#include <userver/server/handlers/http_handler_base.hpp>

Detailed Description

Base class for all the Userver HTTP Handlers.

Static options:

Inherits all the options from server::handlers::HandlerBase and adds the following ones:

Name	Description	Default value
log-level	overrides log level for this handle	<no override>
status-codes-log-level	map of "status": log_level items to override span log level for specific status codes	{}
middlewares.pipeline-builder	name of a component to build a middleware pipeline for this particular handler	default-handler-middleware-pipeline-builder

Example usage:

#pragma once
 
#include <userver/components/component_list.hpp>
#include <userver/server/handlers/http_handler_base.hpp>
 
// Note: this is for the purposes of tests/samples only
#include <userver/utest/using_namespace_userver.hpp>
 
namespace samples::hello {
 
class HelloHandler final : public server::handlers::HttpHandlerBase {
public:
    // `kName` is used as the component name in static config
    static constexpr std::string_view kName = "handler-hello-sample";
 
    // Component is valid after construction and is able to accept requests
    using HttpHandlerBase::HttpHandlerBase;
 
    std::string HandleRequestThrow(const server::http::HttpRequest& request, server::request::RequestContext&)
        const override;
};
 
}  // namespace samples::hello

#include "hello_handler.hpp"
 
#include "say_hello.hpp"
 
namespace samples::hello {
 
std::string HelloHandler::
    HandleRequestThrow(const server::http::HttpRequest& request, server::request::RequestContext& /*request_context*/)
        const {
    // Setting Content-Type: text/plain in a microservice response ensures
    // the client interprets it as plain text, preventing misinterpretation or
    // errors. Without this header, the client might assume a different format,
    // such as JSON, HTML or XML, leading to potential processing issues or
    // incorrect handling of the data.
    request.GetHttpResponse().SetContentType(http::content_type::kTextPlain);
    return samples::hello::SayHelloTo(request.GetArg("name"));
}
 
}  // namespace samples::hello

Examples: postgresql/functional_tests/basic_chaos/postgres_service.cpp, samples/hello_service/src/hello_handler.hpp, samples/http_caching/http_caching.cpp, samples/mongo_service/mongo_service.cpp, samples/multipart_service/service.cpp, samples/postgres_auth/postgres_service.cpp, samples/postgres_service/postgres_service.cpp, and samples/redis_service/redis_service.cpp.

Definition at line 66 of file http_handler_base.hpp.

Inheritance diagram for server::handlers::HttpHandlerBase:

Public Member Functions
	HttpHandlerBase (const components::ComponentConfig &config, const components::ComponentContext &component_context, bool is_monitor=false)

void	HandleRequest (request::RequestBase &request, request::RequestContext &context) const override

void	ReportMalformedRequest (request::RequestBase &request) const final

virtual const std::string &	HandlerName () const

const std::vector< http::HttpMethod > &	GetAllowedMethods () const

virtual logging::Level	GetLogLevelForResponseStatus (http::HttpStatus status) const

virtual FormattedErrorData	GetFormattedExternalErrorBody (const CustomHandlerException &exc) const

std::string	GetResponseDataForLoggingChecked (const http::HttpRequest &request, request::RequestContext &context, const std::string &response_data) const

void	HandleCustomHandlerException (const http::HttpRequest &request, const CustomHandlerException &ex) const

void	HandleUnknownException (const http::HttpRequest &request, const std::exception &ex) const

void	LogUnknownException (const std::exception &ex, std::optional< logging::Level > log_level_override={}) const
	Helper function to log an unknown exception.

const std::optional< logging::Level > &	GetLogLevel () const
	Returns the default log level for the handler.

bool	IsMonitor () const
	Returns whether this is a monitoring handler.

const HandlerConfig &	GetConfig () const
	Returns handler config.

ComponentHealth	GetComponentHealth () const override

void	OnLoadingCancelled () override

void	OnAllComponentsLoaded () override

void	OnAllComponentsAreStopping () override

Static Public Member Functions
static yaml_config::Schema	GetStaticConfigSchema ()

Protected Types
using	HandlerErrorCode = handlers::HandlerErrorCode

using	InternalMessage = handlers::InternalMessage

using	ExternalBody = handlers::ExternalBody

using	ClientError = handlers::ClientError

using	InternalServerError = handlers::InternalServerError

using	LoggableComponentBase = ComponentBase
	Legacy alias, use ComponentBase instead.

Protected Member Functions
void	ThrowUnsupportedHttpMethod (const http::HttpRequest &request) const

virtual std::string	HandleRequestThrow (const http::HttpRequest &request, request::RequestContext &context) const

virtual void	HandleStreamRequest (const server::http::HttpRequest &, server::request::RequestContext &, server::http::ResponseBodyStream &) const

virtual bool	IsStreamed () const

virtual bool	IsMethodStatisticIncluded () const

virtual bool	NeedCheckAuth () const

virtual std::string	GetRequestBodyForLogging (const http::HttpRequest &request, request::RequestContext &context, const std::string &request_body) const
	Override it if you need a custom request body logging.

virtual std::string	GetResponseDataForLogging (const http::HttpRequest &request, request::RequestContext &context, const std::string &response_data) const
	Override it if you need a custom response data logging.

virtual void	ParseRequestData (const http::HttpRequest &, request::RequestContext &) const

virtual std::string	GetMetaType (const http::HttpRequest &) const

Member Typedef Documentation

◆ ClientError

using server::handlers::HandlerBase::ClientError = handlers::ClientError

protectedinherited

Definition at line 80 of file handler_base.hpp.

