Struct template header_t

Boost C++ Libraries

Struct template header_t

boost::taar::matcher::header_t — A placeholder that produces matchers over individual request headers.

Synopsis

// In header: <boost/taar/matcher/header.hpp>

template<typename FieldsType = boost::beast::http::fields> 
struct header_t {
  // types
  typedef boost::beast::http::request_header< FieldsType > request_type;  // The request type these matchers accept. 

  // member classes/structs/unions

  // A handle to a particular header by key.
  template<typename KeyType> 
  struct header_item {

    // friend functions
    auto exist(header_item);

    // public data members
    KeyType key;    // The header key this item refers to. 
  };

  // public member functions
  auto operator()(boost::beast::http::field) const;
  auto operator()(std::string) const;
};

Description

header_t is not used directly; call its function-call operator with a well-known boost::beast::http::field value or a string field name to obtain a header_item, then compose that with the equality operators or with the free function exist().

using boost::taar::matcher::header;
namespace http = boost::beast::http;

auto is_json   = header(http::field::content_type) == "application/json";
auto has_auth  = exist(header("X-Auth"));

The produced operand carries header_eq_constraint, header_ne_constraint, or header_exists_constraint metadata with the field key (as a header_key variant) and the constrained value in its captures tuple. Existence matchers leave the captured value empty.

Template Parameters

```
typename FieldsType = boost::beast::http::fields
```
The Beast HTTP fields container of the request to inspect. Defaults to boost::beast::http::fields.

`header_t` public member functions

auto operator()(boost::beast::http::field field) const;

Build a header_item for a well-known Beast field.

```
auto operator()(std::string field) const;
```
Build a header_item for an arbitrary header name.