ESP32 Forum

Posted: **Mon Oct 01, 2018 8:20 am**

Hi all,
Im still a newbie and Im trying no move working code I wrote for the ESP8266 to the ESP32 but its not working.

I have a root certificate that I have stored in SPIFFS and I want to pass it to WifiClientSecure. On the ESP8266 I do it this way (which works):

Code: Select all

  // Load CA file from SPIFFS
  File ca = SPIFFS.open("/site.cer", "r"); 
  if (!ca) {
    Serial.println("Failed to open ca ");
  }
  else
    Serial.println("Success to open ca");
  delay(1000);

  // Set server CA file
  if (wifiClient.loadCACert(ca))
    Serial.println("ca loaded");
  else
    Serial.println("ca failed");

}

My first problem was that loadCACert() isnt supported by WiFiClientSecure on the ESP32 so I changed it to setCACert(). The problem I have now is that when I pass the file into this method ( wifiClient.setCACert(ca);) i get the following error:

no suitable conversion function from "fs::File" to "const char *" exists

So my question is , how do I convert a File to a const char ??

Thanks
Kev

Posted: **Tue Oct 09, 2018 12:35 am**

Try, reading your "ca" and store it in a buffer of type char then pass that buffer in your function.

Posted: **Wed Feb 17, 2021 6:03 pm**

I have the same issue... Do you solve your problem?

Posted: **Thu May 13, 2021 8:13 am**

I do this with the ESP32. Spestano is correct, you just have to load into a buffer. To give you an example, I define

char myCertificate[N_BYTES_CERTIFICATE];

where N_BYTES_CERTIFICATE needs to be about 1500, and then read and load the certificate like this

Code: Select all

myFServer.read2String(SPIFFS, REMOTE_CERT_FILE, myCertificate);
 //Serial.printf("\n%s\n", myCertificate);
 http_client_Secure.setCACert(myCertificate);

myFServer is just a class I created using SPIFFS.h and FS.h. The relevant read2String function is this:

Code: Select all

void fServices::read2String(fs::FS &fs, const char * path, char *myString){
;
    File file = fs.open(path);
    if(!file || file.isDirectory()){
        return;
    }

    int iChar = 0;
    while(file.available()){
      myString[iChar] = file.read();
      iChar++;
    }

    file.close();
}

Hope this helps.

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