Why doesnt client.connect accept a full adress-CodePudding

i am trying to write a piece of code in which the ESP32 connect securely to my api-server and post some sensor data. For this i use the WifiClientSecure library.

Through trial and error i have found out that client.connect(www.myserver.com, 443); works.

But client.connect(www.myserver.com/api, 443); will throw an error. I have searched the internet for a solution but can't manage to find one.

Full code:

#include <arduino.h>
#include <WiFiClientSecure.h>

const char* ssid     = "filled out ssid";     // your network SSID 
const char* password = "filled out password"; // your network password

const char*  server = "www.server.com/api";  // Server URL

/* use 
openssl s_client -showcerts -connect www.howsmyssl.com:443 </dev/null 
to get this certificate */
const char* ca_cert = \ 
"-----BEGIN CERTIFICATE-----\n" \
"MIIF3jCCA8agAwIBAgIQAf1tMPyjylGoG7xkDjUDLTANBgkqhkiG9w0BAQwFADCB\n" \
"iDELMAkGA1UEBhMCVVMxEzARBgNVBAgTCk5ldyBKZXJzZXkxFDASBgNVBAcTC0pl\n" \
"cnNleSBDaXR5MR4wHAYDVQQKExVUaGUgVVNFUlRSVVNUIE5ldHdvcmsxLjAsBgNV\n" \
"BAMTJVVTRVJUcnVzdCBSU0EgQ2VydGlmaWNhdGlvbiBBdXRob3JpdHkwHhcNMTAw\n" \
"MjAxMDAwMDAwWhcNMzgwMTE4MjM1OTU5WjCBiDELMAkGA1UEBhMCVVMxEzARBgNV\n" \
"BAgTCk5ldyBKZXJzZXkxFDASBgNVBAcTC0plcnNleSBDaXR5MR4wHAYDVQQKExVU\n" \
"aGUgVVNFUlRSVVNUIE5ldHdvcmsxLjAsBgNVBAMTJVVTRVJUcnVzdCBSU0EgQ2Vy\n" \
"dGlmaWNhdGlvbiBBdXRob3JpdHkwggIiMA0GCSqGSIb3DQEBAQUAA4ICDwAwggIK\n" \
"AoICAQCAEmUXNg7D2wiz0KxXDXbtzSfTTK1Qg2HiqiBNCS1kCdzOiZ/MPans9s/B\n" \
"3PHTsdZ7NygRK0faOca8Ohm0X6a9fZ2jY0K2dvKpOyuR OJv0OwWIJAJPuLodMkY\n" \
"tJHUYmTbf6MG8YgYapAiPLz E/CHFHv25B O1ORRxhFnRghRy4YUVD 8M/5 bJz/\n" \
"Fp0YvVGONaanZshyZ9shZrHUm3gDwFA66Mzw3LyeTP6vBZY1H1dat//O T23LLb2\n" \
"VN3I5xI6Ta5MirdcmrS3ID3KfyI0rn47aGYBROcBTkZTmzNg95S UzeQc0PzMsNT\n" \
"79uq/nROacdrjGCT3sTHDN/hMq7MkztReJVni 49Vv4M0GkPGw/zJSZrM233bkf6\n" \
"c0Plfg6lZrEpfDKEY1WJxA3Bk1QwGROs0303p tdOmw1XNtB1xLaqUkL39iAigmT\n" \
"Yo61Zs8liM2EuLE/pDkP2QKe6xJMlXzzawWpXhaDzLhn4ugTncxbgtNMs 1b/97l\n" \
"c6wjOy0AvzVVdAlJ2ElYGn SNuZRkg7zJn0cTRe8yexDJtC/QV9AqURE9JnnV4ee\n" \
"UB9XVKg /XRjL7FQZQnmWEIuQxpMtPAlR1n6BB6T1CZGSlCBst6 eLf8ZxXhyVeE\n" \
"Hg9j1uliutZfVS7qXMYoCAQlObgOK6nyTJccBz8NUvXt7y CDwIDAQABo0IwQDAd\n" \
"BgNVHQ4EFgQUU3m/WqorSs9UgOHYm8Cd8rIDZsswDgYDVR0PAQH/BAQDAgEGMA8G\n" \
"A1UdEwEB/wQFMAMBAf8wDQYJKoZIhvcNAQEMBQADggIBAFzUfA3P9wF9QZllDHPF\n" \
"Up/L M ZBn8b2kMVn54CVVeWFPFSPCeHlCjtHzoBN6J2/FNQwISbxmtOuowhT6KO\n" \
"VWKR82kV2LyI48SqC/3vqOlLVSoGIG1VeCkZ7l8wXEskEVX/JJpuXior7gtNn3/3\n" \
"ATiUFJVDBwn7YKnuHKsSjKCaXqeYalltiz8I 8jRRa8YFWSQEg9zKC7F4iRO/Fjs\n" \
"8PRF/iKz6y O0tlFYQXBl2 odnKPi4w2r78NBc5xjeambx9spnFixdjQg3IM8WcR\n" \
"iQycE0xyNN 81XHfqnHd4blsjDwSXWXavVcStkNr/ XeTWYRUc ZruwXtuhxkYze\n" \
"Sf7dNXGiFSeUHM9h4ya7b6NnJSFd5t0dCy5oGzuCr yDZ4XUmFF0sbmZgIn/f3gZ\n" \
"XHlKYC6SQK5MNyosycdiyA5d9zZbyuAlJQG03RoHnHcAP9Dc1ew91Pq7P8yF1m9/\n" \
"qS3fuQL39ZeatTXaw2ewh0qpKJ4jjv9cJ2vhsE/zB 4ALtRZh8tSQZXq9EfX7mRB\n" \
"VXyNWQKV3WKdwrnuWih0hKWbt5DHDAff9Yk2dDLWKMGwsAvgnEzDHNb842m1R0aB\n" \
"L6KCq9NjRHDEjf8tM7qtj3u1cIiuPhnPQCjY/MiQu12ZIvVS5ljFH4gxQ 6IHdfG\n" \
"jjxDah2nGN59PRbxYvnKkKj9\n" \
"-----END CERTIFICATE-----\n" ;


