Sending HTTP request from STM32 to Firebase via ESP8266

[mavishak]

Some pointers:

• It seems that Cloud Firestore can't be used for embedded devices. Integration with Firestore?
• Since we haven't seen even one example that contradicts what we wrote above we decided to use the Real-Time database for this part of the project.
• Firebase Real-Time database accepts only HTTPS requests What Is the Difference Between HTTP and HTTPS?
• cURL - this might be helpful
• convert curl to http request
• Firebase REST API
• https example to curl

[mavishak]

We managed to send a post msg to the Real-time database in Firebase

04.03.2021:

We sent a POST HTTPS request using port 443 and SSL

1. We needed to write: AT+CIPSSLSIZE=4096 ESPRESSIF: Board index English Forum Explore General Discussion
2. We needed to write: _sprintf((char)command, "AT+CIPSTART=\"SSL\",\"%s\",%ld\r\n",(char)firebase_host, httpsport) StackExchange: Making HTTPS requests using ESP8266 AT commands
3. The POST message was:

   POST /rest/test/posts.json? HTTP/1.1 Host: **** Content-Type: application/json Content-Length: 49

   {"author": "Nemo Resh", "title": "Fish are blue"}

Note: we got the format of the HTTP message using Postman and Firebase documentation Firebase: Saving Data

[mavishak]

Moving Forwards

The HTTP request to firebase should be as follows:

PUT /devices/[device_id]/history/[dd-mm-yyyy]/[hh:mm].json?auth=[DATABASE_SECRET] HTTP/1.1

Host: [DATABASE_HOST] Content-Type: application/json Content-Length: [BODY LENGTH]

{"image_path": "image", "notes": "alarm went off"}

see: How do I authenticate my Firebase with just a string key

A Few Issues

• user must be able to change Wi-Fi SSID and PSW without passing through the web. There are two ways to achieve this:

  1. usart2 - this is probably possible
  2. Key matrix - this is probably preferable

• device authentication will be done using the database secret and device id.

[mavishak]

We need to find a way to get the actual date and time when an alert is created. We don't expect to work because this is an embedded system, but we checked it anyways: see: c function localtime

void timestamp(void){

       time_t rawtime;
       struct tm *info;
       time( &rawtime );
       info = localtime( &rawtime );
       memset((char*)command, '\0', COMMAND_SIZE*sizeof(uint8_t));
       sprintf((char*)command, "Current local time and date: %s", asctime(info));
       write_usart2((uint8_t*)command);

}

The output time and date was not correct:

Current local time and date: Wed Dec 31 23:59:59 1969

We tried playing with firebase server value - timestamp:

_{"imagepath": "image", "notes": "alarm went off!", "time": {".sv": "timestamp"}}

We did not find a way to insert the timestamp in the path and it seems the timestamp does not indicate the actual time and date as it is the time since UNIX epoch, in milliseconds. see: Firebase Timestamp and: Firebase server values Rest API

[mavishak]

06.03.2021

After consulting our instructor we have decided to use the Firebase timestamp and convert it to the date and time using: UNIX timestamp converters.

var s = new Date(1504095567183).toLocaleDateString("en-US") // expected output "8/30/2017"
console.log(s);

see: convert UNIX timestamp to date and time convert timestamp to date and time in angular

[NaomiCreate]

07.03.2021

We organized the code. Now the alert is recorded under the device-ID in the Real-Time Database. !TBD:

• [ ] AT+RST is very important but it doesn't work properly -> need to find a way to make it work
• [ ] Create a systematized status: PASS, FAIL, STANDBY to deal with infinite loops.
• [ ] Some of the PASS\FAIL responses are irrelevant and could cause problems-> go over them, carefully.
• [ ] Should we use on the HTTP request: print=silent?
• [ ] Need to minimize constant arrays holding Strings. (e.g. content array) -not so important according to instructure
• [ ] Add timeouts to AT-command responses
• [ ] Enable event queue