server

package
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 Go to latest Published: May 18, 2026 License: MIT Imports: 30 Imported by: 0

Documentation

Overview

Package server: MCP (Model Context Protocol) glue.

The MCP protocol itself lives in github.com/osauer/hyperserve/pkg/mcp. This file wires *Server up to *mcp.Handler: server options that flip MCP modes, the discovery endpoint registration, and the thin Register* helpers that delegate into the handler.

Package server provides built-in middleware for common HTTP server functionality.

The middleware package includes:

  • Request logging with structured output
  • Panic recovery to prevent server crashes
  • Request metrics collection
  • Authentication (Basic, Bearer token, custom)
  • Rate limiting per IP address
  • Security headers (HSTS, CSP, etc.)
  • Request/Response timing

Middleware can be applied globally or to specific routes: 

// Global middleware
srv.AddMiddleware("*", server.RequestLoggerMiddleware)

// Route-specific middleware
srv.AddMiddleware("/api", server.AuthMiddleware(srv.Options))

// Combine multiple middleware
srv.AddMiddlewareGroup("/admin",
	server.AuthMiddleware(srv.Options),
	server.RateLimitMiddleware(srv),
)

Package hyperserve provides configuration options for the HTTP server.

Configuration follows a hierarchical priority:

  1. Function parameters (highest priority)
  2. Environment variables
  3. Configuration file (options.json)
  4. Default values (lowest priority)

Environment Variables:

  • SERVER_ADDR: Main server address (default ":8080")
  • HEALTH_ADDR: Health check server address (default ":8081")
  • HS_HARDENED_MODE: Enable security headers (default "false")
  • HS_MCP_ENABLED: Enable Model Context Protocol (default "false")
  • HS_MCP_ENDPOINT: MCP endpoint path (default "/mcp")
  • HS_MCP_DEV: Enable MCP developer tools (default "false")
  • HS_MCP_OBSERVABILITY: Enable MCP observability resources (default "false")
  • HS_MCP_TRANSPORT: MCP transport type: "http" or "stdio" (default "http")
  • HS_CSP_WEB_WORKER_SUPPORT: Enable Web Worker CSP headers (default "false")
  • HS_LOG_LEVEL: Set log level (DEBUG, INFO, WARN, ERROR) (default "INFO")
  • HS_DEBUG: Enable debug mode and debug logging (default "false")
  • HS_SUPPRESS_BANNER: Suppress the HyperServe ASCII banner at startup (default "false")

Example configuration file (options.json): 

{
  "addr": ":3000",
  "tls": true,
  "cert_file": "server.crt",
  "key_file": "server.key",
  "run_health_server": true,
  "hardened_mode": true,
  "debug_mode": false,
  "log_level": "INFO"
}

Package server provides a lightweight, high-performance HTTP server framework with minimal external dependencies (golang.org/x/time/rate for rate limiting only).

Key Features:

  • Zero configuration with sensible defaults
  • Built-in middleware for logging, recovery, and metrics
  • Graceful shutdown handling with application hooks
  • Health check endpoints for Kubernetes
  • Model Context Protocol (MCP) support for AI assistants
  • WebSocket support for real-time communication (standard library only)
  • TLS/HTTPS support with automatic certificate management
  • Rate limiting and authentication
  • Template rendering support
  • Server-Sent Events (SSE) support

Basic Usage: 

srv, err := server.NewServer()
if err != nil {
	log.Fatal(err)
}

srv.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
	fmt.Fprintln(w, "Hello, World!")
})

srv.Run() // Blocks until shutdown signal

With Options: 

srv, err := server.NewServer(
	server.WithAddr(":8080"),
	server.WithHealthServer(),
	server.WithTLS("cert.pem", "key.pem"),
	server.WithMCPSupport("MyApp", "1.0.0"),
)

Graceful Shutdown with Hooks: 

srv, err := server.NewServer(
	server.WithAddr(":8080"),
	server.WithOnShutdown(func(ctx context.Context) error {
		log.Println("Stopping background workers...")
		// Stop your application's goroutines, close connections, etc.
		return nil
	}),
)

WebSocket Support (import websocket "github.com/osauer/hyperserve/pkg/websocket"): 

upgrader := websocket.Upgrader{
	CheckOrigin: func(r *http.Request) bool {
		return true // Configure based on your needs
	},
}

srv.HandleFunc("/ws", func(w http.ResponseWriter, r *http.Request) {
	conn, err := upgrader.Upgrade(w, r, nil)
	if err != nil {
		log.Printf("WebSocket upgrade error: %v", err)
		return
	}
	defer conn.Close()

