web

Documentation

Overview

Package web contains a small web framework extension.

Index

• Constants
• func Decode(r *http.Request, val interface{}) error
• func IsShutdown(err error) bool
• func NewRequestError(err error, status int) error
• func NewShutdownError(message string) error
• func Params(r *http.Request) map[string]string
• func Respond(ctx context.Context, w http.ResponseWriter, data interface{}, statusCode int) error
• func RespondError(ctx context.Context, w http.ResponseWriter, err error) error
• type App
  • func NewApp(shutdown chan os.Signal, mw ...Middleware) *App
  • func (a *App) Handle(method string, path string, handler Handler, mw ...Middleware)
  • func (a *App) HandleDebug(method string, path string, handler Handler, mw ...Middleware)
  • func (a *App) ServeHTTP(w http.ResponseWriter, r *http.Request)
  • func (a *App) SignalShutdown()
• type Error
  • func (err *Error) Error() string
• type ErrorResponse
• type FieldError
• type Handler
• type Middleware
• type Values

Constants

const KeyValues ctxKey = 1

KeyValues is how request values are stored/retrieved.

Functions

func Decode

func Decode(r *http.Request, val interface{}) error

Decode reads the body of an HTTP request looking for a JSON document. The body is decoded into the provided value.

If the provided value is a struct then it is checked for validation tags.

func IsShutdown

func IsShutdown(err error) bool

IsShutdown checks to see if the shutdown error is contained in the specified error value.

func NewRequestError

func NewRequestError(err error, status int) error

NewRequestError wraps a provided error with an HTTP status code. This function should be used when handlers encounter expected errors.

func NewShutdownError

func NewShutdownError(message string) error

NewShutdownError returns an error that causes the framework to signal a graceful shutdown.

func Params

func Params(r *http.Request) map[string]string

Params returns the web call parameters from the request.

func Respond

func Respond(ctx context.Context, w http.ResponseWriter, data interface{}, statusCode int) error

Respond converts a Go value to JSON and sends it to the client.

func RespondError

func RespondError(ctx context.Context, w http.ResponseWriter, err error) error

RespondError sends an error reponse back to the client.

Types

type App

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

App is the entrypoint into our application and what configures our context object for each of our http handlers. Feel free to add any configuration data/logic on this App struct

func NewApp

func NewApp(shutdown chan os.Signal, mw ...Middleware) *App

NewApp creates an App value that handle a set of routes for the application.

func (*App) Handle

func (a *App) Handle(method string, path string, handler Handler, mw ...Middleware)

Handle sets a handler function for a given HTTP method and path pair to the application server mux.

func (*App) HandleDebug

func (a *App) HandleDebug(method string, path string, handler Handler, mw ...Middleware)

HandleDebug sets a handler function for a given HTTP method and path pair to the default http package server mux. /debug is added to the path.

func (*App) ServeHTTP

func (a *App) ServeHTTP(w http.ResponseWriter, r *http.Request)

ServeHTTP implements the http.Handler interface. It's the entry point for all http traffic and allows the opentelemetry mux to run first to handle tracing. The opentelemetry mux then calls the application mux to handle application traffic. This was setup on line 58 in the NewApp function.

func (*App) SignalShutdown

func (a *App) SignalShutdown()

SignalShutdown is used to gracefully shutdown the app when an integrity issue is identified.

type Error

type Error struct {
	Err    error
	Status int
	Fields []FieldError
}

Error is used to pass an error during the request through the application with web specific context.

func (*Error) Error

func (err *Error) Error() string

Error implements the error interface. It uses the default message of the wrapped error. This is what will be shown in the services' logs.

type ErrorResponse

type ErrorResponse struct {
	Error  string       `json:"error"`
	Fields []FieldError `json:"fields,omitempty"`
}

ErrorResponse is the form used for API responses from failures in the API.

type FieldError

type FieldError struct {
	Field string `json:"field"`
	Error string `json:"error"`
}

FieldError is used to indicate an error with a specific request field.

type Handler

type Handler func(ctx context.Context, w http.ResponseWriter, r *http.Request) error

A Handler is a type that handles an http request within our own little mini framework.

type Middleware

type Middleware func(Handler) Handler

Middleware is a function designed to run some code before and/or after another Handler. It is designed to remove boilerplate or other concerns not direct to any given Handler.

type Values

type Values struct {
	TraceID    string
	Now        time.Time
	StatusCode int
}

Values represent state for each request.