rqp

package module
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 Go to latest Published: Sep 9, 2020 License: Apache-2.0 Imports: 9 Imported by: 0

README

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.

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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.

Documentation

Index

Constants

View Source 
const NULL = "NULL"

NULL constant

Variables

View Source 
var (
	ErrRequired           = NewError("required")
	ErrBadFormat          = NewError("bad format")
	ErrEmptyValue         = NewError("empty value")
	ErrUnknownMethod      = NewError("unknown method")
	ErrNotInScope         = NewError("not in scope")
	ErrSimilarNames       = NewError("similar names of keys are not allowed")
	ErrMethodNotAllowed   = NewError("method are not allowed")
	ErrFilterNotAllowed   = NewError("filter are not allowed")
	ErrFilterNotFound     = NewError("filter not found")
	ErrValidationNotFound = NewError("validation not found")
)

Errors list:

Functions

This section is empty.

Types

type Error 

type Error struct {
	// contains filtered or unexported fields
}

Error special rqp.Error type

func NewError 

func NewError(msg string) *Error

NewError constructor for internal errors

func (*Error) Error 

func (e *Error) Error() string

type Filter 

type Filter struct {
	Key    string // key from URL (eg. "id[eq]")
	Name   string // name of filter, takes from Key (eg. "id")
	Method Method // compare method, takes from Key (eg. EQ)
	Value  interface{}
	Or     bool
}

Filter represents a filter defined in the query part of URL

func (*Filter) Args 

func (f *Filter) Args() ([]interface{}, error)

Args returns arguments slice depending on filter condition

func (*Filter) Where 

func (f *Filter) Where() (string, error)

Where returns condition expression

type Method 

type Method string

Method is a compare method type 

var (
	EQ    Method = "EQ"
	NE    Method = "NE"
	GT    Method = "GT"
	LT    Method = "LT"
	GTE   Method = "GTE"
	LTE   Method = "LTE"
	LIKE  Method = "LIKE"
	ILIKE Method = "ILIKE"
	NOT   Method = "NOT"
	IN    Method = "IN"
)

Compare methods:

type Query 

type Query struct {
	Fields  []string
	Offset  int
	Limit   int
	Sorts   []Sort
	Filters []*Filter

	Error error
	// contains filtered or unexported fields
}

Query the main struct of package

func New 

func New() *Query

New creates new instance of Query

func NewParse 

func NewParse(q url.Values, v Validations) (*Query, error)

NewParse creates new Query instance and Parse it

func NewQV 

func NewQV(q url.Values, v Validations) *Query

NewQV creates new Query instance with parameters

func (*Query) AddField 

func (q *Query) AddField(field string) *Query

AddField returns true if request asks for field

func (*Query) AddFilter 

func (q *Query) AddFilter(name string, m Method, value interface{}) *Query

AddFilter adds a filter to Query

func (*Query) AddSortBy 

func (q *Query) AddSortBy(by string, desc bool) *Query

AddSortBy adds an order rule to Query

func (*Query) AddValidation 

func (q *Query) AddValidation(NameAndTags string, v ValidationFunc) *Query

AddValidation adds a validation to Query

func (*Query) Args 

func (q *Query) Args() []interface{}

Args returns slice of arguments for WHERE statement

func (*Query) FieldsString 

func (q *Query) FieldsString() string

FieldsString returns elements list separated by comma (",") for querying in SELECT statement or a star ("*") if nothing provided

Return example:

When "fields" empty or not provided: `*`.

When "fields=id,email": `id, email`.

func (*Query) GetFilter 

func (q *Query) GetFilter(name string) (*Filter, error)

GetFilter returns filter by name

func (*Query) HaveField 

func (q *Query) HaveField(field string) bool

HaveField returns true if request asks for field

func (*Query) HaveFilter 

func (q *Query) HaveFilter(name string) bool

HaveFilter returns true if request contains some filter

func (*Query) HaveSortBy 

func (q *Query) HaveSortBy(by string) bool

HaveSortBy returns true if request contains some sorting

func (*Query) IgnoreUnknownFilters 

func (q *Query) IgnoreUnknownFilters(i bool) *Query

IgnoreUnknownFilters set behavior for Parser to raise ErrFilterNotAllowed to undefined filters or not

func (*Query) LIMIT 

func (q *Query) LIMIT() string

LIMIT returns LIMIT statement return example: `LIMIT 100`

func (*Query) OFFSET 

func (q *Query) OFFSET() string

OFFSET returns OFFSET statement return example: `OFFSET 0`

func (*Query) ORDER 

func (q *Query) ORDER() string

ORDER returns ORDER BY statement with list of elements for sorting you can use +/- prefix to specify direction of sorting (+ is default) return example: `ORDER BY id DESC, email`

func (*Query) Order 

func (q *Query) Order() string

Order returns list of elements for ORDER BY statement you can use +/- prefix to specify direction of sorting (+ is default) return example: `id DESC, email`

func (*Query) Parse 

func (q *Query) Parse() (err error)