	// Handle WebSocket messages
	for {
		messageType, p, err := conn.ReadMessage()
		if err != nil {
			break
		}
		// Echo message back
		conn.WriteMessage(messageType, p)
	}
})

Index

Constants

View Source 
const (
	// LevelDebug enables debug-level logging with detailed information
	LevelDebug = slog.LevelDebug
	// LevelInfo enables info-level logging for general information
	LevelInfo = slog.LevelInfo
	// LevelWarn enables warning-level logging for important but non-critical events
	LevelWarn = slog.LevelWarn
	// LevelError enables error-level logging for error conditions only
	LevelError = slog.LevelError
)

Log level constants for server configuration. These wrap slog levels to provide a consistent API while hiding the logging implementation details.

View Source 
const GlobalMiddlewareRoute = "*"

GlobalMiddlewareRoute is a special route identifier that applies middleware to all routes. Use this constant when registering middleware that should run for every request.

Variables

View Source 
var (
	Version   = "dev"     // Version from git tags
	BuildHash = "unknown" // Git commit hash
	BuildTime = "unknown" // Build timestamp
)

Build information set at compile time using -ldflags

Functions

func DefaultLogger 

func DefaultLogger() *slog.Logger

DefaultLogger returns the logger used by the server package.

func EnsureTrailingSlash 

func EnsureTrailingSlash(dir string) string

EnsureTrailingSlash ensures that a directory path ends with a trailing slash. This utility function is used to normalize directory paths for consistent handling.

func GetVersionInfo 

func GetVersionInfo() string

GetVersionInfo returns formatted version information

func HealthCheckHandler 

func HealthCheckHandler(w http.ResponseWriter, r *http.Request)

HealthCheckHandler returns a 204 No Content status code for basic health checks. This handler can be used as a simple liveness or readiness probe.

func MCPDev 

func MCPDev() mcp.TransportConfig

MCPDev configures MCP with developer tools for local development.

SECURITY WARNING: Only use in development environments. Enables powerful tools that can restart your server and modify its behavior.

Tools provided:

  • mcp__hyperserve__server_control
  • mcp__hyperserve__route_inspector
  • mcp__hyperserve__request_debugger
  • mcp__hyperserve__dev_guide

Resources provided:

  • logs://server/stream, routes://server/all, requests://debug/recent

func MCPObservability 

func MCPObservability() mcp.TransportConfig

MCPObservability configures MCP with observability resources for production use. This preset provides read-only access to system state with no control plane access:

  • config://server/current (sanitized server config, no secrets)
  • health://server/status (uptime and health metrics)
  • logs://server/recent (circular buffer of recent log entries)

func PanicHandler 

func PanicHandler(w http.ResponseWriter, r *http.Request)

PanicHandler simulates a panic situation in a handler to test proper recovery middleware. This handler is intended for testing purposes only and should not be used in production.

func RecoveryMiddleware 

func RecoveryMiddleware(next http.Handler) http.HandlerFunc

RecoveryMiddleware returns a middleware function that recovers from panics in request handlers. Catches panics, logs the error, and returns a 500 Internal Server Error response.

func RequestLoggerMiddleware 

func RequestLoggerMiddleware(next http.Handler) http.HandlerFunc

RequestLoggerMiddleware returns a middleware function that logs structured request information. It captures and logs:

  • Client IP address
  • HTTP method and URL path
  • Trace ID (if present in X-Trace-ID header)
  • Response status code
  • Request duration
  • Response size in bytes

This middleware is included by default in NewServer(). For high-traffic applications, consider the performance impact of logging.

func SetBuiltinPresetHooks added in v0.25.1 

func SetBuiltinPresetHooks(tools, standardResources, observability, developer func(*Server))

SetBuiltinPresetHooks lets pkg/mcp/builtin (and only it, in practice) wire itself into the auto-registration flow used by NewServer when MCP is enabled. Pass nil for any preset you don't implement.

func SetDefaultLogger 

func SetDefaultLogger(l *slog.Logger)

SetDefaultLogger overrides the logger used by the server package.

func TraceMiddleware 

func TraceMiddleware(next http.Handler) http.HandlerFunc

TraceMiddleware returns a middleware function that adds trace IDs to requests. Generates unique trace IDs for request tracking and distributed tracing.

