go-cmw/main.go

319 lines
9.3 KiB
Go

package main
import (
"fmt"
"io"
"io/ioutil"
"log"
"net/http"
"os"
"strings"
kingpin "gopkg.in/alecthomas/kingpin.v2"
)
// VERSION The version release
const VERSION = "0.1.0"
// AUTHOR The author name
const AUTHOR = "Elia el Lazkani"
var (
switchesFlags = []string{"m", "u", "M", "0", "1", "2", "A", "F", "n", "q", "Q", "T", "p"}
)
// We create a weather struct with the url
type weather struct {
url string
}
// `weather` method to handle creating new requests with proper headers
func (w weather) newRequest(headers map[string]string) *http.Request {
req, err := http.NewRequest("GET", w.url, nil)
if err != nil {
log.Fatal("Error reading request. ", err)
}
return w.formatHeader(req, headers)
}
// `weather` method to format the headers and inject required ones
func (w weather) formatHeader(req *http.Request, headers map[string]string) *http.Request {
req.Header.Set("Content-Type", "text/plain; charset=utf-8")
// I had to read the wttr.in code to figure this one out.
// It wasn't Golang, it was 2 wasted hours that I won't be getting back.
req.Header.Set("User-Agent", "curl")
for key, value := range headers {
req.Header.Add(key, value)
}
return req
}
// `weather` method to create a client and get a weather response
// This method handles printing or downloading the weather
func (w weather) get(req *http.Request, download bool) {
client := &http.Client{}
client.Jar = nil
resp, err := client.Do(req)
if err != nil {
log.Fatal("Error reading response. ", err)
}
defer resp.Body.Close()
if download {
w.download(resp)
} else {
w.print(resp)
}
}
// `weather` method to print the weather
func (w weather) print(resp *http.Response) {
body, err := ioutil.ReadAll(resp.Body)
if err != nil {
log.Fatal("Error reading body. ", err)
}
fmt.Printf("%s", body)
}
// `weather` method to download the weather
func (w weather) download(resp *http.Response) {
var fName string
if *fileName != "" {
fName = *fileName
} else {
splitURL := strings.Split(w.url, "/")
fName = splitURL[len(splitURL)-1]
}
f, err := os.Create(fName)
if err != nil {
log.Fatal("Error opening file. ", err)
}
defer f.Close()
_, err = io.Copy(f, resp.Body)
}
// Wraper function around the weather struct
func getWheather(url string, headers map[string]string, download bool) {
w := weather{url}
req := w.newRequest(headers)
w.get(req, download)
}
// Create a method to figure out the command parameters
// provided and translate them into uri parameters.
// This will figure out if we need to download the PNG image
// as well.
func generateParamFormat() (string, bool, error) {
var params strings.Builder
var prefix = "?"
var downloadMode = *download
// If --free-syle is specified, let's not bother and simply return it
if *freeStyle != "" {
return *freeStyle, downloadMode, nil
}
// If --format is specified, let's return the format the user wants
if *format != "" {
var str strings.Builder
str.WriteString("?format=\"")
str.WriteString(*format)
str.WriteString("\"")
return str.String(), downloadMode, nil
}
// If --one-liner is specified, we know the format is set so let's return it
if *oneLiner {
return "?format=3", downloadMode, nil
}
for i, s := range switches {
if *s {
params.WriteString(switchesFlags[i])
}
}
if *png {
prefix = "_"
if *addFrame {
params.WriteString(switchesFlags[12])
}
if *transparency >= 0 && *transparency <= 255 {
params.WriteString("_transparency=")
params.WriteString(string(*transparency))
}
params.WriteString(".png")
downloadMode = true
}
var affix strings.Builder
affix.WriteString(prefix)
affix.WriteString(params.String())
return affix.String(), downloadMode, nil
}
// Defining the command-line interface
var (
app = kingpin.New("go-cmw", "A small terminal wrapper around the wttr.in weather endpoint.")