Parse parses the query of URL as query you can use standart http.Request query by r.URL.Query()

func (*Query) RemoveFilter 

func (q *Query) RemoveFilter(name string) error

RemoveFilter removes the filter by name

func (*Query) RemoveValidation 

func (q *Query) RemoveValidation(NameAndOrTags string) error

RemoveValidation remove a validation from Query You can provide full name of filer with tags or only name of filter: RemoveValidation("id:int") and RemoveValidation("id") are same

func (*Query) ReplaceNames 

func (q *Query) ReplaceNames(r Replacer)

ReplaceNames replace all specified name to new names Sometimes we've to hijack properties, for example when we do JOINs, so you can ask for filter/field "user_id" but replace it with "users.user_id". Parameter is a map[string]string which means map[currentName]newName. The library provide beautiful way by using special type rqp.Replacer. Example: 

  rqp.ReplaceNames(rqp.Replacer{
	   "user_id": "users.user_id",
  })

func (*Query) SELECT 

func (q *Query) SELECT() string

SELECT returns word SELECT with fields from Filter "fields" separated by comma (",") from URL-Query or word SELECT with star ("*") if nothing provided'

Return examples:

When "fields" empty or not provided: `SELECT *`.

When "fields=id,email": `SELECT id, email`.

func (*Query) SQL 

func (q *Query) SQL(table string) string

SQL returns whole SQL statement

func (*Query) Select 

func (q *Query) Select() string

Select returns elements list separated by comma (",") for querying in SELECT statement or a star ("*") if nothing provided

Return examples:

When "fields" empty or not provided: `*`

When "fields=id,email": `id, email`

func (*Query) SetDelimiterIN 

func (q *Query) SetDelimiterIN(d string) *Query

SetDelimiterIN sets delimiter for values of filters

func (*Query) SetDelimiterOR 

func (q *Query) SetDelimiterOR(d string) *Query

SetDelimiterOR sets delimiter for OR filters in query part of URL

func (*Query) SetUrlQuery 

func (q *Query) SetUrlQuery(query url.Values) *Query

SetUrlQuery change url in the Query for parsing uses when you need provide Query from http.HandlerFunc(w http.ResponseWriter, r *http.Request) you can do q.SetUrlValues(r.URL.Query())

func (*Query) SetUrlString 

func (q *Query) SetUrlString(Url string) error

SetUrlString change url in the Query for parsing uses when you would like to provide raw URL string to parsing

func (*Query) SetValidations 

func (q *Query) SetValidations(v Validations) *Query

SetValidations change validations rules for the instance

func (*Query) WHERE 

func (q *Query) WHERE() string

WHERE returns list of filters for WHERE SQL statement with `WHERE` word return example: `WHERE id > 0 AND email LIKE 'some@email.com'`

func (*Query) Where 

func (q *Query) Where() string

Where returns list of filters for WHERE statement return example: `id > 0 AND email LIKE 'some@email.com'`

type Replacer 

type Replacer map[string]string

Replacer struct for ReplaceNames method

type Sort 

type Sort struct {
	By   string
	Desc bool
}

Sort is ordering struct

type ValidationFunc 

type ValidationFunc func(value interface{}) error

ValidationFunc represents validator for Filters

func In 

func In(values ...interface{}) ValidationFunc

In validation if values contatin value

func Max 

func Max(max int) ValidationFunc

Max validation if value lower or equal then max

func Min 

func Min(min int) ValidationFunc

Min validation if value greater or equal then min

func MinMax 

func MinMax(min, max int) ValidationFunc

MinMax validation if value between or equal min and max

func Multi 

func Multi(values ...ValidationFunc) ValidationFunc

Multi multiple validation func usage: Multi(Min(10), Max(100))

func NotEmpty 

func NotEmpty() ValidationFunc

NotEmpty validation if string value length more then 0

type Validations 

type Validations map[string]ValidationFunc

Validations type replacement for map. Used in NewParse(), NewQV(), SetValidations()

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