Initial commit

.gitignore

@@ -0,0 +1,2 @@
+.idea/
+/webmentionhelper

Dockerfile

@@ -0,0 +1,13 @@
+FROM golang:1.14-alpine as build
+ADD . /app
+WORKDIR /app
+RUN go build
+
+FROM alpine:3.11
+RUN apk add --no-cache tzdata ca-certificates
+COPY --from=build /app/webmentionhelper /bin/
+WORKDIR /app
+VOLUME /app/storage
+EXPOSE 8080
+ENV LAST_ARTICLE_DIR /app/storage
+CMD ["webmentionhelper"]

feed.go

@@ -0,0 +1,35 @@
+package main
+
+import (
+	"encoding/json"
+	"errors"
+	"net/http"
+)
+
+type Article struct {
+	Url      string `json:"url"`
+	Modified string `json:"date_modified"`
+}
+
+func LatestArticle(url string) (*Article, error) {
+	jsonFeed := &struct {
+		Items []Article `json:"items"`
+	}{}
+	req, err := http.NewRequest(http.MethodGet, url, nil)
+	if err != nil {
+		return nil, errors.New("failed to create req to get json feed")
+	}
+	req.Header.Add("User-Agent", "WebmentionHelper")
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return nil, errors.New("failed to get json feed")
+	}
+	err = json.NewDecoder(resp.Body).Decode(&jsonFeed)
+	if err != nil {
+		return nil, errors.New("failed to parse json feed")
+	}
+	if len(jsonFeed.Items) < 1 {
+		return nil, errors.New("no articles in feed")
+	}
+	return &jsonFeed.Items[0], nil
+}

go.mod

@@ -0,0 +1,10 @@
+module git.jlel.se/jlelse/webmentionhelper
+
+go 1.14
+
+require (
+	github.com/andybalholm/cascadia v1.1.0 // indirect
+	github.com/google/go-cmp v0.4.0 // indirect
+	golang.org/x/net v0.0.0-20200421231249-e086a090c8fd // indirect
+	willnorris.com/go/webmention v0.0.0-20200126231626-5a55fff6bf71
+)

go.sum

@@ -0,0 +1,22 @@
+github.com/andybalholm/cascadia v1.0.0 h1:hOCXnnZ5A+3eVDX8pvgl4kofXv2ELss0bKcqRySc45o=
+github.com/andybalholm/cascadia v1.0.0/go.mod h1:GsXiBklL0woXo1j/WYWtSYYC4ouU9PqHO0sqidkEA4Y=
+github.com/andybalholm/cascadia v1.1.0 h1:BuuO6sSfQNFRu1LppgbD25Hr2vLYW25JvxHs5zzsLTo=
+github.com/andybalholm/cascadia v1.1.0/go.mod h1:GsXiBklL0woXo1j/WYWtSYYC4ouU9PqHO0sqidkEA4Y=
+github.com/google/go-cmp v0.3.0 h1:crn/baboCvb5fXaQ0IJ1SGTsTVrWpDsCWC8EGETZijY=
+github.com/google/go-cmp v0.3.0/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
+github.com/google/go-cmp v0.4.0 h1:xsAVV57WRhGj6kEIi8ReJzQlHHqcBYCElAvkovg3B/4=
+github.com/google/go-cmp v0.4.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/wsxiaoys/terminal v0.0.0-20160513160801-0940f3fc43a0/go.mod h1:IXCdmsXIht47RaVFLEdVnh1t+pgYtTAhQGj73kz+2DM=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/net v0.0.0-20180218175443-cbe0f9307d01/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+golang.org/x/net v0.0.0-20180911220305-26e67e76b6c3 h1:czFLhve3vsQetD6JOJ8NZZvGQIXlnN3/yXxbT6/awxI=
+golang.org/x/net v0.0.0-20180911220305-26e67e76b6c3/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+golang.org/x/net v0.0.0-20200421231249-e086a090c8fd h1:QPwSajcTUrFriMF1nJ3XzgoqakqQEsnZf9LdXdi2nkI=
+golang.org/x/net v0.0.0-20200421231249-e086a090c8fd/go.mod h1:qpuaurCH72eLCgpAm/N6yyVIVM9cpaDIP3A8BGJEC5A=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20200323222414-85ca7c5b95cd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+willnorris.com/go/webmention v0.0.0-20200126231626-5a55fff6bf71 h1:F//bgirx4BIsJYHrqAYCZHODn0gSRej/KfueFlarXhs=
+willnorris.com/go/webmention v0.0.0-20200126231626-5a55fff6bf71/go.mod h1:p+ZRAsZS2pzZ6kX3GKWYurf3WZI2ygj7VbR8NM8qwfM=

