Ada

Ada is a fast and spec-compliant URL parser written in C++. Specification for URL parser can be found from the WHATWG website.

Ada library also includes a URLPattern implementation that is compatible with the web-platform tests.

The Ada library passes the full range of tests from the specification, across a wide range of platforms (e.g., Windows, Linux, macOS). It fully supports the relevant Unicode Technical Standard.

A common use of a URL parser is to take a URL string and normalize it. The WHATWG URL specification has been adopted by most browsers. Other tools, such as curl and many standard libraries, follow the RFC 3986. The following table illustrates possible differences in practice (encoding of the host, encoding of the path):

string source	string value
input string	https://www.7‑Eleven.com/Home/Privacy/Montréal
ada's normalized string	https://www.xn--7eleven-506c.com/Home/Privacy/Montr%C3%A9al
curl 7.87	(returns the original unchanged)

Ada is fast.

On a benchmark where we need to validate and normalize thousands URLs found on popular websites, we find that ada can be several times faster than popular competitors (system: Apple MacBook 2022 with LLVM 14).

      ada ▏  188 ns/URL ███▏
servo url ▏  664 ns/URL ███████████▎
     CURL ▏ 1471 ns/URL █████████████████████████

Ada has improved the performance of the popular JavaScript environment Node.js:

Since Node.js 18, a new URL parser dependency was added to Node.js — Ada. This addition bumped the Node.js performance when parsing URLs to a new level. Some results could reach up to an improvement of 400%. (State of Node.js Performance 2023)

The Ada library is used by important systems besides Node.js such as Redpanda, Kong, Telegram and Cloudflare Workers.

Requirements

The project is otherwise self-contained and it has no dependency. A recent C++ compiler supporting C++20. We test GCC 12 or better, LLVM 14 or better and Microsoft Visual Studio 2022.

Installation

Binary packages for the following systems are currently available:

Quick Start

Linux or macOS users might follow the following instructions if they have a recent C++ compiler installed and a standard utility (wget)

1. Pull the library in a directory

   wget https://github.com/ada-url/ada/releases/download/v3.0.0/ada.cpp
   wget https://github.com/ada-url/ada/releases/download/v3.0.00/ada.h
   

2. Create a new file named demo.cpp with this content:

    #include "ada.cpp"
    #include "ada.h"
    #include <iostream>
   
    int main(int, char *[]) {
      auto url = ada::parse("https://www.google.com");
      if (!url) {
        std::cout << "failure" << std::endl;
        return EXIT_FAILURE;
      }
      url->set_protocol("http");
      std::cout << url->get_protocol() << std::endl;
      std::cout << url->get_host() << std::endl;
      return EXIT_SUCCESS;
    }

3. Compile

   c++ -std=c++20 -o demo demo.cpp
   

4. ./demo

   http:
   www.google.com
   

Bindings of Ada

The following libraries are maintained by the Ada team and available under Ada GitHub organization.

• Rust: Rust bindings for Ada
• Go: Go bindings for Ada
• Python: Python bindings for Ada

Community maintained

• R: R wrapper for Ada
• PHP: PHP Wrapper for Ada URL
• LuaJIT: LuaJIT FFI bindings for Ada
• Zig: Unofficial Zig bindings for Ada
• Python: Python bindings for Ada
• React Native: A Fast URL and URLSearchParams polyfill for React Native.
• D: D bindings for Ada, @nogc, nothrow and @safe compat.

Usage

Ada supports two types of URL instances, ada::url and ada::url_aggregator. The usage is the same in either case: we have an parsing function template ada::parse which can return either a result of type ada::result<ada::url> or of type ada::result<ada::url_aggregator> depending on your needs. The ada::url_aggregator class is smaller and it is backed by a precomputed serialized URL string. The ada::url class is made of several separate strings for the various components (path, host, and so forth).

Parsing & Validation

• Parse and validate a URL from an ASCII or a valid UTF-8 string.

auto url = ada::parse<ada::url_aggregator>("https://www.google.com");
if (url) { /* URL is valid */ }

After calling 'parse', you must check that the result is valid before accessing it when you are not sure that it will succeed. The following code is unsafe:

auto> url = ada::parse<ada::url_aggregator>("some bad url");
url->get_href();

For simplicity, in the examples below, we skip the check because we know that parsing succeeds. All strings are assumed to be valid UTF-8 strings.

Examples

URL Parser

auto url = ada::parse<ada::url_aggregator>("https://www.google.com");

url->set_username("username"); // Update credentials
url->set_password("password");
// ada->get_href() will return "https://username:[email protected]/"

url->set_protocol("wss"); // Update protocol
// url->get_protocol() will return "wss:"

url->set_host("github.com"); // Update host
// url->get_host() will return "github.com"

url->set_port("8080"); // Update port
// url->get_port() will return "8080"

url->set_pathname("/my-super-long-path"); // Update pathname
// url->get_pathname() will return "/my-super-long-path"

url->set_search("target=self"); // Update search
// url->get_search() will return "?target=self"

url->set_hash("is-this-the-real-life"); // Update hash/fragment
// url->get_hash() will return "#is-this-the-real-life"

URL Search Params

ada::url_search_params search_params("a=b&c=d&e=f");
search_params.append("g=h");

search_params.get("g");  // will return "h"

auto keys = search_params.get_keys();
while (keys.has_next()) {
  auto key = keys.next();  // "a", "c", "e", "g"
}

URLPattern

Our implementation doesn't provide a regex engine and leaves the decision of choosing the right engine to the user. This is done as a security measure since the default std::regex engine is not safe and open to DDOS attacks. Runtimes like Node.js and Cloudflare Workers use the V8 regex engine, which is safe and performant.

