[Feature] Limit number of countries in TE request

[hjoaquim]

1. Why? (1-3 sentences or a bullet point list):

   • Allowing more than N countries in a TE request would break with a http code of 400 - this PR enhances the UX.

2. What? (1-3 sentences or a bullet point list):

   • Added a validation for the number of countries in the fetcher.

3. Impact (1-2 sentences or a bullet point list):

   • Low - small improvement on UX.

4. Testing Done:

   • Experiment with any amount of countries from openbb_platform/providers/tradingeconomics/openbb_tradingeconomics/utils/countries.py:

from openbb import obb
countries = [...]
obb.economy.calendar(provider="tradingeconomics", country=countries).to_df()

5. Reviewer Notes (optional):

   • It looks like it depends on the countries we're sending. Sometimes it fails for 28, other times 31/32. I wasn't able to get more than 32 with any combination of countries. Also, couldn't find any information related with this limit on TE API docs. cc @andrewkenreich

[deeleeramone]

   * Allowing more than N countries in a TE request would break with a http code of 400 - this PR enhances the UX.

   * It looks like it depends on the countries we're sending. Sometimes it fails for 28, other times 31/32. I wasn't able to get more than 32 with any combination of countries. Also, couldn't find any information related with this limit on TE API docs. cc @andrewkenreich

Is there a reason why "All" is not used instead of trying to get a huge list? It could quite easily create a URL string that is too long for HTTP requests.

It would be pretty simple to filter post-request, and storing that data in cache would dramatically reduce the number of API calls.

[hjoaquim]

   * Allowing more than N countries in a TE request would break with a http code of 400 - this PR enhances the UX.

   * It looks like it depends on the countries we're sending. Sometimes it fails for 28, other times 31/32. I wasn't able to get more than 32 with any combination of countries. Also, couldn't find any information related with this limit on TE API docs. cc @andrewkenreich

Is there a reason why "All" is not used instead of trying to get a huge list? It could quite easily create a URL string that is too long for HTTP requests.

It would be pretty simple to filter post-request, and storing that data in cache would dramatically reduce the number of API calls.

Is all even an option? Couldn't find that on TE API docs.
I like the idea, if possible.

Although, we can still set a limit for number of countries in one request, if TE has one (as it look it does), using the validator.

[IgorWounds]

@deeleeramone

[deeleeramone]

Is all even an option? Couldn't find that on TE API docs. I like the idea, if possible.

Although, we can still set a limit for number of countries in one request, if TE has one (as it look it does), using the validator.

All is what you get when you only enter a start/end date. A different way of going about restricting the length of the URL would be by the character count instead of the number of countries.

2000 characters is a general "safe" limit for URL length, although this can vary by platform.

[hjoaquim]

Is all even an option? Couldn't find that on TE API docs. I like the idea, if possible.
Although, we can still set a limit for number of countries in one request, if TE has one (as it look it does), using the validator.

All is what you get when you only enter a start/end date. A different way of going about restricting the length of the URL would be by the character count instead of the number of countries.

2000 characters is a general "safe" limit for URL length, although this can vary by platform.

That seems to be the case - let's do that instead.