Types

type CORSOptions 

type CORSOptions struct {
	AllowedOrigins   []string `json:"allowed_origins,omitempty"`
	AllowedMethods   []string `json:"allowed_methods,omitempty"`
	AllowedHeaders   []string `json:"allowed_headers,omitempty"`
	ExposeHeaders    []string `json:"expose_headers,omitempty"`
	AllowCredentials bool     `json:"allow_credentials,omitempty"`
	MaxAgeSeconds    int      `json:"max_age_seconds,omitempty"`
}

CORSOptions captures configuration for Cross-Origin Resource Sharing handling.

type DataFunc 

type DataFunc func(r *http.Request) any

DataFunc is a function type that generates data for template rendering. It receives the current HTTP request and returns data to be passed to the template. 

type Header struct {
	// contains filtered or unexported fields
}

Header represents an HTTP header key-value pair used in middleware configuration.

type MiddlewareFunc 

type MiddlewareFunc func(http.Handler) http.HandlerFunc

MiddlewareFunc is a function type that wraps an http.Handler and returns a new http.HandlerFunc. This is the standard pattern for HTTP middleware in Go.

func AuthMiddleware 

func AuthMiddleware(options *ServerOptions) MiddlewareFunc

AuthMiddleware returns a middleware function that validates bearer tokens in the Authorization header. Requires requests to include a valid Bearer token, otherwise returns 401 Unauthorized.

func HeadersMiddleware 

func HeadersMiddleware(options *ServerOptions) MiddlewareFunc

HeadersMiddleware returns a middleware function that adds security headers to responses. Includes headers for XSS protection, content type sniffing prevention, HSTS, CSP, and CORS. Automatically handles CORS preflight requests.

func MetricsMiddleware 

func MetricsMiddleware(srv *Server) MiddlewareFunc

MetricsMiddleware returns a middleware function that collects request metrics. It tracks total request count and response times for performance monitoring.

func RateLimitMiddleware 

func RateLimitMiddleware(srv *Server) MiddlewareFunc

RateLimitMiddleware returns a middleware function that enforces rate limiting per client IP address. Uses token bucket algorithm with configurable rate limit and burst capacity. Returns 429 Too Many Requests when rate limit is exceeded. Optimized for Go 1.24's Swiss Tables map implementation.

type MiddlewareRegistry 

type MiddlewareRegistry struct {
	// contains filtered or unexported fields
}

MiddlewareRegistry manages middleware stacks for different routes.

func NewMiddlewareRegistry 

func NewMiddlewareRegistry(globalMiddleware MiddlewareStack) *MiddlewareRegistry

NewMiddlewareRegistry creates a new MiddlewareRegistry with optional global middleware. If globalMiddleware is provided, it will be applied to all routes by default.

func (*MiddlewareRegistry) Add 

func (mwr *MiddlewareRegistry) Add(route string, middleware MiddlewareStack)

Add registers a MiddlewareStack for a specific route in the registry. Use GlobalMiddlewareRoute ("*") to apply middleware to all routes.

func (*MiddlewareRegistry) Get 

func (mwr *MiddlewareRegistry) Get(route string) MiddlewareStack

Get retrieves the MiddlewareStack for a specific route. Returns an empty MiddlewareStack if no middleware is registered for the route.

func (*MiddlewareRegistry) RemoveStack 

func (mwr *MiddlewareRegistry) RemoveStack(route string)

RemoveStack removes all middleware for a specific route from the registry. Does nothing if no middleware is registered for the route.

type MiddlewareStack 

type MiddlewareStack []MiddlewareFunc

MiddlewareStack is a collection of middleware functions that can be applied to an http.Handler. Middleware in the stack is applied in order, with the first middleware being the outermost.

func DefaultMiddleware 

func DefaultMiddleware(server *Server) MiddlewareStack

DefaultMiddleware returns a predefined middleware stack with essential server functionality. Includes metrics collection, request logging, and panic recovery. This middleware is applied by default unless explicitly excluded.

func SecureAPI 

func SecureAPI(srv *Server) MiddlewareStack

SecureAPI returns a middleware stack configured for secure API endpoints. Includes authentication and rate limiting middleware.

func SecureWeb 

func SecureWeb(options *ServerOptions) MiddlewareStack

SecureWeb returns a middleware stack configured for secure web endpoints. Includes security headers middleware for web applications.

