# `HTTPower.Adapter.Tesla`
[🔗](https://github.com/mdepolli/httpower/blob/v0.22.0/lib/httpower/adapter/tesla.ex#L2)

Tesla adapter for HTTPower.

This adapter allows HTTPower to work with existing Tesla clients, enabling you
to add HTTPower's production features (circuit breakers, rate limiting, retry
logic, PCI logging) on top of your existing Tesla setup without rewriting your
HTTP infrastructure.

## Features

- Works with any Tesla client configuration
- Preserves Tesla middleware stack
- Supports all Tesla adapters (Finch, Hackney, Mint, Gun, etc.)
- Transparent pass-through of Tesla features

## Configuration

The Tesla adapter requires a Tesla client to be passed in the options:

    # Create your Tesla client
    tesla_client = Tesla.client([
      Tesla.Middleware.BaseUrl.new("https://api.example.com"),
      Tesla.Middleware.JSON,
      Tesla.Middleware.Logger
    ])

    # Use with HTTPower
    client = HTTPower.new(
      adapter: {HTTPower.Adapter.Tesla, tesla_client}
    )

    HTTPower.get(client, "/users")

## Testing

For testing, you can use Tesla's testing capabilities:

    # Use Tesla.Mock for testing
    Tesla.Mock.mock(fn
      %{method: :get, url: "https://api.example.com/users"} ->
        %Tesla.Env{status: 200, body: %{"users" => []}}
    end)

Or use HTTPower's test mode blocking:

    Application.put_env(:httpower, :test_mode, true)
    # Requests will be blocked unless using a test adapter

## Tesla Client Middleware

The Tesla adapter respects all middleware in your Tesla client:

- Authentication middleware (Bearer, Basic, OAuth)
- Retry middleware (note: disable if using HTTPower's retry)
- Logging middleware
- Custom middleware

## Important: JSON Middleware

If your Tesla client includes `Tesla.Middleware.JSON`, you should remove it
when wrapping with HTTPower. HTTPower handles JSON encoding/decoding via
`HTTPower.Codec`, and having both active will cause double-decoding:

    # Before (double-decoding risk)
    Tesla.client([Tesla.Middleware.JSON])

    # After (correct)
    Tesla.client([])  # HTTPower handles JSON via json: option

## Example

    # Define Tesla client with middleware
    defmodule MyApp.ApiClient do
      use Tesla

      plug Tesla.Middleware.BaseUrl, "https://api.example.com"
      plug Tesla.Middleware.JSON
      plug Tesla.Middleware.Headers, [{"authorization", "Bearer token"}]

      # Use Finch adapter
      adapter Tesla.Adapter.Finch, name: MyApp.Finch
    end

    # Wrap with HTTPower for production features
    tesla_client = MyApp.ApiClient.client()

    client = HTTPower.new(
      adapter: {HTTPower.Adapter.Tesla, tesla_client},
      circuit_breaker: [threshold: 5],  # Future feature
      rate_limit: [requests: 100, per: :second]  # Future feature
    )

    # Make requests - Tesla handles HTTP, HTTPower adds reliability
    {:ok, response} = HTTPower.get(client, "/users")

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*Consult [api-reference.md](api-reference.md) for complete listing*