This package is still under development and not ready for production use.

qparser is a simple package that help parse query parameters into struct in Go. It is inspired by gorilla/schema with main focus on query parameters. Built on top of Go stdlib, it uses custom struct tag qp to define the query parameter key .

go get -u github.com/prawirdani/qparser

Here's an example of how to use qparser to parse query parameters into struct.

// Representing basic pagination, /path?page=1&limit=5
type Pagination struct {
    Page    int `qp:"page"`
    Limit   int `qp:"limit"`
}

func MyHandler(w http.ResponseWriter, r *http.Request) {
    var pagination Pagination

    err := qparser.ParseRequest(r, &pagination)
    if err != nil {
        // Handle Error
    }
        
    // Do something with pagination
}

By default, it does not validate empty query values. To perform empty value validation or implement some business rules validation, you can create your own validator or use a validator package like validator.

To allow multiple values for a single query parameter, you can use a slice type.

// Representing filter for menu
type MenuFilter struct {
    Categories []string `qp:"categories"`
    Available  bool     `qp:"available"`
}

type Pagination struct {
    Page    int `qp:"page"`
    Limit   int `qp:"limit"`
}

type MenuQueryParams struct {
    Filter     MenuFilter
    Pagination Pagination
}

func GetMenus(w http.ResponseWriter, r *http.Request) {
    var f MenuQueryParams
    if err := qparser.ParseRequest(r, &f); err != nil {
        // Handle Error
    }
    // Do something with f.Filter and f.Pagination
}

The multiple values are separated by comma , in the query string. For example, /menus?categories=desserts,beverages. For the nested struct, simply just pass the qp tag definition in the nested struct field. So the final query string will look like /menus?categories=desserts,beverages&available=true&page=1&limit=5.

You can also parse query parameters from URL string by calling the ParseURL function. Here's an example:

func main() {
    var pagination Pagination

    url := "http:https://example.com/path?page=1&limit=5"

    err := qparser.ParseURL(url, &pagination)
    if err != nil {
        // Handle Error
    }

    // Do something with pagination
}

Currently, it only supports basic primitive types such as:

• String
• Boolean
• Integers (int, int8, int16, int32 and int64)
• Unsigned Integers (uint, uint8, uint16, uint32 and uint64)
• Floats (float64 and float32)
• Slice of above types
• Nested Struct
• A pointer to one of above

• Support for various types such as multidimensional slice and slice of Struct
• Default value mechanism
• Mapped Errors
• Custom multivalues separator

Contributions are welcome! If you have any improvements, bug fixes, or new features you'd like to add.