type RateLimit 

type RateLimit = rate.Limit

RateLimit limits requests per second that can be requested from the httpServer. Requires to add RateLimitMiddleware

type SSEMessage 

type SSEMessage struct {
	Event string `json:"event"` // Optional: Allows sending multiple event types
	Data  any    `json:"data"`  // The actual data payload
}

SSEMessage represents a Server-Sent Events message with an optional event type and data payload. It follows the SSE format with event and data fields that can be sent to clients.

func NewSSEMessage 

func NewSSEMessage(data any) *SSEMessage

NewSSEMessage creates a new SSE message with the given data and a default "message" event type. This is a convenience function for creating standard SSE messages.

func (*SSEMessage) String 

func (sse *SSEMessage) String() string

String formats the SSE message according to the Server-Sent Events specification. Returns a string in the format "event: <event>\ndata: <data>\n\n".

type Server 

type Server struct {
	Options *ServerOptions
	// contains filtered or unexported fields
}

Server represents an HTTP server with built-in middleware support, health checks, template rendering, and various configuration options.

The Server manages both the main HTTP server and an optional health check server. It handles graceful shutdown, request metrics, and can be extended with custom middleware.

Example: 

srv, _ := server.NewServer(
	server.WithAddr(":8080"),
	server.WithHealthServer(),
)

srv.HandleFunc("/api/users", handleUsers)
srv.Run()

func NewServer 

func NewServer(opts ...ServerOptionFunc) (*Server, error)

NewServer creates a new instance of the Server with the given options. By default, the server includes request logging, panic recovery, and metrics collection middleware. The server will listen on ":8080" unless configured otherwise.

Options can be provided to customize the server behavior: 

srv, err := server.NewServer(
	server.WithAddr(":3000"),
	server.WithHealthServer(),          // Enable health checks on :8081
	server.WithTLS("cert.pem", "key.pem"), // Enable HTTPS
	server.WithRateLimit(100, 200),     // 100 req/s, burst of 200
)

Returns an error if any of the options fail to apply.

func (*Server) AddMetrics added in v0.25.1 

func (srv *Server) AddMetrics(deltaRequests uint64, deltaResponseTime int64)

AddMetrics is a test affordance: it bumps the request count by one and adds to the cumulative response time. See SetMetrics.

func (*Server) AddMiddleware 

func (srv *Server) AddMiddleware(route string, mw MiddlewareFunc)

AddMiddleware adds a single middleware function to the specified route. Use "*" as the route to apply middleware globally to all routes.

func (*Server) AddMiddlewareStack 

func (srv *Server) AddMiddlewareStack(route string, mw MiddlewareStack)

AddMiddlewareStack adds a collection of middleware functions to the specified route. The middleware stack is applied in the order provided.

func (*Server) ClientLimiterCount added in v0.25.1 

func (srv *Server) ClientLimiterCount() int

ClientLimiterCount returns the number of active per-client rate limiters.

func (*Server) CompleteDeferredInit added in v0.24.0 

func (srv *Server) CompleteDeferredInit(ctx context.Context, err error) error

CompleteDeferredInit allows applications to manually finalize deferred initialization after addressing failures. Passing a nil error reruns any pending OnReady hooks and marks the server ready. Passing a non-nil error records the failure and leaves the server in an initializing state.

func (*Server) Handle 

func (srv *Server) Handle(pattern string, handlerFunc http.HandlerFunc)

Handle registers the handler function for the given pattern. This is a wrapper around http.ServeMux.Handle that integrates with the server's middleware system. Example usage: 

srv.Handle("/static", http.FileServer(http.Dir("./static")))

func (*Server) HandleFunc 

func (srv *Server) HandleFunc(pattern string, handler http.HandlerFunc)

func (*Server) HandleFuncDynamic 

func (srv *Server) HandleFuncDynamic(pattern, tmplName string, dataFunc DataFunc) error

HandleFuncDynamic registers a handler that renders templates with dynamic data. The dataFunc is called for each request to generate the data passed to the template. Returns an error if template parsing fails.

func (*Server) HandleStatic 

func (srv *Server) HandleStatic(pattern string)

HandleStatic registers a handler for serving static files from the configured static directory. The pattern should typically end with a wildcard (e.g., "/static/"). Uses os.Root for secure file access when available (Go 1.24+).

func (*Server) HandleTemplate 

func (srv *Server) HandleTemplate(pattern, t string, data any) error

HandleTemplate registers a handler that renders a specific template with static data. Unlike HandleFuncDynamic, the data is provided once at registration time. Returns an error if template parsing fails.

