fhttp

Features

Ordered Headers

The package allows for both pseudo header order and normal header order. Most of the code is from this this Pull Request.

Note on HTTP/1.1 header order Although the header key is capitalized, the header order slice must be in lowercase.

	req.Header = http.Header{
		"X-NewRelic-ID":         {"12345"},
		"x-api-key":             {"ABCDE12345"},
		"MESH-Commerce-Channel": {"android-app-phone"},
		"mesh-version":          {"cart=4"},
		"X-Request-Auth":        {"hawkHeader"},
		"X-acf-sensor-data":     {"3456"},
		"Content-Type":          {"application/json; charset=UTF-8"},
		"Accept":                {"application/json"},
		"Transfer-Encoding":     {"chunked"},
		"Host":                  {"example.com"},
		"Connection":            {"Keep-Alive"},
		"Accept-Encoding":       {"gzip"},
		HeaderOrderKey: {
			"x-newrelic-id",
			"x-api-key",
			"mesh-commerce-channel",
			"mesh-version",
			"user-agent",
			"x-request-auth",
			"x-acf-sensor-data",
			"transfer-encoding",
			"content-type",
			"accept",
			"host",
			"connection",
			"accept-encoding",
		},
		PHeaderOrderKey: {
			":method",
			":path",
			":authority",
			":scheme",
		},
	}

Connection settings

fhhtp has Chrome-like connection settings, as shown below:

SETTINGS_HEADER_TABLE_SIZE = 65536 (2^16)
SETTINGS_ENABLE_PUSH = 1
SETTINGS_MAX_CONCURRENT_STREAMS = 1000
SETTINGS_INITIAL_WINDOW_SIZE = 6291456
SETTINGS_MAX_FRAME_SIZE = 16384 (2^14)
SETTINGS_MAX_HEADER_LIST_SIZE = 262144 (2^18)

The default net/http settings, on the other hand, are the following:

SETTINGS_HEADER_TABLE_SIZE = 4096
SETTINGS_ENABLE_PUSH = 0
SETTINGS_MAX_CONCURRENT_STREAMS = unlimited
SETTINGS_INITIAL_WINDOW_SIZE = 4194304
SETTINGS_MAX_FRAME_SIZE = 16384
SETTINGS_MAX_HEADER_LIST_SIZE = 10485760

The ENABLE_PUSH implementation was merged from this Pull Request.

Pseudo header order

fhttp supports pseudo header order for http2, helping mitigate fingerprinting. You can read more about how it works here.

Backward compatible with net/http

Although this library is an extension of net/http, it is also meant to be backward compatible. Replacing

import (
   "net/http"
)

with

import (
    http "github.com/Danny-Dasilva/fhttp"
)

SHOULD not break anything.

Versatile Content-Length and Transfer-Encoding headers

fhttp user to set custom Content-Length and Transfer-Encoding headers of all types.

To set an empty Content-Length header

req.Header = http.Header{
	"Content-Length": {http.ContentLengthEmpty},
}

To ignore setting the Content-Length header

req.Header = http.Header{
    "Content-Length": {http.ContentLengthDelete},
}

Any Content-Length or Transfer-Encoding headers set will be prioritized and fhttp will not set proper Content-length or Transfer-Encoding headers

Credits

Special thanks to the following people for helping me with this project.

• cc for guiding me when I first started this project and inspiring me with cclient

• umasi for being good rubber ducky and giving me tips for http2 headers