◆ ExternalBody

using server::handlers::HandlerBase::ExternalBody = handlers::ExternalBody

protectedinherited

Definition at line 78 of file handler_base.hpp.

◆ HandlerErrorCode

using server::handlers::HandlerBase::HandlerErrorCode = handlers::HandlerErrorCode

protectedinherited

Definition at line 76 of file handler_base.hpp.

◆ InternalMessage

using server::handlers::HandlerBase::InternalMessage = handlers::InternalMessage

protectedinherited

Definition at line 77 of file handler_base.hpp.

◆ InternalServerError

using server::handlers::HandlerBase::InternalServerError = handlers::InternalServerError

protectedinherited

Definition at line 81 of file handler_base.hpp.

◆ LoggableComponentBase

using components::ComponentBase::LoggableComponentBase = ComponentBase

protectedinherited

Legacy alias, use ComponentBase instead.

Definition at line 67 of file component_base.hpp.

Member Function Documentation

◆ GetComponentHealth()

ComponentHealth components::ComponentBase::GetComponentHealth ( ) const

inlineoverridevirtualinherited

Override this function to inform the world of the state of your component.

Warning: The function is called concurrently from multiple threads.

Reimplemented from components::RawComponentBase.

Reimplemented in server::handlers::Restart.

Definition at line 35 of file component_base.hpp.

◆ GetLogLevelForResponseStatus()

virtual logging::Level server::handlers::HttpHandlerBase::GetLogLevelForResponseStatus ( http::HttpStatus status ) const

virtual

Override it if you need a custom logging level for messages about finish of request handling for some http statuses.

◆ GetRequestBodyForLogging()

virtual std::string server::handlers::HttpHandlerBase::GetRequestBodyForLogging	(	const http::HttpRequest &	request,
		request::RequestContext &	context,
		const std::string &	request_body ) const

protectedvirtual

Override it if you need a custom request body logging.

Reimplemented in server::handlers::HttpHandlerFlatbufBase< InputType, ReturnType >.

◆ GetResponseDataForLogging()

virtual std::string server::handlers::HttpHandlerBase::GetResponseDataForLogging	(	const http::HttpRequest &	request,
		request::RequestContext &	context,
		const std::string &	response_data ) const

protectedvirtual

Override it if you need a custom response data logging.

Reimplemented in server::handlers::HttpHandlerFlatbufBase< InputType, ReturnType >.

◆ HandleCustomHandlerException()

void server::handlers::HttpHandlerBase::HandleCustomHandlerException	(	const http::HttpRequest &	request,
		const CustomHandlerException &	ex ) const

Takes the exception and formats it into response, as specified by exception.

◆ HandleRequest()

void server::handlers::HttpHandlerBase::HandleRequest	(	request::RequestBase &	request,
		request::RequestContext &	context ) const

overridevirtual

Parses request, executes processing routines, and fills response accordingly. Does not throw.

Implements server::handlers::HandlerBase.

◆ HandleRequestThrow()

virtual std::string server::handlers::HttpHandlerBase::HandleRequestThrow	(	const http::HttpRequest &	request,
		request::RequestContext &	context ) const

protectedvirtual

The core method for HTTP request handling. request arg contains HTTP headers, full body, etc. The method should return response body.

Note: It is used only if IsStreamed() returned false.

Reimplemented in server::handlers::DnsClientControl, server::handlers::Jemalloc, server::handlers::Restart, server::handlers::DynamicDebugLog, server::handlers::HttpHandlerStatic, server::handlers::LogLevel, server::handlers::OnLogRotate, server::handlers::ServerMonitor, server::handlers::HttpHandlerFlatbufBase< InputType, ReturnType >, server::handlers::HttpHandlerJsonBase, server::handlers::Ping, and server::handlers::ImplicitOptions.

Examples: samples/http_caching/http_caching.cpp.

◆ HandleStreamRequest()

virtual void server::handlers::HttpHandlerBase::HandleStreamRequest	(	const server::http::HttpRequest &	,
		server::request::RequestContext &	,
		server::http::ResponseBodyStream &	) const

protectedvirtual

The core method for HTTP request handling. request arg contains HTTP headers, full body, etc. The response body is passed in parts to ResponseBodyStream. Stream transmission is useful when: 1) The body size is unknown beforehand. 2) The client may take advantage of early body transmission (e.g. a Web Browser may start rendering the HTML page or downloading dependant resources). 3) The body size is huge and we want to have only a part of it in memory.

Note: It is used only if IsStreamed() returned true.

