rest_verb.h

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// Copyright (c) Microsoft Corporation. All rights reserved.
// Licensed under the Apache 2.0 License.
#pragma once
 
#include "ccf/ds/hash.h"
 
#include <llhttp/llhttp.h>
#include <string>
 
namespace ccf
{
  static inline llhttp_method http_method_from_str(const std::string_view& s)
  {
    const auto hashed_name = ccf::ds::fnv_1a<size_t>(s);
 
#define XX(num, name, string) \
  case (ccf::ds::fnv_1a<size_t>(#string)): \
  { \
    return llhttp_method(num); \
  }
 
    switch (hashed_name)
    {
      HTTP_METHOD_MAP(XX)
 
      default:
      {
        throw std::logic_error(fmt::format("Unknown HTTP method '{}'", s));
      }
    }
#undef XX
  }
 
  class RESTVerb
  {
  private:
    int verb;
 
  public:
    RESTVerb() : verb(std::numeric_limits<int>::min()) {}
    RESTVerb(const llhttp_method& hm) : verb(hm) {}
    RESTVerb(const std::string& s)
    {
      verb = http_method_from_str(s.c_str());
    }
 
    std::optional<llhttp_method> get_http_method() const
    {
      return static_cast<llhttp_method>(verb);
    }
 
    const char* c_str() const
    {
      return llhttp_method_name(static_cast<llhttp_method>(verb));
    }
 
    bool operator<(const RESTVerb& o) const
    {
      return verb < o.verb;
    }
 
    bool operator==(const RESTVerb& o) const
    {
      return verb == o.verb;
    }
 
    bool operator!=(const RESTVerb& o) const
    {
      return !(*this == o);
    }
  };
 
  // Custom to_json and from_json specializations which encode RESTVerb in a
  // lower-cased string, so it can be used in OpenAPI and similar documents
  inline void to_json(nlohmann::json& j, const RESTVerb& verb)
  {
    std::string s(verb.c_str());
    ccf::nonstd::to_lower(s);
    j = s;
  }
 
  inline void from_json(const nlohmann::json& j, RESTVerb& verb)
  {
    if (!j.is_string())
    {
      throw std::runtime_error(fmt::format(
        "Cannot parse RESTVerb from non-string JSON value: {}", j.dump()));
    }
 
    std::string s = j.get<std::string>();
    ccf::nonstd::to_upper(s);
 
    verb = RESTVerb(s.c_str());
  }
 
  inline std::string schema_name(const RESTVerb*)
  {
    return "HttpMethod";
  }
 
  inline void fill_json_schema(nlohmann::json& schema, const RESTVerb*)
  {
    schema["type"] = "string";
  }
}