show-rss/src/cmd/fetch/main.go

134 lines
2.5 KiB
Go

package fetch
import (
"bytes"
"context"
"fmt"
"io"
"log"
"net/http"
"net/url"
"show-rss/src/cron"
"show-rss/src/feeds"
"show-rss/src/webhooks"
"strings"
"text/template"
"time"
)
func Main(ctx context.Context) error {
return cron.Cron(ctx, feeds.Next, One)
}
func One(ctx context.Context) error {
return feeds.ForEach(ctx, func(feed feeds.Feed) error {
if err := one(ctx, feed); err != nil {
return fmt.Errorf("failed to cron %s (%+v): %w", feed.Entry.ID, feed.Version, err)
}
return nil
})
}
func one(ctx context.Context, feed feeds.Feed) error {
if should, err := feed.ShouldExecute(); err != nil {
return err
} else if !should {
return nil
}
log.Printf("fetching %s", feed.Version.URL)
items, err := feed.Fetch(ctx)
if err != nil {
return err
}
log.Printf("fetched feed %s: %d items", feed.Version.URL, len(items))
for _, item := range items {
if err := oneItem(ctx, feed, item); err != nil {
return err
}
}
return feed.Executed(ctx)
}
func oneItem(ctx context.Context, feed feeds.Feed, item feeds.Item) error {
type Arg struct {
Feed feeds.Feed
Item feeds.Item
}
arg := Arg{
Feed: feed,
Item: item,
}
wmethod, wurl, wbody := feed.Webhook(ctx)
method, err := render(wmethod, arg)
if err != nil {
return err
}
wurl, err = render(wurl, arg)
if err != nil {
return err
}
body, err := render(wbody, arg)
if err != nil {
return err
}
var user *url.Userinfo
if u, _ := url.Parse(wurl); u.User != nil {
user = u.User
u.User = &url.Userinfo{}
wurl = u.String()
}
if did, err := webhooks.Did(ctx, method, wurl, body); err != nil || did {
return err
}
log.Printf("webhooking %s %s: %s", method, wurl, body)
req, err := http.NewRequest(method, wurl, strings.NewReader(body))
if err != nil {
return err
}
req = req.WithContext(ctx)
if user != nil {
u := user.Username()
p, _ := user.Password()
req.SetBasicAuth(u, p)
}
c := http.Client{
Timeout: time.Minute,
Transport: &http.Transport{DisableKeepAlives: true},
}
resp, err := c.Do(req)
if err != nil {
return err
}
defer resp.Body.Close()
defer io.Copy(io.Discard, resp.Body)
if resp.StatusCode > 204 {
b, _ := io.ReadAll(resp.Body)
return fmt.Errorf("failed %s %s w/ %s: (%d) %s", method, wurl, body, resp.StatusCode, b)
}
return webhooks.Record(ctx, method, wurl, body)
}
func render(text string, arg any) (string, error) {
tmpl, err := template.New("render").Parse(text)
if err != nil {
return "", err
}
b := bytes.NewBuffer(nil)
err = tmpl.Execute(b, arg)
return string(b.Bytes()), err
}