main.go

@@ -0,0 +1,124 @@
+package main
+
+import (
+	"encoding/base64"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"os"
+	"path"
+	"strings"
+
+	"willnorris.com/go/webmention"
+)
+
+func main() {
+	lastArticleDir, lastArticleDirSet := os.LookupEnv("LAST_ARTICLE_DIR")
+	blacklistString, _ := os.LookupEnv("BLACKLIST")
+	blacklist := strings.Split(blacklistString, ",")
+	if lastArticleDirSet {
+		http.HandleFunc("/hook", func(w http.ResponseWriter, r *http.Request) {
+			if r.Method != http.MethodPost {
+				http.Error(w, "Wrong HTTP method", http.StatusMethodNotAllowed)
+				return
+			}
+
+			feeds, feedsPresent := r.URL.Query()["feed"]
+			if feedsPresent {
+				go func() {
+					for _, feed := range feeds {
+						fmt.Println("Check webmentions for feed:", feed)
+						article, err := LatestArticle(feed)
+						if err != nil {
+							fmt.Println(err.Error())
+							continue
+						}
+						lastArticleUrl, lastArticleDate := lastArticle(lastArticleDir, feed)
+						if lastArticleUrl != article.Url || lastArticleDate != article.Modified {
+							err := sendWebmentions(article.Url, blacklist)
+							if err != nil {
+								fmt.Println(err.Error())
+								continue
+							}
+							err = updateLastArticle(lastArticleDir, feed, article.Url, article.Modified)
+							if err != nil {
+								fmt.Println(err.Error())
+								continue
+							}
+						} else {
+							fmt.Println("No new article")
+							continue
+						}
+					}
+				}()
+			}
+
+			urls, urlsPresent := r.URL.Query()["url"]
+			if urlsPresent {
+				go func() {
+					for _, url := range urls {
+						fmt.Println("Check webmentions for url:", url)
+						err := sendWebmentions(url, blacklist)
+						if err != nil {
+							fmt.Println(err.Error())
+							continue
+						}
+					}
+				}()
+			}
+
+		})
+		log.Fatal(http.ListenAndServe(":8080", nil))
+	} else {
+		log.Fatal("Not configured")
+	}
+}
+
+func lastArticle(dirname string, feed string) (url string, date string) {
+	fileContent, _ := ioutil.ReadFile(path.Join(dirname, base64.StdEncoding.EncodeToString([]byte(feed))))
+	if len(string(fileContent)) == 0 {
+		return
+	}
+	urlDate := strings.SplitN(string(fileContent), ";", 2)
+	return urlDate[0], urlDate[1]
+}
+
+func updateLastArticle(dirname string, feed string, url string, date string) error {
+	return ioutil.WriteFile(path.Join(dirname, base64.StdEncoding.EncodeToString([]byte(feed))), []byte(url+";"+date), 0644)
+}
+
+func sendWebmentions(url string, blacklist []string) error {
+	client := webmention.New(nil)
+	discovered, err := client.DiscoverLinks(url, ".h-entry")
+	if err != nil {
+		return err
+	}
+	var filtered []string
+	allowed := func(link string) bool {
+		for _, black := range blacklist {
+			if strings.Contains(link, black) {
+				return false
+			}
+		}
+		return true
+	}
+	for _, link := range discovered {
+		if allowed(link) {
+			filtered = append(filtered, link)
+		}
+	}
+	for _, link := range filtered {
+		endpoint, err := client.DiscoverEndpoint(link)
+		if err != nil || len(endpoint) < 1 {
+			continue
+		}
+		_, err = client.SendWebmention(endpoint, url, link)
+		if err != nil {
+			log.Println("Sending webmention to " + link + " failed")
+			continue
+		}
+		fmt.Println("Sent webmention to " + link)
+	}
+	return nil
+}