EchoValidator is a fail fast extensible validation library only compatible with Echo Framework.

When provided a list of validation rules to check, echovalidate will bail on the first error and return the error message. As opposed to running all validations and collecting errors in a bag.

    package main

    import (
        "github.com/labstack/echo/v4"
        "github.com/jcobhams/echovalidate/v2"
    )
    
    func main() {
        
        //Initialize Echo Instance
        e := echo.New()
        
        //Register Validator 
        e.Validator = echovalidate.New()
        
        //Register Route Handler
        e.POST("/some-endpoint", handler)
        
        //Start Server
        e.Start(":9009")
    }


    func handler(ctx echo.Content) error {
        username := "jcobhams" // Could come from post request body
    	
        v := echovalidate.Validator{
    		Rules: echovalidate.Rules{
    			{echovalidate.Required, "username", username},
    			/** more validation rules here **/
    			{echovalidate.MinLen, "username", len(username), 5},
    		},
    	}
    	err := ctx.Validate(v)
    	if err != nil {
    		return  ctx.JSON(400, err)
    	}
        
        /** All is well - continue as normal **/
        return ctx.JSON(200, "OK")
    }

1. Required - Checks that value is not empty if type is string | only string type supported for now - PR for Slices/Maps?
2. ValidEmail - Checks that an email is properly formed. Uses regex to pattern match - Valid Email: [email protected] - PR for MX validation?
3. In - Checks that needle exist in a haystack | Only supports string slices
4. MinLen - Checks if the provided length (int) is less than the minimum length and returns error if true.
5. MaxLen - Checks if the provided length (int) is greater than the maximum length and returns error if true.
6. ValidMongoObjectID - Checks if provided value conforms to MongoDB object ID hexadecimal
7. ValidDateTime - Checks if provided date parses according to provided layout string.

Validation Rules are pure functions and must follow a certain format. Signature: func FuncName(args...) error {} This means that Your custom validation functions can exists anywhere in your program as long as they can be imported and used to build the Rules list

Your validation functions must always have a return type of error, which should contain the error message if validation fails or nil if validation passes.

The args to your validation function must be provided to Rules in the order in which they are defined at function definition

func SuperChecker(value string) error {
    /** 
    Do something with value, if successful, return nil else return error
    **/
    
    if len(value) > 1 {
        return nil
    }
    return errors.New("value should be more than 1 char")
}
...

    v := echovalidate.Validator{
    		Rules: echovalidate.Rules{
    			{SuperChecker, username},
    		},
    	}
...

Because I needed something simple, lightweight, flexible and most importantly didn't follow the errorbag design. I needed something that would fail fast on first validation error.

Use if you have a need/like/curious/dislike etc.

PR/Feedback welcomed and encouraged.

Project was originally on gitlab but was moved to github. To avoid confusion, the github version starts at 2.x