hypp

hypp is a client-oriented HTTP library for C++. It can parse and generate HTTP/1.1 messages and URIs.

To send or receive HTTP messages, you must use hypp along with another library such as hypr.

Conformance

hypp aims to conform to the syntax and semantics of HTTP/1.1 elements according to the following specification documents:

• RFC 3986 - Uniform Resource Identifier (URI): Generic Syntax
• RFC 5234 - Augmented BNF for Syntax Specifications: ABNF
• RFC 7230 - Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing
• RFC 7231 - Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content

Exceptions

• OPTIONAL requirements
• Obsolete grammar rules (e.g. obsolete line folding)

Error Handling

hypp's parser functions return an Expected object, which contains either the expected result or an Error. For more information, see the std::expected proposal or the Usage section below.

hypp treats unsupported HTTP versions as errors, and does not attempt to recover usable protocol elements from invalid constructs.

Usage

This is a work in progress. Usage in public applications is not yet recommended.

#include <iostream>
#include <hypp.hpp>

int main() {
  // Example response from RFC 7230 Section 2.1
  constexpr auto example =
      "HTTP/1.1 200 OK\r\n"
      "Date: Mon, 27 Jul 2009 12:28:53 GMT\r\n"
      "Server: Apache\r\n"
      "Last-Modified: Wed, 22 Jul 2009 19:15:56 GMT\r\n"
      "ETag: \"34aa387-d-1568eb00\"\r\n"
      "Accept-Ranges: bytes\r\n"
      "Content-Length: 51\r\n"
      "Vary: Accept-Encoding\r\n"
      "Content-Type: text/plain\r\n"
      "\r\n"
      "Hello World! My payload includes a trailing CRLF.\r\n";

  // Returns hypp::Expected<hypp::Response>
  const auto expected = hypp::ParseResponse(example);

  if (!expected) {
    std::cout << "Error: " << hypp::to_string(expected.error()) << '\n';
    return 1;
  }

  const auto& r = expected.value();
  std::cout << r.start_line.code << '\n';             // 200
  std::cout << r.header_fields.back().value << '\n';  // text/plain
  std::cout << r.body.substr(0, 12) << '\n';          // Hello World!

  return 0;
}

License

Licensed under the MIT License.