func (*Server) Handler 

func (srv *Server) Handler() http.Handler

func (*Server) IsReady added in v0.25.1 

func (srv *Server) IsReady() bool

IsReady reports whether the server is ready to accept traffic.

func (*Server) IsRunning added in v0.25.1 

func (srv *Server) IsRunning() bool

IsRunning reports whether the server is currently running.

func (*Server) MCPEnabled 

func (srv *Server) MCPEnabled() bool

MCPEnabled reports whether MCP support has been initialized for this server.

func (*Server) MCPHandler added in v0.25.1 

func (srv *Server) MCPHandler() *mcp.Handler

MCPHandler returns the MCP handler attached to this server, or nil if MCP is not enabled.

func (*Server) MiddlewareRoutes added in v0.25.1 

func (srv *Server) MiddlewareRoutes() map[string]MiddlewareStack

MiddlewareRoutes returns a snapshot of the registered route-to-middleware mapping. The returned map is a shallow copy; mutating it does not affect the server.

func (*Server) Mux added in v0.25.1 

func (srv *Server) Mux() *http.ServeMux

Mux returns the server's underlying http.ServeMux. Exposed so tests can mount the server's handler in an httptest server without going through (*Server).Run.

func (*Server) RegisterMCPExtension 

func (srv *Server) RegisterMCPExtension(ext mcp.Extension) error

RegisterMCPExtension registers all tools and resources from an extension.

func (*Server) RegisterMCPNamespace 

func (srv *Server) RegisterMCPNamespace(name string, configs ...mcp.NamespaceConfig) error

RegisterMCPNamespace registers an entire MCP namespace with its tools and resources.

func (*Server) RegisterMCPResource 

func (srv *Server) RegisterMCPResource(resource mcp.Resource) error

RegisterMCPResource registers a custom MCP resource.

func (*Server) RegisterMCPResourceInNamespace 

func (srv *Server) RegisterMCPResourceInNamespace(resource mcp.Resource, namespace string) error

RegisterMCPResourceInNamespace registers a custom MCP resource in the specified namespace.

func (*Server) RegisterMCPTool 

func (srv *Server) RegisterMCPTool(tool mcp.Tool) error

RegisterMCPTool registers a custom MCP tool. Must be called after server creation but before Run().

func (*Server) RegisterMCPToolInNamespace 

func (srv *Server) RegisterMCPToolInNamespace(tool mcp.Tool, namespace string) error

RegisterMCPToolInNamespace registers a custom MCP tool in the specified namespace.

func (*Server) Run 

func (srv *Server) Run() error

Run starts the server and blocks until a shutdown signal is received. It automatically:

  • Starts the main HTTP/HTTPS server
  • Starts the health check server (if enabled)
  • Sets up graceful shutdown on SIGINT/SIGTERM
  • Handles cleanup of resources
  • Waits for active requests to complete before shutting down

The method will block until the server is shut down, either by signal or error. Returns an error if the server fails to start or encounters a fatal error.

Example: 

if err := srv.Run(); err != nil {
    log.Fatal("Server failed:", err)
}

func (*Server) ServerStart added in v0.25.1 

func (srv *Server) ServerStart() time.Time

ServerStart returns the timestamp when the server began serving.

func (*Server) SetMetrics added in v0.25.1 

func (srv *Server) SetMetrics(totalRequests uint64, totalResponseTime int64)

SetMetrics is a test affordance: it overrides the request count and cumulative response time. Production code should never call this; metrics are populated by the request-handling middleware.

func (*Server) Stop 

func (srv *Server) Stop() error

Stop gracefully stops the server with a default timeout of 10 seconds

func (*Server) TotalRequests added in v0.25.1 

func (srv *Server) TotalRequests() uint64

TotalRequests returns the total number of requests served so far.

func (*Server) TotalResponseTime added in v0.25.1 

func (srv *Server) TotalResponseTime() int64

TotalResponseTime returns the cumulative response time in microseconds.

func (*Server) WebSocketUpgrader 

func (srv *Server) WebSocketUpgrader() *websocket.Upgrader

WebSocketUpgrader returns a WebSocket upgrader that tracks connections in server telemetry. Use this instead of creating a standalone Upgrader to ensure WebSocket connections are counted in the server's request metrics.

type ServerOptionFunc 

type ServerOptionFunc func(srv *Server) error

ServerOptionFunc is a function type used to configure Server instances. It follows the functional options pattern for flexible server configuration.

