pageable

Gorm-Pageable

A page query management of GORM

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Installation

We Recommend to use package manager vgo to manage this package

import pageable "github.com/BillSJC/gorm-pageable"

Usage

Just prepare a struct and FOLLOW the code below

package main

import (
    "fmt"
    pageable "github.com/BillSJC/gorm-pageable"
    "github.com/jinzhu/gorm"
)

var DB *gorm.DB //your gorm DB connection

// the struct you want to search
type User struct{
    gorm.Model
    Active bool
    UserName string
    Age uint
}

// a function to get ddata
func getResultSet (page int,rowsPerPage int)(*pageable.Response,error){
    //your empty result set
    resultSet := make([]*User,0,30)
    //prepare a handler to query
    handler := DB.
        Module(&User{}).
        Where(&User{Active:true})
    //use PageQuery to get data
    resp,err := pageable.PageQuery(page,rowsPerPage,handler,&resultSet)
    // if need, you can turn to next/last page
    resp,err = resp.GetNextPage() //to next page
    resp,err = resp.GetLastPage() //to last page
    resp,err = resp.GetFirstPage() //to first page
    resp,err = resp.GetEndPage() //to end page
    // you can use both resp.ResultSet or the resultSet you input to access the result
    // handle error
    if err != nil {
        //print the err or do sth else
        fmt.Println("something happened...")
        fmt.Println(err)
        return nil,err
    }
    // Here are the response
    // NOTICE:  all element of Response should be READ ONLY! once it changed, the logic of the query may broke
	fmt.Println(resp.PageNow)    //PageNow: current page of query
	fmt.Println(resp.PageCount)  //PageCount: total page of the query
	fmt.Println(resp.RawCount)   //RawCount: total raw of query
	fmt.Println(resp.RawPerPage) //RawPerPage: rpp
	fmt.Println(resp.ResultSet)  //ResultSet: result data
	fmt.Println(resultSet)          //the same as resp.ResultSet and have the raw type
	fmt.Println(resp.FirstPage)  //FirstPage: if the result is the first page
	fmt.Println(resp.LastPage)   //LastPage: if the result is the last page
	fmt.Println(resp.Empty)  //Empty: if the result is empty
	fmt.Println(resp.StartRow)  //StartRow: the first row of the result set, 0 when result set is empty
	fmt.Println(resp.EndRow)  //EndRow: the last row of the result set, 0 when result set is empty
}

Notice: when access to the result, you can use both resp.ResultSet in Response or the param resultSet you input into the function, both of then have same pointer and same data, but the type of resp.ResultSet is interface{} and you mat need to convert to the raw type if you need to do any operation of the result set

Guidance

Use 0 as the first page

the default first page is 1. However,if u want to use 0 as the first page, just follow this step:

    pageable.Use0AsFirstPage()

Set Default Result Per Page(rpp)

Sometimes you just want to use same rpp in every query, then u just need do this:

    pageable.SetDefaultRPP(25) //set 25 rows per page in every query

And next time, you can use rpp=0 to use Default rpp

    pageable.PageQuery(page:1, rpp:0, queryHandler: ..., resultPtr: ...)

Use custom recovery

The default recovery will only print stack trace. If you want to use your custom Recovery handler, just follow the step:

package main
import (
    "fmt"
    pageable "github.com/BillSJC/gorm-pageable"
)

//your recovery
func myRecovery(){
    if err := recover ; err != nil {
        fmt.Println("something happend")
        fmt.Println(err)
        //then you can do some logs...
    } 
}

func init(){
    //setup your recovery
    pageable.SetRecovery(myRecovery)
}