language

README

Language package for Golang

Package language provides HTTP middleware for parsing language from HTTP request and passing it via context.

How to install

Run the following command to install the package:

go get -u github.com/muonsoft/language

Example of reading language from Accept-Language header

package main

import (
    "fmt"
    "net/http"
    "net/http/httptest"
    
    "github.com/muonsoft/language"
)

func main() {
    h := http.HandlerFunc(func (writer http.ResponseWriter, request *http.Request) {
        tag := language.FromContext(request.Context())
        fmt.Println("language:", tag)
    })
    m := language.NewMiddleware(h, language.SupportedLanguages(language.English, language.Russian))
    
    r := httptest.NewRequest(http.MethodGet, "/", nil)
    r.Header.Set("Accept-Language", "ru")
    w := httptest.NewRecorder()
    
    m.ServeHTTP(w, r)
    // Output: language: ru
}

Example of reading language from Cookie

package main

import (
    "fmt"
    "net/http"
    "net/http/httptest"
    
    "github.com/muonsoft/language"
)

func main() {
    h := http.HandlerFunc(func(writer http.ResponseWriter, request *http.Request) {
        tag := language.FromContext(request.Context())
        fmt.Println("language:", tag)
    })
    m := language.NewMiddleware(
        h,
        language.SupportedLanguages(language.English, language.Russian),
        language.ReadFromCookie("lang"),
    )
    
    r := httptest.NewRequest(http.MethodGet, "/", nil)
    r.AddCookie(&http.Cookie{Name: "lang", Value: "ru"})
    w := httptest.NewRecorder()
    
    m.ServeHTTP(w, r)
    // Output: language: ru
}

Documentation

Overview

Package language provides HTTP middleware for parsing language from HTTP request and passing it via context.

Index

• Variables
• func Equal(tag1, tag2 Tag) bool
• func WithContext(ctx context.Context, tag Tag) context.Context
• type Middleware
  • func NewMiddleware(next http.Handler, options ...MiddlewareOption) *Middleware
  • func (middleware *Middleware) ServeHTTP(writer http.ResponseWriter, request *http.Request)
• type MiddlewareOption
  • func ReadFromAcceptHeader() MiddlewareOption
  • func ReadFromCookie(name string) MiddlewareOption
  • func SupportedLanguages(tags ...Tag) MiddlewareOption
• type Tag
  • func FromContext(ctx context.Context) Tag

Examples

• Equal
• Middleware.ServeHTTP (ReadFromAcceptLanguageHeader)
• Middleware.ServeHTTP (ReadFromCookie)

Variables

var (
	Und = language.Und

	Afrikaans            = language.Afrikaans
	Amharic              = language.Amharic
	Arabic               = language.Arabic
	ModernStandardArabic = language.ModernStandardArabic
	Azerbaijani          = language.Azerbaijani
	Bulgarian            = language.Bulgarian
	Bengali              = language.Bengali
	Catalan              = language.Catalan
	Czech                = language.Czech
	Danish               = language.Danish
	German               = language.German
	Greek                = language.Greek
	English              = language.English
	AmericanEnglish      = language.AmericanEnglish
	BritishEnglish       = language.BritishEnglish
	Spanish              = language.Spanish
	EuropeanSpanish      = language.EuropeanSpanish
	LatinAmericanSpanish = language.LatinAmericanSpanish
	Estonian             = language.Estonian
	Persian              = language.Persian
	Finnish              = language.Finnish
	Filipino             = language.Filipino
	French               = language.French
	CanadianFrench       = language.CanadianFrench
	Gujarati             = language.Gujarati
	Hebrew               = language.Hebrew
	Hindi                = language.Hindi
	Croatian             = language.Croatian
	Hungarian            = language.Hungarian
	Armenian             = language.Armenian
	Indonesian           = language.Indonesian
	Icelandic            = language.Icelandic
	Italian              = language.Italian
	Japanese             = language.Japanese
	Georgian             = language.Georgian
	Kazakh               = language.Kazakh
	Khmer                = language.Khmer
	Kannada              = language.Kannada
	Korean               = language.Korean
	Kirghiz              = language.Kirghiz
	Lao                  = language.Lao
	Lithuanian           = language.Lithuanian
	Latvian              = language.Latvian
	Macedonian           = language.Macedonian
	Malayalam            = language.Malayalam
	Mongolian            = language.Mongolian
	Marathi              = language.Marathi
	Malay                = language.Malay
	Burmese              = language.Burmese
	Nepali               = language.Nepali
	Dutch                = language.Dutch
	Norwegian            = language.Norwegian
	Punjabi              = language.Punjabi
	Polish               = language.Polish
	Portuguese           = language.Portuguese
	BrazilianPortuguese  = language.BrazilianPortuguese
	EuropeanPortuguese   = language.EuropeanPortuguese
	Romanian             = language.Romanian
	Russian              = language.Russian
	Sinhala              = language.Sinhala
	Slovak               = language.Slovak
	Slovenian            = language.Slovenian
	Albanian             = language.Albanian
	Serbian              = language.Serbian
	SerbianLatin         = language.SerbianLatin
	Swedish              = language.Swedish
	Swahili              = language.Swahili
	Tamil                = language.Tamil
	Telugu               = language.Telugu
	Thai                 = language.Thai
	Turkish              = language.Turkish
	Ukrainian            = language.Ukrainian
	Urdu                 = language.Urdu
	Uzbek                = language.Uzbek
	Vietnamese           = language.Vietnamese
	Chinese              = language.Chinese
	SimplifiedChinese    = language.SimplifiedChinese
	TraditionalChinese   = language.TraditionalChinese
	Zulu                 = language.Zulu
)