func WithAddr 

func WithAddr(addr string) ServerOptionFunc

WithAddr sets the address and port for the server to listen on. The address must be in the format "host:port" (e.g., ":8080", "localhost:3000").

func WithAuthTokenValidator 

func WithAuthTokenValidator(validator func(token string) (bool, error)) ServerOptionFunc

WithAuthTokenValidator sets the token validator for the server.

func WithBannerColor added in v0.23.0 

func WithBannerColor(enabled bool) ServerOptionFunc

WithBannerColor enables or disables ANSI color output for the startup banner.

func WithCORS 

func WithCORS(opts *CORSOptions) ServerOptionFunc

WithCORS configures Cross-Origin Resource Sharing options for HTTP handlers.

func WithCSPWebWorkerSupport 

func WithCSPWebWorkerSupport() ServerOptionFunc

WithCSPWebWorkerSupport enables Content Security Policy support for Web Workers using blob: URLs. This is required for modern web applications that use libraries like Tone.js, PDF.js, or other libraries that create Web Workers with blob: URLs for performance optimization. By default, this is disabled for security reasons and must be explicitly enabled.

func WithDebugMode 

func WithDebugMode() ServerOptionFunc

WithDebugMode enables debug logging and additional debug features. This is equivalent to WithLoglevel(LevelDebug) plus additional debug information.

func WithDeferredInit added in v0.23.0 

func WithDeferredInit(fn func(context.Context, *Server) error) ServerOptionFunc

WithDeferredInit registers a callback that runs after the server listener is active but before the server is marked ready. While the callback is executing, non-health endpoints receive 503.

func WithDeferredInitStopOnFailure added in v0.23.0 

func WithDeferredInitStopOnFailure(stop bool) ServerOptionFunc

WithDeferredInitStopOnFailure configures whether the server should shut down if the deferred initialization callback returns an error. Defaults to true.

func WithFIPSMode 

func WithFIPSMode() ServerOptionFunc

WithFIPSMode restricts the TLS handshake to FIPS-approved cipher suites and elliptic curves.

This is NOT full FIPS 140-3 compliance:

  • it does not switch the Go toolchain into FIPS mode (build with GOFIPS140 for that);
  • it does not constrain non-TLS crypto (hashes, RNGs, signatures outside TLS);
  • it does not invoke a FIPS-validated cryptographic module.

Use this for "TLS handshake uses FIPS-approved primitives." For deployments that require true FIPS 140-3 compliance, combine with a FIPS-validated toolchain build.

func WithHardenedMode 

func WithHardenedMode() ServerOptionFunc

WithHardenedMode enables hardened security mode for enhanced security headers. In hardened mode, the server header is suppressed and additional security measures are applied.

func WithHealthServer 

func WithHealthServer() ServerOptionFunc

WithHealthServer enables the health server on a separate port. The health server provides /healthz/, /readyz/, and /livez/ endpoints for monitoring.

func WithIdleTimeout 

func WithIdleTimeout(timeout time.Duration) ServerOptionFunc

WithIdleTimeout sets the maximum time to wait for the next request when keep-alives are enabled.

func WithLoglevel 

func WithLoglevel(level slog.Level) ServerOptionFunc

WithLoglevel sets the global log level for the server. Accepts slog.Level values (LevelDebug, LevelInfo, LevelWarn, LevelError).

func WithMCPBuiltinResources 

func WithMCPBuiltinResources(enabled bool) ServerOptionFunc

WithMCPBuiltinResources toggles the built-in MCP resources (Config, Metrics, System, ServerLog, ServerHealth). Default off. Same blank-import requirement as WithMCPBuiltinTools.

func WithMCPBuiltinTools 

func WithMCPBuiltinTools(enabled bool) ServerOptionFunc

WithMCPBuiltinTools toggles the built-in MCP tools (Calculator, FileRead, HTTPRequest, ListDirectory). Default off. Requires `_ "github.com/osauer/hyperserve/pkg/mcp/builtin"` to be blank-imported by the consumer; otherwise NewServer logs a warning and registers nothing.

func WithMCPDiscoveryFilter 

func WithMCPDiscoveryFilter(filter func(toolName string, r *http.Request) bool) ServerOptionFunc

WithMCPDiscoveryFilter sets a custom filter function for MCP discovery.

The filter function receives the tool name and HTTP request, allowing for context-aware filtering based on auth tokens, IP addresses, etc.

