go-radar/gif_grabber.go

package main

import (
	"fmt"
	"image/gif"
	"io"
	"net/http"
	"os"
)

func GrabPascoGif() error {
	resp, err := http.Get("https://cdn.tegna-media.com/wtsp/weather/radar/880x495/pasco30.gif")
	if err != nil {
		return fmt.Errorf("http.Get('%s') => %v", "https://cdn.tegna-media.com/wtsp/weather/radar/880x495/pasco30.gif", err)
	}
	defer resp.Body.Close()
	file, err := os.Create("pasco.gif")
	if err != nil {
		return fmt.Errorf("os.Create('pasco.gif') => %v", err)
	}
	defer file.Close()
	_, err = io.Copy(file, resp.Body)
	if err != nil {
		return fmt.Errorf("io.Copy => %v", err)
	}
	return nil
}

func GrabCentralFloridaGif() error {
	resp, err := http.Get("https://cdn.tegna-media.com/wtsp/weather/radar/880x495/central_florida.gif")
	if err != nil {
		return fmt.Errorf("http.Get('%s') => %v", "https://cdn.tegna-media.com/wtsp/weather/radar/880x495/central_florida.gif", err)
	}
	defer resp.Body.Close()
	file, err := os.Create("central_florida.gif")
	if err != nil {
		return fmt.Errorf("os.Create('central_florida.gif') => %v", err)
	}
	defer file.Close()
	_, err = io.Copy(file, resp.Body)
	if err != nil {
		return fmt.Errorf("io.Copy => %v", err)
	}
	return nil
}

func DecodeGif(filename string) (*gif.GIF, error) {
	file, err := os.Open(filename)
	if err != nil {
		return nil, fmt.Errorf("os.Open('%s') => %v", filename, err)
	}
	defer file.Close()
	g, err := gif.DecodeAll(file)
	if err != nil {
		return nil, fmt.Errorf("gif.DecodeAll => %v", err)
	}
	return g, nil
}

func EncodeGif(filename string, g *gif.GIF, separate ...bool) error {
	sep := false
	if len(separate) != 0 {
		sep = separate[0]
	}
	if !sep {
		file, err := os.Create(filename + ".gif")
		if err != nil {
			return fmt.Errorf("os.Create('%s') => %v", filename, err)
		}
		defer file.Close()
		err = gif.EncodeAll(file, g)
		if err != nil {
			return fmt.Errorf("gif.EncodeAll => %v", err)
		}
		return nil
	}
	for idx, frame := range g.Image {
		file, err := os.Create(fmt.Sprintf("%s-%d.png", filename, idx))
		if err != nil {
			return fmt.Errorf("os.Create('%s-%d.png') => %v", filename, idx, err)
		}
		defer file.Close()
		err = gif.Encode(file, frame, &gif.Options{
			NumColors: 256,
		})
		if err != nil {
			return fmt.Errorf("gif.Encode(%d) => %v", idx, err)
		}
	}
	return nil
}