118 lines
3.2 KiB
Go
118 lines
3.2 KiB
Go
// Common tools and helper functions
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package common
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import (
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"fmt"
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"math/rand"
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"os"
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"time"
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"hammond/db"
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"github.com/dgrijalva/jwt-go"
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"github.com/gin-gonic/gin"
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"github.com/gin-gonic/gin/binding"
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"github.com/go-playground/validator/v10"
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)
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var letters = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789")
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// A helper function to generate random string
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func RandString(n int) string {
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b := make([]rune, n)
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for i := range b {
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b[i] = letters[rand.Intn(len(letters))]
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}
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return string(b)
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}
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// A helper to convert from litres to gallon
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func LitreToGallon(litres float32) float32 {
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gallonConversionFactor := 0.21997
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return litres * float32(gallonConversionFactor);
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}
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// A helper to convert from gallon to litres
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func GallonToLitre(gallons float32) float32 {
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litreConversionFactor := 3.785412
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return gallons * float32(litreConversionFactor);
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}
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// A helper to convert from km to miles
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func KmToMiles(km float32) float32 {
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kmConversionFactor := 0.62137119
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return km * float32(kmConversionFactor);
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}
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// A helper to convert from miles to km
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func MilesToKm(miles float32) float32 {
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milesConversionFactor := 1.609344
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return miles * float32(milesConversionFactor);
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}
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// A Util function to generate jwt_token which can be used in the request header
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func GenToken(id string, role db.Role) (string, string) {
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jwt_token := jwt.New(jwt.GetSigningMethod("HS256"))
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// Set some claims
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jwt_token.Claims = jwt.MapClaims{
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"id": id,
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"role": role,
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"exp": time.Now().Add(time.Hour * 24 * 3).Unix(),
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}
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// Sign and get the complete encoded token as a string
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token, _ := jwt_token.SignedString([]byte(os.Getenv("JWT_SECRET")))
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refreshToken := jwt.New(jwt.SigningMethodHS256)
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rtClaims := refreshToken.Claims.(jwt.MapClaims)
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rtClaims["id"] = id
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rtClaims["exp"] = time.Now().Add(time.Hour * 24 * 20).Unix()
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rt, _ := refreshToken.SignedString([]byte(os.Getenv("JWT_SECRET")))
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return token, rt
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}
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// My own Error type that will help return my customized Error info
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// {"database": {"hello":"no such table", error: "not_exists"}}
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type CommonError struct {
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Errors map[string]interface{} `json:"errors"`
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}
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// To handle the error returned by c.Bind in gin framework
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// https://github.com/go-playground/validator/blob/v9/_examples/translations/main.go
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func NewValidatorError(err error) CommonError {
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res := CommonError{}
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res.Errors = make(map[string]interface{})
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errs := err.(validator.ValidationErrors)
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for _, v := range errs {
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// can translate each error one at a time.
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//fmt.Println("gg",v.NameNamespace)
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if v.Param() != "" {
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res.Errors[v.Field()] = fmt.Sprintf("{%v: %v}", v.Tag(), v.Param())
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} else {
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res.Errors[v.Field()] = fmt.Sprintf("{key: %v}", v.Tag())
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}
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}
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return res
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}
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// Warp the error info in a object
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func NewError(key string, err error) CommonError {
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res := CommonError{}
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res.Errors = make(map[string]interface{})
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res.Errors[key] = err.Error()
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return res
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}
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// Changed the c.MustBindWith() -> c.ShouldBindWith().
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// I don't want to auto return 400 when error happened.
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// origin function is here: https://github.com/gin-gonic/gin/blob/master/context.go
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func Bind(c *gin.Context, obj interface{}) error {
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b := binding.Default(c.Request.Method, c.ContentType())
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return c.ShouldBindWith(obj, b)
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}
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