Marko Tikvić / webutility

Browse Code »

Commit 4635f2c3cd374ddaf963f577535485bcddcf1bf4

Authored by Marko Tikvić 2019-11-27 11:07:48 +0100

1 parent b3f624151c

Exists in master

pagination utility

Showing 2 changed files with 45 additions and 42 deletions Show diff stats

pagination.go

Diff comments View file @4635f2c

File was created	1	package webutility
	2
	3	import "net/http"
	4
	5	type PaginationParams struct {
	6	URL string
	7	Offset int64
	8	Limit int64
	9	SortBy string
	10	Order string
	11	}
	12
	13	func (p *PaginationParams) links() PaginationLinks {
	14	return PaginationLinks{}
	15	}
	16
	17	// PaginationLinks ...
	18	type PaginationLinks struct {
	19	Count int64
	20	Total int64
	21	Base string `json:"base"`
	22	Next string `json:"next"`
	23	Prev string `json:"prev"`
	24	Self string `json:"self"`
	25	}
	26
	27	func GetPaginationParameters(req *http.Request) (p PaginationParams) {
	28	p.Offset = StringToInt64(req.FormValue("offset"))
	29	p.Limit = StringToInt64(req.FormValue("limit"))
	30	p.SortBy = req.FormValue("sortBy")
	31	p.Order = req.FormValue("order")
	32
	33	return p
	34	}
	35

