slideshow-api/internal/api/server.go

package api

import (
	"net/http"
	"strconv"
	"strings"
	"time"

	"git.velvettear.de/velvettear/loggo"
	"git.velvettear.de/velvettear/slideshow-api/internal"
	"git.velvettear.de/velvettear/slideshow-api/internal/config"
)

// start the web server
func Run() {
	address := config.ServerAddress + ":" + strconv.Itoa(config.ServerPort)
	loggo.Info("starting web server...", "address: "+address)
	registerHandlers()
	error := http.ListenAndServe(address, nil)
	if error != nil {
		loggo.Fatal("encountered an error starting the web server", "address: "+address, error.Error())
	}
}

// register the handlers
func registerHandlers() {
	http.HandleFunc("/", serveRandomImageName)
	http.HandleFunc("/image/", serveImage)
	http.HandleFunc("/palette/", servePalette)
}

// request url: '/' - serve the name of a random image
func serveRandomImageName(writer http.ResponseWriter, request *http.Request) {
	timestamp := time.Now().UnixMilli()
	var response response
	response.Content, response.error = internal.GetRandomImage()
	if response.error != nil {
		response.StatusCode = 404
	}
	response.send(writer)
	loggo.DebugTimed("served random image '"+response.Content+"'", timestamp)
}

// request url: '/image' - serve an image
func serveImage(writer http.ResponseWriter, request *http.Request) {
	var response response
	image, _ := strings.CutPrefix(request.URL.Path, "/image/")
	image, error := internal.GetImagePath(image)
	if error != nil {
		response.error = error
		response.StatusCode = 404
		response.send(writer)
		return
	}
	streamImage(writer, image, request.URL.Query().Get("resolution"))
}

// request url: '/palette' - serve the color palette of an image
func servePalette(writer http.ResponseWriter, request *http.Request) {
	var response response
	image, _ := strings.CutPrefix(request.URL.Path, "/palette/")
	image, error := internal.GetImagePath(image)
	if error != nil {
		response.error = error
		response.StatusCode = 404
		response.send(writer)
		return
	}
	amount, _ := strconv.Atoi(request.URL.Query().Get("colors"))
	if amount <= 0 {
		amount = 16
	}
	streamColorPalette(writer, image, amount, request.URL.Query().Get("algorithm"))
}