4.5 KiB
ESP Local Control using HTTPS server
This example creates a esp_local_ctrl service over HTTPS transport, for securely controlling the device over local network. In this case the device name is resolved through mDNS, which in this example is my_esp_ctrl_device.local.
See the esp_local_ctrl component documentation for details.
Before using the example, run idf.py menuconfig (or idf.py menuconfig if using CMake build system) to configure Wi-Fi or Ethernet. See "Establishing Wi-Fi or Ethernet Connection" section in examples/protocols/README.md for more details.
Client Side Implementation
A python test script scripts/esp_local_ctrl.py has been provided for as a client side application for controlling the device over the same Wi-Fi network. The script relies on a pre-generated main/certs/rootCA.pem to verify the server certificate. The server side private key and certificate can also be found under main/certs, namely prvtkey.pem and cacert.pem.
After configuring the Wi-Fi, flashing and booting the device, run the following command to test the device name resolution through mDNS:
ping my_esp_ctrl_device.local
Sample output:
64 bytes from 192.168.32.156 (192.168.32.156): icmp_seq=1 ttl=255 time=58.1 ms
64 bytes from 192.168.32.156 (192.168.32.156): icmp_seq=2 ttl=255 time=89.9 ms
64 bytes from 192.168.32.156 (192.168.32.156): icmp_seq=3 ttl=255 time=123 ms
After you've tested the name resolution, run:
python scripts/esp_local_ctrl.py
Sample output:
python scripts/esp_local_ctrl.py
==== Acquiring properties information ====
==== Acquired properties information ====
==== Available Properties ====
S.N. Name Type Flags Value
[ 1] timestamp (us) TIME(us) Read-Only 168561481
[ 2] property1 INT32 123456
[ 3] property2 BOOLEAN Read-Only True
[ 4] property3 STRING
Select properties to set (0 to re-read, 'q' to quit) : 0
==== Available Properties ====
S.N. Name Type Flags Value
[ 1] timestamp (us) TIME(us) Read-Only 22380117
[ 2] property1 INT32 123456
[ 3] property2 BOOLEAN Read-Only False
[ 4] property3 STRING
Select properties to set (0 to re-read, 'q' to quit) : 2,4
Enter value to set for property (property1) : -5555
Enter value to set for property (property3) : hello world!
==== Available Properties ====
S.N. Name Type Flags Value
[ 1] timestamp (us) TIME(us) Read-Only 55110859
[ 2] property1 INT32 -5555
[ 3] property2 BOOLEAN Read-Only False
[ 4] property3 STRING hello world!
Select properties to set (0 to re-read, 'q' to quit) : q
Quitting...
The script also allows to connect over BLE, and provide a custom service name. To display the list of supported parameters, run:
python scripts/esp_local_ctrl.py --help
Certificates
You can generate a new server certificate using the OpenSSL command line tool.
For the purpose of this example, lets generate a rootCA, which we will use to sign the server certificates and which the client will use to verify the server certificate during SSL handshake. You will need to set a password for encrypting the generated rootkey.pem.
openssl req -new -x509 -subj "/CN=root" -days 3650 -sha256 -out rootCA.pem -keyout rootkey.pem
Now generate a certificate signing request for the server, along with its private key prvtkey.pem.
openssl req -newkey rsa:2048 -nodes -keyout prvtkey.pem -days 3650 -out server.csr -subj "/CN=my_esp_ctrl_device.local"
Now use the previously generated rootCA to process the server's certificate signing request, and generate a signed certificate cacert.pem. The password set for encrypting rootkey.pem earlier, has to be entered during this step.
openssl x509 -req -in server.csr -CA rootCA.pem -CAkey rootkey.pem -CAcreateserial -out cacert.pem -days 500 -sha256
Now that we have rootCA.pem, cacert.pem and prvtkey.pem, copy these into main/certs. Note that only the server related files (cacert.pem and prvtkey.pem) are embedded into the firmware.
Expiry time and metadata fields can be adjusted in the invocation.
Please see the openssl man pages (man openssl-req) for more details.
It is strongly recommended to not reuse the example certificate in your application; it is included only for demonstration.