location = app.Flag("location", "Specify explicite location (--expert-mode)").Short('L').OverrideDefaultFromEnvar("GO_CMW_LOCATION").String()
language = app.Flag("language", "Specify explicite language (--expert-mode)").Short('l').OverrideDefaultFromEnvar("GO_CMW_LANGUAGE").String()
v2 = app.Flag("v2", "Display Data-Rich output").Default("false").Bool()
switches = []*bool{
app.Flag("metric", "Display weather in metric").Short('m').Default("false").Bool(),
app.Flag("uscs", "Display weather in imperial").Short('u').Default("false").Bool(),
app.Flag("meter-second", "Display wind in m/s").Short('M').Default("false").Bool(),
app.Flag("zero", "Display current weather").Short('z').Default("false").Bool(),
app.Flag("one", "Display current weather + 1 day").Short('o').Default("false").Bool(),
app.Flag("two", "Display current weather + 2 days").Short('w').Default("false").Bool(),
app.Flag("ignore-user-agent", "Ignore User-Agent and force ANSI output").Short('A').Default("false").Bool(),
app.Flag("follow-link", "Do not display the 'Follow' line").Short('F').Default("true").Bool(),
app.Flag("narrow", "Display narrow view (only day/night)").Short('n').Default("false").Bool(),
app.Flag("quiet", "Display quiet version (no weather report)").Short('q').Default("false").Bool(),
app.Flag("super-quiet", "Display super quiet version (no weather report and no city)").Short('Q').Default("false").Bool(),
app.Flag("no-colors", "Display no colors (always enabled on windows").Short('N').Default("false").Bool()}
png = app.Flag("png", "Download a weather PNG image").Short('P').Default("false").Bool()
addFrame = app.Flag("add-frame", "Add a frame to the output (PNG only)").Short('p').Default("false").Bool()
transparency = app.Flag("transparency", "Set transparency level (0-255) (PNG only) (--expert-mode)").OverrideDefaultFromEnvar("GO_CMW_TRANSPARENCY").Short('t').Default("0").Int()
download = app.Flag("download", "Enables download mode (--expert-mode)").Short('d').Default("false").Bool()
fileName = app.Flag("file-name", "Name download file (--expert-mode)").OverrideDefaultFromEnvar("GO_CMW_FILE_NAME").Default("").String()
oneLiner = app.Flag("one-liner", "One liner outpet (for the terminal multiplexer lovers out there)").Short('O').Default("false").Bool()
format = app.Flag("format", "Specify a format query (e.g. \"%l:+%c+%t\") (--expert-mode)").OverrideDefaultFromEnvar("GO_CMW_FORMAT").String()
freeStyle = app.Flag("free-style", "Specify a free-style API call (--expert-mode)").OverrideDefaultFromEnvar("GO_CMW_FREE_STYLE").String()
expertMode = app.Flag("expert-mode", "Print expert mode information").Default("false").Bool()
)
// Special help menu
func printExpertMode() {
eInfo := `
Expert Mode
-----------
All commands flagged with --expert-mode override
values/flags added by go-cmw.
This gives the user full control over
the queries requested.
Environment Variables
---------------------
go-cmw makes use of the following environment
variables:
* GO_CMW_LOCATION for --location
* GO_CMW_LANGUAGE for --language
* GO_CMW_FORMAT for --format
* GO_CMW_FREE_STYLE for --free-style
* GO_CMW_FILE_NAME for --file-name
* GO_CMW_TRANSPARENCY for --transparency
Supported Location Types
------------------------
City name: Paris
Unicode name: Москва
Airport code (3 letters): muc
Domain name: @stackoverflow.com
Area code: 94107
GPS coordinates: -78.46,106.79
Special Location
----------------
Moon phase (add ,+US or
,+France for these cities): moon
Moon phase for a date: moon@2016-10-25
Format Flags (--format)
------------
c Weather condition
C Weather condition textual name
h Humidity
t Temperature
w Wind
l Location
m Moonphase
M Moonday
p precipitation (mm)
o Probability of Precipitation
P pressure (hPa)
Supported languages
-------------------
Supported: af be ca da de el et fr fa hu id it
nb nl pl pt-br ro ru tr th uk vi
zh-cn zh-tw
`
println(eInfo)
}
// Create a function to parse all the command line parameters
// provided.
func flagParser() {
app.Version(VERSION)
app.Author(AUTHOR)
kingpin.MustParse(app.Parse(os.Args[1:]))
if *expertMode {
printExpertMode()
os.Exit(0)
}
// Windows terminal does not have color encoding
// so let's make sure windows users are happy
if os.Getenv("TERM") == "" && !*png && *format != "" && *freeStyle != "" {
*switches[11] = true
}
}
// Create a function to generate the url that we'll be calling shortly.
func generateURL(domain string, v2 bool, location string, lang string, affix string) (string, map[string]string) {
var link strings.Builder
var headers = make(map[string]string)
link.WriteString("https://")
if v2 {
link.WriteString("v2.")
}
link.WriteString(domain)
link.WriteString("/")
if location != "" {
link.WriteString(location)
}
if affix != "" {
link.WriteString(affix)
}
if lang != "" {
headers["Accept-Language"] = lang
}
return link.String(), headers
}
// This is the main function that glues everything together.
func main() {
var domain string = "wttr.in"
flagParser()
affix, downloadFile, _ := generateParamFormat()
link, headers := generateURL(domain, *v2, *location, *language, affix)
getWheather(link, headers, downloadFile)
}