esp_modem at_raw has the wrong length output string (IDFGH-13911)

[txf-]

Answers checklist.

• I have read the documentation for esp-protocols components and the issue is not addressed there.
• I have updated my esp-protocols branch (master or release) to the latest version and checked that the issue is present there.
• I have searched the issue tracker for a similar issue and not found a similar issue.

General issue report

Using a SIM7000 (on the lilygo Tsim7000), I'm executing the following function:

  void getGps(){
    std::string out;
    command_result res = dce->at_raw("AT+CGNSINF\r",out,"+CGNSINF:","ERROR", 10000);
    ESP_LOGI(COMM_TAG,"get gps str: %s", out.c_str()); 
  }

And the response output I get is this (gps coords hidden) :
+CGNSINF: 1,1,20241018103437.000,xx.yyyyyy,-x.yyyyyy,-11.900,0
or this:
+CGNSINF: 1,1,20241018103421.000,xx.yyyyyy,-x.yyyyyy,95.000,0.

its seems the string length is of a fixed size, the whole string should be something like this:
+CGNSINF: 1,1,20241018103758.000,xx.yyyyyyy,-x.yyyyyy,15.300,0.00,4.8,1,,1.1,1.5,0.9,,27,4,3,,37,,

is there a way to set the response buffer size?

[david-cermak]

@txf- Are your really calling the C++ API and not the esp_modem_at_raw() plain C wrapper? The C functions indeed have fixed output length parameter, but C++ use standard strings which could grow.

Isn't is possible that the response comes in chunks? Your pass criteria ("+CGNSINF:") are located in the beginning of the reply so that when the first chunk comes, all's good for returning OK with the partial response.

Could you please try:

  void getGps(){
    std::string out;
    command_result res = dce->at_raw("AT+CGNSINF\r",out,"SomethingThatNeverComes:","ERROR", 10000);
    ESP_LOGI(COMM_TAG,"get gps str: %s", out.c_str()); 
  }

Now this should fail, but once it would, should include the entire string.

[txf-]

@david-cermak
I changed it to look for the "OK", which is sent a few moments after the CGNSINF result string. It then captures the whole string.