keyboard-reader/rest.go

package main

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"log"
	"net/http"
	"strings"
	"sync"
	"time"
)

const timeout = 1 * time.Second

type MonitorIdTag struct {
	ConnectorId uint   `json:"connectorId"`
	IdTag       string `json:"idTag"`
}

type ResponseEntity struct {
	Timestamp *time.Time `json:"timestamp"`
	Status    uint       `json:"status"`
	Error     *string    `json:"error"`
	Path      *string    `json:"path"`
}

type RestInterface interface {
	Send(id rune)
}

type rest struct {
	connectorId uint
	url         string
	timeout     time.Duration
	mutex       sync.Mutex
	timer       *time.Timer
	sb          strings.Builder
	nospace     bool
}

func NewRest(connectorId uint, url string, timeout time.Duration, nospace bool) RestInterface {
	r := rest{connectorId: connectorId, url: url, timeout: timeout, nospace: nospace}
	return &r
}

func (c *rest) Send(r rune) {
	c.mutex.Lock()
	defer c.mutex.Unlock()

	if !(c.nospace && r == ' ') {
		c.sb.WriteRune(r)
	}

	if c.timer != nil {
		c.timer.Reset(timeout)
	} else {
		f := func() {
			s := c.sb.String()
			log.Printf("Sent '%s'", s)
			go c.send(s)
			c.sb.Reset()
		}

		c.timer = time.AfterFunc(timeout, f)
	}
}

func (c *rest) send(id string) {
	tag := &MonitorIdTag{IdTag: id, ConnectorId: c.connectorId}

	//if c.connectorId > 0 {
	//	tag.ConnectorId = &c.connectorId
	//}

	var b []byte
	var err error
	var request *http.Request
	var response *http.Response

	if b, err = json.Marshal(tag); err != nil {
		log.Printf("Can't marschal request: %e\n", err)
		return
	}

	ctx, _ := context.WithTimeout(context.Background(), c.timeout)
	byteReader := bytes.NewReader(b)

	if request, err = http.NewRequestWithContext(ctx, "POST", c.url, byteReader); err != nil {
		log.Printf("Can't build new request: %e\n", err)
		return
	}

	request.Header.Add("Content-Type", "application/json")

	if response, err = http.DefaultClient.Do(request); err != nil {
		log.Printf("Error while rerforming request: %e\n", err)
		return
	}

	switch response.StatusCode {
	case 200:
		log.Printf("Result OK for id '%s'\n", id)
	case 401:
		log.Printf("Result UNAUTHORIZED for id '%s'\n", id)
	default:
		log.Printf("Recieve non sucess status code '%d' for id '%s'\n", response.StatusCode, id)
	}

	if response.ContentLength == 0 {
		log.Println("Response body empty")
		return
	}

	if b, err = io.ReadAll(response.Body); err != nil {
		log.Printf("Can't read replay body: %e\n", err)
		return
	}

	if err = response.Body.Close(); err != nil {
		log.Printf("Error while closing response body: %e\n", err)
		return
	}

	entity := &ResponseEntity{}

	if err = json.Unmarshal(b, entity); err != nil {
		log.Printf("Can't unmarschal response body: %e\n", err)
		return
	}

	log.Printf("ResponseEntity: %v\n", entity)
}

func (r *ResponseEntity) String() string {
	var sb strings.Builder

	if r.Path != nil {
		sb.WriteString("path = '")
		sb.WriteString(*r.Path)
		sb.WriteString("'")
	}

	if r.Error != nil {
		if sb.Len() > 0 {
			sb.WriteString(", ")
		}
		sb.WriteString("error = '")
		sb.WriteString(*r.Error)
		sb.WriteString("'")
	}

	if r.Timestamp != nil {
		if sb.Len() > 0 {
			sb.WriteString(", ")
		}
		sb.WriteString("timestamp = '")
		sb.WriteString(r.Timestamp.String())
		sb.WriteString("'")
	}

	if sb.Len() > 0 {
		sb.WriteString(", ")
	}
	sb.WriteString("status = ")
	sb.WriteString(fmt.Sprint(r.Status))

	return sb.String()
}