payload.go

Diff comments View file @4635f2c

 package webutility
 import (
 	"database/sql"
 	"encoding/json"
 	"errors"
 	"fmt"
 	"net/http"
 	"strings"
 	"sync"
 	"time"
 )
 var (
 	mu       = &sync.Mutex{}
 	metadata = make(map[string]Payload)
 	updateQue = make(map[string][]byte)
 	metadataDB    *sql.DB
 	activeProject string
 	inited     bool
 	metaDriver string
 )
 // LangMap ...
 type LangMap map[string]map[string]string
 // Field ...
 type Field struct {
 	Parameter string `json:"param"`
 	Type      string `json:"type"`
 	Visible   bool   `json:"visible"`
 	Editable  bool   `json:"editable"`
 }
 // CorrelationField ...
 type CorrelationField struct {
 	Result   string   `json:"result"`
 	Elements []string `json:"elements"`
 	Type     string   `json:"type"`
 }
 // Translation ...
 type Translation struct {
 	Language     string            `json:"language"`
 	FieldsLabels map[string]string `json:"fieldsLabels"`
 }
-// PaginationLinks ...
-type PaginationLinks struct {
-	Base string `json:"base"`
-	Next string `json:"next"`
-	Prev string `json:"prev"`
-	Self string `json:"self"`
-}
-// PaginationParameters ...
-type PaginationParameters struct {
-	URL    string `json:"-"`
-	Offset int64  `json:"offset"`
-	Limit  int64  `json:"limit"`
-	SortBy string `json:"sortBy"`
-	Order  string `json:"order"`
-}
-// GetPaginationParameters ...
-// TODO(marko)
-func GetPaginationParameters(req *http.Request) (p PaginationParameters) {
-	return p
-}
-// TODO(marko)
-func (p *PaginationParameters) paginationLinks() (links PaginationLinks) {
-	return links
-}
 // Payload ...
 type Payload struct {
 	Method       string             `json:"method"`
 	Params       map[string]string  `json:"params"`
 	Lang         []Translation      `json:"lang"`
 	Fields       []Field            `json:"fields"`
 	Correlations []CorrelationField `json:"correlationFields"`
 	IDField      string             `json:"idField"`
-	// Pagination
-	Count int64           `json:"count"`
-	Total int64           `json:"total"`
 	Links PaginationLinks `json:"_links"`
 	// Data holds JSON payload. It can't be used for itteration.
 	Data interface{} `json:"data"`
 }
+// NewPayload returs a payload sceleton for entity described with key.
+func NewPayload(r *http.Request, key string) Payload {
+	p := metadata[key]
+	p.Method = r.Method + " " + r.RequestURI
+	return p
+}
 func (p *Payload) addLang(code string, labels map[string]string) {
 	t := Translation{
 		Language:     code,
 		FieldsLabels: labels,
 	}
 	p.Lang = append(p.Lang, t)
 }
 // SetData ...
 func (p *Payload) SetData(data interface{}) {
 	p.Data = data
 }
 // SetPaginationInfo ...
-func (p *Payload) SetPaginationInfo(count, total int64, params PaginationParameters) {
+func (p *Payload) SetPaginationInfo(count, total int64, params PaginationParams) {
-	p.Count = count
+	p.Links.Count = count
-	p.Total = total
+	p.Links.Total = total
-	p.Links = params.paginationLinks()
+	p.Links = params.links()
-}
-// NewPayload returs a payload sceleton for entity described with key.
-func NewPayload(r *http.Request, key string) Payload {
-	p := metadata[key]
-	p.Method = r.Method + " " + r.RequestURI
-	return p
 }
 // InitPayloadsMetadata loads all payloads' information into 'metadata' variable.
 func InitPayloadsMetadata(drv string, db *sql.DB, project string) error {
 	var err error
 	if drv != "ora" && drv != "mysql" {
 		err = errors.New("driver not supported")
 		return err
 	}
 	metaDriver = drv
 	metadataDB = db
 	activeProject = project
 	mu.Lock()
 	defer mu.Unlock()
 	err = initMetadata(project)
 	if err != nil {
 		return err
 	}
 	inited = true
 	return nil
 }
 // EnableHotloading ...
 func EnableHotloading(interval int) {
 	if interval > 0 {
 		go hotload(interval)
 	}
 }
 // GetMetadataForAllEntities ...
 func GetMetadataForAllEntities() map[string]Payload {
 	return metadata
 }
 // GetMetadataForEntity ...
 func GetMetadataForEntity(t string) (Payload, bool) {
 	p, ok := metadata[t]
 	return p, ok
 }
 // QueEntityModelUpdate ...
 func QueEntityModelUpdate(entityType string, v interface{}) {
 	updateQue[entityType], _ = json.Marshal(v)
 }
 // UpdateEntityModels ...
 func UpdateEntityModels(command string) (total, upd, add int, err error) {
 	if command != "force" && command != "missing" {
 		return total, 0, 0, errors.New("webutility: unknown command: " + command)
 	}
 	if !inited {
 		return 0, 0, 0, errors.New("webutility: metadata not initialized but update was tried")
 	}
 	total = len(updateQue)
 	toUpdate := make([]string, 0)
 	toAdd := make([]string, 0)
 	for k := range updateQue {
 		if _, exists := metadata[k]; exists {
 			if command == "force" {
 				toUpdate = append(toUpdate, k)
 			}
 		} else {
 			toAdd = append(toAdd, k)
 		}
 	}
 	var uStmt *sql.Stmt
 	if metaDriver == "ora" {
 		uStmt, err = metadataDB.Prepare("update entities set entity_model = :1 where entity_type = :2")
 		if err != nil {
 			return
 		}
 	} else if metaDriver == "mysql" {
 		uStmt, err = metadataDB.Prepare("update entities set entity_model = ? where entity_type = ?")
