Query Parser for REST

Query Parser is a library for easy building dynamic SQL queries to Database. It provides a simple API for web-applications which needs to do some filtering throught GET queries. It is a connector between the HTTP handler and the DB engine, and manages validations and translations for user inputs.

Installation

go get -u github.com/timsolov/rest-query-parser

Fast start

See cmd/main.go and tests for more examples.

    package main
    
    import (
        "errors"
        "fmt"
        "net/url"
    
        rqp "github.com/timsolov/rest-query-parser"
    )
    
    func main() {
        url, _ := url.Parse("http://localhost/?sort=+name,-id&limit=10&id=1&i[eq]=5&s[eq]=one&email[like]=*tim*|name[like]=*tim*")
        q, _ := rqp.NewParse(url.Query(), rqp.Validations{
            "limit:required": rqp.MinMax(10, 100),  // limit must present in the Query part and must be between 10 and 100 (default: Min(1))
            "sort":           rqp.In("id", "name"), // sort could be or not in the query but if it is present it must be equal to "in" or "name"
            "s":      rqp.In("one", "two"), // filter: s - string and equal
            "id:int": nil,                  // filter: id is integer without additional validation
            "i:int": func(value interface{}) error { // filter: custom func for validating
                if value.(int) > 1 && value.(int) < 10 {
                    return nil
                }
                return errors.New("i: must be greater then 1 and lower then 10")
            },
            "email": nil,
            "name":  nil,
        })

        fmt.Println(q.SQL("table")) // SELECT * FROM table WHERE id = ? AND i = ? AND s = ? AND (email LIKE ? OR name LIKE ?) ORDER BY name, id DESC LIMIT 10
        fmt.Println(q.Where())      // id = ? AND i = ? AND s = ? AND (email LIKE ? OR name LIKE ?)
        fmt.Println(q.Args())       // [1 5 one %tim% %tim%]

        q.AddValidation("fields", rqp.In("id", "name"))
        q.SetUrlString("http://localhost/?fields=id,name&limit=10")
        q.Parse()

        fmt.Println(q.SQL("table")) // SELECT id, name FROM table ORDER BY id LIMIT 10
        fmt.Println(q.FieldsSQL())  // id, name
        fmt.Println(q.Args())       // []
    }

Top level fields:

• fields - fields for SELECT clause separated by comma (",") Eg. &fields=id,name. If nothing provided will use "*" by default. Attention! If you want to use this filter you have to define validation func for it. Use rqp.In("id", "name") func for limit fields for your query.
• sort - sorting fields list separated by comma (","). Must be validated too. Could include prefix +/- which means ASC/DESC sorting. Eg. &sort=+id,-name will print ORDER BY id, name DESC. You have to filter fields in this parameter by adding rqp.In("id", "name").
• limit - is limit for LIMIT clause. Should be greater then 0 by default. Definition of the validation for limit is not required. But you may use rqp.Max(100) to limit top threshold.
• offset - is offset for OFFSET clause. Should be greater then or equal to 0 by default. Definition of the validation for offset is not required.

Validation modificators:

• :required - parameter is required. Must present in the query string. Raise error if not.
• :int - parameter must be convertable to int type. Raise error if not.
• :bool - parameter must be convertable to bool type. Raise error if not.

Supported types

• string - the default type for all provided filters if not specified another. Could be compared by eq, ne, like, ilike, in methods.
• int - integer type. Must be specified with tag ":int". Could be compared by eq, ne, gt, lt, gte, lte, in methods.
• bool - boolean type. Must be specified with tag ":bool". Could be compared by eq method.

TODO:

• new type time.