reference to `SHA1Update' /home/uli/.platformio/packages/[email protected]+2021r2-patch3/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld: .pio/build/esp32dev/lib67a/libESP Async WebServer.a(AsyncWebSocket.cpp.o):(.literal._ZN22AsyncWebSocketResponseC2ERK6StringP14AsyncWebSocket+0x1c): undefined reference to `SHA1Final' /home/uli/.platformio/packages/[email protected]+2021r2-patch3/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld: .pio/build/esp32dev/lib67a/libESP Async WebServer.a(AsyncWebSocket.cpp.o): in function `AsyncWebSocketResponse::AsyncWebSocketResponse(String const&, AsyncWebSocket*)': /home/uli/dev/My-Firmware/.pio/libdeps/esp32dev/ESP Async WebServer/src/AsyncWebSocket.cpp:1269: undefined reference to `SHA1Init' /home/uli/.platformio/packages/[email protected]+2021r2-patch3/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld: /home/uli/dev/My-Firmware/.pio/libdeps/esp32dev/ESP Async WebServer/src/AsyncWebSocket.cpp:1270: undefined reference to `SHA1Update' /home/uli/.platformio/packages/[email protected]+2021r2-patch3/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld: /home/uli/dev/My-Firmware/.pio/libdeps/esp32dev/ESP Async WebServer/src/AsyncWebSocket.cpp:1271: undefined reference to `SHA1Final' /home/uli/.platformio/packages/[email protected]+2021r2-patch3/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld: .pio/build/esp32dev/lib67a/libESP Async WebServer.a(WebAuthentication.cpp.o):(.literal._ZL6getMD5PhtPc+0x4): undefined reference to `mbedtls_md5_starts' /home/uli/.platformio/packages/[email protected]+2021r2-patch3/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld: .pio/build/esp32dev/lib67a/libESP Async WebServer.a(WebAuthentication.cpp.o): in function `getMD5(unsigned char*, unsigned short, char*)': /home/uli/dev/My-Firmware/.pio/libdeps/esp32dev/ESP Async WebServer/src/WebAuthentication.cpp:73: undefined reference to `mbedtls_md5_starts'
Solution:
This is a bug in the ESPAsyncWebserver official library, which is not regularly maintained. But you can use use the esphome fork of ESPAsyncWebserver and their fork of AsyncTCP instead.
In platformio.ini
, instead of
lib_deps = ESP Async [email protected]
use the esphome fork and AsyncTCP:
lib_deps = esphome/AsyncTCP-esphome@^1.2.2 esphome/ESPAsyncWebServer-esphome@^2.1.0
After that, try to build / upload, the linking errors should be gone.
Full platformio.ini
example
[env:esp32dev] platform = espressif32 platform_packages = framework-arduinoespressif32 @ https://github.com/espressif/arduino-esp32.git#2.0.3 board = esp32dev framework = arduino lib_deps = esphome/AsyncTCP-esphome@^1.2.2 esphome/ESPAsyncWebServer-esphome@^2.1.0 [email protected] upload_speed = 460800 monitor_speed = 115200