Functions

func Equal

func Equal(tag1, tag2 Tag) bool

Equal compares language tags by base ISO 639 language code.

Example

package main

import (
	"fmt"

	"github.com/muonsoft/language"
	textlanguage "golang.org/x/text/language"
)

func main() {
	fmt.Println(language.Equal(language.English, language.English))
	fmt.Println(language.Equal(language.English, language.Russian))
	fmt.Println(language.Equal(textlanguage.MustParse("ru"), textlanguage.MustParse("ru-RU")))
}

Output:

true
false
true

func WithContext

func WithContext(ctx context.Context, tag Tag) context.Context

WithContext adds language tag to context.

Types

type Middleware

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

Middleware is used to parse language from Accept-Language header or custom cookie from current request and pass best matching language via context to next http.Handler.

func NewMiddleware

func NewMiddleware(next http.Handler, options ...MiddlewareOption) *Middleware

NewMiddleware creates middleware for parsing language from Accept-Language header or a cookie and passing its value via context.

By default Middleware uses only English language and Accept-Language header as source.

To set up supported languages list use SupportedLanguages option.

To set up sources of language value use ReadFromCookie and ReadFromAcceptHeader options. Order of sources should be preserved.

func (*Middleware) ServeHTTP

func (middleware *Middleware) ServeHTTP(writer http.ResponseWriter, request *http.Request)

Example (ReadFromAcceptLanguageHeader)

package main

import (
	"fmt"
	"net/http"
	"net/http/httptest"

	"github.com/muonsoft/language"
)

func main() {
	h := http.HandlerFunc(func(writer http.ResponseWriter, request *http.Request) {
		tag := language.FromContext(request.Context())
		fmt.Println("language:", tag)
	})
	m := language.NewMiddleware(h, language.SupportedLanguages(language.English, language.Russian))

	r := httptest.NewRequest(http.MethodGet, "/", nil)
	r.Header.Set("Accept-Language", "ru")
	w := httptest.NewRecorder()

	m.ServeHTTP(w, r)
}

Output:

language: ru

Example (ReadFromCookie)

package main

import (
	"fmt"
	"net/http"
	"net/http/httptest"

	"github.com/muonsoft/language"
)

func main() {
	h := http.HandlerFunc(func(writer http.ResponseWriter, request *http.Request) {
		tag := language.FromContext(request.Context())
		fmt.Println("language:", tag)
	})
	m := language.NewMiddleware(
		h,
		language.SupportedLanguages(language.English, language.Russian),
		language.ReadFromCookie("lang"),
	)

	r := httptest.NewRequest(http.MethodGet, "/", nil)
	r.AddCookie(&http.Cookie{Name: "lang", Value: "ru"})
	w := httptest.NewRecorder()

	m.ServeHTTP(w, r)
}

Output:

language: ru

type MiddlewareOption

type MiddlewareOption func(middleware *Middleware)

MiddlewareOption is used to set up Middleware.

func ReadFromAcceptHeader

func ReadFromAcceptHeader() MiddlewareOption

ReadFromAcceptHeader can be used to set up middleware to read language value from Accept-Language header.

func ReadFromCookie

func ReadFromCookie(name string) MiddlewareOption

ReadFromCookie can be used to set up middleware to read language value from cookie with given name.

func SupportedLanguages

func SupportedLanguages(tags ...Tag) MiddlewareOption

SupportedLanguages is used to set up list of supported languages. See language.NewMatcher() for details.

type Tag

type Tag = language.Tag

Tag is an alias for language.Tag.

func FromContext

func FromContext(ctx context.Context) Tag

FromContext returns language tag. If language tag does not exist it returns language.Und value.