0_18_0.md

doc/release_notes/0_18_0.md
Last Update: 2021-11-23 10:43:08 +0000

0.18.0

Features

Response Cache

gitlab.com/honeyryderchuck/httpx/-/wikis/Response-Cache

The :response_cache plugin handles transparent usage of HTTP caching and conditional requests to improve performance and bandwidth usage.

client = HTTPX.plugin(:response_cache)
r1 = client.get("https://nghttp2.org/httpbin/cache")
r2 = client.get("https://nghttp2.org/httpbin/cache")

r1.status #=> 200
r2.status #=> 304
r1.body == r2.body #=> true

jitter on “retry-after”

On the :retries plugin, jitter calculation is now applied to the value in seconds defined by user after which a request should be retried (i.e. if :retry_after option is set to 2, the retry interval may be 1.5422312 seconds, for example). This is important to avoid cases of synchronized “thundering herd”, where server rejects requests, but they all get retried at the same time because the retry interval is exactly the same.

You can override the jitter calculation function by using the :retry_jitter option:

HTTPX.plugin(:retries, retry_after: 2, retry_jitter: ->(interval) { interval + rand }) # interval is 3

You can opt out of this by setting HTTPX_NO_JITTER=1 environment variable.

Response#error

HTTPX::Response#error was added, to match HTTPX::Response#error. It returns an exception for 4xx/5xx responses (HTTPX::HTTPError), nil otherwise. It allows for end users to write such code:

if (response = HTTPX.get(uri)).error
  # success
else
  #error
end

Improvements

timers not a dependency

The functionality provided by the timers gem was replaced by a simpler custom implementation. Although powerful, its complexity was somewhat unnecessary for httpx's simpler event loop, where user-defined timeouts are usually the same for a given batch of requests. The removal of timers reduces the number of dependencies to 1, which is http-2-next and is maintained by me.

AWS plugins

  • aws_sdk_authentication plugin: removed implementation relying on aws-sdk-s3, replacing it with an aws-sdk-core relying implementation, which only uses credentials strategies and region discovery (the whole point of this SDK is to use a minimal subset of AWS SDK).

Bugfixes

  • Fixed Error class declaration on response decoders when mime type is invalid (gitlab.com/honeyryderchuck/httpx/-/merge_requests/166).

  • ErrorResponse#to_s now removes ANSI escape sequences from error backtraces.

  • Persistent connections were kept around both in the pool and in the selector; the first is necessary, but the second caused busy loop scenarios all over; they are now removed when no requests are being handled.

  • Connections which failed connection handshake were removed from the pool, but not from the selector list, causing busy loop scenarios in a few cases; this has been fixed.

  • Fixed issue where HTTP/2 streams were being closed twice (and signaling it also twice), messing connection accounting in the pool.

  • DoH resolver was always subscribed to the default thread "connection pool", which broke scenarios were session was patched to use its custom pool; it now ensures that it subscribes to the pool it was created in.

  • :aws_sigv4 plugin: removed require of aws-sdk-s3, left there by mistake (the whole point of the plugin is to run without the AWS SDK).

    Chore

  • HTTPX::ErrorResponse#status is now deprecated.