pingora-http

Active contributors: ewang, yuchen, andrew

Purpose

HTTP request and response header types that preserve case. Standard http crate types lowercase header names; Pingora needs to forward headers to upstreams that may care about original casing (notably some legacy origin servers and HTTP/1 clients sniffing for Set-Cookie exactly).

Directory layout

pingora-http/src/
├── lib.rs               RequestHeader, ResponseHeader, prelude
└── case_header_name.rs  Case-preserving header name storage

Key abstractions

Type	File	What it is
RequestHeader	pingora-http/src/lib.rs	HTTP request header (method, uri, headers, version) with case preservation
ResponseHeader	pingora-http/src/lib.rs	Counterpart for responses (added to prelude in 0.7.0)
CaseHeaderName	pingora-http/src/case_header_name.rs	Header name that remembers original case
IntoCaseHeaderName	pingora-http/src/lib.rs	Conversion trait for various string-y inputs
RequestHeader::insert_header_value etc.	pingora-http/src/lib.rs	Mutators that maintain case

How it works

The http crate's HeaderMap lowercases names. pingora-http builds on top of it by tracking original case in a side table keyed by header name. When you serialize a RequestHeader to the wire, the original casing is restored.

Otherwise the API mirrors http::request::Parts and http::response::Parts closely. RequestHeader is what ProxyHttp callbacks see for the downstream and upstream request; ResponseHeader is what they see for responses.

Integration points

• Re-exported as pingora::http::*.
• Used by every protocol implementation (pingora-core/src/protocols/http/) and the proxy.

Entry points for modification

• Adding a new convenience method → lib.rs. The file is ~1,100 lines; most of it is mutators and accessors that need to update both the lowercase map and the case side table.
• Header serialization changes → case_header_name.rs plus the writer code in pingora-core/src/protocols/http/v1/.

Key source files

File	Purpose
pingora-http/src/lib.rs	RequestHeader, ResponseHeader, prelude
pingora-http/src/case_header_name.rs	CaseHeaderName storage