// Define a regex engine that conforms to the following interface
// For example we will use v8 regex engine

class v8_regex_provider {
 public:
  v8_regex_provider() = default;
  using regex_type = v8::Global<v8::RegExp>;
  static std::optional<regex_type> create_instance(std::string_view pattern,
                                                   bool ignore_case);
  static std::optional<std::vector<std::optional<std::string>>> regex_search(
      std::string_view input, const regex_type& pattern);
  static bool regex_match(std::string_view input, const regex_type& pattern);
};

// Define a URLPattern
auto pattern = ada::parse_url_pattern<v8_regex_provider>("/books/:id(\\d+)", "https://example.com");

// Check validity
if (!pattern) { return EXIT_FAILURE; }

// Match a URL
auto match = pattern->match("https://example.com/books/123");

// Test a URL
auto matched = pattern->test("https://example.com/books/123");

C wrapper

See the file include/ada_c.h for our C interface. We expect ASCII or UTF-8 strings.

#include "ada_c.h"
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>

static void ada_print(ada_string string) {
  printf("%.*s\n", (int)string.length, string.data);
}

int main(int c, char *arg[] ) {
  const char* input =
      "https://username:[email protected]:8080/"
      "pathname?query=true#hash-exists";
  ada_url url = ada_parse(input, strlen(input));
  if(!ada_is_valid(url)) { puts("failure"); return EXIT_FAILURE; }
  ada_print(ada_get_href(url)); // prints https://username:password@host:8080/pathname?query=true#hash-exists
  ada_print(ada_get_protocol(url)); // prints https:
  ada_print(ada_get_username(url)); // prints username
  ada_set_href(url, "https://www.yagiz.co", strlen("https://www.yagiz.co"));  
  if(!ada_is_valid(url)) { puts("failure"); return EXIT_FAILURE; }
  ada_set_hash(url, "new-hash", strlen("new-hash"));
  ada_set_hostname(url, "new-host", strlen("new-host"));
  ada_set_host(url, "changed-host:9090", strlen("changed-host:9090"));
  ada_set_pathname(url, "new-pathname", strlen("new-pathname"));
  ada_set_search(url, "new-search", strlen("new-search"));
  ada_set_protocol(url, "wss", 3);  
  ada_print(ada_get_href(url)); // will print wss://changed-host:9090/new-pathname?new-search#new-hash

  // Manipulating search params
  ada_string search = ada_get_search(url);
  ada_url_search_params search_params =
      ada_parse_search_params(search.data, search.length);
  ada_search_params_append(search_params, "a", 1, "b", 1);
  ada_owned_string result = ada_search_params_to_string(search_params);
  ada_set_search(url, result.data, result.length);
  ada_free_owned_string(result);
  ada_free_search_params(search_params);

  ada_free(url);
  return EXIT_SUCCESS;
}

When linking against the ada library from C++, be minding that ada requires access to the standard C++ library. E.g., you may link with the C++ compiler.

E.g., if you grab our single-header C++ files (ada.cpp and ada.h), as well as the C header (ada_c.h), you can often compile a C program (demo.c) as follows under Linux/macOS systems:

c++ -c ada.cpp -std=c++20
cc -c demo.c
c++ demo.o ada.o -o cdemo
./cdemo

Command-line interface

For more information about command-line options, please refer to the CLI documentation.

CMake dependency

See the file tests/installation/CMakeLists.txt for an example of how you might use ada from your own CMake project, after having installed ada on your system.

Contributing

Building

Ada uses cmake as a build system, but also supports Bazel. It's recommended you to run the following commands to build it locally.

Without tests:

• Build: cmake -B build && cmake --build build

With tests (requires git):

• Build: cmake -B build -DADA_TESTING=ON && cmake --build build
• Test: ctest --output-on-failure --test-dir build

With tests (requires available local packages):

• Build: cmake -B build -DADA_TESTING=ON -D CPM_USE_LOCAL_PACKAGES=ON && cmake --build build
• Test: ctest --output-on-failure --test-dir build

Windows users need additional flags to specify the build configuration, e.g. --config Release.

The project can also be built via docker using default docker file of repository with following commands.

docker build -t ada-builder . && docker run --rm -it -v ${PWD}:/repo ada-builder

Amalgamation

You may amalgamate all source files into only two files (ada.h and ada.cpp) by typing executing the Python 3 script singleheader/amalgamate.py. By default, the files are created in the singleheader directory.

License

This code is made available under the Apache License 2.0 as well as the MIT license.

Our tests include third-party code and data. The benchmarking code includes third-party code: it is provided for research purposes only and not part of the library.

Further reading

• Yagiz Nizipli, Daniel Lemire, Parsing Millions of URLs per Second, Software: Practice and Experience 54(5) May 2024.