/* create an instance of WiFiClientSecure */
WiFiClientSecure client;

void setup() {
    Serial.begin(115200);

    WiFi.begin(ssid, password);

    /* waiting for WiFi connect */
    while (WiFi.status() != WL_CONNECTED) {
        Serial.print(".");
        delay(100);
    }

    Serial.print("Connected to ");
    Serial.println(ssid);

    /* set SSL/TLS certificate */
    client.setCACert(ca_cert);

    Serial.println("Connect to server via port 443");
    if (!client.connect(server, 443)){
        Serial.println("Connection failed!");
    } else {
        Serial.println("Connected to server!");
        /* create HTTP request */
        
        Serial.print("Waiting for response ");
        while (!client.available()){
            delay(50); //
            Serial.print(".");
        }  
        /* if data is available then receive and print to Terminal */
        while (client.available()) {
            char c = client.read();
            Serial.write(c);
        }

        /* if the server disconnected, stop the client */
        if (!client.connected()) {
            Serial.println();
            Serial.println("Server disconnected");
            client.stop();
        }
  }
}

void loop() {
}

CodePudding user response：

www.server.com/api is a partial URL. The complete URL will be https://www.server.com/api, where:

https - This part is called scheme or protocol. HTTPS implies a default TCP port 443 (http mean port 80 by default)
www.server.com - The domain part, can be called also server address.
api- This is a path on the server

WiFiClient, or WiFiClientSecure, is TCP clients, it doesn't know anything about URLs. TCP client recognizes just address, given in form of IP address (192.168.1.20) or FNDQ (which is then translated into IP address).

It is easier to use HTTPClient for requesting HTTP resources.