describe_endpoint.h File Reference

GET /actions, on whichever server happens to hold the port. More...

#include <functional>
#include <memory>
#include <optional>
#include <string>
#include <string_view>
#include <absl/base/nullability.h>
#include <absl/status/statusor.h>
#include "a11/concurrency/future.h"
#include "a11/net/http2.h"

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Classes
struct	a11::net::DescribeEndpointOptions
	Where and whether a server answers discovery over plain HTTP. More...

Namespaces
namespace	a11
namespace	a11::net

Typedefs
using	a11::net::DescribeActionsHandler = std::function< absl::StatusOr< std::string >(std::string_view name, std::string_view query)>
	Answers a discovery request without opening a wire stream.

Functions
bool	a11::net::MatchDescribePath (std::string_view path, const DescribeEndpointOptions &options, std::string *absl_nonnull name)
	Whether path addresses the describe endpoint, and what it names.
std::optional< a11::Task >	a11::net::TryDescribeOverHttp (const DescribeEndpointOptions &options, const HttpRequest &request, const std::shared_ptr< Http2ResponseWriter > &response, HttpHeaders extra_headers={})
	Answers request from options, if it is addressed to it.
std::string_view	a11::net::QueryOfPath (std::string_view path)
	The query part of path, without the ?.

Variables
constexpr std::string_view	a11::net::kDefaultDescribeEndpoint = "/actions"
	Default path serving the action descriptors.

Detailed Description

GET /actions, on whichever server happens to hold the port.

A11 is a protocol before it is an HTTP API, and discovery is an action (__list_actions__) that works over every transport. These endpoints exist anyway, because a service is a thing people curl, and because the answer to "what is listening on 8011" should not require an A11 client to ask.

Why a function and not a registry. a11::net sits below a11::actions – the dependency runs net -> actions, never back – so an options struct here cannot hold an ActionRegistry. What it holds instead is a callback the layer above fills in, which has the useful side effect that the endpoint and the action are answered by the same describer and so cannot disagree.