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package main
import (
"context"
"errors"
"flag"
"fmt"
"io"
"net/http"
"regexp"
"strings"
"github.com/beevik/etree"
)
type ErrorRequestHandler func(w http.ResponseWriter, r *http.Request) error
var RegexCollection = map[string]string{
"nerdcast": "NerdCast [0-9]+[a-c]* -",
"empreendedor": "Empreendedor [0-9]+ -",
"mamicas": "Caneca de Mamicas [0-9]+ -",
"english": "Speak English [0-9]+ -",
"nerdcash": "NerdCash [0-9]+ -",
"bunker": "Lá do Bunker [0-9]+ -",
"tech": "NerdTech [0-9]+ -",
"genera": "Generacast [0-9]+ -",
}
const (
FeedUrl = "https://api.jovemnerd.com.br/feed-nerdcast/"
)
func getSeries(r *http.Request) []string {
query := r.URL.Query().Get("q")
var series []string
for _, q := range strings.Split(query, ",") {
if _, ok := RegexCollection[q]; ok {
series = append(series, q)
}
}
if len(series) > 0 {
return series
}
return []string{"nerdcast"}
}
func match(title string, series []string) bool {
for _, s := range series {
if ok, err := regexp.MatchString(RegexCollection[s], title); err == nil && ok {
return true
}
}
return false
}
func fetchXML(_ context.Context) ([]byte, error) {
res, err := http.Get(FeedUrl)
if err != nil {
return nil, err
}
defer res.Body.Close()
if res.StatusCode == http.StatusOK {
return io.ReadAll(res.Body)
}
return nil, errors.New("Invalid http code")
}
func appendTag(tag *etree.Element, ap string) {
text := tag.Text()
tag.SetText(text + ap)
}
func filterBySeries(series []string, xml []byte, temper bool) ([]byte, error) {
doc := etree.NewDocument()
err := doc.ReadFromBytes(xml)
if err != nil {
return nil, err
}
channel := doc.FindElement("//channel")
if temper {
tmp := strings.ToUpper(strings.Join(series, ","))
tmp = fmt.Sprintf(" [%s]", tmp)
appendTag(channel.FindElement("title"), tmp)
appendTag(channel.FindElement("description"), tmp)
appendTag(channel.FindElement("link"), "?"+tmp)
appendTag(channel.FindElement("author[namespace-prefix()='itunes']"), tmp)
appendTag(channel.FindElement("subtitle[namespace-prefix()='itunes']"), tmp)
appendTag(channel.FindElement("summary[namespace-prefix()='itunes']"), tmp)
appendTag(channel.FindElement("author[namespace-prefix()='googleplay']"), tmp)
}
for _, tag := range channel.FindElements("item") {
title := tag.FindElement("title").Text()
if !match(title, series) {
channel.RemoveChild(tag)
}
}
return doc.WriteToBytes()
}
func wrap(next ErrorRequestHandler) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
if err := next(w, r); err != nil {
w.WriteHeader(http.StatusInternalServerError)
}
}
}
func titles(w http.ResponseWriter, r *http.Request) error {
xml, err := fetchXML(r.Context())
if err != nil {
return err
}
doc := etree.NewDocument()
err = doc.ReadFromBytes(xml)
if err != nil {
return err
}
series := getSeries(r)
els := doc.FindElements("//channel/item")
for _, e := range els {
txt := e.FindElement("title").Text() + "\n"
if match(txt, series) {
_, err = w.Write([]byte(txt))
if err != nil {
return err
}
}
}
return nil
}
func podcast(w http.ResponseWriter, r *http.Request) error {
xml, err := fetchXML(r.Context())
if err != nil {
return err
}
series := getSeries(r)
filterdXML, err := filterBySeries(series, xml, true)
if err != nil {
return err
}
_, err = w.Write(filterdXML)
if err != nil {
return err
}
return nil
}
func main() {
var (
addr = flag.String("addr", ":8080", "Server address")
)
flag.Parse()
mux := http.NewServeMux()
mux.HandleFunc("/titles", wrap(titles))
mux.HandleFunc("/", wrap(podcast))
server := http.Server{
Handler: mux,
Addr: *addr,
}
err := server.ListenAndServe()
if err != nil {
fmt.Printf("Server error: %s", err.Error())
}
}
|
