[ESPHOME] mqtt write payload to global variable

ESPHome
1

Hello,

im trying to get the payload from an topic into an variable but it does not work i always get an error.
i would like to get an string into a global variable but since i didnt find anything about that i tried to write an INT

what i tried is:

globals:
  - id: mqttvalue
    type: int
    restore_value: yes
    initial_value: '0'

    - topic: Effect
      qos: 1
      then:
        - globals.set:
            id: mqttvalue
            value: !lambda |-
              return x;

which give me this error:


In file included from src/esphome/components/api/user_services.h:6:0,
                 from src/esphome/components/api/api_server.h:13,
                 from src/esphome/components/api/api_connection.h:7,
                 from src/esphome.h:2,
                 from src/main.cpp:3:
src/esphome/core/automation.h: In instantiation of 'esphome::TemplatableValue<T, X>::TemplatableValue(F) [with F = setup()::__lambda58; typename std::enable_if<esphome::is_callable<F, X ...>::value, int>::type <anonymous> = 0; T = int; X = {std::basic_string<char, std::char_traits<char>, std::allocator<char> >}]':
src/esphome/components/globals/globals_component.h:70:3:   required from 'void esphome::globals::GlobalVarSetAction<C, Ts>::set_value(V) [with V = setup()::__lambda58; C = esphome::globals::RestoringGlobalsComponent<int>; Ts = {std::basic_string<char, std::char_traits<char>, std::allocator<char> >}]'
/config/esphome/wemos.yaml:153:4:   required from here
src/esphome/core/automation.h:28:46: error: no matching function for call to 'std::function<int(std::basic_string<char>)>::function(setup()::__lambda58&)'
   TemplatableValue(F f) : type_(LAMBDA), f_(f) {}
                                              ^
src/esphome/core/automation.h:28:46: note: candidates are:
In file included from src/esphome/core/component.h:4:0,
                 from src/esphome/components/api/api_connection.h:3,
                 from src/esphome.h:2,
                 from src/main.cpp:3:
/data/cache/platformio/packages/toolchain-xtensa/xtensa-lx106-elf/include/c++/4.8.2/functional:2443:7: note: template<class _Functor, class> std::function<_Res(_ArgTypes ...)>::function(_Functor)
       function<_Res(_ArgTypes...)>::
       ^
/data/cache/platformio/packages/toolchain-xtensa/xtensa-lx106-elf/include/c++/4.8.2/functional:2443:7: note:   template argument deduction/substitution failed:
/data/cache/platformio/packages/toolchain-xtensa/xtensa-lx106-elf/include/c++/4.8.2/functional:2226:7: note: std::function<_Res(_ArgTypes ...)>::function(std::function<_Res(_ArgTypes ...)>&&) [with _Res = int; _ArgTypes = {std::basic_string<char, std::char_traits<char>, std::allocator<char> >}]
       function(function&& __x) : _Function_base()
       ^
/data/cache/platformio/packages/toolchain-xtensa/xtensa-lx106-elf/include/c++/4.8.2/functional:2226:7: note:   no known conversion for argument 1 from 'setup()::__lambda58' to 'std::function<int(std::basic_string<char>)>&&'
/data/cache/platformio/packages/toolchain-xtensa/xtensa-lx106-elf/include/c++/4.8.2/functional:2429:5: note: std::function<_Res(_ArgTypes ...)>::function(const std::function<_Res(_ArgTypes ...)>&) [with _Res = int; _ArgTypes = {std::basic_string<char, std::char_traits<char>, std::allocator<char> >}]
     function<_Res(_ArgTypes...)>::
     ^
/data/cache/platformio/packages/toolchain-xtensa/xtensa-lx106-elf/include/c++/4.8.2/functional:2429:5: note:   no known conversion for argument 1 from 'setup()::__lambda58' to 'const std::function<int(std::basic_string<char>)>&'
/data/cache/platformio/packages/toolchain-xtensa/xtensa-lx106-elf/include/c++/4.8.2/functional:2206:7: note: std::function<_Res(_ArgTypes ...)>::function(std::nullptr_t) [with _Res = int; _ArgTypes = {std::basic_string<char, std::char_traits<char>, std::allocator<char> >}; std::nullptr_t = std::nullptr_t]
       function(nullptr_t) noexcept
       ^
/data/cache/platformio/packages/toolchain-xtensa/xtensa-lx106-elf/include/c++/4.8.2/functional:2206:7: note:   no known conversion for argument 1 from 'setup()::__lambda58' to 'std::nullptr_t'
/data/cache/platformio/packages/toolchain-xtensa/xtensa-lx106-elf/include/c++/4.8.2/functional:2199:7: note: std::function<_Res(_ArgTypes ...)>::function() [with _Res = int; _ArgTypes = {std::basic_string<char, std::char_traits<char>, std::allocator<char> >}]
       function() noexcept
       ^
/data/cache/platformio/packages/toolchain-xtensa/xtensa-lx106-elf/include/c++/4.8.2/functional:2199:7: note:   candidate expects 0 arguments, 1 provided
*** [/data/elekstube/.pioenvs/elekstube/src/main.cpp.o] Error 1
========================== [FAILED] Took 2.08 seconds ==========================

i also tried

    - topic: Effect
      qos: 1
      then:
        - lambda: |-
            id(mqttvalue) = int(x);
            #and also  --> id(mqttvalue) = x;

/config/esphome/wemos.yaml: In lambda function:
/config/esphome/wemos.yaml:148:33: error: invalid cast from type 'std::string {aka std::basic_string<char>}' to type 'int'
             id(mqttvalue) = int(x);
                                 ^
*** [/data/elekstube/.pioenvs/elekstube/src/main.cpp.o] Error 1
========================== [FAILED] Took 2.08 seconds ==========================

how can i solve that?

2

Guessing here, but '0' is not an int?

3

thank you, you are probably right. meanwhile i solved it.

but still would like to know how to get an string payload like “HELLO” and insert it into an global variable

4

Did you try to define your global var using a string type?
I would start with one of these (untested):

globals:
  - id: myStringVar
    type: string

globals:
  - id: myStringVar
    type: std::string

(The second one is probably the correct syntax.)

5

But didn’t tell how? And you ask another question?

Rude.

2 Likes
6

@nickrout
hi, i solved it exactly like you wrote it. maybe 10 minutes before you wrote your answer.

@Jpsy

thank you i will try that