Example - Hide admin tools from external requests: 

srv, _ := server.NewServer(
    server.WithMCPDiscoveryFilter(func(toolName string, r *http.Request) bool {
        if strings.Contains(toolName, "admin") {
            return strings.HasPrefix(r.RemoteAddr, "10.") ||
                   strings.HasPrefix(r.RemoteAddr, "192.168.")
        }
        return true
    }),
)

func WithMCPDiscoveryPolicy 

func WithMCPDiscoveryPolicy(policy mcp.DiscoveryPolicy) ServerOptionFunc

WithMCPDiscoveryPolicy sets the discovery policy for MCP tools and resources.

Example: 

srv, _ := server.NewServer(
    server.WithMCPDiscoveryPolicy(mcp.DiscoveryCount),
)

func WithMCPEndpoint 

func WithMCPEndpoint(endpoint string) ServerOptionFunc

WithMCPEndpoint configures the MCP endpoint path. Default is "/mcp".

func WithMCPFileToolRoot 

func WithMCPFileToolRoot(rootDir string) ServerOptionFunc

WithMCPFileToolRoot scopes MCP file tools to rootDir via os.Root, so they cannot read or list paths outside it.

func WithMCPSupport 

func WithMCPSupport(name, version string, configs ...mcp.TransportConfig) ServerOptionFunc

WithMCPSupport enables MCP (Model Context Protocol) support on the server. Server name and version identify the server to MCP clients. By default, MCP uses HTTP transport on the "/mcp" endpoint; pass mcp.TransportConfig values to switch to stdio or to install a preset (DeveloperMode, ObservabilityMode).

Example: 

server.NewServer(server.WithMCPSupport("MyServer", "1.0.0"))

func WithOnReady added in v0.23.0 

func WithOnReady(hook func(context.Context, *Server) error) ServerOptionFunc

WithOnReady registers hooks that run after deferred initialization succeeds but before the server is marked ready. Hooks are executed sequentially in the order they were registered.

func WithOnShutdown 

func WithOnShutdown(hook func(context.Context) error) ServerOptionFunc

WithOnShutdown registers a function to be called when the server receives a shutdown signal. Multiple hooks can be registered and are executed sequentially in the order they were added. Hooks are called before the HTTP server shutdown begins, allowing applications to cleanly stop their own goroutines and release resources.

Each hook receives a context with a timeout (typically 5 seconds of the total 10-second shutdown budget). Hooks should respect the context deadline and return promptly. Errors from hooks are logged but don't prevent shutdown from proceeding.

Example: 

srv, _ := server.NewServer(
	server.WithOnShutdown(func(ctx context.Context) error {
		log.Println("Stopping background workers...")
		return stopWorkers(ctx)
	}),
)

func WithRateLimit 

func WithRateLimit(limit RateLimit, burst int) ServerOptionFunc

WithRateLimit configures rate limiting for the server. limit: maximum number of requests per second per client IP burst: maximum number of requests that can be made in a short burst

func WithReadHeaderTimeout 

func WithReadHeaderTimeout(timeout time.Duration) ServerOptionFunc

WithReadHeaderTimeout sets the amount of time allowed to read request headers. This helps prevent Slowloris attacks.

func WithReadTimeout 

func WithReadTimeout(timeout time.Duration) ServerOptionFunc

WithReadTimeout sets the maximum duration for reading the entire request.

func WithSuppressBanner 

func WithSuppressBanner(suppress bool) ServerOptionFunc

WithSuppressBanner suppresses the HyperServe ASCII banner at startup. Useful when building white-label products on top of HyperServe.

func WithTLS 

func WithTLS(certFile, keyFile string) ServerOptionFunc

WithTLS enables TLS on the server with the specified certificate and key files. Returns a ServerOptionFunc that configures TLS settings and validates file existence.

func WithTemplateDir 

func WithTemplateDir(dir string) ServerOptionFunc

WithTemplateDir sets the directory path where HTML templates are located. Templates in this directory can be used with HandleTemplate and HandleFuncDynamic methods. Returns an error if the specified directory does not exist or is not accessible.

func WithTimeouts 

func WithTimeouts(readTimeout, writeTimeout, idleTimeout time.Duration) ServerOptionFunc

WithTimeouts configures the HTTP server timeouts. readTimeout: maximum duration for reading the entire request writeTimeout: maximum duration before timing out writes of the response idleTimeout: maximum time to wait for the next request when keep-alives are enabled

func WithWriteTimeout 

func WithWriteTimeout(timeout time.Duration) ServerOptionFunc

WithWriteTimeout sets the maximum duration before timing out writes of the response.

