owl-blogs/app/webmention_service.go

167 lines
3.9 KiB
Go

package app
import (
"bytes"
"errors"
"io"
"net/http"
"owl-blogs/app/owlhttp"
"owl-blogs/app/repository"
"owl-blogs/interactions"
"strings"
"time"
"golang.org/x/net/html"
)
type WebmentionService struct {
InteractionRepository repository.InteractionRepository
EntryRepository repository.EntryRepository
Http owlhttp.HttpClient
}
type ParsedHEntry struct {
Title string
}
func NewWebmentionService(
interactionRepository repository.InteractionRepository,
entryRepository repository.EntryRepository,
http owlhttp.HttpClient,
) *WebmentionService {
return &WebmentionService{
InteractionRepository: interactionRepository,
EntryRepository: entryRepository,
Http: http,
}
}
func readResponseBody(resp *http.Response) (string, error) {
defer resp.Body.Close()
bodyBytes, err := io.ReadAll(resp.Body)
if err != nil {
return "", err
}
return string(bodyBytes), nil
}
func collectText(n *html.Node, buf *bytes.Buffer) {
if n.Type == html.TextNode {
buf.WriteString(n.Data)
}
for c := n.FirstChild; c != nil; c = c.NextSibling {
collectText(c, buf)
}
}
func (WebmentionService) ParseHEntry(resp *http.Response) (ParsedHEntry, error) {
htmlStr, err := readResponseBody(resp)
if err != nil {
return ParsedHEntry{}, err
}
doc, err := html.Parse(strings.NewReader(htmlStr))
if err != nil {
return ParsedHEntry{}, err
}
var interpretHFeed func(*html.Node, *ParsedHEntry, bool) (ParsedHEntry, error)
interpretHFeed = func(n *html.Node, curr *ParsedHEntry, parent bool) (ParsedHEntry, error) {
attrs := n.Attr
for _, attr := range attrs {
if attr.Key == "class" && strings.Contains(attr.Val, "p-name") {
buf := &bytes.Buffer{}
collectText(n, buf)
curr.Title = buf.String()
return *curr, nil
}
}
for c := n.FirstChild; c != nil; c = c.NextSibling {
interpretHFeed(c, curr, false)
}
return *curr, nil
}
var findHFeed func(*html.Node) (ParsedHEntry, error)
findHFeed = func(n *html.Node) (ParsedHEntry, error) {
attrs := n.Attr
for _, attr := range attrs {
if attr.Key == "class" && strings.Contains(attr.Val, "h-entry") {
return interpretHFeed(n, &ParsedHEntry{}, true)
}
}
for c := n.FirstChild; c != nil; c = c.NextSibling {
entry, err := findHFeed(c)
if err == nil {
return entry, nil
}
}
return ParsedHEntry{}, errors.New("no h-entry found")
}
return findHFeed(doc)
}
func (s *WebmentionService) GetExistingWebmention(entryId string, source string, target string) (*interactions.Webmention, error) {
inters, err := s.InteractionRepository.FindAll(entryId)
if err != nil {
return nil, err
}
for _, interaction := range inters {
if webm, ok := interaction.(*interactions.Webmention); ok {
m := webm.MetaData().(interactions.WebmentionInteractionMetaData)
if m.Source == source && m.Target == target {
return webm, nil
}
}
}
return nil, nil
}
func (s *WebmentionService) ProcessWebmention(source string, target string) error {
resp, err := s.Http.Get(source)
if err != nil {
return err
}
hEntry, err := s.ParseHEntry(resp)
if err != nil {
return err
}
entryId := UrlToEntryId(target)
_, err = s.EntryRepository.FindById(entryId)
if err != nil {
return err
}
webmention, err := s.GetExistingWebmention(entryId, source, target)
if err != nil {
return err
}
if webmention != nil {
data := interactions.WebmentionInteractionMetaData{
Source: source,
Target: target,
Title: hEntry.Title,
}
webmention.SetMetaData(data)
webmention.SetEntryID(entryId)
webmention.SetCreatedAt(time.Now())
err = s.InteractionRepository.Update(webmention)
return err
} else {
webmention = &interactions.Webmention{}
data := interactions.WebmentionInteractionMetaData{
Source: source,
Target: target,
Title: hEntry.Title,
}
webmention.SetMetaData(data)
webmention.SetEntryID(entryId)
webmention.SetCreatedAt(time.Now())
err = s.InteractionRepository.Create(webmention)
return err
}
}