117 lines
3.6 KiB
Markdown
117 lines
3.6 KiB
Markdown
<img alt="Finch" height="350px" src="assets/Finch_logo_onWhite.png#gh-light-mode-only">
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<img alt="Finch" height="350px" src="assets/Finch_logo_all-White.png#gh-dark-mode-only">
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[](https://github.com/sneako/finch/actions) [](https://hex.pm/packages/finch) [](https://hexdocs.pm/finch/)
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<!-- MDOC !-->
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An HTTP client with a focus on performance, built on top of
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[Mint](https://github.com/elixir-mint/mint) and [NimblePool](https://github.com/dashbitco/nimble_pool).
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We attempt to achieve this goal by providing efficient connection pooling strategies and avoiding copying of memory wherever possible.
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Most developers will most likely prefer to use the fabulous HTTP client [Req](https://github.com/wojtekmach/req) which takes advantage of Finch's pooling and provides an extremely friendly and pleasant to use API.
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## Usage
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In order to use Finch, you must start it and provide a `:name`. Often in your
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supervision tree:
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```elixir
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children = [
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{Finch, name: MyFinch}
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]
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```
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Or, in rare cases, dynamically:
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```elixir
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Finch.start_link(name: MyFinch)
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```
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Once you have started your instance of Finch, you are ready to start making requests:
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```elixir
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Finch.build(:get, "https://hex.pm") |> Finch.request(MyFinch)
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```
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When using HTTP/1, Finch will parse the passed in URL into a `{scheme, host, port}`
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tuple, and maintain one or more connection pools for each `{scheme, host, port}` you
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interact with.
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You can also configure a pool size and count to be used for specific URLs that are
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known before starting Finch. The passed URLs will be parsed into `{scheme, host, port}`,
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and the corresponding pools will be started. See `Finch.start_link/1` for configuration
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options.
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```elixir
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children = [
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{Finch,
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name: MyConfiguredFinch,
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pools: %{
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:default => [size: 10],
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"https://hex.pm" => [size: 32, count: 8]
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}}
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]
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```
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Pools will be started for each configured `{scheme, host, port}` when Finch is started.
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For any unconfigured `{scheme, host, port}`, the pool will be started the first time
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it is requested. Note pools are not automatically terminated by default, if you need to
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terminate them after some idle time, use the `pool_max_idle_time` option (available only for HTTP1 pools).
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## Telemetry
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Finch uses Telemetry to provide instrumentation. See the `Finch.Telemetry`
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module for details on specific events.
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## Logging TLS Secrets
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Finch supports logging TLS secrets to a file. These can be later used in a tool such as
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Wireshark to decrypt HTTPS sessions. To use this feature you must specify the file to
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which the secrets should be written. If you are using TLSv1.3 you must also add
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`keep_secrets: true` to your pool `:transport_opts`. For example:
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```elixir
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{Finch,
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name: MyFinch,
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pools: %{
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default: [conn_opts: [transport_opts: [keep_secrets: true]]]
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}}
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```
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There are two different ways to specify this file:
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1. The `:ssl_key_log_file` connection option in your pool configuration. For example:
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```elixir
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{Finch,
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name: MyFinch,
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pools: %{
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default: [
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conn_opts: [
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ssl_key_log_file: "/writable/path/to/the/sslkey.log"
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]
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]
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}}
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```
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2. Alternatively, you could also set the `SSLKEYLOGFILE` environment variable.
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<!-- MDOC !-->
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## Installation
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The package can be installed by adding `finch` to your list of dependencies in `mix.exs`:
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```elixir
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def deps do
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[
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{:finch, "~> 0.19"}
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]
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end
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```
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The docs can be found at [https://hexdocs.pm/finch](https://hexdocs.pm/finch).
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