type ServerOptions 

type ServerOptions struct {
	Addr                   string        `json:"addr,omitempty"`
	EnableTLS              bool          `json:"tls,omitempty"`
	TLSAddr                string        `json:"tls_addr,omitempty"`
	TLSHealthAddr          string        `json:"tls_health_addr,omitempty"`
	KeyFile                string        `json:"key_file,omitempty"`
	CertFile               string        `json:"cert_file,omitempty"`
	HealthAddr             string        `json:"health_addr,omitempty"`
	RateLimit              RateLimit     `json:"rate_limit,omitempty"`
	Burst                  int           `json:"burst,omitempty"`
	ReadTimeout            time.Duration `json:"read_timeout,omitempty"`
	WriteTimeout           time.Duration `json:"write_timeout,omitempty"`
	IdleTimeout            time.Duration `json:"idle_timeout,omitempty"`
	ReadHeaderTimeout      time.Duration `json:"read_header_timeout,omitempty"`
	StaticDir              string        `json:"static_dir,omitempty"`
	TemplateDir            string        `json:"template_dir,omitempty"`
	RunHealthServer        bool          `json:"run_health_server,omitempty"`
	AuthTokenValidatorFunc func(token string) (bool, error)
	FIPSMode               bool `json:"fips_mode,omitempty"`
	HardenedMode           bool `json:"hardened_mode,omitempty"`
	// MCP (Model Context Protocol) configuration
	MCPEnabled          bool                                        `json:"mcp_enabled,omitempty"`
	MCPEndpoint         string                                      `json:"mcp_endpoint,omitempty"`
	MCPServerName       string                                      `json:"mcp_server_name,omitempty"`
	MCPServerVersion    string                                      `json:"mcp_server_version,omitempty"`
	MCPToolsEnabled     bool                                        `json:"mcp_tools_enabled,omitempty"`
	MCPResourcesEnabled bool                                        `json:"mcp_resources_enabled,omitempty"`
	MCPFileToolRoot     string                                      `json:"mcp_file_tool_root,omitempty"`
	MCPLogResourceSize  int                                         `json:"mcp_log_resource_size,omitempty"`
	MCPTransport        mcp.TransportType                           `json:"mcp_transport,omitempty"`
	MCPDev              bool                                        `json:"mcp_dev,omitempty"`
	MCPObservability    bool                                        `json:"mcp_observability,omitempty"`
	MCPDiscoveryPolicy  mcp.DiscoveryPolicy                         `json:"mcp_discovery_policy,omitempty"`
	MCPDiscoveryFilter  func(toolName string, r *http.Request) bool `json:"-"` // Custom filter function

	// CSP (Content Security Policy) configuration
	CSPWebWorkerSupport bool         `json:"csp_web_worker_support,omitempty"`
	CORS                *CORSOptions `json:"cors,omitempty"`
	// Logging configuration
	LogLevel  string `json:"log_level,omitempty"`
	DebugMode bool   `json:"debug_mode,omitempty"`
	// Banner configuration
	SuppressBanner bool `json:"suppress_banner,omitempty"`
	BannerColor    bool `json:"banner_color,omitempty"`

	// OnShutdownHooks are functions called when the server receives a shutdown signal.
	// Hooks are executed sequentially in the order they were added, before HTTP server shutdown.
	// Each hook receives a context with timeout and should respect the deadline.
	// Errors from hooks are logged but don't prevent shutdown.
	OnShutdownHooks []func(context.Context) error `json:"-"`

	// OnReadyHooks run after deferred initialization succeeds and before the server is marked ready.
	OnReadyHooks []func(context.Context, *Server) error `json:"-"`
	// StopOnDeferredInitFailure indicates whether the server should shut down if deferred init fails.
	StopOnDeferredInitFailure bool `json:"stop_on_deferred_init_failure,omitempty"`
	// contains filtered or unexported fields
}

ServerOptions contains all configuration settings for the HTTP server. Options can be set via WithXXX functions when creating a new server, environment variables, or a configuration file.

Zero values are sensible defaults for most applications.

func NewServerOptions 

func NewServerOptions() *ServerOptions

NewServerOptions creates a new ServerOptions instance with values loaded in priority order: 1. Environment variables (highest priority) 2. Configuration file (options.json) 3. Default values (lowest priority) Returns a fully initialized ServerOptions struct ready for use.

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