 		if err != nil {
 			return
 		}
 	}
 	for _, k := range toUpdate {
 		_, err = uStmt.Exec(string(updateQue[k]), k)
 		if err != nil {
 			return
 		}
 		upd++
 	}
 	blankPayload, _ := json.Marshal(Payload{})
 	var iStmt *sql.Stmt
 	if metaDriver == "ora" {
 		iStmt, err = metadataDB.Prepare("insert into entities(projekat, metadata, entity_type, entity_model) values(:1, :2, :3, :4)")
 		if err != nil {
 			return
 		}
 	} else if metaDriver == "mysql" {
 		iStmt, err = metadataDB.Prepare("insert into entities(projekat, metadata, entity_type, entity_model) values(?, ?, ?, ?)")
 		if err != nil {
 			return
 		}
 	}
 	for _, k := range toAdd {
 		_, err = iStmt.Exec(activeProject, string(blankPayload), k, string(updateQue[k]))
 		if err != nil {
 			return
 		}
 		metadata[k] = Payload{}
 		add++
 	}
 	return total, upd, add, nil
 }
 func initMetadata(project string) error {
 	rows, err := metadataDB.Query(`select
 		entity_type,
 		metadata
 		from entities
 		where projekat = ` + fmt.Sprintf("'%s'", project))
 	if err != nil {
 		return err
 	}
 	defer rows.Close()
 	if len(metadata) > 0 {
 		metadata = nil
 	}
 	metadata = make(map[string]Payload)
 	for rows.Next() {
 		var name, load string
 		rows.Scan(&name, &load)
 		p := Payload{}
 		err := json.Unmarshal([]byte(load), &p)
 		if err != nil {
 			fmt.Printf("webutility: couldn't init: '%s' metadata: %s:\n%s\n", name, err.Error(), load)
 		} else {
 			metadata[name] = p
 		}
 	}
 	return nil
 }
 // LoadMetadataFromFile expects file in format:
 //
 // [ payload A identifier ]
 // key1 = value1
 // key2 = value2
 // ...
 // [ payload B identifier ]
 // key1 = value1
 // key2 = value2
 // ...
 //
 // TODO(marko): Currently supports only one hardcoded language...
 func LoadMetadataFromFile(path string) error {
 	lines, err := ReadFileLines(path)
 	if err != nil {
 		return err
 	}
 	metadata = make(map[string]Payload)
 	var name string
 	for i, l := range lines {
 		// skip empty lines
 		if l = strings.TrimSpace(l); len(l) == 0 {
 			continue
 		}
 		if IsWrappedWith(l, "[", "]") {
 			name = strings.Trim(l, "[]")
 			p := Payload{}
 			p.addLang("sr", make(map[string]string))
 			metadata[name] = p
 			continue
 		}
 		if name == "" {
 			return fmt.Errorf("webutility: LoadMetadataFromFile: error on line %d: [no header] [%s]", i+1, l)
 		}
 		parts := strings.Split(l, "=")
 		if len(parts) != 2 {
 			return fmt.Errorf("webutility: LoadMetadataFromFile: error on line %d: [invalid format] [%s]", i+1, l)
 		}
 		k := strings.TrimSpace(parts[0])
 		v := strings.TrimSpace(parts[1])
 		if v != "-" {
 			metadata[name].Lang[0].FieldsLabels[k] = v
 		}
 	}
 	return nil
 }
 func hotload(n int) {
 	entityScan := make(map[string]int64)
 	firstCheck := true
 	for {
 		time.Sleep(time.Duration(n) * time.Second)
 		rows, err := metadataDB.Query(`select
 			ora_rowscn,
 			entity_type
 			from entities where projekat = ` + fmt.Sprintf("'%s'", activeProject))
 		if err != nil {
 			fmt.Printf("webutility: hotload failed: %v\n", err)
 			time.Sleep(time.Duration(n) * time.Second)
 			continue
 		}
 		var toRefresh []string
 		for rows.Next() {
 			var scanID int64
 			var entity string
 			rows.Scan(&scanID, &entity)
 			oldID, ok := entityScan[entity]
 			if !ok || oldID != scanID {
 				entityScan[entity] = scanID
 				toRefresh = append(toRefresh, entity)
 			}
 		}
 		rows.Close()
 		if rows.Err() != nil {
 			fmt.Printf("webutility: hotload rset error: %v\n", rows.Err())
 			time.Sleep(time.Duration(n) * time.Second)
 			continue
 		}
 		if len(toRefresh) > 0 && !firstCheck {
 			mu.Lock()
 			refreshMetadata(toRefresh)
 			mu.Unlock()
 		}
 		if firstCheck {
 			firstCheck = false
 		}
 	}
 }
 func refreshMetadata(entities []string) {
 	for _, e := range entities {
 		fmt.Printf("refreshing %s\n", e)
 		rows, err := metadataDB.Query(`select
 			metadata
 			from entities
 			where projekat = ` + fmt.Sprintf("'%s'", activeProject) +
 			` and entity_type = ` + fmt.Sprintf("'%s'", e))
 		if err != nil {
 			fmt.Printf("webutility: refresh: prep: %v\n", err)
 			rows.Close()
 			continue
 		}
 		for rows.Next() {
 			var load string
 			rows.Scan(&load)
 			p := Payload{}
 			err := json.Unmarshal([]byte(load), &p)
 			if err != nil {
 				fmt.Printf("webutility: couldn't refresh: '%s' metadata: %s\n%s\n", e, err.Error(), load)
 			} else {
 				metadata[e] = p
 			}
 		}
 		rows.Close()
 	}
 }
 /*
 func ModifyMetadataForEntity(entityType string, p *Payload) error {
 	md, err := json.Marshal(*p)
 	if err != nil {
 		return err
 	}
 	mu.Lock()
 	defer mu.Unlock()
 	_, err = metadataDB.PrepAndExe(`update entities set
 		metadata = :1
 		where projekat = :2
 		and entity_type = :3`,
 		string(md),
 		activeProject,
 		entityType)
 	if err != nil {
 		return err
 	}
 	return nil
 }
 func DeleteEntityModel(entityType string) error {
 	_, err := metadataDB.PrepAndExe("delete from entities where entity_type = :1", entityType)
 	if err == nil {
 		mu.Lock()