package middleware import ( "regexp" "strings" "github.com/labstack/echo/v4" ) type ( // RewriteConfig defines the config for Rewrite middleware. RewriteConfig struct { // Skipper defines a function to skip middleware. Skipper Skipper // Rules defines the URL path rewrite rules. The values captured in asterisk can be // retrieved by index e.g. $1, $2 and so on. // Example: // "/old": "/new", // "/api/*": "/$1", // "/js/*": "/public/javascripts/$1", // "/users/*/orders/*": "/user/$1/order/$2", // Required. Rules map[string]string `yaml:"rules"` rulesRegex map[*regexp.Regexp]string } ) var ( // DefaultRewriteConfig is the default Rewrite middleware config. DefaultRewriteConfig = RewriteConfig{ Skipper: DefaultSkipper, } ) // Rewrite returns a Rewrite middleware. // // Rewrite middleware rewrites the URL path based on the provided rules. func Rewrite(rules map[string]string) echo.MiddlewareFunc { c := DefaultRewriteConfig c.Rules = rules return RewriteWithConfig(c) } // RewriteWithConfig returns a Rewrite middleware with config. // See: `Rewrite()`. func RewriteWithConfig(config RewriteConfig) echo.MiddlewareFunc { // Defaults if config.Rules == nil { panic("echo: rewrite middleware requires url path rewrite rules") } if config.Skipper == nil { config.Skipper = DefaultBodyDumpConfig.Skipper } config.rulesRegex = map[*regexp.Regexp]string{} // Initialize for k, v := range config.Rules { k = regexp.QuoteMeta(k) k = strings.Replace(k, `\*`, "(.*)", -1) k = k + "$" config.rulesRegex[regexp.MustCompile(k)] = v } return func(next echo.HandlerFunc) echo.HandlerFunc { return func(c echo.Context) (err error) { if config.Skipper(c) { return next(c) } req := c.Request() // Rewrite for k, v := range config.rulesRegex { replacer := captureTokens(k, req.URL.Path) if replacer != nil { req.URL.Path = replacer.Replace(v) break } } return next(c) } } }