How to sanitize and validate user input in HTML forms in Go?

To sanitize and validate user input in HTML forms in Go, you can follow these steps:

1. Sanitizing input:

   • Use the html.EscapeString() function from the "html" package to sanitize HTML input. It escapes special characters like <, >, and & to prevent XSS attacks. An example can be:

     sanitizedInput := html.EscapeString(r.FormValue("inputFieldName"))

2. Validating input:

   • Use the built-in validation functions from the "net/http" package to validate user input. For example, the http.Request object has a method called FormValue(key string) that retrieves the values associated with a given key in the POST form data. You can use this method and check it against specific conditions or patterns. An example can be:

     input := r.FormValue("inputFieldName") if input == "" { // Handle empty input } // Other validation conditions or pattern matching

3. Return appropriate validation errors:

   • If validation fails, you can return an error message to the user, notifying them about the validation error. This can be done by rendering an error template or by sending a JSON response. An example can be:

     if input == "" { errorMessage := "Input is required." // Render an error template or send a JSON response with the error message return } // Other validation conditions

It's important to note that HTML form input sanitization and validation should also be performed on the server-side, even if you have client-side validation in place. Client-side validation can be bypassed, so server-side validation is necessary to ensure data integrity and security.