◆ HandleUnknownException()

void server::handlers::HttpHandlerBase::HandleUnknownException	(	const http::HttpRequest &	request,
		const std::exception &	ex ) const

Takes the exception and formats it into response as an internal server error.

◆ IsMethodStatisticIncluded()

virtual bool server::handlers::HttpHandlerBase::IsMethodStatisticIncluded ( ) const

inlineprotectedvirtual

Override it to show per HTTP-method statistics besides statistics for all methods

Definition at line 154 of file http_handler_base.hpp.

◆ IsMonitor()

bool server::handlers::HandlerBase::IsMonitor ( ) const

inlineinherited

Returns whether this is a monitoring handler.

Definition at line 67 of file handler_base.hpp.

◆ IsStreamed()

virtual bool server::handlers::HttpHandlerBase::IsStreamed ( ) const

inlineprotectedvirtual

If IsStreamed() returns true, call HandleStreamRequest() for request handling, HandleRequestThrow() is not called. If it returns false, HandleRequestThrow() is called instead, and HandleStreamRequest() is not called.

Note: The default implementation returns the cached value of "response-body-streamed" value from static config.

Definition at line 150 of file http_handler_base.hpp.

◆ NeedCheckAuth()

virtual bool server::handlers::HttpHandlerBase::NeedCheckAuth ( ) const

inlineprotectedvirtual

Override it if you want to disable auth checks in handler by some condition

Definition at line 158 of file http_handler_base.hpp.

◆ OnAllComponentsAreStopping()

void components::ComponentBase::OnAllComponentsAreStopping ( )

inlineoverridevirtualinherited

Component may use this function to stop doing work before the stop of the components that depend on it.

Base components may override it and make final to do some work before the derived object constructor is called. Don't use it otherwise.

Reimplemented from components::RawComponentBase.

Reimplemented in urabbitmq::ConsumerComponentBase, and components::Server.

Definition at line 58 of file component_base.hpp.

◆ OnAllComponentsLoaded()

void components::ComponentBase::OnAllComponentsLoaded ( )

inlineoverridevirtualinherited

Component may use this function to finalize registration of other components that depend on it (for example, handler components register in server component, and the latter uses OnAllComponentsLoaded() to start processing requests).

Base components may override it and make final to do some work after the derived object constructor is called. Don't use it otherwise.

Reimplemented from components::RawComponentBase.

Reimplemented in urabbitmq::ConsumerComponentBase, components::Server, and server::handlers::Ping.

Definition at line 51 of file component_base.hpp.

◆ OnLoadingCancelled()

void components::ComponentBase::OnLoadingCancelled ( )

inlineoverridevirtualinherited

Called once if the creation of any other component failed. If the current component expects some other component to take any action with the current component, this call is a signal that such action may never happen due to components loading was cancelled. Application components might not want to override it.

Reimplemented from components::RawComponentBase.

Definition at line 42 of file component_base.hpp.

◆ ParseRequestData()

virtual void server::handlers::HttpHandlerBase::ParseRequestData	(	const http::HttpRequest &	,
		request::RequestContext &	) const

inlineprotectedvirtual

For internal use. You don't need to override it. This method is overridden in format-specific base handlers.

Reimplemented in server::handlers::HttpHandlerFlatbufBase< InputType, ReturnType >, and server::handlers::HttpHandlerJsonBase.

Definition at line 176 of file http_handler_base.hpp.

◆ ReportMalformedRequest()

void server::handlers::HttpHandlerBase::ReportMalformedRequest ( request::RequestBase & ) const

finalvirtual

Produces response to a request unrecognized by the protocol based on provided generic response. Does not throw.

Reimplemented from server::handlers::HandlerBase.

Friends And Related Symbol Documentation

◆ middlewares::Auth

friend class middlewares::Auth

friend

Definition at line 182 of file http_handler_base.hpp.

◆ middlewares::HandlerAdapter

friend class middlewares::HandlerAdapter

friend

Definition at line 181 of file http_handler_base.hpp.

The documentation for this class was generated from the following file:

userver/server/handlers/http_handler_base.hpp

Detailed Description

Static options:

Example usage:

Public Member Functions

Static Public Member Functions

Protected Types

Protected Member Functions

Member Typedef Documentation

◆ ClientError

◆ ExternalBody

◆ HandlerErrorCode

◆ InternalMessage

◆ InternalServerError

◆ LoggableComponentBase

Member Function Documentation

◆ GetComponentHealth()

◆ GetLogLevelForResponseStatus()

◆ GetRequestBodyForLogging()

◆ GetResponseDataForLogging()

◆ HandleCustomHandlerException()

◆ HandleRequest()

◆ HandleRequestThrow()

◆ HandleStreamRequest()

◆ HandleUnknownException()

◆ IsMethodStatisticIncluded()

◆ IsMonitor()

◆ IsStreamed()

◆ NeedCheckAuth()

◆ OnAllComponentsAreStopping()

◆ OnAllComponentsLoaded()

◆ OnLoadingCancelled()

◆ ParseRequestData()

◆ ReportMalformedRequest()

Friends And Related Symbol Documentation

◆ middlewares::Auth

◆ middlewares::HandlerAdapter