add support for early responses 1xx (informational)

CHANGELOG.md

@@ -3,10 +3,11 @@
 This document records all notable changes to [HTTPie](https://httpie.io).
 This project adheres to [Semantic Versioning](https://semver.org/).
 
-## [4.0.0.b1](https://github.com/httpie/cli/compare/3.2.2...master) (unreleased)
+## [4.0.0](https://github.com/httpie/cli/compare/3.2.3...master) (unreleased)
 
 - Switched from the [`requests`](https://github.com/psf/requests) library to the compatible [`niquests`](https://github.com/jawah/niquests). ([#1531](https://github.com/httpie/cli/pull/1531))
 - Added support for HTTP/2, and HTTP/3 protocols. ([#523](https://github.com/httpie/cli/issues/523), [#692](https://github.com/httpie/cli/issues/692), [#1531](https://github.com/httpie/cli/pull/1531))
+- Added support for early (informational) responses. ([#752](https://github.com/httpie/cli/issues/752)) ([#1531](https://github.com/httpie/cli/pull/1531))
 - Added support for IPv4/IPv6 enforcement with `-6` and `-4`. ([#94](https://github.com/httpie/cli/issues/94), [#1531](https://github.com/httpie/cli/pull/1531))
 - Added support for alternative DNS resolvers via `--resolver`. DNS over HTTPS, DNS over TLS, DNS over QUIC, and DNS over UDP are accepted. ([#99](https://github.com/httpie/cli/issues/99), [#1531](https://github.com/httpie/cli/pull/1531))
 - Added support for binding to a specific network adapter with `--interface`. ([#1422](https://github.com/httpie/cli/issues/1422), [#1531](https://github.com/httpie/cli/pull/1531))

httpie/client.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import argparse
 import json
 import sys
@@ -43,7 +45,7 @@ def collect_messages(
     env: Environment,
     args: argparse.Namespace,
     request_body_read_callback: Callable[[bytes], None] = None,
-    prepared_request_readiness: Callable[[niquests.PreparedRequest], None] = None,
+    request_or_response_callback: Callable[[niquests.PreparedRequest | niquests.Response], None] = None,
 ) -> Iterable[RequestsMessage]:
     httpie_session = None
     httpie_session_headers = None
@@ -155,8 +157,8 @@ def collect_messages(
     # It will help us yield the request before it is
     # actually sent. This will permit us to know about
     # the connection information for example.
-    if prepared_request_readiness:
+    if request_or_response_callback:
-        hooks = {"pre_send": [prepared_request_readiness]}
+        hooks = {"pre_send": [request_or_response_callback], "early_response": [request_or_response_callback]}
 
     request = niquests.Request(**request_kwargs, hooks=hooks)
     prepared_request = requests_session.prepare_request(request)

httpie/core.py

@@ -3,6 +3,7 @@ import os
 import platform
 import sys
 import socket
+from time import monotonic
 from typing import List, Optional, Union, Callable
 
 import niquests
@@ -211,21 +212,26 @@ def program(args: argparse.Namespace, env: Environment) -> ExitStatus:
             downloader = Downloader(env, output_file=args.output_file, resume=args.download_resume)
             downloader.pre_request(args.headers)
 
-        def prepared_request_readiness(pr):
+        def request_or_response_callback(delayed_message):
-            """This callback is meant to output the request part. It is triggered by
+            """This callback is called in two scenario:
-            the underlying Niquests library just after establishing the connection."""
+
+            (i) just after initializing a connection to remote host
+            (ii) an early response has been received (1xx responses)"""
 
             oo = OutputOptions.from_message(
-                pr,
+                delayed_message,
                 args.output_options
             )
 
-            oo = oo._replace(
+            if hasattr(delayed_message, "body"):
-                body=isinstance(pr.body, (str, bytes)) and (args.verbose or oo.body)
+                oo = oo._replace(
-            )
+                    body=isinstance(delayed_message.body, (str, bytes)) and (args.verbose or oo.body)
+                )
+            else:
+                delayed_message._httpie_headers_parsed_at = monotonic()
 
             write_message(
-                requests_message=pr,
+                requests_message=delayed_message,
                 env=env,
                 output_options=oo,
                 processing_options=processing_options
@@ -238,7 +244,7 @@ def program(args: argparse.Namespace, env: Environment) -> ExitStatus:
             env,
             args=args,
             request_body_read_callback=request_body_read_callback,
-            prepared_request_readiness=prepared_request_readiness
+            request_or_response_callback=request_or_response_callback
         )
 
         force_separator = False

setup.cfg

@@ -71,7 +71,7 @@ install_requires =
     pip
     charset_normalizer>=2.0.0
     defusedxml>=0.6.0
-    niquests[socks]>=3.7
+    niquests[socks]>=3.9
     Pygments>=2.5.2
     setuptools
     importlib-metadata>=1.4.0; python_version<"3.8"

tests/test_early_response.py

@@ -0,0 +1,11 @@
+from .utils import http
+
+
+def test_early_response_show(remote_httpbin_secure):
+    r = http(
+        "--verify=no",
+        'https://early-hints.fastlylabs.com/'
+    )
+
+    assert "103 Early Hints" in r
+    assert "200 OK" in r