fix(cloud-function): sanitize pong/get input

[caugner]

Summary

(MP-1167)

Problem

We don't validate/sanitize the input on the /pong/get endpoint, causing HTTP 500 errors in our logs.

Solution

Validate and sanitize the input.

---

Screenshots

Before

% xh post http://localhost:5100/pong/get
HTTP/1.1 500 Internal Server Error
Connection: keep-alive
Content-Length: 49
Content-Type: text/html; charset=utf-8
Date: Fri, 31 May 2024 17:33:11 GMT
Keep-Alive: timeout=5
X-Google-Status: crash

Cannot read properties of null (reading 'filter')

% xh post http://localhost:5100/pong/get --json 'pong:="foo"' 
HTTP/1.1 500 Internal Server Error
Connection: keep-alive
Content-Length: 49
Content-Type: text/html; charset=utf-8
Date: Fri, 31 May 2024 17:32:54 GMT
Keep-Alive: timeout=5
X-Google-Status: crash

Cannot read properties of null (reading 'filter')

% xh post http://localhost:5100/pong/get --json 'pongs:=["foo"]'
HTTP/1.1 200 OK
Cache-Control: no-store
Connection: keep-alive
Content-Length: 2
Content-Type: application/json
Date: Fri, 31 May 2024 17:32:23 GMT
Keep-Alive: timeout=5

{}

% xh post http://localhost:5100/pong/get --json 'pongs:=["foo", "side"]'
HTTP/1.1 200 OK
Cache-Control: no-store
Connection: keep-alive
Content-Length: 2
Content-Type: application/json
Date: Fri, 31 May 2024 17:33:39 GMT
Keep-Alive: timeout=5

{}

After

% xh post http://localhost:5100/pong/get
HTTP/1.1 400 Bad Request
Cache-Control: no-store
Connection: keep-alive
Content-Length: 20
Content-Type: application/json
Date: Fri, 31 May 2024 17:34:05 GMT
Keep-Alive: timeout=5

{
    "status": "invalid"
}

% xh post http://localhost:5100/pong/get --json 'pongs:="foo"'
HTTP/1.1 400 Bad Request
Cache-Control: no-store
Connection: keep-alive
Content-Length: 20
Content-Type: application/json
Date: Fri, 31 May 2024 17:34:18 GMT
Keep-Alive: timeout=5

{
    "status": "invalid"
}

% xh post http://localhost:5100/pong/get --json 'pongs:=["foo"]'
HTTP/1.1 400 Bad Request
Cache-Control: no-store
Connection: keep-alive
Content-Length: 18
Content-Type: application/json
Date: Fri, 31 May 2024 17:34:31 GMT
Keep-Alive: timeout=5

{
    "status": "empty"
}

% xh post http://localhost:5100/pong/get --json 'pongs:=["side","newType"]'
HTTP/1.1 200 OK
Cache-Control: no-store
Connection: keep-alive
Content-Length: 28
Content-Type: application/json
Date: Fri, 31 May 2024 17:34:44 GMT
Keep-Alive: timeout=5

{
    "status": "geo_unsupported"
}

---

How did you test this change?

Ran npm i && npm start in /cloud-function, and the following commands in a separate terminal:

xh post http://localhost:5100/pong/get
xh post http://localhost:5100/pong/get --json 'pongs:="foo"'
xh post http://localhost:5100/pong/get --json 'pongs:=["foo"]'
xh post http://localhost:5100/pong/get --json 'pongs:=["side","newType"]'