Analytics array variable substitutions

[micajuine-ho]

For #21224

Variable substitutions can now be handled in arrays:

vars: {
  foo: bar,
  array: [${foo},'hello']
}

${array} -> 'bar,hello'

This will not work for nested arrays (see test case). Should we allow/disallow nested arrays? Or leave as is?

[lannka]

thanks for fixing this!

[micajuine-ho]

@lannka Should we worry about nested array expansion?

[zhouyx]

LGTM Two questions

1. Does this work with extraUrlParams as well?
2. If we support nested objects within the extraUrlParams, like this

{
  'a': {
    'a1': 'b1', 
  },
  'b': 'b'
}

are we also supporting nested arrays like

{
  'a': {
    'a1': ['b1', 'b2'...], 
  },
  'b': 'b'
}

Thanks.

[micajuine-ho]

@zhouyx

1. Does this work with extraUrlParams as well?

extraUrlParams already handled arrayt

2. If we support nested objects within the extraUrlParams, ... are we also supporting nested arrays...

Do you mean using nested arrays in extraUrlParams with useBody? If so, then yes. The nested array is sent within the POST request body.

Also just to clarify, expanding extraUrlParams does not work:

"extraUrlParams": {
  "a":  ["${b}", "bar"],
  "b": "foo"
}
// Will generate a url request with: a=&a=bar&b=foo

[zhouyx]

That should be fine. What about nested array within the array. For example

{
  'a': {
    'a1': [
     'b1', 
     ['c1', 'c2']
   ], 
  },
  'b': 'b'
}

Or it doesn't matter given the way we handle extraUrlParams in the request body?

[micajuine-ho]

Or it doesn't matter given the way we handle extraUrlParams in the request body?

Yes, it handle nested arrays in the request body.

[zhouyx]

Sounds good, thanks for confirming

[micajuine-ho]

@zhouyx What I am worried about is arrays expanding arrays:

vars: {
  foo: 1,
  bar: 2,
  array: [${foo}, ${array2}]
  array2: [${bar}, 'hello']
}
// ${array} would ideally turn into 1,2,hello
// but instead turns into 1,2%2Chello (because array2 gets turned into a string and serialized)

Should we worry about this? To fix it would take a good amount of effort, I believe.

[micajuine-ho]

Should we worry about this? To fix it would take a good amount of effort, I believe.

Discussed offline. We will leave as is and document that this is not the intended behavior.

If requested, we will fix.

[zhouyx]

SGTM. I'll let @lannka approve the PR since they've started the review : )

[zhouyx]

The code breaks with an array like ["test", 123], because we are checking if the value type of string for items from the array.

This breaks use case like:

"request": "example.com?data=${data1}"    
"vars": {
      "abc": "${timestamp}.${requestCount}",
      "data1": ["ds", 123]
    },

Let's fix before next canary cut, thanks.