Retry-After Header Lookup

[TheUltimateC0der]

Would be nice to check the time given in the "Retry-After" handler, to not overload the Spotify API.

It would be clever to have that in the "SpotifyAPI.Web.Models.Error" as Property or as a Property in an "SpotifyAPI.Web.SpotifyWebAPI" instance

For reference please check this : https://developer.spotify.com/web-api/user-guide/#rate-limiting

[JohnnyCrazy]

Sounds like a good idea, will have a look at it tomorrow! :+1:

[erinxocon]

I was thinking the same thing the other day!

[JohnnyCrazy]

Turns out this won't be as easy as I thought.

My idea was adding a HeaderCollection to the BasicModel which will be automatically filled once the client got the response-headers. To achieve this, we would need to add where T : BasicModel to all the Download-Methods so the Method can set the HeaderCollection appropriately. This works for 90% of the API-Calls, but sadly we also have those weird array API-Calls CheckSavedTracks CheckSavedAlbums etc.. Their response can either be a JArray or an Error-Object. I couldn't find a solution for creating a class for this kind of responses which will deserialize correctly and suits T DownloadData<T> where T : BasicModel.

So, you guys got any ideas for a clean implementation or a workaround for my approach?

(Maybe you have some thoughts @JimmyAppelt )

[TheUltimateC0der]

I think it will be totally okay if we have the headers only on the Error-Object. In my opinion you don't have to look at the headers when everything is okay.

[JohnnyCrazy]

I just pushed an implementation to the headers branch. Every Model now contains a ResponseInfo Response-property, which currently only holds WebHeaderCollection Headers but may contain more in the future.

Usage:

FullAlbum album = _spotify.GetAlbum("1KFttYHEjNkDMYQrV6qYMA");

//'Response' is marked as JsonIgnore
//Will contain response headers
album.Response.Headers 

I'm not quite happy with it, but I can't think of a nicer solution currently. I plan to move to HttpClient in the near future, then this hopefully will get a makeover.

Thoughts? @S3NS4Ti0N @erinxocon @JimmyAppelt

[JohnnyCrazy]

Implemented in 15d8fd87e22a9e0ae4a9a5f0071152eefcf6d384

string model.Header(string headerName)
WebHeaderCollection model.Headers()

[petrroll]

Just out of curiosity what's the point of WebHeaderCollection? I can see it being passed around but not really used anywhere...

[JohnnyCrazy]

@petrroll Rate limit detection. If your exceeding the rate limit, a header will be set by the web api and users can detect it via that header collection

[pentiumii400mhz]

I can't get the Header to work, can you please add a example, the Header and the Headers Collection is allways empty? One problem is also that when Header("Retry-After") is "Nothing" I get a exception if I don't check if the Headers Collection is Nothing. Can this be more simple?

I really would like to have a simple way of getting how long time I should wait befor retrying agin?

[JohnnyCrazy]

@pentiumii400mhz

Can't reproduce it, headers are working fine:

Header(string name) will return null if there is no header with that name, so there should be everything you need for a Retry-After-check

[pentiumii400mhz]

Hi

I'm sorry but when I'm getting a Error 429 the headers is Empty!

[pentiumii400mhz]

Anyone?

[JohnnyCrazy]

I will have a look at this the next days, kinda got out of my sight

[pentiumii400mhz]

Thanks, created a new Issue for this.